Patent Application
20230307153
The present disclosure relates generally to the synthesis and fabrication of nanomaterials and nanocomposites, and more particularly to the synthesis of nanowires, whiskers, elongated nanomaterials, porous elongated nanomaterials, and the like, and their use in polymer, ceramic, glass, and metal composites, as well as in catalysts, energy storage devices, membranes/separators, filters, optical devices, and other applications.
Owing in part to their relatively light weight, high surface area, and good mechanical properties, elongated ceramic materials with a diameter less than around 10 microns down to a few nanometers, a length from around 10 nm to around 1 mm, an aspect ratio from around 4 to around 20,000, and specific surface area in the range from around 2 to around 3,000 m2/g may be utilized in a broad range of composites and nanocomposites for enhancement of various mechanical properties, optical properties, thermal stabilities, and other properties. The production of such materials, often called ceramic nanowires, nanofibers, or whiskers (depending on their dimensions and morphology), with controlled dimensions and at a low cost would be desirable for a wide range of composite applications as reinforcement. Thermally stable nanowires and whiskers may be particularly attractive in high temperature applications. In contrast to carbon nanotubes and carbon (nano)fibers (other types of elongated nanomaterials made primarily of carbon atoms), ceramic nanowires may offer improved dispersion, optical transparency, stability against oxidation at elevated temperatures, electrical insulation, more easily modifiable surfaces, and other properties, which make them attractive for various applications.
However, despite the useful properties and the commercial potential of ceramic nanowires, nanofibers, and whiskers, their applications have been rather limited due to the high cost of the conventionally-employed synthesis techniques (such as chemical vapor deposition, hydrothermal synthesis, and others) and the limited experimental ability to tune their characteristic dimensions, surface morphology, and other properties.
Accordingly, there remains a need for improved methods for synthesis of ceramic nanowires, nanofibers, whiskers, and other related materials, as well as their modification and use in composites. There additionally remains a need for improved materials and improved manufacturing processes.
The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.
Embodiments disclosed herein address the above stated needs by providing improved methods of synthesis of nanowires, whiskers, elongated nanomaterials, porous elongated nanomaterials, and the like.
Embodiments disclosed herein also address various applications of nanowires, whiskers, elongated nanomaterials, porous elongated nanomaterials, and the like, including those for improved battery components, improved batteries made therefrom, and methods of making and using the same.
As an example, a catalyst-free synthesis method is provided for the formation of a metalorganic compound comprising a desired (first) metal. The method may include, for example, selecting another (second) metal and an organic solvent, with the second metal being selected to (i) be more reactive with respect to the organic solvent than the first metal and (ii) form, upon exposure of the second metal to the organic solvent, a reaction by-product comprising the second metal that is more soluble in the organic solvent than the metalorganic compound comprising the first metal. An alloy comprising the first metal and the second metal may be first produced (e.g., formed or otherwise obtained) and then treated with the organic solvent in a liquid phase or a vapor phase to form a mixture comprising (i) the reaction by-product comprising the second metal and (ii) the metalorganic compound comprising the first metal. The metalorganic compound may then be separated from the mixture in the form of a solid, as described in more detail below.
In some designs, the second metal may have a reactivity with respect to the organic solvent that is at least five times higher than that of the first metal. Example elements for the first metal include Ti, Cr, Fe, Co, Ni, Cu, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, Al, Zn, Cd, In, Sn, Sb, Bi, P, La, Ce, Ca, Mg, Sr, and Be. Example elements for the second metal include Li, K, Ca, and Na.
When the organic solvent is in the form of a liquid, the treating may be performed at a temperature in the range of about −20° C. to about +200° C., for example.
In some designs, the metalorganic compound may comprise porous particles. In addition or as an alternative, the metalorganic compound may comprise elongated particles. The elongated particles may exhibit, for example, a width in the range of about 2 nm to about 10 microns, a length in the range of about 50 nm to about 50 mm, and a corresponding width-to-length aspect ratio in the range of about 1:4 to about 1:10,000,000. Example metalorganic compounds include various alkoxides.
For some applications, the method may further comprise converting the metalorganic compound to a metal oxide compound in the form of elongated particles. The elongated metal oxide particles may be porous. The converting may be performed at a temperature in the range of about −20° C. to about +1500° C. in an oxygen-containing environment.
In some designs, a coating layer may be deposited on a surface of the elongated metal oxide particles or a precursor thereof. The coating layer may be a metal, a polymer, or a ceramic material, for example. The coating layer may be deposited via chemical vapor deposition or atomic vapor deposition.
For some applications, elongated particles of the metalorganic compound may be formed into a membrane or body and converted into elongated metal oxide compound particles to form a porous oxide membrane or body. The converting may partially bond at least some of the elongated metal oxide compound particles to each other. For some applications, the porous oxide membrane or body may be infiltrated with a filler material (e.g., a metal, a glass, or a polymer).
In an example application, the porous oxide membrane or body may be integrated into an electrochemical energy storage device as a separator. In this case, a polymer layer may also be deposited onto the surface of the porous oxide membrane or body (e.g., to close the pores of the porous oxide membrane or body to prevent ion transport at temperatures above a threshold temperature in the range of about 70° C. to about 130° C.).
In an aspect, an integrated electrode-separator component includes an electrode substrate; and a separator comprising a first layer, the first layer comprising small wires, the first layer being directly deposited on the electrode substrate, wherein: a total thickness of the separator ranges between about 0.5 μm and about 10 μm; and the small wires exhibit diameters in the range of about 2 nm to about 10 μm and diameter-to-length aspect ratios in the range of about 1:4 to about 1:10,000,000.
In some aspects, the small wires exhibit diameters in a range of about 3 nm to about 2 μm.
In some aspects, the small wires exhibit diameter-to-length aspect ratios in a range of about 1:20 to about 1:100,000.
In some aspects, the small wires in the first layer are preferentially aligned in a first direction.
In some aspects, the separator comprises a second layer of the separator directly on the first layer of the separator.
In some aspects, the second layer comprises an adhesive.
In some aspects, the small wires in the first layer are first small wires; and the second layer of the separator comprises second small wires.
In some aspects, the second small wires in the second layer are preferentially aligned in a second direction.
In some aspects, the total thickness of the separator ranges between about 0.5 μm and about 5 μm.
In some aspects, the separator further comprises a polymer at a weight fraction of the separator in a range of about 0.1 wt. % to about 90 wt. %.
In some aspects, the polymer comprises a thermoplastic with a melting point in a range of about 70 to about 150° C.
In some aspects, a porosity of the separator is in a range of about 30 vol. % to about 95 vol. %.
In some aspects, the porosity of the separator is in a range of about 50 vol. % to about 70 vol. %.
In some aspects, the porosity of the separator is in a range of about 30 vol. % to about 50 vol. %.
In some aspects, the small wires comprise one or more of the following materials: a metal alkoxide, a metal hydroxide, a metal oxyhydroxide, and a metal oxide.
In some aspects, the small wires comprise one or more of the following materials: aluminum alkoxide, aluminum hydroxide, aluminum oxyhydroxide, aluminum oxide, magnesium alkoxide, magnesium hydroxide, magnesium oxyhydroxide, magnesium oxide, a mixture thereof, an alloy thereof.
In some aspects, at least one of the one or more materials in the small wires is doped.
In some aspects, the small wires exhibit lengths in a range of about 50 nm to about 50 mm.
In some aspects, the small wires comprise a functional surface coating that exhibits surface layer thicknesses in a range of about 0.3 nm to about 30 nm.
In some aspects, at least some of the small wires are bundled.
In some aspects, the integrated electrode-separator component is of a non-rectangular shape when the integrated electrode-separator component is viewed in a plan view.
In some aspects, the integrated electrode-separator component is of an L-like shape, a non-rectangular polygonal shape, a round shape, or a truncated round shape, when the integrated electrode-separator component is viewed in a plan view.
In some aspects, the integrated electrode-separator component comprises a hole penetrating therethrough.
In some aspects, an outer periphery of the integrated electrode-separator component comprises an edge region; the separator is present in the edge region; and the edge region is devoid of an electrode.
In some aspects, the electrode substrate comprises a current collector and a first electrode attached to or deposited onto a first side of the current collector.
In some aspects, the separator is a first separator; the electrode substrate further comprises a second electrode on a second side of the current collector opposite the first side; and the integrated electrode-separator component further comprises a second separator deposited directly on the second electrode.
In some aspects, the first separator and the second separator are discontiguous.
In an aspect, a battery component stack includes an integrated electrode-separator component; and an opposite electrode substrate disposed adjacent to the integrated electrode-separator component, the opposite electrode substrate comprising an opposite current collector and an opposite electrode on a first side of the opposite current collector, wherein: the opposite electrode substrate and the integrated electrode-separator component are aligned to each other; and the opposite electrode and the separator of the integrated electrode-separator component are in contact with each other.
In some aspects, the opposite electrode and the separator of the integrated electrode-separator component are laminated to each other by an adhesive.
In an aspect, a battery cell includes a battery component stack; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the opposite electrode substrate and the electrode substrate of the integrated electrode-separator component are configured to be of opposite polarity to each other.
In an aspect, a battery component stack includes a first instantiation of an integrated electrode-separator component, configured as a first integrated electrode-separator component; a second instantiation of the integrated electrode-separator component configured as a second integrated electrode-separator component and disposed adjacent to the first integrated electrode-separator component, wherein: the first integrated electrode-separator component and the second integrated electrode-separator component are aligned to each other; and the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component are in contact with each other.
In some aspects, the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component are laminated to each other by an adhesive.
In some aspects, the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component satisfy one or more of the following: a thickness of the separator of the first integrated electrode-separator component differs from a thickness of the separator of the second integrated electrode-separator component; a density of the separator of the first integrated electrode-separator component differs from a density of the separator of the second integrated electrode-separator component; a porosity of the separator of the first integrated electrode-separator component differs from a porosity of the separator of the second integrated electrode-separator component; and the small wires of the first layer of the separator of the first integrated electrode-separator component are preferentially aligned in a first direction, and the small wires of the first layer of separator of the second integrated electrode-separator component are preferentially aligned in a second direction different from the first direction.
In an aspect, a battery cell includes a battery component stack; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the electrode substrate of the first integrated electrode-separator component and the electrode substrate of the second integrated electrode-separator component are of opposite polarity to each other.
In an aspect, a battery component stack includes an opposite electrode substrate comprising an opposite current collector and a respective opposite electrode on each side of the opposite current collector; and a plurality of instantiations of an integrated electrode-separator component, including a first integrated electrode-separator component and a second integrated electrode-separator component, the opposite electrode substrate being positioned between the first integrated electrode-separator component and the second integrated electrode-separator component, wherein: the first integrated electrode-separator component, the second integrated electrode-separator component, and the opposite electrode substrate are aligned to each other; the separator of the first integrated electrode-separator component and the opposite electrode on one of the sides of the opposite current collector are in contact with each other; and the separator of the second integrated electrode-separator component and the opposite electrode on another one of the sides of the opposite current collector are in contact with each other.
In some aspects, the first integrated electrode-separator component is characterized by a first outer periphery; the second integrated electrode-separator component is characterized by a second outer periphery; the first outer periphery and the second outer periphery differ from each other in at least one lateral dimension of the first and the second integrated electrode-separator components.
In some aspects, the opposite electrode substrate is a first opposite electrode substrate; the battery component stack comprises a second opposite electrode substrate comprising a second opposite current collector and a respective opposite electrode on each side of the second opposite current collector; the plurality of instantiations includes a third integrated electrode-separator component, the second opposite electrode substrate being positioned between the second integrated electrode-separator component and the third integrated electrode-separator component; the third integrated electrode-separator component is characterized by a third outer periphery; and the third outer periphery differs from the first outer periphery and/or the second outer periphery in the at least one lateral dimension.
In some aspects, the third outer periphery is greater than the second outer periphery in the at least one lateral dimension; and the second outer periphery is greater than the first outer periphery in the at least one lateral dimension.
In some aspects, each of the first and the second integrated electrode-separator components comprises a respective strip extending from the respective current collector thereof; and the respective separator of each of the first and the second integrated electrode-separator components covers at least a portion of each of the respective strips.
In an aspect, a battery cell includes a battery component stack; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the opposite electrode substrate is configured to be of opposite polarity to the electrode substrates of the first and the second integrated electrode-separator components.
In an aspect, a method of making an integrated electrode-separator component includes providing a suspension comprising small wires; forming a separator directly on an electrode substrate; and fashioning the integrated electrode-separator component from the electrode substrate having the separator deposited thereon, wherein: the forming of the separator comprises depositing the suspension directly on the electrode substrate to form a first layer of the separator; a total thickness of the separator ranges between about 0.5 μm and about 10 μm; and the small wires exhibit diameters in a range of about 2 nm to about 10 μm and diameter-to-length aspect ratios in a range of about 1:4 to about 1:10,000,000.
In some aspects, the small wires exhibit diameters in a range of about 3 nm to about 2 μm.
In some aspects, the small wires exhibit diameter-to-length aspect ratios in a range of about 1:20 to about 1:100,000.
In some aspects, the small wires in the first layer are preferentially aligned in a first direction.
In some aspects, the forming of the separator comprises forming a second layer of the separator directly on the first layer of the separator.
In some aspects, the second layer comprises an adhesive.
In some aspects, the suspension is a first suspension; the small wires are first small wires; the method further comprises providing a second suspension comprising second small wires; and the forming of the second layer of the separator comprises depositing the second suspension directly on the first layer of the separator to form the second layer of the separator.
In some aspects, the second small wires in the second layer are preferentially aligned in a second direction.
In some aspects, heat-treating at least the separator.
In some aspects, the method includes compacting at least the separator.
In some aspects, the total thickness of the separator ranges between about 0.5 μm and about 5 μm.
In some aspects, the separator further comprises a polymer at a weight fraction of the separator in a range of about 0.1 wt. % to about 90 wt. %.
In some aspects, the polymer comprises a thermoplastic with a melting point in a range of about 70 to about 150° C.
In some aspects, a porosity of the separator is in a range of about 30 vol. % to about 95 vol. %.
In some aspects, the porosity of the separator is in a range of about 50 vol. % to about 70%.
In some aspects, the porosity of the separator is in a range of about 30 vol. % to about 50 vol. %.
In some aspects, the small wires comprise one or more of the following materials: a metal alkoxide, a metal hydroxide, a metal oxyhydroxide, and a metal oxide.
In some aspects, the small wires comprise one or more of the following materials: aluminum alkoxide, aluminum hydroxide, aluminum oxyhydroxide, aluminum oxide, magnesium alkoxide, magnesium hydroxide, magnesium oxyhydroxide, magnesium oxide, a mixture thereof, or an alloy thereof.
In some aspects, at least one of the one or more materials in the small wires is doped.
In some aspects, the small wires exhibit lengths in a range of about 50 nm to about 50 mm.
In some aspects, the method includes depositing a functional surface coating on the small wires that exhibits surface layer thicknesses in a range of about 0.3 nm to about 30 nm.
In some aspects, the suspension is a liquid suspension.
In some aspects, at least some of the small wires are bundled.
In some aspects, the depositing of the suspension is carried out by casting, spray deposition, field-assisted deposition, and/or dip coating.
In some aspects, the fashioning of the integrated electrode-separator component comprises segmenting a portion of the electrode substrate having the separator deposited thereon to form the integrated electrode-separator component.
In some aspects, the segmented portion is of a non-rectangular shape when the segmented portion is viewed in a plan view.
In some aspects, the segmented portion is of an L-like shape, a non-rectangular polygonal shape, a round shape, or a truncated round shape, when the segmented portion is viewed in a plan view.
In some aspects, the segmented portion comprises a hole penetrating through the integrated electrode-separator component.
In some aspects, the segmenting comprises cutting the electrode substrate at at least one edge region; wherein: the edge region is devoid of an electrode part of the electrode substrate.
In some aspects, the electrode substrate comprises a current collector and a first electrode attached to or deposited onto a first side of the current collector.
In some aspects, the current collector is in a form of a roll.
In some aspects, the separator is a first separator; the electrode substrate comprises at least a second electrode on a second side of the current collector opposite the first side; and the method further comprises forming a second separator directly on the electrode substrate, the second separator being formed on the second electrode.
In an aspect, a method of making a battery component stack includes making a first instantiation of the integrated electrode-separator component according to a method, configured as a first integrated electrode-separator component; making a second instantiation of the integrated electrode-separator component according to the method configured as a second integrated electrode-separator component; and disposing the second integrated electrode-separator component adjacent to the first integrated electrode-separator component to form a battery component stack, wherein: the disposing comprises aligning the first integrated electrode-separator component and the second integrated electrode-separator component to each other; and the disposing comprises contacting the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component to each other.
In some aspects, the disposing comprises laminating the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component to each other by an adhesive.
In an aspect, a method of making a battery cell includes making a battery component stack according; infiltrating an electrolyte into the battery component stack; and configuring the electrode substrate of the first integrated electrode-separator component and the electrode substrate of the second integrated electrode-separator component to be of opposite polarity to each other to form the battery cell.
In an aspect, a method of making a battery component stack includes making the integrated electrode-separator component according to a method; and disposing an opposite electrode substrate adjacent to the integrated electrode-separator component to form a battery component stack, the opposite electrode substrate comprising an opposite current collector and an opposite electrode on a first side of the opposite current collector, wherein: the disposing comprises aligning the opposite electrode substrate and the integrated electrode-separator component to each other; and the disposing comprises contacting the opposite electrode and the separator of the integrated electrode-separator component to each other.
In some aspects, the disposing comprises laminating the opposite electrode and the separator of the integrated electrode-separator component to each other by an adhesive.
In an aspect, a method of making a battery cell includes making a battery component stack according to a method; infiltrating an electrolyte into the battery component stack; and configuring the opposite electrode substrate and the electrode substrate of the integrated electrode-separator component to be of opposite polarity to each other to form the battery cell.
Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description.
The accompanying drawings are presented to aid in the description of embodiments of the disclosure and are provided solely for illustration of the embodiments and not limitation thereof. Unless otherwise stated or implied by context, different hatchings, shadings, and/or fill patterns in the drawings are meant only to draw contrast between different components, elements, features, etc., and are not meant to convey the use of particular materials, colors, or other properties that may be defined outside of the present disclosure for the specific pattern employed.
Aspects of the present invention are disclosed in the following description and related drawings directed to specific embodiments of the invention. The term “embodiments of the invention” does not require that all embodiments of the invention include the discussed feature, advantage, process, or mode of operation, and alternate embodiments may be devised without departing from the scope of the invention. Additionally, well-known elements of the invention may not be described in detail or may be omitted so as not to obscure other, more relevant details.
While the description below may describe certain examples in the context of aluminum-(Al) or oxygen-(O) comprising small (nano)wires, whiskers, fibers, and other elongated particles, as well as various porous materials (including porous elongated particles), it will be appreciated that various aspects may be applicable to other compositions.
The description below may describe certain examples of the formation of alkoxides of nonreactive metal(s) (metals and semimetals that typically exhibit very small reactivity upon direct contact with alcohols) by forming alloys with significantly more reactive metals in the context of Al as a nonreactive metal and Li as a reactive metal. However, it will be appreciated that alkoxides of many other nonreactive metals (not just Al) or mixtures of nonreactive metals may be formed using this approach and other reactive metals (not just Li) and reactive metal mixtures may be utilized as alloy elements.
While the description below also may describe certain examples of the formation of certain organometallic compounds of nonreactive metal(s) in the context of alkoxides, it will be appreciated that various aspects of the present disclosure may be applicable to other organometallic (metalorganic) compounds, where alloys of nonreactive metals with reactive metals (e.g., metals having a reactivity, with respect to a given organic compound, that is preferably 5 times higher or more than the reactivity of the nonreactive metals) are used in the synthesis instead of pure nonreactive metals (or instead of their salts and other compounds). Similarly, the solubility of metalorganic compound(s) of reactive metals in the organic solvent (or solvent mix) used in the reaction may preferably be 5 times higher or more than the solubility of the metalorganic compound(s) of nonreactive metals in this solvent.
While the description below also may describe certain examples in the context of the formation of certain oxides of metal(s) (of various particle shapes as well as porous bulk materials), it will be appreciated that various aspects of the present disclosure may be applicable to the formation of other ceramic materials (not necessarily oxides, but also fluorides, oxy-fluorides, carbides, oxy-carbides, nitrides, oxy-nitrides, phosphides, oxy-phosphides, sulfides, selenides, and others) as well as metals and metal alloys.
For simplicity and illustration purposes, all elongated particles of suitable size, shape, aspect ratios, density, porosity, crystal structure, and morphology may be generally referred to herein as “small wires.” In various aspects of the present disclosure, the suitable diameter (or width) of individual small wires may range from around 2 nm to around 10 microns and the suitable length of individual small wires may range from around 50 nm to around 50 mm. The suitable aspect ratio (width-to-length) of individual small wires may range from around 1:4 to around 1:10,000,000. Depending on the application, the suitable true density (taking into consideration closed porosity) may range from around 0.1 to around 4 g/cm3 (for small wires comprising only Al metal in their composition) and to around 7 g/cm3 (for small wires comprising metals other than Al in their composition). Depending on the application and the processing conditions, the suitable pore volume within individual small wires may range from around 0 to around 5 cm3/g. Depending on the application and the processing conditions, the microstructure may range from amorphous to nanocrystalline to polycrystalline to single crystalline to a mixture of those to other types. Depending on the application and synthesis conditions, the suitable surface roughness of the small wires may range from around 0 to around 50 nm.
Conventional techniques for the synthesis of ceramic nanowires, whiskers, and fibers include catalyst-assisted chemical vapor deposition (CVD), cylindrical template-based synthesis, hydrothermal synthesis, electrospinning, formation of small rolls from platelets, and others. Such techniques typically suffer from high cost and small yield (particularly in the case of CVD, electrospinning, and hydrothermal synthesis at high pressures), often short length and low aspect ratio of the elongated particles (particularly in the case of rolling platelets and hydrothermal syntheses), poor control over the dimensions (diameter and length) of the elongated particles, often the inability to produce porous elongated particles with high aspect ratios, limited (or the lack of) control in porosity and surface morphology of elongated particles, and other limitations.
Carbon nanotubes (CNTs) are typically used as conventional fillers for many polymer and metal composites to improve various mechanical and other properties. However, CNTs are difficult to disperse uniformly and are difficult to form an interface having controllable strength therewith. In addition, they are not transparent and are typically electrically conductive (which may be undesirable for some applications), suffer from poor thermal stability in oxygen-containing environments (due to oxidation), and have other limitations.
The present disclosure offers routes to overcome (or significantly reduce) the above limitations.
Conventional production of many metal alkoxides (e.g., aluminum alkoxides) as well as many other metalorganic compounds typically requires the use of catalysts. For example, formation of aluminum ethoxide (Al(EtO)3) and aluminum isopropoxide (Al(i-PrO)3) typically requires the use of HgCl2, I2, AlCl3, FeCl3, SnCl4, or B2O3 catalysts (some of which are toxic and corrosive). This makes the synthesis process relatively expensive, requires additional purification steps, and limits the purity of the end result.
The present disclosure describes examples of methods for a low cost and large volume (bulk) production of these materials. Furthermore, it provides avenues for the formation of organometallic compounds (for example, aluminum alkoxides) in the form of elongated particles (which are referred to herein as “small wires”) of controlled dimensions and high aspect ratios. This may be attractive for different applications, including those that involve further chemical modifications of these materials to produce other materials (such as metal (e.g., Al) oxyhydroxides, hydroxides, oxides, oxy-halides, halides, oxy-carbides, carbides, nitrides, oxy-nitrides, phosphides, oxy-phosphides, sulfides, selenides, tellurides, and various mixed ceramics and doped ceramic materials, among others, to name a few examples) in the form of high surface area small wires as well as membranes and various porous structures having high specific surface area (e.g., from around 1 to around 3,000 m2/g) and other useful properties (e.g., high strength, high toughness, high activity, high thermal stability, low thermal expansion, high surface area, etc., depending on the final material form).
In one illustrative example, aluminum alkoxides may be produced by the reaction of an Al alloy of a suitable composition with an alcohol. Suitable Al alloy compositions may include both aluminum and a significant atomic fraction (e.g., typically greater than 40 at. %) of a metal that is highly reactive with alcohols, forming, for example, alkoxides of the corresponding metal. It is typically preferable that these reaction product(s) (metal alkoxides) be dissolved in the alcohol solution during the reaction while having a majority of the aluminum alkoxide product remaining undissolved (which would typically require these metal alkoxides to have significantly higher solubility than aluminum alkoxide, preferably by at least 5 times higher or more; even more preferably 50 times higher or more). Reactivity of metals (or materials, in general) as well as their solubility depends not only on the element, but also on the solvent (such as an organic compound or water or their mixture) and the reaction temperature and pressure. However, for many solvents and for moderate temperatures (e.g., 0-100° C.) and for near atmospheric pressures some of the metals (electropositive elements) may typically be relatively reactive. Examples of such reactive metals include, but are not limited to, alkali metals (e.g., Li, Na, K, etc.) and alkaline earth metals (e.g., Ca, Mg, Sr, Be, etc.), to provide a few examples. Combinations of the reactive metals may also be used in the alloy. In a more particular example, an aluminum-alkali metal alloy (e.g., aluminum-lithium alloy) may react with an alcohol (e.g., with ethanol, methanol, propanol and many others alcohols, discussed in turn below), forming aluminum alkoxides. This finding by the inventors was unexpected because Al is generally understood not to be reactive with alcohols. The inventors hypothesize that when Al atoms are finely intermixed with more reactive metal atoms in the alloy (particularly, when aluminum forms intermetallic compounds (e.g., line compounds in the corresponding phase diagrams) with such elements), formation of aluminum alkoxide becomes possible. In addition to aluminum alkoxides, such a method (the use of alloys of “non-reactive” metals with “reactive” metals) may be suitable for the formation of “non-reactive” or “poorly reactive” alkoxides of other metals. These include, but are not limited to, various alkoxides of transition metals (e.g., Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, etc.), various poor metals (Al, Zn, Ga, Cd, In, Sn, Sb, Hg, Tl, Pb, Bi, P, etc.), various rare earth metals (La, Ce, Gd, etc.), and nonmetals (B, Si, P, As, Ge, Se, Te, etc.). Similarly, using alloys of nonreactive (or substantially less reactive) metals with reactive metals (instead of pure nonreactive metals or their salts and other compounds) may allow low-cost synthesis of a broad range of other organometallic (or metalorganic) compounds. Depending on the nature of the metal-carbon bond, these include, but are not limited to: (i) various ionic organometallic compounds, (ii) various organometallic compounds containing metal-carbon sigma bonds, (iii) various ylides, (iv) various organometallic compounds with multicenter bonds, and (v) various organometallic compounds with pi bonded ligands, among others. It should be noted, however, that the term “reactivity” is relative. In some examples, two relatively reactive metals (for example, Li and Mg) could be utilized to form an alloy (e.g., Li—Mg alloy), where preferential or faster reaction and dissolution of Li into selected organic solvents (such as alcohols) may lead to a faster formation of Mg-containing organometallic nanostructures (such as Mg alkoxides). If the amount of solvent is limited, Mg (in this example) organometallic dissolution may be minimized in order to separate solid Mg-containing compounds (such as Mg-containing nanostructures).
Returning to the example of exposure of the aluminum alloy to an alcohol, the formation of aluminum alkoxides and reactive metal (e.g., alkali metal) alkoxides may take place. In the simplest case, such a reaction may proceed in a liquid phase (e.g., in an alcohol or an alcohol-comprising solution). The reaction temperature may vary in a broad range from around the freezing point of the alcohol (or alcohol-comprising solution) to above the boiling point of the alcohol (or alcohol-comprising solution). If the reaction proceeds at above atmospheric pressure, the temperature of the reaction may be increased to significantly above the boiling point of the alcohol (or alcohol-comprising solution). Overall, depending on the synthesis conditions, alcohols, the desired form of the final compounds (alkoxides), and thermal stability of the alkoxides, the suitable temperature range may vary from around −120° C. to around +1000° C. Lower temperatures typically reduce reaction rates and change the diameter of the resultant small wires. Higher temperatures may induce melting of alkoxides and too high of a temperature may induce decomposition of alkoxides. For economic and other reasons, it may be preferred in some applications to conduct such reactions at around atmospheric pressure and in a temperature range from around −20° C. to around +200° C. As will be discussed below, by changing the reaction temperature, the shape and morphology of the produced aluminum alkoxide may be tuned as desired. Upon exposure of aluminum-lithium alloy to an alcohol (or alcohol-comprising) solution, formation of aluminum alkoxides and lithium alkoxides was found to take place. Higher solubility of lithium alkoxides leads to their dissolution into the alcohol or alcohol-comprising solution. As a result, aluminum alkoxides may be easily separated from such a solution in the form of the solid products (e.g., in the form of aluminum alkoxide small wires).
The suitable composition of such an aluminum alloy may vary. For example, such an alloy may primarily (e.g., 97-100%) comprise: (i) aluminum and (ii) reactive metal (e.g., alkali, alkali earth, or various mixtures of alkali and/or alkali earth elements). As illustrative examples, an alloy composition may be Al0.5Li0.5 or Al2Li3 or A4Li9 or various other compositions AlxLi1-x, where x>0, etc. In some configurations, it may be preferred that the majority (50-100%) of alkali metal atoms in the alloy are Li atoms. In the case of an AlxLi1-x alloy, too high of an atomic fraction of Al atoms (e.g., greater than around 53%) typically leads to a microstructure comprising a mixture of Al and AlLi phases. If the size of Al phase grains is large (e.g., greater than around 2-10 nm, depending on reaction conditions), the reaction of the alloy with a suitable alcohol (or alcohol-comprising) solution may yield a mixture of Al and Al alkoxides. In some cases (particularly when the atomic fraction of Al atoms in such an alloy is relatively high (e.g., greater than around 60%), Al may form an interconnected porous network, which may be useful for some applications. For example, formation and further dissolution of Al alkoxide in such an Al—Al alkoxide composite may yield porous Al, which may also be a useful product for electronic, energy storage, energy conversion, energy dampening, and various structural or multifunctional applications. In cases where the atomic fraction of Al atoms in an AlxLi1-x alloy is reduced and becomes too low (e.g., less than around 40%), the yield of the Al alkoxide (as the wt. % of the initial alloy) will naturally be reduced. However, by varying the relative Al content, one may tune the morphology of the Al alkoxide products and the rate of the alkoxide formation reaction, which may be advantageous for industrial production. In addition to using alloys that primarily (e.g., 97-100%) comprise aluminum and alkali metal (e.g., Li) atoms, a suitable alloy may also comprise 3% or more of other elements (e.g., either as impurities or as useful alloy components).
As discussed briefly above, another significant advantage of the disclosed formation of nonreactive metal (e.g., Al) alkoxide products is that the disclosed process may result in the formation of elongated particles (small wires) of alkoxides. Furthermore, the size, morphology, and aspect ratio of such small wires is tunable in a broad range by changing the synthesis reaction conditions, the composition of the alloy, and the composition of the reactive alcohol solution. A low cost, large volume (bulk) production of alkoxides (or other compounds) of Al or other metals of controllable (tunable) dimensions may be particularly attractive in many applications.
In some applications, it may be advantageous to convert alkoxide (e.g., aluminum alkoxide) or other metalorganic or metallic samples into oxide samples. In particular, if the alkoxide (e.g., aluminum alkoxide) or other metalorganic or metallic samples are in the form of small wires (either individual or bonded), it may be advantageous for some applications to transform them into oxide small wires (either individual or bonded, thus forming a porous oxide body or a porous oxide membrane). In one example, such a conversion may take place by heating alkoxide samples in an oxygen-comprising (or, in some cases, ozone-comprising) gaseous environment (e.g., in air). Pressure for such a conversion reaction may vary over a broad range, from around 0.0000000001 atm to around 100,000 atm. Lower pressure typically reduces the reaction rate. For economical or other reasons, it may be preferred for the conversion reaction to proceed at around atmospheric pressure. Suitable reaction temperatures depend on the particular chemistry of the alkoxide, reaction pressure, the composition of the gaseous environment, the partial pressure of oxygen, and other parameters. Higher temperatures increase conversion reaction rates, but may induce sintering and coarsening of the oxide particles or oxide melting (which may be undesirable in some applications). Typically, suitable reaction temperatures are in the range from around 0° C. to around 2000° C. Even more typically, suitable reaction temperatures are in the range from around 20° C. to around 1500° C. In some applications, it may be preferable to gradually increase the annealing temperature in an oxygen-containing environment in order to initially form a more thermally stable shell around the particles and thus prevent significant shape change of the alkoxide particles during heating to higher temperatures (alkoxide particles (small wires) may otherwise sinter, coarsen, and melt). For example, melting points of aluminum ethoxide, aluminum methoxide, aluminum propoxide, and many other aluminum alkoxides is in the range from around 120 to around 200° C. It is, therefore, advantageous for some applications to prevent alkoxide small wires from melting during heating (e.g., by the formation of such a more thermally stable shell/surface layer). In some applications, such a shape preserving shell may also be formed prior to heating in a gaseous or liquid environment. In some applications when formation of porous oxide membranes or porous oxide bodies is desirable, bonding (cross-linking or sintering) of individual small wires during heating may be preferable. As such, depending on the particular application and the desired end-product, the conditions, environment, and protocol of the alkoxide-to-oxide conversion reaction may vary. It is noted that alkoxide-to-oxide conversion reactions typically lead to a significant volume reduction of the material. In some applications, such a volume reduction may lead to the formation of porous oxide samples (e.g., porous oxide small wires) with either internal (closed) or external (open) pores, or both. Formation of pores may increase the surface area of the oxide samples and may also reduce their density, which may be preferred in some applications.
In addition to the conversion of various organometallic compounds to oxides, it may be advantageous for some applications to convert organometallic compounds (particularly in the form of small wires or porous materials) into other chemical compounds (materials), such as metal oxyhydroxides, hydroxides, etc., and other ceramic materials, such as oxy-halides, halides, oxy-carbides, carbides, nitrides, oxy-nitrides, phosphides, oxy-phosphides, sulfides, selenides, tellurides, and various mixed ceramics and doped ceramic materials, among others, to name a few examples. It may similarly be advantageous if the shape of the samples does not change significantly during such transformations. Like the previously described case of oxide(s) formation, a similarly broad range of temperatures and pressures and similar methods may be utilized, depending on the particular chemistry. If the conversion takes place in a gaseous environment, the environment may comprise other reactive species with electronegative ceramic-forming elements instead of (or in addition to) oxygen-containing reactive gases, such as reactive gases comprising: halogens (F, Cl, I, Br), sulfur (S), selenium (Se), nitrogen (N), phosphorous (P), carbon (C), and other ceramic-forming elements (depending on the desired composition of the nanostructured ceramic materials).
In some designs, it may be advantageous to convert species from the initially formed metalorganic compounds into final compounds using one or more intermediate steps. For example, in some applications (e.g., to further produce oxide small wires with reduced or no porosity (including formation of single crystalline oxide small wires) during subsequent treatments), it may be advantageous to convert metalorganic (e.g., alkoxide, such as aluminum alkoxide) samples (e.g., aluminum alkoxide small wires, etc.) to oxyhydroxide (e.g., boehmite (AlOOH) or another polymorph crystalline or amorphous microstructure) or hydroxide (e.g., Al(OH)3— having, for example, bayerite, gibbsite, nordstrandite, pseudoboehmite, or another polymorph microstructure) samples. In some applications, it may be further advantageous to preserve the elongated shape and individuality of the small wire samples during such transformations. In other applications, it may be advantageous and useful to produce porous structures of controlled porosity and dimensions from the initial alkoxide small wires (or porous alkoxide material). Several methods may be employed for this conversion. For example, one may use a controlled hydrolysis of aluminium alkoxide samples in water-containing solvent(s) or water under controlled temperature to produce either aluminum hydroxide or aluminum oxyhydroxide/monohydroxide AlO(OH) either of amorphous microstructure (typically at temperatures lower than around 50-70° C.) or crystalline (e.g., boehmite) structure (typically at higher temperatures, e.g., at or above around 70-90° C.). Treatment/reaction time may range from around 1 minute to around 30 days. Shorter time is typically difficult to control. Longer time may become less economical. In some applications, it may be advantageous to heat the water-free alkoxide powder-comprising solution to the desired temperature before introducing a water-comprising solution (e.g., also preheated) to conduct hydrolysis. It may be preferred that this solution exhibits minimal solubility (e.g., below around 0.02M) for both the alkoxide and the final product (e.g., oxyhydroxide, hydroxide, etc.) in order to largely preserve the elongated shape of the small wires and avoid significant material losses. Alkali metal alkoxides (e.g., lithium alkoxide) or alkaline earth metal alkoxides (e.g., magnesium alkoxide or calcium alkoxide) or other compounds that have higher solubility in these solutions may be pre-dissolved in them in order to reduce the solubility of aluminum alkoxides or the final product in these (e.g., in water or water-containing) solutions. In some applications, it may be preferred for the alcohol tail(s) of all the alkoxides to be identical (e.g., if aluminum ethoxides are being transformed it may be preferred in some applications to use alkali metal ethoxide for the pre-dissolution in the solution). In some applications, a water solution in ionic liquids may be used for the transformation reactions. Once alkoxide samples (e.g., small wires) are first converted to oxyhydroxide or hydroxide samples (preferably crystalline small wires), these samples may be further converted to oxide samples (e.g., oxide small wires) having minimal (or no) pores and having an ordered crystalline microstructure. By controlling the concentration of water, the composition of the reactive solution, and the reaction temperature, one may control the morphology, chemistry, and crystal structure of the converted oxyhydroxide or hydroxide samples.
Changing one or more properties (e.g., increasing pH) of the water or water-containing solution may be another tool employed for controlling microstructure, composition, and morphology of the converted oxyhydroxide or hydroxide samples. LiOH may be used to increase the pH of the treatment (hydrolysis) solution. KOH or NaOH or other bases may similarly be used for this purpose. Higher pH may favor transformation to Al(OH)3. Higher treatment temperature similarly favors formation of crystalline microstructure. In some applications, it may be further advantageous to first transform Al alkoxide particles to AlOOH before further transforming to Al(OH)3. Similarly, control OF pH (typically in the range from about 5 to about 14) may be utilized to tune the morphology of other conversion (or transformation) reaction products as well as the morphology of the nanostructured materials produced by the selective dissolution of one (or more) metals from metal alloys.
In some designs, it may be advantageous to add organic or inorganic salts or “inert” co-solvents to the “reactive” solvent (by which it will be understood that “reactive” refers to the solvent which may form organometallic compounds upon immersion of the suitable alloy into it) in order to tune the morphology of the desired organometallic compound (e.g., alkoxide) or in order to reduce the solubility of at least one of the alloy components. In some designs, the added salt may comprise the component of the alloy (e.g., Al salt such as AlCl3 and others, etc., or Li salt such as LiCl and others in the case of a reaction with an AlLi alloy).
In some designs and alloy compositions, water may be used in addition to (or instead of) organic solvents to selectively dissolve one or more metals from metal alloys and produce nanostructured (porous materials, small wire-shaped particles, nanoparticles, etc.) metal-comprising compounds of less reactive metals. A broad range of pressures and temperatures may be utilized, as described above for the formation of alkoxides.
In some designs, instead of transforming (converting) metalorganic small wires (or porous materials) (e.g., formed as disclosed herein) into oxide or other ceramic small wires or porous materials by direct (or indirect) transformation reaction(s), one may transform nanostructured metalorganic compounds into small metal wires or porous metals. In contrast to conventional methods for the formation of small metal wires and porous metal structures, here metalorganic small wires or metal-containing ceramic (e.g., oxides, sulfides, nitrides, selected chalcogenides, etc.) small wires (or the corresponding porous structures) may be first formed (step A) according to (or conceptually similar to) the above-discussed methodology and then (step B) reduced to the corresponding metal form. Such a reduction process may proceed, for example, by using a gaseous reducing agent or in a liquid environment by using a liquid reducing agent (e.g. in a solution). In one example method, formation of the small metal wires (or porous metal structures) may involve an initial formation of silver oxide or silver-based metalorganic small wires (or porous structures) (e.g., by forming Ag—Li, Ag—Na, Ag—Ca, Ag—K, Ag—Mg, or another suitable Ag alloy and its reaction with a suitable solvent under suitable conditions to form silver-containing small wires (or porous structures)), which may be then transformed into silver oxide wires (e.g., upon annealing in an oxygen containing environment) and then reduced into small silver wires. In some cases, metal (e.g., silver) oxide or other metal ceramic or metal-based metalorganic small wires (or porous structures) may be directly transformed into metal small wires or porous metal structures. In some cases, metal (e.g., silver) alloys may be directly transformed into metal small wires or porous metal wires or other porous structures upon preferential dissolution of the more reactive metal into a suitable solvent. Various suitable organic compounds (solvents) may be used instead (not just suitable alcohols) for the formation of organometallic wires. Other metal (not just Ag) and metalloid small wires and porous materials may be produced similarly. Examples of such metals and metalloids include, but are not limited to, Au, Pt, Cu, Ti, Ni, Co, Zn, W, Hf, Ta, Nb, Mo, Ru, Rh, Pd, Bi, La, In, Sn, Ge, and Si, to name a few.
Such small metal wires may be used in various composites, optically transparent conductive coatings, as magnetic materials (in a broad range of applications of soft and hard magnets), scanning probe microscopy tips, surface enhanced Raman scattering techniques, metamaterials (negative refractive index materials), nano-optics, molecular electronics, biological tags, anti-bacterial materials, field emission electron emitters, gas sensors, catalysts, electrically conductive additives (e.g., to enhance electrical conductivity of various paints, plastics, battery or capacitor or supercapacitor electrodes, etc.), conductive inks, current collectors and other applications. In some designs, it may be advantageous for metal small wires (e.g., Cu or Ag and others) to be incorporated into fabrics to provide antibacterial properties. In some designs, it may be advantageous for metal small wires (e.g., Cu or Ag and others) (particularly the small wires produced according to the disclosed methods herein) to be components of the anti-static paints, electromagnetic shielding, conductive inks for touchscreen displays, sensors, smart lenses, and other applications. In some designs, it may be advantageous for metal small wires and porous metal structures (particularly those produced according to the disclosed methods) to be component(s) of rocket fuel or explosives. Different metals (in the form of porous structures or small metal wires) may be more effectively utilized in different applications. For example, small Ta wires and porous Ta may be particularly attractive for applications in electrolytic capacitors. In another illustrative example, Cu, Ag, Cu—Ni alloys and other alloys (in the form of small wires or porous structures) may be attractive for applications in anti-bacterial coatings or paints, or anti-bacterial clothing or fabrics. In yet another illustrative example, Pt, Au, Cu, Ni, and other metal small wires or porous structures may be particularly effective when utilized as catalysts. In yet another illustrative example, Au, Cu, Ni, and Ti small wires may be very effective when used as conductive additives. Some of these applications (e.g., sensors, molecular electronics, biological tags, catalyst, etc.) may benefit from the formation of porous metal wires, which are also enabled by the disclosed methodology herein. In addition to pure small metal wires, the described methodology may allow formation of mixed metal alloys. In this case, alloys of two or more “nonreactive” metals and one or more “reactive” metals may be used as the initial materials.
In addition to the above-discussed solution-based methods for the formation of nanostructured metal-comprising compounds or for various transformation reactions, gas phase conversion may also be utilized in a similar way.
Several example embodiments and corresponding synthesis procedures are described, in turn, below. In a first example, the first synthesis step included formation of 3-AlLi by mixing and melting Al and Li components. Battery grade lithium foil and 0.25 mm thick aluminum foil (either 1145 Al alloy or 99.999% pure Al, with the results being nearly identical in terms of the composition and morphology of the final products) were cut into 12.7 mm rounds and Li was sandwiched between Al foils. The mass of Li in this example was chosen to be approximately 20 wt. % (50 at. %) of the total (approximately 80 wt. % and 50 at. % of Al) in order to produce 3-AlLi at the congruent melting point. A graphite crucible was used as a sample holder for melting. Samples were rapidly heated to 750° C. at a heating rate of 895° C./min in the graphite crucible with an induction heater. The temperature was measured via an optical pyrometer during heating. After reaching 750° C. the heating was stopped immediately while the molten sample was allowed to cool in an inert environment (Ar gas) at a cooling rate of 150° C./min.
The second step included exposure of the AlLi samples to various solvents (alcohols in this example). More specifically, the produced AlLi pellet samples were placed in 20 mL of an alcohol in a glovebox. The chemical reaction resulted in the formation of hydrogen and possibly other gases, which may be evacuated (e.g., via a bubbler) or collected. All solvents selected in this example were anhydrous alcohols, such as four different homologous series: various linear chain alcohols (e.g., methanol, ethanol, 1-propanol, 1-butanol, 1-hexanol, 1-octanol, among others), various branched alcohols (e.g., ethanol, 2-propanol, t-butanol, among others), various cyclic alcohols (e.g., phenol, among others), and various multi OH group alcohols (e.g., ethylene glycol, among others). A low content of water in alcohols was found to be preferable for the Al alkoxide small wire formation. The maximum tolerable (for small wire formation) H2O content in alcohols was found to depend on the particular alcohol. Typically, it was found that alcohols should preferably contain below 1000 ppm (often preferably below 100-150 ppm and in some cases (e.g., in the case of ethanol and other low molecular weight alcohols) preferably below 40-50 ppm) of moisture to reproducibly yield Al alkoxide in the shape of small wires. Formation of other metalorganic or metallic nanostructures (including nanoporous and small wire structures comprising non-Al metals) may be more tolerant to water content. After completion of the reaction, solid Al alkoxide products were decanted from the solution to remove residual LiOH products.
SEM image analysis including small wire diameter measurements were performed manually using open source software ImageJ. Diameter measurements were performed with a sample size N≥150 for each sample type.
As small wires form uniformly around the crystalline grains (see
Other metalorganic (organometallic) and metallic small wires may form according to a similar mechanism.
Formation and size of both the Al and Al alkoxide nuclei in the example above depends on the interplay between the strain energy release upon the crack formation and increase in the interfacial energy. As such, the morphology of the Al alkoxide surface layer may be influenced by the alcohol composition.
In some aspects of the present disclosure, it may be advantageous to deposit a layer of another material on the surface of the metal, metal alkoxide, metal hydroxide, metal oxyhydroxide, metal oxide, and ceramic small wires or porous metal, porous metal alkoxide, porous metal hydroxide, porous metal oxyhydroxide, porous metal oxide, porous ceramic and other porous materials. This may be for a desired modification of mechanical properties, modification of electrical or dielectric properties, modification of interfacial properties (such as interfacial energy, strength, wetting angle, tribological properties, etc.) (e.g., if used in composites), modification of optical properties, protection against undesirable actions of the outside environment, enabling enhanced chemical reaction rates (e.g., for catalysis), and other reasons. The suitable surface layer thickness may range from as thin as sub-monolayer (discontinuous monolayer, typically 0.01-0.2 nm in average thickness) to as thick as 1,000 nm. However, an average layer thickness ranging from around 0.3 nm to around 30 nm has been found to work well for many applications.
Depending on the applications of the produced metal, alkoxide, hydroxide, oxyhydroxide, oxide, and ceramic small wires (or porous materials), the layer may be a metal, polymer, carbon, dielectric, or ceramic material. Examples of suitable ceramic surface layers include, but are not limited to, various oxides, various chalcogenides (e.g., sulfides) and oxy-chalcogenides, various halides (e.g., fluorides) and oxy-halides, various nitrides and oxy-nitrides, various carbides and oxy-carbides, various borides, their mixtures, and others. In some applications, it may also be advantageous to form a composite surface layer coating. In some applications, it may also be advantageous to form a porous coating layer. The pores in the coating layer may be filled with another functional material. In some applications, the coating layer may leave closed pores within the porous alkoxide, hydroxide, oxyhydroxide, and oxide materials (e.g., small wires). In some applications, these closed pores may be filled (pre-filled) with another functional material. In some applications, the pores may also be open.
In some applications, it may be advantageous to put two or more layers of materials as a coating. These layers may have different composition, density, porosity, surface chemistry, mechanical or electrical or optical properties, or other substantial differences. For example, if the inner alkoxide, hydroxide, oxyhydroxide and oxide materials (e.g., small wires) have internal porosity, the inner layer of the coating may have smaller pores and the outer layer of the coating may have no pores.
Different methods may be suitable for the formation of surface layers on alkoxide, hydroxide, oxyhydroxide, and oxide materials (e.g., small wires or porous materials). These include, but are not limited to: conversion and deposition reactions conducted in gaseous or liquid environments and their combinations. Examples of suitable deposition methods in a gaseous phase include, but are not limited to, various types of chemical vapor deposition (CVD) (including plasma enhanced deposition), atomic layer deposition (ALD), molecular beam epitaxy (MBE), physical vapor deposition (PVD, such as sputtering, pulsed laser deposition, thermal evaporation, etc.), and their various combinations. CVD and ALD may be preferable in some applications requiring more conformal and more uniform (yet relatively economical) deposition. Examples of suitable liquid phase depositions include, but are not limited to: electrodeposition, plating, electrophoretic deposition, layer-by-layer deposition, sol-gel, chemical solution deposition or chemical bath deposition (CSD or CBD), and others.
As discussed above, instead of using organic solvents as shown in
In some designs, it may be advantageous to utilize alloys (of more reactive and less reactive metals) in the form of the wires of well-defined dimensions, various porous structures of the desired pore size (e.g., a mesh or a foam) or particles of well-defined size and shape (e.g., spherical particles or wire-shaped particles) prior to the selective dissolution procedure. The size (e.g., diameter) of such particles may range from around 0.1 microns to around 10,000 microns, depending on the application. This method may allow formation of nanostructured or porous particles of less reactive metal (or less reactive metal compounds) with hierarchical morphology and additional control of their structure, dimensions, and properties.
Formation of porous nanostructures (including flexible porous structures, such as flexible membranes) comprising metal or ceramic compositions may be particularly attractive for some applications.
In some applications, it may be advantageous for the porous oxide (or porous ceramic) material to be composed of individual layers. It may also be advantageous to exhibit a horizontal (or vertical) alignment of the small wires within an individual layer. In some applications, it may be advantageous for the horizontally aligned small wires to have a different orientation in the subsequent layers (e.g., with an angle anywhere between 0 and 90 degrees in the neighboring layers). Controlling orientation of individual layers provides opportunities to tailor the mechanical properties of the composites in multiple directions and have a different resistance to fracture and tunable bending modulus.
Other aspects of the present disclosure include the use of oxide (or other ceramic) small wires and porous oxide (or other porous ceramic) materials in several applications. Such uses may provide unique benefits of achieving attractive (and sometimes remarkable) properties at a low cost.
One aspect of the present disclosure includes the use of aluminum oxide (and other oxide as well as other ceramic) small wires (particularly those described herein, including but not limited to porous aluminum oxide small wires) in biocompatible materials. In this case, the utilization of such small wires may favorably enhance chemical, biological, physical, and structural (mechanical) properties, allow control over permeation (of species of interest), control density and/or enhance compatibility with the surrounding host tissues. Depending on the particular application, mechanical properties of interest may include: higher elastic modulus, higher strength, higher hardness, higher wear resistance, higher stiffness, higher toughness, or optimal load transmission. Example applications may include, but are not limited to, composites for (i) external fixators, bone plates, and screws (including those that comprise epoxide, poly(methyl methacrylate), polypropylene, polyethylene, PS, nylon, polybutylterephthalate, polyether ether ketone, and other polymers or titanium, various titanium alloys (e.g., titanium aluminum, titanium aluminum vanadium, titanium aluminum niobium, titanium molybdenum, gold, biocompatible stainless steel (e.g., 316LL), cobalt-chromium-molybdenum alloys, or other biocompatible metals and/or carbon); (ii) joint replacement (including those that comprise examples of polymers, metals, and carbon above); (iii) total hip replacement; (iv) bone cement; (v) dental applications; (vi) catheters; and (vii) prosthetic limbs, to name a few. In addition, the described aluminum oxide nano small wires may be advantageously utilized in superparamagnetic nanocomposites for biology, medicine, diagnostics, and therapy. The suitable volume fraction of small wires in biomaterial composites may range from around 0.05 vol. % to around 70 vol. %.
In some applications (e.g., transparent armor, screens, windshields, displays, among others), the use of aluminum oxide (and other oxide and other optically transparent ceramic) small wires (particularly those described herein) as fillers in optically transparent glasses and glass coatings may be highly advantageous in terms of tuning glass optical properties, increasing glass hardness, wear resistance, scratch resistance, fracture toughness, manufacturability in thin sheet states, and other important properties. When small wires are small in dimensions (e.g., below around 50-100 nm in diameter) and uniformly distributed within a glass, scattering of visible light might be avoided even if the glass matrix exhibits a substantially different refractive index because optical non-uniformities may be sufficiently below half of the visible light wavelengths. However, if optical non-uniformities are larger than around 100 nm, matching the refractive index of the small wires with that of glass may be important to maximize transparency of the small wire-glass composites. This may be accomplished either by tuning the refractive index of a glass or by tuning the refractive index of the small wires. For example, if small wires are composed of 100% solid Al2O3 small wires with no closed pores they would typically exhibit a refractive index of around n=1.75-1.81 (for visible light). As such, selecting a glass (ceramic) that approximately (preferably within 4% or less; more preferably within 2% or less; or even more preferably within 1% or less) matches its refractive index n may be advantageous for maximizing transparency of the Al2O3 small wire/glass composites. Illustrative examples of such glasses with matching refractive index may include, but are not limited to, various flint glasses, beryllium oxides, magnesium oxides, various suitable mixtures of oxides comprising at least two (preferably at least three; or even more preferably at least four) of the following oxides: boron oxide, barium oxide, beryllium oxides, bismuth oxide, magnesium oxides, calcium oxide, cesium oxide, rubidium oxide, potassium oxide, aluminum oxide, lanthanum oxide, cerium oxide, lithium oxide, magnesium oxide, manganese oxide, sodium oxide, niobium oxide, neodymium oxide, phosphorous oxide, antimony oxide, silicon oxide, germanium oxide, strontium oxide, tin oxide, titanium oxide, tantalum oxide, hafnium oxide, tungsten oxide, zinc oxide, and zirconium oxide. Examples of suitable commercial glasses include but are not limited to N-BASF64 with n=1.7, N-LAK8 with n=1.72, N-SF18 with n=1.72, N-SF10 with n=1.73, S-TIH13 with n=1.74, N-SF11 with n=1.78, N-SF56 with n=1.78, N-LASF44 with n=1.8, N-SF6 with n=1.81, N-SF57 with n=1.85, N-LASF9 with n=1.85, and many others). In another embodiment, for a given refractive index of a glass (e.g., aluminosilicate-type glass) of, for example, 1.52, a closed internal porosity of porous Al2O3 small wires may be tuned in order to achieve a matching refractive index (preferably within 4% or less; more preferably within 2% or less; or even more preferably within 1% or less). By increasing the closed pore volume within porous Al2O3 small wires, one may reduce their effective refractive index from around n=1.75-1.81 to below 1.3, in some applications. In some applications, optically transparent polymers (e.g., particularly those that exhibit a high refractive index, such as polycarbonate, trivex, crown glass, etc.) may be utilized instead of oxide glasses or optically transparent ceramic materials as matrix materials in Al2O3 small wire-comprising composites. Porous oxide particles (not only Al2O3) with matching effective refractive index may also be used in optically transparent polymer-oxide composites that exhibit more favorable mechanical properties and scratch resistance than pure polymers. In some applications of transparent materials with enhanced toughness and scratch resistance, polymer small wire, glass small wire, and ceramic small wire composites may be manufactured by first producing a porous scaffold (including both bulk parts of various shapes and sizes and porous sheets or thin membranes) composed of the small wire material that is then infiltrated with a matrix material (such as a suitable polymer, oxide glass, transparent ceramic, etc.). The suitable mass and volume fractions of the small wires in such wire-glass composites typically ranges from around 0.01 vol. % (and around 0.01 wt. %) to around 85 vol. % (and around 85 wt. %).
Examples of suitable uses of such glass small wire composites include, but are not limited to, watches, screens/monitors of various sizes (e.g., computer monitors, cell phone screens, monitors in laptops, ultrabooks, tablets, electronic books, television screens, credit card terminals, monitors of various other electronic devices or components of devices, etc.), various optical lenses (including those used in glasses, cameras, microscopes, spectroscopes and other research tools, etc.), sensors, window glasses, various applications in automotive and transport (windscreens/windshields, backlights, light-weight but reinforced structural components of cars, aircrafts, ships, etc.), various appliances (oven doors, cook tops, etc.), glass bulbs, tableware glass (e.g., drinking glasses, plates, cups, bowls, etc.), jewelry, protection equipment (transparent armor, safety screens, helmets, personal protection equipment, radiation protection screens (e.g., from X-Rays, gamma-rays, etc.)), various interior design and furniture (mirrors, partitions, balustrades, tables, shelves, lighting, etc.), various reinforcement structures, packaging, fiber optic cables, life science engineering, and electrical insulation, to name a few.
In some applications, it may be advantageous to add a particular color to otherwise transparent oxide small wire/glass composites or to the small wires themselves. In some applications, suitable dyes or quantum dots may be attached to the surface of the small wires or be infiltrated into the pores (if present in the small wires). In some applications, it may be advantageous to seal these pores in order to prevent direct contact between the dyes (or quantum dots) and surrounding environment. In some applications, the sealing material may be a glass (e.g., oxide glass, etc.) or a ceramic or a polymer.
In some applications, the use of aluminum oxide (and other oxide and other ceramic) small wires (particularly those described herein, including but not limited to porous aluminum oxide small wires) as well as aluminum oxide (and other oxide based and other ceramic based) porous membranes as fillers in polymer composites (including various polymer-ceramic, polymer-carbon, polymer-metal, polymer-ceramic-metal composites) may be advantageous for enhancing various properties (e.g., mechanical, thermal, dielectrical, etc.) of such polymer-comprising composites. The one dimensional (1D) wire geometry may be particularly advantageous for the formation of dense composites with excellent mechanical properties, flexibility, uniformity and controlled (e.g., either high, medium, or low) volume fraction of the small wires. Depending on the particular application, mechanical properties of interest (at room temperature, elevated temperatures, or low temperatures) may include, but are not limited to: higher elastic modulus, higher strength, higher hardness, higher scratch resistance, higher wear resistance, higher stiffness, higher toughness, better resistance to creep, better resistance to fatigue, and better tribological properties, to name a few. Similarly, the use of small wires as discussed above may allow achieving a desired effective dielectric constant and refractive index in small wire/polymer composites. The suitable weight fraction of the small wires in such polymer-comprising composites depends on the particular application and desired properties, but typically ranges from around 0.01 wt. % to around 95 wt. %.
In some applications, it may be advantageous to add a particular color to otherwise transparent oxide small wire/polymer composites. In some applications, suitable dyes or quantum dots may be attached to the surface of the small wires or be infiltrated into the pores (if present in the small wires). In some applications, it may be advantageous to seal these pores in order to prevent direct contact between the dyes (or quantum dots) and surrounding environment. In some applications, the sealing material may be a glass (e.g., oxide glass, etc.) or a ceramic or a polymer.
A broad range of natural, semi-synthetic, and synthetic polymers may benefit from the use of aluminum oxide small wires and other ceramic as well as metal wires (particularly those described herein). Structure-wise, these polymers may also be classified into linear polymers, branched chain polymers, and cross-linked polymers. These polymers may also be classified into various thermoplastics, thermosets (or resins), elastomers (or rubbers), and fibers (or natural polymers). Selected examples of suitable thermoplastics include, but are not limited to, polyethylene (PE), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polypropylene (PP), polyvinyl chloride (PVC), polyether sulfone (PES), polyether ether ketone (PEEK), polyetherimide (PEI), polycarbonate (PC), various polyamides (e.g., nylon), various polyesters (e.g., aliphatic polyester), acrylic (poly(methyl methacrylate), PMMA), polytetrafluoroethylene (PTFE), polybenzimidazole (PBI), polyacrylonitrile (PAN), polybutadiene, polystyrene (PS), polyoxymethylene (POM), and co-polymers of the above polymers, among others. Selected examples of suitable thermoset polymers include, but are not limited to, various alkyds or polyester fiberglass polymers and polyester resins, various amino (urea, melamine) polymers (including urea-formaldehyde, phenol formaldehyde, melamine formaldehyde, etc.), various epoxy resins (including those after esterification and other modifications—e.g., vinyl ester), various phenolic resins (bakelite or phenol-formaldehyde (PF)), various polyimides, various silicones, various polyurethanes, polyisocyanurate (PIR), various rubbers/elastomers (vulcanized rubber, neoprene, nitrile, styrene butadiene, etc.), various heterocyclic compounds (e.g., polyhexahydrotriazine), and cyanate esters, to mention a few. Other specific examples of other suitable polymers include, but are not limited to, various (para-) aramid fibers, poly(vinyl alcohol) (PVA), various proteins and polypeptides (including enzymes), chitin (poly(N-acetylglucosamine)), silk (including spider silk) and various polysaccharides (including starch, cellulose and carboxymethyl cellulose, alginic acid and salts of alginic acid), to name a few.
Suitable methods for the synthesis of composites comprising aluminum oxide small wires (particularly those described herein, including but not limited to porous aluminum oxide small wires) and other ceramic small wires and metal small wires may include, but are not limited to: various solution mixing techniques, solution blending, melt blending, in-situ polymerization, solid-state shear pulverization, and vacuum (e.g., resin) infusion, among others. Solution blending involves dispersion of small wires in a suitable solvent, mixing with a suitable polymer (at room temperature or an elevated temperature), and recovering the composite by precipitating or casting a film or a bulk sample or by other suitable methods. A wet annealing method may be considered as a variation of the solution blending—it involves partially drying a small wire/polymer suspension on a substrate and then increasing the temperature to above the glass transition temperature rapidly to complete the drying process. Melt blending uses high temperature and high shear forces to disperse small wires in a polymer matrix. At high concentrations of small wires the viscosities of the composites may be relatively high, which should be taken into consideration (for some blending methods, too high of a viscosity may reduce efficiency of uniform mixing). In-situ polymerization involves dispersing small wires in a monomer followed by polymerizing the monomers. It is noted that functionalization of small wires may assist in improving the dispersion of the nanotubes in a monomer (and similarly in a solvent for solution mixing and in a polymer for melt blending). Strong covalent bonding may be formed between small wires (particularly if they are functionalized) and the polymer matrix (e.g., by using various condensation reactions). For example, epoxy nanocomposites produced using in-situ polymerization methods involving dispersion of small (optionally functionalized) wires in a resin followed by curing the resin with a hardener may allow formation of composites with a strongly enhanced tensile modulus and other properties even with a small mass fraction (e.g., less than 10 wt. %) of small oxide wires. In some applications, the reactive agents may be first infiltrated into the pores of the porous small wires before being subsequently polymerized. In some applications, one may utilize reduced temperatures to increase viscosity of the suspension to the level when processing effectively proceeds in the solid state. Solid-state mechano-chemical pulverization/mixing processes may be used to mix small wires with polymers. Pulverization methods may be used alone or followed by melt mixing. This may induce grafting of the polymer on the surface of the small wires, which may result in the improved dispersion, improved interfacial adhesion, improved tensile modulus, improved hardness, and other positive improvements in the mechanical properties of the small wire/polymer composites. In another suitable method, small wires may be first processed into dry porous membranes or porous solid bodies and laid into a suitable mold. The polymer (resin) is then infiltrated (infused or sucked) into the porous membranes/bodies comprising mold by applying negative pressure (e.g., vacuum). Excess resin may be removed out of the bodies by applying negative pressure (e.g., vacuum).
Small wire/polymer composite fibers may be produced by melt fiber spinning, where the composite melt may be extruded through a spinneret hole, and the extruded rod is air cooled and drawn under tension by a windup spool to produce aligned composite fibers. Electrospinning is yet another method to produce composite (nano)fibers using electrostatic forces.
Examples of suitable uses of such small wire/polymer composites include, but are not limited to, components of musical instruments or whole musical instruments (for example, violin bows, guitar pick-guards, drum shells, bagpipe chanters, cellos, violas, violins, acoustic guitars, electric guitars, guitar picks, ukuleles, etc.), bags and cases (for example, laptop cases, backpacks, purses, etc.), cases, frames and components of various electronic devices (for example, laptops, ultrabooks, tablets, servers, printers, scanners, electronic books, monitors, televisions, credit card terminals, cameras, microscopes, spectroscopes and other research tools, monitors of various other electronic devices or components of devices, etc.), audio components (for example, turntables, loudspeakers, etc.), sporting goods and sporting good components (for example, components of bicycles, kite systems, etc.), various firearms use (for example, to replace certain metal, wood, and fiberglass components, etc.), components of automotive, aerospace and aircraft, ship, and other transport devices (for example, components of cars, buses, planes, ships and boats, spacecraft, drones, including rotor blades and propellers, etc.), various legs, rods and poles (for example, tripod legs, tent poles, fishing rods, billiards cues, walking sticks, poles for high reach, such as the ones used by window cleaners and water fed poles, posts that are used in restoring root canal treated teeth, etc.), many other light and durable consumer or military items (for example, handles of knives and tools, various toys, cases for various devices, tents, etc.), clothes and components of clothes (jackets, coats, shirts, pants and tights, hats, gloves, masks, stockings, buttons, etc.), footwear and components of footwear (boots, shoes, sandals, slippers, wides, narrows, etc.), cases of watches and other wearable devices, furniture, frames of reading glasses, components of various appliances (ovens, stoves, blenders, grinders, vacuum cleaners, refrigerators, dryers, washing machines, etc.), tableware, jewelry, components of various protection equipment (safety screens, helmets, personal protection equipment, etc.), furniture and design components (chairs, mirrors, partitions, balustrades, tables, shelves, lighting), electrical insulation materials, thermal insulation materials, fire resistant materials, tires, and various protective (for example, against corrosion or chemical attack) coatings on metal or wood or ceramic parts, to provide a few examples.
In some applications, the use of aluminum oxide (and other oxide as well as other ceramic and metal) small wires (particularly those described herein) in combination with carbon small wires (carbon (nano)fibers or carbon nanotubes) or carbon platelets (graphene, exfoliated graphite, etc.) may provide even more advantages than using aluminum oxide (or other ceramic or metal) small wires (or carbon small wires/platelets/tubes) alone in various composites (such as ceramic composites, glass composites, metal composites, polymer composites, carbon composites, etc.). The utility may depend on the particular application and chemistry. For example, in some cases, carbon may provide the needed electrical conductivity to the composite, but may be hard to disperse uniformly. The addition of aluminum oxide (or other ceramic small wires) may assist in such a dispersion and additionally enhance the strength of the composite. In other cases (applications), the combination of oxide small wires and carbon may enhance thermal stability (when compared to only using carbon), enhance catalytical activity (when compared to either only carbon or only oxide), enhance the modulus of toughness, etc. In yet another case, it may be desirable to provide enhanced mechanical performance and electrical connectivity within a composite with the smallest volume fraction of small wires, but conductive carbon may undesirably induce certain side reactions (e.g., as in battery electrodes). Combining aluminum oxide (or other suitable ceramic) small wires with carbon small wires (or carbon nanotubes, graphene, etc.) may provide the desired mechanical property enhancement and sufficient conductivity to the composite, while minimizing side reactions induced by carbon.
In some applications, the use of aluminum oxide (and other oxide and other ceramic and metal) small wires and other porous materials (particularly those described herein, including but not limited to porous aluminum oxide small wires and other porous membranes and particles composed of ceramic or metal(s)) in various types of solar cells (e.g., in perovskite solar cells, in organic solar cells, tin sulfide solar cells, etc.) and light emitting diodes (e.g., in organic LEDs, perovskite LEDs, various porous LEDs including GaN-based ones, etc.) may be advantageous in terms of improving their performance characteristics and long-term stability. In some applications, catalyst-free formation of organometallic compounds may be very advantageous for applications in organic solar cells and organic light emitting diodes.
In some applications of the present disclosure, the use of porous oxide (e.g., aluminum oxide) membranes (or porous ceramic membranes or, in some cases, porous metal membranes), particularly those produced according to the methods described herein (including those comprising bonded small porous (as well as dense, essentially pore-free) wires) as separation membranes may be advantageous. Such membranes may offer excellent mechanical properties (high strength, high toughness, high modulus, excellent creep and fatigue resistance), excellent thermal stability, high permeability, excellent chemical stability, high durability, lightweight, low cost, high uniformity, good wetting by a broad range of liquid materials, good flexibility, and many other attractive attributes. Conventional aluminum oxide membranes are produced by anodization of aluminum. This method suffers from long synthesis procedures and very high cost, while the produced membranes are typically very brittle, difficult to handle, and form cracks upon bending. Furthermore, the pores in such membranes are typically straight (see-through), which may be undesirable in some applications. In addition, such conventional membranes are difficult to mass-produce thinly (the minimum thickness is typically at least 50 microns). In contrast, the suitable thickness of the disclosed membranes herein may range from around 1 micron to around 20 mm for standalone membranes and from around 100 nm to around 5 mm for membranes deposited on another (e.g., porous) substrate. In some applications, it may be advantageous for such membranes to additionally comprise 0.1-90 wt. % polymer, 0.1-80 wt. % metal, or 0.1-80 wt. % carbon (e.g., for enhancing mechanical properties, for enhancing separation properties, or for other functionality, such as anti-bacterial, catalytic, etc., to name a few). Depending on the particular application and membrane composition, the suitable porosity in the disclosed membranes may range from around 0.001 vol. % up to around 99 vol. %. These separation membranes may be utilized for various filtration applications separating various particles (e.g., in the liquid or gaseous suspension state; including, but not limited to, various soft matter (including bio-related) particles, various ceramic particles, various carbon particles, various composite particles, dust, etc., the size of which may range from sub-mm to micron-scale and all the way up to nanoparticles), separating various liquids and gases (particularly if additionally comprising metals or polymers), among other species. These membranes may also be utilized in various applications requiring electrical insulation (e.g., in various electrochemical and electrical devices, including energy storage and energy harvesting devices, sensors, etc.). These membranes may also be utilized in applications requiring air and water filtration, including those where killing bacteria and bacteria spores is important. For these applications, it may be advantageous to deposit antibacterial (or anti-fungus) particles or coatings on the inner (and/or outer) surface of the porous membranes. Copper, its various alloys (e.g., brasses, bronzes, cupronickel, copper-nickel-zinc, etc.) and its various complexes (including those that comprise halogen atoms, such as Cl or Br), silver and silver alloys and various silver complexes, various antifungal complexes of Ni and Au, various organosilanes, various quaternary ammonium compounds (including those covalently bonded to a membrane surface or to a polymer layer on the membrane surfaces), and antifungal peptides, among others, are illustrative examples of materials suitable for use in such antibacterial or anti-fungus particles and coatings. Titanium oxide coatings on the membrane surface may also be used for catalytic decomposition of organic matter. Similarly, formation and utilization of porous membranes comprising copper, its various alloys (e.g., brasses, bronzes, cupronickel, copper-nickel-zinc, etc.) and its various complexes (including those that comprise halogen atoms, such as Cl or Br), silver and silver alloys and various silver complexes, various antifungal complexes of Ni and Au, titanium oxide and other suitable compounds as main membrane constituent(s) (not just as surface layer(s) or surface particles) may be advantageous.
The use of porous oxide (e.g., aluminum oxide) and other suitable electrically isolative ceramic membranes, particularly those produced according to the methods herein (including those comprising bonded small porous (as well as dense, essentially pore-free) wires), as separator membranes in electrochemical energy storage applications (e.g., fuel cells, batteries, supercapacitors, hybrid devices, etc.) may be particularly advantageous in view of the growing importance of these applications and thus will be described in more detail. The suitable thickness of such membranes may range from around 0.1 microns to around 200 microns (typically more desirable, from around 0.5 microns to around 100 microns). Advantages of using small aluminum oxide wires as compared to regular aluminum oxide particles include flexibility, strength, the ability to achieve very high porosity (e.g., over 70%, which may be important for high permeability), the ability to achieve a small size of the pores (which may be important for the prevention of potential Li dendrite penetration) and the ability to prepare thin membranes. Advantages of using porous small wires as compared to dense small wires include higher porosity (and thus higher permeation) for the same wire packing density. In addition, porous small wires may pack less densely compared with regular wires due to their higher surface roughness and lower density, which further increases separator permeation. Advantages of the described process (e.g., versus casting of individual wires) include bonding between individual wires, which helps to maintain robustness and resistance to fracture of the separator (even if it is very thin), while keeping it flexible. In some applications, it may be advantageous for such membranes to additionally comprise 0.1-10 wt. % polymer or 0.01-10 wt. % of another ceramic (e.g., for enhancing mechanical properties). Depending on the particular application, and membrane composition, the suitable porosity in the disclosed membranes may range from around 5 vol. % up to around 99.9 vol. % (more commonly from around 30 vol. % to around 95 vol. %; in some designs, from around 30 vol. % to around 50 vol. %; in some designs, from around 50 vol. % to around 70 vol. %; in some designs, from around 70 vol. % to around 95 vol. %), where typically higher porosity may be desired for thicker separator membranes or for applications requiring faster ion transport. Such membranes in energy storage applications may be infiltrated with a liquid or a solid electrolyte when used in devices. Superior strength, puncture resistance, outstanding thermal stability, low thermal expansion coefficient, relatively high dielectric constant, low cost, scalable manufacturability in thin form (down to 0.1 microns), good wetting properties for a broad range of materials, stability against reduction at low potentials (e.g., as low as 0 V vs. Li/Li+ in the case of aluminum oxide) and against oxidation at high potentials (e.g., as high as 10 V vs. Li/Li+), resistance against dendrite growth and other positive attributes of the disclosed membranes make them particularly attractive in a broad range of energy storage applications, including but not limited to various metal ion (such as Li-ion, Na-ion, Mg-ion, etc.) based energy storage devices (e.g., batteries including Li and Li-ion batteries, Na and Na-ion batteries, Mg and Mg-ion batteries, electrochemical capacitors, hybrid devices, etc.), to name a few.
Conventional polymer separators for Li-ion batteries suffer from limited mechanical strength and low thermal stability, which may lead to thermal runaway and cell explosions. Formation of flexible, strong, and thermally stable ceramic separators may overcome serious limitations of polymer separators.
Overall, the use of extra-thin (e.g., less than 5-10 μm) and highly porous (e.g., porosity greater than 75%) aluminum oxide (and other suitable oxide and suitable ceramic) membranes may allow one to noticeably increase the rate capability and energy density of Li and Li-ion batteries as well as that of other batteries, while increasing or maintaining the required level of safety. This level of porosity, beneficial for high rate capabilities, in combination with mechanical integrity and flexibility is only attainable using small wire-like structures because regular (e.g., near spherical) particle-based ceramic structures require substantially denser packing to produce a mechanical network and are typically not very flexible. By moving away from the typical use of polymers in the Li-ion battery separator, the thinner (e.g., to around 5 μm) ceramic separators (such as those described herein) will demonstrate higher strength and fracture toughness than thicker (e.g., a 20 μm thick) polymer separator with ceramic coating(s), while also reducing the thickness of the Anode/Separator/Cathode stack by approximately 10%, thereby increasing the energy density of the Li-ion battery by 10%—a major benefit. Increased cell energy density will also reduce the system costs ($/kWh) of battery packs as, for example, 10% fewer cells may be packaged and monitored for the same capacity. Due to their high stability at high potentials, such membranes may be used in combination with high voltage cathodes (e.g., cathodes having an average lithiation potential from around 3.9 to around 5.6 V vs. Li/Li+) in Li and Li-ion battery cells. It is noted that in addition to using a standalone porous aluminum oxide membrane, small wires (e.g., made of aluminum oxide or porous aluminum oxide) may be directly deposited on at least one of the electrodes by using casting or spray deposition or by field-assisted deposition or dip coating, or another suitable method. Such deposited wires may serve as an integrated (thin and flexible) membrane separating anodes and cathodes from direct electrical contact, while providing small resistance to ion transport and occupying a relatively small space.
In addition to Al2O3 membranes, other ceramic membranes (including those produced from or comprising small wires, including porous small wires) may be utilized as separators in Li-ion and other batteries. These include MgO, ZrO2, and many others. The important parameters are mechanical properties, stability of the ceramic membrane in electrolyte and (in case of direct contact with positive or negative electrodes) the lack of electrochemical side reactions (such as significant lithiation or dissolution, in contact with electrodes).
In some applications, it may be advantageous to deposit a porous polymer layer on one or both sides of the ceramic (Al2O3, MgO, ZrO2, WO2, W2O3, etc.) separator membrane in order to further reduce small side reactions with electrodes. For example, when such membranes are used in Li or Li-ion (or Na or Na-ion or other metal or metal-ion) batteries, depositing such a porous polymer layer (e.g., porous ethylene, porous propylene, porous aramid, porous cellulose, etc.) on the anode side of the membrane may prevent undesirable side reactions (e.g., lithiation, reduction, etc.) between the anode and the ceramic separator. Similarly, formation of such a porous polymer layer on the cathode side of the membrane may reduce potential undesirable oxidation reactions. A suitable thickness of such a porous polymer layer may range from around 10 nm to around 10 microns. In some applications of Li and Li-ion (or other metal or metal-ion batteries), it may be advantageous to deposit a thin (e.g., from about 1 nm to about 200 nm), mostly nonporous (dense) polymer layer on the inner surface of the membrane (e.g., around individual or bonded wires) to prevent direct Li contact with the ceramic wires (e.g., in case of Li dendrite formation). It may be further preferable for such a polymer layer to be stable in contact with Li and exhibit high interfacial energy at the polymer/Li interface. In this case, formation of the Li dendrite would result in a substantial increase in the energy of the system and its growth may be significantly reduced or eliminated. In contrast, direct contact of Li with many ceramic materials may result in the formation of a low-energy interface, which would reduce the surface energy of the Li dendrite and thus undesirably favor its propagation.
In some applications, it may be advantageous for the porous polymer layer on one or both sides of the ceramic (Al2O3, MgO, ZrO2, WO2, W2O3, etc.) membrane to be thermally responsive (or comprise a thermally responsive layer) and close pores above a certain temperature. This may provide an additional safety feature of the cell because above a certain temperature (e.g., selected in the range from about 70 to about 150° C., for typical applications; for some applications, above 100° C.) the membrane would shut the current flow. In some designs, a thermally responsive layer may comprise a thermoplastic with a melting point above a critical temperature (e.g., selected in the range from about 70 to about 150° C., for typical applications) to cut off Li ion conduction. In some designs, the thermally responsive layer (e.g., the thermoplastic) may form at least part of the adhesive layer.
In some applications, the use of oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, etc.) or other suitable ceramic small wire (including but not limited to porous small wires) membranes (particularly in combination with the above-discussed polymer coatings) in metal anode-based battery cells in medium sized (from around 10 mAh to around 200 mAh), large (from around 200 mAh to around 10,000 mAh), or extra-large (above around 10,000 mAh) cells may be particularly advantageous. Example of suitable metal anode-based battery cells include, but are not limited to, cells with a Li anode (e.g., as in Li metal batteries), Mg anode (e.g., as in Mg metal batteries), Na anode (e.g., as in Li metal batteries), Zn anode (many battery chemistries comprising Zn or Zn alloy anodes and electrolytes that do not induce dissolution or reduction of small wire membranes), and K anode (e.g., as in K metal batteries), to name a few. Rechargeable metal anode batteries may particularly benefit from this membrane technology. Metal anodes in such rechargeable battery cells typically undergo metal stripping (dissolution into electrolyte as ions) during discharging and re-plating during charging. This process typically leads to the formation of dendrites that may induce internal shorting, which may lead to battery failure (and, in some cases, to various safety risks such as fires, particularly known in Li battery chemistries). The use of solid electrolytes or surface layer protection with a solid ceramic protective layer is often expensive, not always feasible, and does not always protect the cell from dendrite penetration (particularly in situations where the battery may be shocked or exposed to various stresses, as when used in transportation). While it is common in battery research for scientists to utilize so-called half cells with metal anodes (e.g., Li half cells) in order to evaluate the performance of their electrode materials or separators (typically in very small coin cells having a capacity below 10 mAh), the use of metal anodes in commercial cells (particularly in rechargeable cells with liquid aqueous and organic electrolytes) is rare because of their higher cost as well as reliability and safety concerns (larger sized cells would release more energy during dendrite-induced thermal runaway and rapid disassembling, particularly when flammable organic electrolytes are utilized). The use of small wire membranes as described herein (e.g., porous aluminum oxide, magnesium oxide, or zirconium oxide membranes, to provide a few examples) with a relatively high elastic modulus of the membrane material, high porosity, and (potentially importantly) small (e.g., below 2 microns, more preferably below 0.25 microns, on average) and tortuous pores may greatly suppress or eliminate dendrite growth, while providing relatively fast metal (e.g., Li, Mg, Zn, etc.) deposition (plating) and thus high power density. While a detailed understanding of this phenomena is still lacking, it may be related to the associated increase in surface area (and thus surface energy) of a dendrite, which leads to a high energy barrier for dendrite formation, particularly if the individual wires are coated with a suitable polymer layer (e.g., a polymer that is stable in direct contact with a metal anode, exhibits high elastic modulus and exhibits high interfacial energy in such a contact). While metal dendrites may penetrate through many polymer membranes (during metal dendrite growth in a cell with a polymer separator membrane), the metals dendrites are typically too soft to penetrate through individual small oxide wires (e.g., small aluminum oxide wires) even if these are coated with polymer layers. Therefore, metal dendrite formation may require dendrites to grow around the small wires (within small and tortuous pores formed between the small wires in a membrane), which significantly increases the dendrite specific surface area. The small features of the membrane walls, its roughness, its dielectric properties, or its surface properties may also be responsible for the suppression of dendrite growth.
In some applications, the use of oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, etc.) and other suitable ceramic small wires (including but not limited to porous small wires) membranes in battery cells comprising so-called “conversion”-type (including so-called “chemical transformation”-type) electrode materials (particularly in medium sized, from around 10 mAh to around 200 mAh), large (from around 200 mAh to around 10,000 mAh) or extra-large (above around 10,000 mAh) cells) may be particularly advantageous. In contrast to so-called “intercalation” electrodes, conversion materials break and create new chemical bonds during insertion and extraction of ions (e.g., Li ions in the case of Li-ion and Li-metal batteries). Two types of conversion reactions may be distinguished for Li chemistries:
Type A (true conversion): M′Xz+yLi↔M+zLi(y/z)X (Eq. 1)
Type B (chemical transformation): yLi+X′↔LiyX, (Eq. 2)
where M′=cation, M=reduced cation material, and X′=anion.
For the type A cathodes, M′ are typically transition metal ions, such as Fe3+, Fe2+, Ni2+, Cu2+, Co2+, Bi2+, Ag+, Mn3+, etc., while X′ are typically halogen ions (such as F−, Cl−, Br−, and I−) or chalcogenide ions (such as S2−, Se2−, etc.). X′ may also be O2−. Suitable examples of “conversion”-type active electrode materials include, but are not limited to, various metal halides and oxy-halides, various chalcogenides (including, but not limited to, Li2S and S), various metal oxides, various metal hydroxides and oxyhydroxides, their mixtures and alloys, etc. During operation of rechargeable cells, conversion-type electrodes typically exhibit some undesirable interactions with electrolytes. For example, liquid electrolytes may induce dissolution or etching of such electrode materials (the dissolution of lithium polysulfides in lithium-sulfur cells is particularly well-known; the dissolution of metal components of the conversion-type electrodes is another example). In addition to the loss of active material in the electrode (e.g., in a cathode), the components of the dissolved species may travel to an opposite electrode (e.g., to an anode) and induce undesirable damage to its surface (e.g., damage to the anode solid electrolyte interphase) or at least partially block ionic pathways to the anode, leading to an undesirable increase in resistance and reduction of capacity of a cell. The use of the above-described small wire membrane may alleviate such negative effects by adsorbing dissolved species on its surface or by adsorbing harmful electrolyte components (e.g., fluorine and fluorine-containing ions, various halogen and halogen-containing ions, H2O, etc.) on its surface or by other mechanisms. High specific surface area resulting from the small diameter of the small wires may be advantageous for maximizing its positive impact.
In some applications, the use of oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, etc.) and other suitable ceramic small wires (including but not limited to porous small wires) membranes in metal and metal-ion (e.g., in Li and Li-ion) battery cells comprising so-called “alloying” active materials (e.g., Si, Sn, P, Al, Ge, Sb, Bi, etc.) may be advantageous. The inventors have found that the presence of traces of water, hydro-halide (e.g., HF) acid, fluorine ions, and other halide-comprising ions in liquid organic electrolytes may induce undesirable damage to the surface of such materials (particularly strong damage to Si, Sn, and Ge) during cell operation. The use of the above-described small wire membrane may alleviate such negative effects by adsorbing harmful electrolyte components (e.g., fluorine and fluorine-containing ions, various halogen and halogen-containing ions, H2O, etc.) on its surface or by other mechanisms. High specific surface area resulting from the small diameter of the small wires may be advantageous for maximizing its positive impact. In addition, stresses and additional heat originating from the volume changes in “alloying” or “conversion” active materials during cycling may induce damage in polymer separators. The use of more robust ceramic separators instead of traditional polymer separators may thus be advantageous in terms of cell stability and performance.
In some applications, the use of oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, tungsten oxide, tantalum oxide, etc.) and other suitable ceramic small wires (including but not limited to porous small wires) membranes in metal and metal-ion (e.g., in Li and Li-ion) battery cells comprising high voltage cathode materials (e.g., materials with average Li extraction potential in the range from around 3.8 V to around 5.8 V vs. Li/Li+ or cathode materials with a maximum charge potential from around 4.4 V to around 6.2 V vs. Li/Li+). At elevated potentials (typically above around 3.8-4.3 V vs. Li/Li+) such a cathode may exhibit some undesirable interactions with electrolytes, such as, for example, dissolution or etching of metal components (e.g., Mn, Co, Ni, etc.) of such cathodes. Such reactions may be particularly harmful if traces of hydro-halide (e.g., HF) acid, fluorine ions, and other halide-comprising ions are present in liquid electrolyte. The use of the above-described small wire membrane may elevate such negative effects by adsorbing harmful electrolyte components (e.g., fluorine and fluorine-containing ions, various halogen and halogen-containing ions, etc.) on its surface or by other mechanisms. High specific surface area resulting from the small diameter of the small wires may be advantageous for maximizing its positive impact.
In some applications, the use of an ionically permeable (e.g., porous) polymer layer between the oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, etc.) small wires (including but not limited to porous small wires) membranes and at least one of the electrodes may be beneficial for their use as separators in electrochemical cells (e.g., battery cells). Such a polymer layer may be deposited on a membrane or on an electrode or simply sandwiched between the ceramic membrane and at least one of the electrodes. Such a polymer layer may serve different useful functions. In one example, it may reduce stress concentration at the interface between an electrode and the porous oxide separator (because polymers are typically softer and more deformable compared to oxides). This may lead to enhanced reliability during cell assembling when the cell stack is pressurized and to a more reliable cell operation. In another example, such a polymer layer may make the oxide separator easier to handle (e.g., during cell assembling or oxide membrane production). In yet another example, such a polymer layer may enhance adhesion between the oxide membrane and an electrode (e.g., essentially serving as a gluing/adhesive layer). In yet another example, such a polymer layer may enhance electrochemical stability of the oxide membrane. As described above, for example, in the case of Li or Li-ion batteries the use of a polymer layer between an oxide membrane and an anode may prevent reduction of the oxide by Li or other unfavorable interactions at low potentials (e.g., below around 0.1-2 V vs. Li/Li, depending on an oxide and electrolyte chemistry). In this case, not only aluminum, magnesium, and zirconium oxides, but also many other oxides that are typically unstable or significantly less table in contact with Li may be utilized (e.g., silicon oxides, zinc oxides, iron oxides, magnesium oxides, cadmium oxides, copper oxides, chromium oxides, titanium oxide, various combination of oxides, etc.). If a polymer layer is placed between an oxide membrane and a cathode, it may prevent or minimize various undesirable interactions between an oxide and electrolyte or a cathode at higher potentials (e.g., above around 3-4 V vs. Li/Li, depending on the oxide and electrolyte chemistry). In yet another example, such a polymer layer may serve as an additional safety mechanism. For example, it may prevent ion transport (e.g., by closing the pores or by becoming impermeable by the electrolyte solvent, or by other mechanisms) if heated above a critical temperature (or cooled below a critical temperature). The suitable porosity of such a polymer layer may range from around 0 to around 99 vol. % (more preferably, from around 10 to around 90 vol. %). The suitable thickness of such a polymer layer may range from around 5 nm to around 20 microns (more preferably, from around 10 nm to around 10 microns). Thicknesses smaller than around 5 nm may typically reduce the usefulness of such a polymer layer, while thickness larger than around 20 microns undesirably increase the total separator stack thickness and may also induce harmful effects (e.g., polymer shrinking during heating may also damage an oxide membrane). The polymer layer may be a part of a multi-layer (oxide wire-comprising) membrane or be deposited on at least one of the electrodes or be prepared as a stand-alone film. The composition of the polymer layer may depend on a particular functionality that is desirable and a particular chemistry of an electrochemical cell, and may be selected from the list of polymer compositions discussed in conjunction with the polymer composites described herein.
In some applications, the use of oxide (e.g., aluminum oxide, magnesium oxide, zirconium oxide, etc.) or other suitable ceramic small wires (including but not limited to porous small wires) as thermally stable, electrically isolative mechanical reinforcement in electrodes, solid (e.g., polymer, ceramic, glass-ceramic, or composite) electrolyte and separators of various batteries (e.g., Li and Li-ion batteries, Na and Na-ion batteries, etc.) and other electrochemical energy storage devices may also be highly advantageous. Small wires may enhance mechanical strength, fatigue resistance, and overall durability of the electrodes without providing undesirable electrochemically active surface area for decomposition of electrolyte due to the lack of electrical conductivity in aluminum oxide and other oxides, in contrast to, for example, carbon nanotubes or carbon fibers and nanofibers. In addition, the use of oxide (e.g., aluminum oxide, magnesium oxide, etc.) or other suitable ceramic small wires may be advantageous for providing (and maintaining during cycling) fast ionic pathways within electrodes. For example, pores in the porous oxide (e.g., aluminum oxide or magnesium oxide, etc.) small wires may be utilized as pathways for ion access from the top surface to the bulk of the electrode. Since these pores may remain filled with electrolyte but empty from electrolyte decomposition products and since mechanical strength of the oxide may be sufficiently large to withstand volume changes in the electrodes during operation without inducing collapse of the pores, such pores may be successfully utilized for maintaining high ionic conductivity within the electrode during cycling. In some applications, the use of oxide (e.g., aluminum oxide or magnesium oxide) small wires (including but not limited to porous small wires) in combination with carbon nanotubes, carbon fibers (nanofibers), carbon small wires, and other carbon particles may be advantageous. The oxide wires may help to disperse binder and/or carbon particles within the electrode and enhance mechanical stability of the electrodes (particularly important for electrodes comprising high capacity (e.g., greater than about 400 mAh/g in the case of anodes and greater than about 250 mAh/g in the case of cathodes) or high volume changing (e.g., greater than about 10 vol. %) active materials), while conductive carbon may enhance electrical connectivity between individual electrode particles comprising active materials.
There may be a particularly strong synergy between the mechanical properties of small inorganic (e.g., ceramic) wires (fibers) of suitable composition (e.g., electrically insulative) and their use for integrated separators (ionically conductive, electron-insulative, preferably porous layer(s) integrated into the top surface of the electrodes) in various battery cell designs. For example, the mechanical flexibility of such small (e.g., electrically insulative) inorganic (e.g., ceramic) wires (fibers), their ability to conform to the surface of electrode particles and current collectors and withstand electrode dimensional changes without breaking the continuity of the porous network (e.g., effectively reducing or preventing formation of internal electrical shorts, even in case of significant and repeated stresses that may take place during charging and discharging of the battery cells or overheating of the battery cells, etc.), their small cross-sectional dimensions (e.g., which may reduce potential damages to the surface of electrode-cutting knives, reduce wear and tear of battery producing equipment, improve quality and yield and provide other benefits), their ability to form highly porous structures (e.g., effectively increasing ion transport rate and thus safety and power characteristics of the batteries, while minimizing total weight), and many others are highly advantageous for both improved manufacturing of batteries and for obtaining superior battery characteristics. In some designs, the overall thickness of the ionically conductive (e.g., when infiltrated with an electrolyte exhibiting sufficient ionic conductivity), preferably porous (e.g., sufficient porosity to permit infiltration of an electrolyte), electrically insulative layer integrated onto the surface at least one of the battery electrodes (e.g., an anode or a cathode or both) and comprising (at least in part) small inorganic (e.g., ceramic) wires (fibers) may preferably range in thickness from about 0.5 micron to about 50 micron (e.g., in some designs, from about 0.5 to about 2 micron; in other designs, from about 2 to about 5 micron; in other designs, from about 5 to about 10 micron; in other designs, from about 10 to about 20 micron; in yet other designs, from about 20 to about 50 micron). Too small a thickness (e.g., below about 0.5 micron) may not provide sufficient protection against internal shorts (e.g., during cell assembling or cell operation), while too large a thickness (e.g., above about 50 micron) may reduce cell energy density, specific energy and/or ionic resistance to unacceptably low levels (or undesirably increase the cell cost). Thicker layers not only increase the battery weight, battery volume, battery materials cost, but are also typically more expensive to deposit (e.g., by casting or extrusion or spraying or by other suitable means and their combination) and require more energy consumption during fabrication (e.g., due to the need to produce more materials, the need to evaporate more solvents (if solvents are used in the layer fabrication), the need to replace manufacturing parts more frequently due to higher wear and tear, etc.). In most designs, the overall minimum separation between the active material particles on the anode (in some designs, graphite or Si-comprising active material particles, among others) and the cathode (in some designs, lithium cobalt oxide (LCO) or lithium nickel cobalt manganese oxide (NCM) or lithium nickel cobalt aluminum oxide (NCA) and other related active material particles, among others) (e.g., the thickness of one ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of a single electrode or the overall thickness of both ionically conductive, preferably porous, electrically insulative layers integrated onto the surface of the respective electrodes) may preferably range from about 2 micron to about 12 micron (in some designs, from about 4 micron to about 8 micron). In some designs, such a range of separation may provide a favorable combination of robust performance, attractive energy storage characteristics, sufficiently fast and inexpensive manufacturing and sufficiently moderate cell costs.
In some designs, the average porosity of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may range from about 0 vol. % to about 95 vol. % (in some designs, from about 0 to about 2 vol. %; in other designs, from about 2 to about 10 vol. %; in other designs, from about 10 to about 20 vol. %; in other designs, from about 20 to about 30 vol. %; in other designs, from about 30 to about 40 vol. %; in other designs, from about 40 to about 50 vol. %; in other designs, from about 50 to about 60 vol. %; in other designs, from about 60 to about 70 vol. %; in other designs, from about 70 to about 95 vol. %). Lower porosity may enhance some mechanical or thermal properties but requires the layer to possess higher inherent ionic conductivity (e.g., Li+ conductivity) rather than relying on the ionic conductivity of liquid electrolyte infiltrating into the pores of the layer. Higher porosity may reduce the weight and price and additionally attain higher conductivity by reducing tortuosity and infiltrating a larger fraction of liquid electrolyte to provide faster ion transport but may reduce mechanical or thermal properties. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. In general, however (particularly when small, electrically insulative inorganic (e.g., ceramic) wires (fibers) are used) the preferable average porosity may range from about 30 vol. % to about 75 vol. % to attain the favorable combination of properties.
In some designs, the average pore size of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may range from about 10 nm to about 1000 nm (1 micron) (in some designs, from about 10 nm to about 100 nm; in other designs, from about 100 nm to about 200 nm; in other designs, from about 200 nm to about 400 nm; in other designs, from about 400 nm to about 600 nm; in other designs, from about 600 nm to about 1000 nm). Smaller pores may typically enable improved protection against internal shorts but may also lead to lower overall porosity and tortuosity. Larger pores may enable higher porosity, but may reduce thermal, mechanical and electrical separating properties of the layer. Note that the largest through-pore defines the size of the largest particle, which may pass through the porous layer. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. In general, (particularly when small, electrically insulative inorganic wires (fibers) are used) the preferable average pore size (e.g., as measured by mercury porosimetry or electron microscopy or X-ray tomography or other suitable technique) ranging from about 50 nm to about 400 nm was found to offer the favorable combination of properties. In some designs, the volume of the pores with sizes ranging from about 5 nm to about 500 nm (in some designs, from about 5 nm to about 100 nm; in other designs, from about 20 nm to about 200 nm; in yet other designs, from about 30 nm to about 300 nm) may preferably occupy about 50-100% of the total pore volume (in some designs, from about 50 to about 60%; in other designs, from about 60 to about 70%; in other designs, from about 70 to about 80%; in other designs, from about 80 to about 90%; in yet other designs, from about 90 to about 100%). Note that in some designs, the pore size distribution in such a layer may vary broadly and may comprise a broad range of pore sizes (e.g., from about 0.5 nm to about 5 micron) in various ratios. Since there are a nearly infinite number of ways to describe the ratio of pore volumes of pores having different size ranges, most of such descriptions are not provided in this description. Yet, it should be understood, that the ratio of pore volumes of pores with size in the range from the Size-1 to the Size-2 to that of the pore with size in the range from the Size-3 to Size-4 (where the Size-1 and Size-3 are different; and/or where the Size-2 and Size-4 are different; and where Size-1, Size-2, Size-3, and Size-4 range from about 0.5 nm to about 5 micron) may vary in a broad range (from about 1000,000:1 to about 1:1000,000), depending on the selected ranges, the design preferences and processing techniques used.
In some designs, the average density (not counting the weight of the e.g., liquid electrolyte which may infiltrate the separating layer) of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may range from about 0.3 g/cc to about 3 g/cc (in some designs, from about 0.3 g/cc to about 0.7 g/cc; in other designs, from about 0.7 g/cc to about 1 g/cc; in other designs, from about 1 g/cc to about 1.5 g/cc; in other designs, from about 1.5 g/cc to about 2 g/cc; in other designs, from about 2 g/cc to about 2.5 g/cc; in yet other designs, from about 2.5 g/cc to about 3 g/cc). Lower density may be preferable from the specific energy density characteristics and price, while higher density may be preferable from some mechanical perspectives. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. In some designs (particularly when small, electrically insulative inorganic wires (fibers) are used), the density range from about 0.7 g/cc to about 2.2 g/cc was found to offer a favorable combination of properties.
In some designs, the average volume fraction of small, electrically insulative inorganic wires (fibers) within the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may preferably range about 2 vol. % to about 70 vol. % (in some designs, from about 2 vol. % to about 5 vol. %; in other designs, from about 5 vol. % to about 10 vol. %; in other designs, from about 10 vol. % to about 20 vol. %; in other designs, from about 20 vol. % to about 40 vol. %; in other designs, from about 40 vol. % to about 60 vol. %; in other designs, from about 60 vol. % to about 70 vol. %). Smaller volume fraction may reduce weight and enhance ion transport, while higher volume fraction may enhance mechanical, insulative and thermal properties. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. Still, in some designs, volume fractions from about 10 vol. % to about 50 vol. % were found to offer a favorable combination of properties.
In some designs, the average weight fraction of small, electrically insulative inorganic wires (fibers) within the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may preferably range from about 10 wt. % to about 98 wt. % (in some designs, from about 10 wt. % to about 30 wt. %; in other designs, from about 30 wt. % to about 50 wt. %; in other designs, from about 50 wt. % to about 70 wt. %; in other designs, from about 70 wt. % to about 85 wt. %; in yet other designs, from about 85 wt. % to about 98 wt. %). Smaller mass fraction may reduce weight and enhance ion transport, while higher mass fraction may enhance mechanical, insulative and thermal properties. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. Still, in some designs, mass fractions from about 30 wt. % to about 70 wt. % were found to offer a favorable combination of properties.
In some designs, the small, electrically insulative inorganic wires (fibers) may be combined with organic (e.g., polymeric) fibers in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane).
In some designs, various polar solvents may be effectively utilized for the formation of suitable dispersion of small ceramic (e.g., oxide, hydroxide, oxyhydroxide and other suitable ceramic) wires (fibers) (or flakes or other suitable particles) for the formation of integrated separator layer (and/or electrically insulative layer covering part of the surface of the battery current collectors or strips). Suitable examples of such solvents include, but are not limited to, water, various alcohols (ethanol, methanol, acetone, propanol, many others), various glycols, various glycol ethers, various ethers, N-Methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), methyl ethyl ketone (MEK), hexamethylphosphoramide, cyclopentanone, acetonitrile, tetramethylene sulfoxide, e-caprolactone and many others (depending on the polymer use, facilities available, costs and other factors). In some designs, suitable viscosities of the dispersion (colloid) of small ceramic wires (fibers) (or flakes or other suitable particles) may range from around 1 to around 10,000 cp (e.g., depending on the coating method used) and may be adjusted by adjusting weight % solids and/or additives. In some designs, high tensile strength requirements established for traditional standalone separators (which are established to enable the processing of wound rolls of separator membranes) may be substantially reduced or even completely eliminated.
In some designs, the small, electrically insulative inorganic wires (fibers) may be combined with organic (e.g., polymeric) material(s) in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) (and/or be used for the formation of electrically insulative layer covering part of the surface of the battery current collectors or strips). In some designs, the organic material may help disperse the small inorganic wires (fibers), help uniformly distribute the small inorganic wires (fibers), improve adhesion of the small inorganic wires (fibers), improve cohesion of the small inorganic wires (fibers) comprising layer, improve mechanical properties of the small inorganic wires (fibers) comprising layer, improve processability and/or safety when handling the small inorganic wires (fibers) or the wires (fibers) comprising layer, and provide other enhancements and benefits to the small wires (fibers) and/or the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes and to the cells comprising such. In some designs, the polymer composition may be in the form of a polymer binder and/or polymer ionic conductor and/or polymer filler or reinforcement particles and/or polymer dielectric (insulator) and/or a surfactant (dispersant) and/or a coupling agent. In some designs, a plasticizer may be used in conjunction with a polymer to enhance the separator layer properties. In some designs, a suitable fraction of the polymer binder in the final integrated separator layer may range from around 0 to around 50 wt. % (e.g., from around 0.5 wt. % to around 50 wt. %). In some designs, such an integrated separator layer may be deposited using pre-metered coating means (such as a spray coating or a slot-die (or gravure) coating methods) or self-metered coating means (such as dip-coating, roller-coating, knife-edge coating, among others). In some designs, the coating layer may be advantageously deposited using a solvent-free (solvent-less) method. Examples of such suitable coatings may include, but are not limited to, a magnetic assisted impaction coating, supercritical fluid spray coating, electrostatic coating, dry powder coating, photo-curable coating/polymerization, thermo-curable coating/polymerization, electron beam-curable coating/polymerization, to name a few. In some designs, it may be advantageous to heat-treat the integrated separator layer prior to final cell assembling. In some designs, a suitable heat-treatment temperature may range from around 40 to around 200° C., depending on the layer composition, electrode binder used and the battery chemistry.
Suitable examples of the organic (e.g., polymeric) material(s) in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (and/or the surface of the battery current collectors or strips) may include, but are not limited to, one or more of the following: simple thermoplastic polymers, thiol-ene linear polymers, thiol-ene cross-linked polymers, imine polymers, carbonate polymers; homopolymers, block copolymers, block copolymers with space groups; various coupling agents (e.g., silane-based); various polysaccharides and mixture of polysaccharides with other polymers including but not limited to proteins (e.g., arabinoxylans, gum arabic, xantham gum, pectins, chitin and chitin derivatives, cellulose and cellulose derivatives including various modified natural polymers, such as cellulose acetate (CA), cellulose acetate butyrate (CBA), carboxymethylcellulose (CMC), cellulose nitrate (CN), ethyl cellulose (EC), among others cellulose derivatives, alginates including alginic acids and its salts, etc.); acrylonitrile-butadiene-styrene (ABS); allyl resin (Allyl); casein (CS); cresol-formaldehyde (CF); chlorinated polyethylene (CPE); chlorinated polyvinyl chloride (CPVC); various epoxies (polyepoxides) (including fluorinated epoxies); epichlorhydrin copolymers (ECO); ethylene-propylene-diene terpolymer (EPDM); ethylene-propylene copolymer (EPM); ethylene vinyl acetate copolymer (EVA); ethylene vinyl alcohol (E/VAL); various fluoropolymers (such as polytetrafluoroethylene (PTFE), polytetrafluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA/MFA), fluorinated ethylene-propylene (FEP), tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride and their co-polymers (e.g., THV), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), various perfluorinated elastomers (FFPM/FFKM), various fluorocarbons including chlorotrifluoroethylenevinylidene fluoride (FPM/FKM), tetrafluoroethylene-propylene (FEPM), perfluoropolyether (PFPE), perfluorosulfonic acid (PFSA), perfluoropolyoxetane, polyvinylfluoride (PVF), polyvinylidene fluoride (PVDF), various fluorosilicone rubbers (vinyl, methyl, etc.), among others); various ionomer—thermoplastic polymers; isobutene-isoprene copolymer (IIR); various liquid crystal polymers (LCP); melamine formaldehyde (MF); natural rubber (NR); phenol-formaldehyde plastic (PF); polyoxymethylene (POM); polyacrylate (ACM); polyacrylic acid (PAA); polyacrylic amide, polyacrylonitrile (PAN); various polyamides (PA) (including various aromatic polyamides often called aramids or polyaramids); polyaryletherketone (PAEK); polybutadiene (PBD); polybutylene (PB); polybutylene terephthalate (PBTP); polycarbonate (PC); polychloromethyloxirane (epichlorohydrin polymer) (CO); polychloroprene (CR); polydicyclopentadiene (PDCP); polyester (in the form of either thermoplastic or thermoset polycondensate); polyetheretherketone (PEEK); polyetherimide (PEI); polyethersulfone (PES); polyethylene (PE); polyethylenechlorinates (PEC); polyethylene terephthalate (PET); poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS); phenol-formaldehyde (PF); polyimide (PI) (as thermoplastic or thermoset polycondensate); polyisobutylene (PIB); polymethyl methacrylate (PMMA); polymethylpentene (PMP); polyoxymethylene (POM); polyketone (PK); polymethylpentene (PMP); polyethylene oxide (PEO); polyphenylene Oxide (PPO); polyphenylene sulfide (PPS); polyphthalamide (PTA); polypropylene (PP); propylene oxide copolymer (GPO); polystyrene (PS); polysulfone (PSU); polyester urethane (AU); polyether urethane (PUR); polyvinylalcohol (PVA); polyvinylacetate (PVAc); polyvinyl butyral (PVB); polyvinylchloride (PVC); polyvinyl formal (PVF); polyvinylidene chloride (PVDC); styrene-acrylonitrile copolymer (SAN); styrene-butadiene copolymers (SBR and YSBR); various silicones (SI) (such as polydimethylsiloxanes, polymethylhydrosiloxane, hexamethyldisiloxane, SYLGARD®, various silicone elastomers ((phenyl, methyl) (PMQ), (phenyl, vinyl, methyl) (PMVQ), (vinyl, methyl) (VMQ), etc.); polyisoprene; urea-formaldehyde (UF); their various co-polymers and polymer mixtures (co-polymers and polymer mixtures comprising one or more of the corresponding monomer, oligomer, and polymer species), among others. In some designs, some of such polymers may be at least partially fluorinated. In some designs, the polymers and co-polymers may comprise at least one of the following monomer constituents: acrylates and modified acrylates (methylacrylate, methylmethacrylate, etc.), diallylphthalates, dianhydrides, amines, alcohols, anhydrides, epoxies, dipodals, imides (polyimides), furans, melamines, parylenes, phenol-formaldehydes, polyesters, urea-formaldehydes, urethanes, acetals, amides, butylene terephthalates, carbonates, ether ketones, ethylenes, phenylene sulfides, propylenes, styrene, sulfones, vinyl, vinyl butyrals, vinyl chlorides, butylenes, chlorobutyls, fluorobutyls, bromobutyls, epichlorohydrins, fluorocarbons, isoprenes, neoprenes, nitriles, sulfides, silicones, among others.
In some designs, the organic (e.g., polymeric) material(s) in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (and/or the surface of the battery current collectors or strips) may exhibit ionic (e.g., Li-ion) conductivity. In some designs, such polymeric material(s) may comprise Li ions. In some designs, such polymeric material(s) may comprise Li salts. In some designs, Li-ion containing homopolymers, block copolymers and/or block copolymers with some spacer groups that allow further tuning of thermal and mechanical properties may be synthesized.
In some designs, a portion of the polymer component of the integrated separator layer (and/or the layer covering a portion of the surface of the battery current collectors or strips) may be produced by thermal polymerization (e.g., in the presence of a small amount of one or more radical initiators (e.g., azobisisobutyronitrile (AIBN) and/or others)) in accordance with embodiments of the disclosure. In some designs, photochemical polymerization may be advantageously utilized. The photochemical polymerization may be applicable to monomers as well as polymers (e.g., the chemistry is typically compatible with both approaches). In some designs, thiol-end polymerization may afford ionically conductive polymers by reaction between alkene monomers and thiols. In some designs, an advantage of using such polymers is that the thiol groups are mildly coordinating, which may be beneficial for Li-ion transport. Both thermal and photochemical means may allow polymerization of the monomers for some applications. In some designs, the stimulus for such types of polymerizations may comprise one or more of the following: heat, light, electron beam.
In some designs, it may be advantageous for the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes to comprise one, two or more salts.
In some designs, the small electrically insulative inorganic wires (fibers) may be combined with other electrically insulative inorganic particles of other shapes (e.g., platelet or planar shape, irregular shape, spherical or spheroidal shape, cubic or cuboid shape, dendritic shape, their various combinations, etc.) in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) (and/or in the design of the electrically insulative layer covering a portion of the surface of the battery current collectors or strips). In some designs, the compositions of various inorganic particles present may be similar. In other designs, the composition of various inorganic particles may be different. In some designs, the weight fraction of inorganic wires (fibers) to inorganic particles exhibiting different shapes may range from about 99:1 to about 1:99 (in some designs, from about 99:1 to about 80:20; in other designs, from about 80:20 to about 50:50; in other designs, from about 50:50 to about 20:80; in yet other designs, from about 20:80 to about 1:99).
In some designs, the individual small, electrically insulative inorganic wires (fibers) utilized in the design of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) (and/or in the design of the electrically insulative layer covering a portion of the surface of the battery current collectors or strips) may be at least partially bundled. In some designs, the average small wire (fiber) bundle may comprise from about 2 to about 1000 individual small wires (fibers) (in some designs, from about 2 to about 10; in other designs, from about 10 to about 30; in other designs, from about 30 to about 100; in yet other designs, from about 100 to about 1000). In some designs, the average bundle diameter may range from about 60 nm to about 600 nm (in some designs, from about 60 to about 100 nm; in other designs, from about 100 nm to about 200 nm; in other designs, from about 200 nm to about 400 nm; in yet other designs, from about 400 nm to about 600 nm). In some designs, the average length of the small wire (fiber) bundle may range from about 10 micron to about 10 mm (in some designs, from about 10 micron to about 50 micron; in other designs, from about 50 micron to about 200 micron; in other designs, from about 200 micron to about 1 mm; in other designs, from about 1 mm to about 10 mm). In some designs, the use of bundles in the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes may favorably enhance the layer's mechanical or ion permeation properties. The average bundle dimensions may be measured using image analysis of the optical or electron microscopy images or by using other suitable techniques.
In some designs, the average tortuosity of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may range from about 1.01 to about 40 (in some designs, from about 1.01 to about 1.10; in other designs, from about 1.10 to about 1.25; in other designs, from about 1.25 to about 1.5; in other designs, from about 1.5 to about 2; in other designs, from about 2 to about 5; in other designs, from about 5 to about 10; in other designs, from about 10 to about 20; in yet other designs, from about 20 to about 40). Lower tortuosity enhances ion transport through the membrane, while higher tortuosity reduces the probability of internal shorts. As such, the proper values may need to be optimized for a particular cell chemistry, cell design and cell applications. In some designs (particularly when small, electrically insulative inorganic wires (fibers) are used), the tortuosity values from about 1.1 to about 6 were found to offer a good combination of properties.
In some designs, the thermal stability of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may be sufficiently capable of maintaining from about 80% to about 100% of the initial ionic conductivity upon heating to 80° C. for 2 hours in air (in some designs, upon heating to 90° C. for 2 hours in air; in other designs, upon heating to 100° C. for 2 hours in air; in other designs, upon heating to 110° C. for 2 hours in air; in other designs, upon heating to 120° C. for 2 hours in air; in other designs, upon heating to 130° C. for 2 hours in air; in other designs, upon heating to 140° C. for 2 hours in air; in other designs, upon heating to 150° C. for 2 hours in air; in other designs, upon heating to 160° C. for 2 hours in air; in other designs, upon heating to 170° C. for 2 hours in air; in other designs, upon heating to 180° C. for 2 hours in air; in other designs, upon heating to 190° C. for 2 hours in air; in yet other designs, upon heating to 200° C. for 2 hours in air). In some designs, the thermal stability of the ionically conductive, preferably porous, electrically insulative layer integrated onto the surface of at least one of the battery electrodes (e.g., to serve as a replacement for the separator membrane) may be sufficiently capable of exhibiting linear shrinkage of less than about 5% upon heating to 80° C. for 2 hours in air (in some designs, upon heating to 90° C. for 2 hours in air; in other designs, upon heating to 100° C. for 2 hours in air; in other designs, upon heating to 110° C. for 2 hours in air; in other designs, upon heating to 120° C. for 2 hours in air; in other designs, upon heating to 130° C. for 2 hours in air; in other designs, upon heating to 140° C. for 2 hours in air; in other designs, upon heating to 150° C. for 2 hours in air; in other designs, upon heating to 160° C. for 2 hours in air; in other designs, upon heating to 170° C. for 2 hours in air; in other designs, upon heating to 180° C. for 2 hours in air; in other designs, upon heating to 190° C. for 2 hours in air; in yet other designs, upon heating to 200° C. for 2 hours in air).
In some designs, it may be advantageous for the composition, the chemical, physical, mechanical and/or electrical properties of such an ionically conductive (and electron insulative) layer(s) between the anode and cathode to change (e.g., on average) along the line perpendicular to electrodes. For example, in some designs, the layer may favorably exhibit a lower density on the surface (e.g., exposed surface) and higher density at the interface with the electrode (e.g., to enhance adhesion). In other designs, the opposite may be more advantageous—e.g., having a higher porosity near the interface with the (integrating) electrode to accommodate stresses during cycling and higher density near the surface to establish superior overall robustness. In another example, in some designs, the layer may exhibit different composition near the anode and near the cathode in the assembled cell (e.g., to attain superior electrochemical or mechanical stability or to improve adhesion between components during cell assembling, etc.). In some designs, the layer may comprise both an organic component (e.g., a polymer binder or an adhesion promoter or a dispensing agent, etc.) and a ceramic component (e.g., small oxide, oxyhydroxide, hydroxide or other suitable ceramic composition) and the layer may comprise a higher fraction of an organic component (e.g., a polymer, etc.) near the anode surface (e.g., to improve adhesion or to improve electrochemical stability) or a higher fraction of the inorganic component (e.g., suitable ceramic small wires or other suitable ceramic particles) near the cathode, or a different composition of the organic component near the anode and the cathode, etc.
The use of the integrated separator layer(s) for manufacturing of stacked cells having irregular (e.g., not rectangular) shape may be particularly attractive. Irregularly shaped batteries may provide a significant boost to the performance of various electronic devices (e.g., smart watches, smart glasses, smart phones, medical devices, military devices, communication devices, virtual reality sets, augmented reality devices, etc.) because the space available for the battery is typically irregular (rather than rectangular or cylindrical or coin-shaped). As such, in order to maximize the energy storage capability, a battery (or batteries) to power such a device should preferably conform to the available space and thus reduce ineffectively used volume (or maximize the use of the “real estate” or space available inside the electronic devices). Unfortunately, formation of irregularly shaped batteries is very challenging. One approach is to assemble such batteries by stacking irregularly shaped electrodes (e.g., of optimized dimensions and shape) and using a separator in between the anode and cathode. While cutting and stacking individual irregular shaped electrodes is relatively easy, the handling and stacking a highly flexible irregularly shaped standalone separator is not an easy task, particularly if a high precision stacking is needed to minimize the waste volume. In contrast, the use of integrated separator layer(s) within at least one of the electrodes (and preferably avoiding the use of standalone separator(s)) may dramatically improve manufacturing of irregularly shaped cells and additionally enhance the energy storage characteristics of irregularly shaped battery cells (e.g., by minimizing ineffectively used volume at the edges of the cells, by enhancing the rate performance and cell quality, etc.). Furthermore, in addition to the fabrication of irregular shaped planar cells with uniform thickness, the electrodes with integrated separator layer(s) (e.g., of suitable or preferable composition and properties) may be assembled into various irregular three-dimensional (3D) batteries where thickness of the stacked cell changes to conform to the available space even more. Such an innovative (e.g., irregularly shaped, stacked) cell design may be further enhanced by using suitable (e.g., electrically insulative) ceramic small wires within the integrated separator layer(s) of suitable or preferable composition and properties.
In some designs, oxide, oxyhydroxide, hydroxide and other suitable (e.g., electrically insulative) ceramic small wires (such as nanowires, nanofibers, core-shell nanowires, core-shell nanofibers, porous nanowires, porous nanofibers, nanotubes, nanobelts, other elongated particles of other morphologies and their various combinations, etc.) may be particularly effective when serving to be a part of a separator layer(s) directly deposited on one (e.g., an anode or a cathode) or both battery electrodes (anode and cathodes). Illustrative examples of suitable batteries include, but are not limited to, Li-ion, Na-ion, and others. In some designs, such small wires may advantageously comprise oxygen (O) (e.g., in the form of an oxide, oxy-fluoride, oxyhydroxide, hydroxide, etc.). In some designs, such small wires may advantageously comprise hydrogen (H) (e.g., in the form of oxyhydroxide, hydroxide, etc.). In some designs, such small wires may advantageously comprise Al (e.g., in the pure form—as Al2O3, AlOOH, Al(OH)3, and their various combinations, etc.) or Mg (e.g., MgO, MgOOH, MgOxHy, where x>0; y>0) or both. In some designs, such small wires (fibers) may comprise “doping” (e.g., from about 0.0001 at. % to about 5 at. %) elements other than Mg, Al, O and H—such as, for example, Li, Na, Ca, B, F, Cl, Br, I, S, Se, N, Ba, P, As, Si, Fe, Zn, Zr, Ce, La, Y, B, etc.). In other designs, such small wires (fibers) may comprise a higher fraction (e.g., from about 5 at. % to about 50 at. %) of elements other than Mg, Al, O and H—such as, for example, Li, Na, Ca, B, F, Cl, Br, I, S, Se, N, Ba, P, As, Si, Fe, Zn, Zr, Ce, La, Y, B, etc.
In some designs, it may be advantageous to produce such small oxide, oxyhydroxide, hydroxide and other suitable (e.g., electrically insulative) ceramic small wires (such as nanowires, nanofibers, core-shell nanowires, core-shell nanofibers, porous nanowires, porous nanofibers, nanotubes, nanobelts, other elongated particles of other morphologies and their various combinations, etc.) from suitable small metal alkoxide (e.g., methoxide, ethoxide, propoxide (e.g., iso-propoxide or n-propoxide), butoxide, other alkoxides or their various combinations) wires (such as nanowires, nanofibers, core-shell nanowires, core-shell nanofibers, porous nanowires, porous nanofibers, nanotubes, nanobelts, other elongated particles of other morphologies and their various combinations, etc.), where metals of the suitable metal alkoxides may comprise one, two or more of the following: Al, Mg, Ca, Ba, Si, Fe, Zn, Zr, Ce, La or their various mixtures, and where alcohols of the metal alkoxides may comprise one, two or more of the following: methanol, ethanol, isopropanol, n-propanol, n-butyl alcohol, sec-butyl alcohol or their various combinations.
In some designs, it may be advantageous to produce such suitable small metal alkoxide (e.g., methoxide, ethoxide, propoxide (e.g., iso-propoxide or n-propoxide), butoxide, other suitable alkoxides or their various combinations) wires (such as nanowires, nanofibers, core-shell nanowires, core-shell nanofibers, porous nanowires, porous nanofibers, nanotubes, nanobelts, other elongated particles of other morphologies and their various combinations, etc.) from the reaction of corresponding alcohols with corresponding metals or metal alloys (e.g., metals or metal alloys comprising one, two or more of the following metals: Al, Mg, Na, Li, Ba, Ce, La, Zr, Zn, and others and their various combinations, etc.). Metals or metal alloys comprising about 20-100% of Al and/or about 20-100 at. % of Mg may be particularly attractive (e.g., Al, Mg, Al—Si, Al—Mg, Al—Mg—Si, Al—Li, Mg—Li, Mg—Al—Li, Al—Li—Zn, Mg—Li—Zn, Mg—Al—Li—Si, Mg—Al—Li—Zn alloys, their various combinations, among others).
In addition to a significant freedom and simplicity to produce and utilize highly space-efficient stacked battery cells that have a planar geometry and relatively uniform thickness, the use of electrode(s) with integrated separator layer(s) may facilitate simpler fabrication and effective use of stacked cells having variable thickness to conform to the ideal (available) space even more.
High-precision, high-speed assembling of stacked cells with integrated separators may be highly beneficial for industrial applications. For some applications, high precision of positioning of anodes and cathodes relative to each other may be particularly important. In some designs, the area occupied by the anode is typically significantly larger than the area occupied by the cathode to account for possible misalignments. For example, it is not uncommon for the anode to be about 1-5 mm longer or wider than a corresponding cathode in stacked cell designs. This may lead to a significant reduction in volumetric capacity and volumetric energy density (as well as specific capacity and specific energy density) of the cells (e.g., sometimes by about 1-2%; sometimes by about 2-5%, sometimes by about 5-10% or even more), especially for small or medium size stacked cells (e.g., stacked cells with top view areas in the range from about 0.25 cm2 to about 200 cm2), wound coin cells (e.g., with height in the range from about 2 mm to about 20 mm), wound cylindrical cells (e.g., with height in the range from about 3 mm to about 150 mm), wound pouch or wound prismatic cells (e.g., with length or width—in the range from about 3 mm to about 200 mm). One or more aspects of the present disclosure are directed to fabrication of small or medium size stacked, wound coin, wound cylindrical and wound prismatic cells with higher volumetric capacity, volumetric energy density, specific capacity and specific energy density by utilizing electrode(s) with integrated separator layer(s). In some designs, the average shortest linear dimension of the anode (e.g., width) may be only slightly larger (e.g., by about 3 mm or less; or by about 2 mm or less; or by about 1.5 mm or less; or by about 1 mm or less; or by about 0.5 mm or less; or by about 0.25 mm or less; or by about 0.15 mm or less; or by about 0.1 mm or less; or by about 0.05 mm or less) than the average shortest linear dimension of the cathode (e.g., width) in the disclosed cell designs.
Below, various cell configurations are described. In some cases, alternative cell configurations may include the same or similar components, despite their different configurations. In such cases, the same reference numbers may be used to characterize such components in a manner that pertains to both configurations, unless stated otherwise.
In some designs, it may be advantageous or desirable to have holes propagating through the electrodes (e.g., stacked electrodes). In some implementations, holes are bored in electrodes (e.g., current collector with electrode(s) deposited thereon) or electrodes with integrated separator(s) by a cutting process. Such holes, for example, may be used to help position the electrodes (e.g., within a stack) or to attain other functionality. One or more embodiments of the disclosure are directed to simplified fabrication of such cells (e.g., by using electrodes with integrated separator layer(s)).
In some designs, it may be advantageous to utilize adhesive (e.g., polymer-based) layer(s) covering at least a position of the anodes or cathodes (or both) comprising integrated separator layer(s) and/or covering at least a portion of the anode or cathode current collector(s) (or current collector strips or tabs). In some designs, such adhesive layer(s) may help fix the position of the anode and cathode relative to each other (e.g., under the application of a heat and/or pressure and/or under the application of another actuation action), which may be very important for maintaining tight cathode-anode alignment and reducing or minimizing the inefficiently used volume in a battery cell. In some designs, an integrated separator layer(s) may already comprise such an adhesive in its composition.
In some designs, it may be advantageous for cathode current collector foils to be of the same size as the anode current collector foils because it would greatly simplify the cathode-anode alignment. However, in some designs, it may still be important for the anode active material coating area to be slightly larger than the cathode active material coating area to reduce or minimize the probability of Li plating or other issues. To accomplish this, in some designs, it may be advantageous to coat one or more areas of a major surface (e.g., facing towards the separator) of a cathode current collector near its edge(s) with an inactive material layer (that is, to replace the active cathode material near the edge with inactive material). Note that in some designs, it may also be possible to fill all the cathode pores in the area of the cathode near the edge with a non-conductive solid material (e.g., a polymer), effectively reducing or shutting down the electrochemical activity of such a cathode material near the edge and making the edge inactive. In some designs, such an inactive material layer may be porous (e.g., store electrolyte and be relatively light-weight; e.g., exhibit density in the range from about 0.3 cc/g to about 2.3 cc/g). In some designs, such an inactive material layer may comprise oxide, hydroxide, oxyhydroxide or other salt or ceramic particles (e.g., Al and/or Mg containing) that do not store a significant amount of Li (or exhibit no or minimal electrochemical activity during repeated battery charging). In some designs, the presence of oxide, hydroxide, oxyhydroxide or other salt or ceramic particles may help maintain good mechanical and dielectric properties at the edge (e.g., reduce or prevent formation of a short circuit). In some designs, such an inactive layer may comprise small (electrically insulative) wires (e.g., with shape, aspect ratio, other properties and composition described in this disclosure). In some designs, such an inactive layer may comprise (electrically insulative) polymer (e.g., with composition and properties described in this disclosure, among others). In some designs, a portion of the current collector strips may be advantageously coated with an insulative material layer (e.g., to prevent formation of shorts when an anode current collector foil strip touches the cathode current collector foil or when a cathode current collector foil strip touches the anode current collector foil, etc.). In some designs, such an insulative material layer may comprise a polymer (e.g., with composition and properties described in this disclosure, among others). In some design, such an insulative material layer may comprise oxide, hydroxide, oxyhydroxide or other salt or ceramic particles (e.g., Al and/or Mg containing). In some designs, such an inactive layer may comprise small (electrically insulative) wires (e.g., with shape, aspect ratio, other properties and composition described in this disclosure). In some designs, the small wires within such an insulative layer may provide high flexibility, good mechanical, electrical and thermal properties and good adhesion to the foils.
As previously discussed, in some designs, it may be advantageous to attain a high degree of cathode-anode alignment.
In some implementations, a stack includes an integrated anode-separator component (e.g., anode separator 2808 integrated with anode 2802) and an integrated cathode-separator component (e.g., cathode separator 2809 integrated with cathode 2801). These components may be disposed adjacent each other, such that the components are aligned with each other and the separators are adjacent to each other (e.g., facing each other and laminated to each other). The characteristics of the separators may be optimized. For example, the small wires in the separator of the integrated anode-separator component may be preferentially aligned in a first direction, and the small wires in the separator of the integrated cathode-separator component may be preferentially oriented in a second direction different from the first direction. Accordingly, when the separators are laminated to each other, a “composite” stack of small wires is created in which the wires are preferentially aligned in different directions. Such an implementation may be more effective in precluding the lithium dendrite formation and other electrical shorts between the anode and the cathode. In addition, characteristics such as the thickness, density, porosity, and material composition may be tuned such that the respective characteristics for the anode separator and the cathode separator are different. Other physical or chemical characteristics may be tuned such that the respective characteristics for the anode separator and the cathode separator are different.
Note that in some designs, the integrated separator layer on the anode (2808) and/or the integrated separator layer (2809) on the cathode (2801) and/or inactive material layer (2807) on the cathode current collector (2803) may comprise one or more of the following: (i) polymer particles (e.g., spherical or elliptical or rectangular or cubic or planar/flake-shaped or irregular or fiber-shaped including small fibers/nanofibers); (ii) wire-shaped (e.g., oxide, hydroxide, oxyhydroxide, other suitable, electrically insulative) salt or ceramic particles; (iii) non-wire-shaped (e.g., spherical or elliptical or rectangular or cubic or planar or irregular, etc.) particles (e.g., oxide, hydroxide, oxyhydroxide, other suitable, electrically insulative ceramic particles); (iv) polymer binder or polymer matrix; and (v) adhesive.
In some cell designs, individual (i.e., non-integrated) separator membranes may be used in combination with the integrated separator layer on one or both of the electrodes.
In some cell designs, it may be advantageous to use integrated electrodes in wound (e.g., cylindrical or pouch or coin or prismatic) cells.
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In some designs, certain designs of the battery cases (e.g., design for a case for a stacked pouch cell or a case for a stacked coin-shaped cell or a case for a stacked prismatic cell, or a case for a stacked cylindrical cell or a case for a rolled cylindrical cell or a case for a rolled prismatic cell, etc.) may be advantageously used for cells comprising electrode(s) with integrated separator layers. For example, in some designs it may be advantageous for the battery cases to comprise two main parts (e.g., a top portion of the case and a bottom portion of the case), where these parts are sealed (e.g., after a cell assembling). In some designs, the two parts of the case remain electrically insulated from each other. In some designs, at least one part of the case (e.g., a bottom portion or a top portion) may be electrically conductive. In some designs, both parts of the case (e.g., both bottom and top portion) may be electrically conductive (e.g., metallic). In some designs, good thermal and mechanical properties of the metal (e.g., relatively high stiffness or elastic modulus, high thermal stability, etc.) may be particularly attractive in some designs (e.g., to reduce or prevent case shape change, etc.). In some designs, the inner area of at least one part of the case (e.g., a bottom portion or a top portion) may be (at least partially) coated with electrically insulative material (e.g., a polymer or a ceramic or a polymer-ceramic composite). In some designs, both parts of the case (e.g., both bottom and top portion) may be (at least partially) coated with electrically insulative material (e.g., a polymer or a ceramic or a polymer-ceramic composite). In some designs, at least one part of the case may be electrically insulative (e.g., a bottom portion or a top portion) (e.g., comprise an outer plastic layer or both an outer and an inner plastic layer as in a typical pouch material comprised of a multi-layer laminate sheet or be made of or comprise a plastic or a polymer composite or a ceramic material, etc.). In some designs, both parts of the case may be electrically insulative (e.g., both a bottom portion and a top portion) (e.g., comprise an outer plastic layer as in a typical pouch material or be made of or comprise a plastic or polymer composite or a ceramic material, etc.). In some designs, the sealed area between the parts may be oriented approximately perpendicular to the side of the battery cell case (e.g., be oriented parallel to the top and bottom surface of a coin cell or a top and bottom of a pouch cell or top and bottom of a cylindrical cell (that is perpendicular to the cylindrical cell orientation) or a prismatic cell, etc.). In some designs, anode current collectors may be electrically connected to the electrically conductive part of the case (e.g., to the electrically conductive top part of the case or to the electrically conductive bottom part of the case). In some designs, cathode current collectors may be electrically connected to the electrically conductive part of the case (e.g., to the electrically conductive top part of the case or to the electrically conductive bottom part of the case). In some designs, the anode and cathode current collectors may be electrically connected to the opposite parts of the case. In some designs, anode current collectors may be electrically insulated from one or both parts of the case. In case when anode current collectors are electrically insulated from both parts of the case, anode current collector strip(s) may be electrically connected to an anode current collector tab and the anode collector tab may connect with the outer terminal through the seal. In some designs, cathode current collectors may be electrically insulated from one or both parts of the case. In case when cathode current collectors are electrically insulated from both parts of the case, cathode current collector strip(s) may be electrically connected to a cathode current collector tab and the cathode collector tab may connect with the outer terminal through the seal. In some designs, the shape of the top view of the case may approximately follow the shape of the electrodes with integrated separators. For example, if the electrodes exhibit an L-shape, the top view of the case may also be an L-shaped.
Commercial rolled cylindrical cells or rolled prismatic cells typically have anode current collector foils connected to the opposite sides of the cell (e.g., anode current collector foils being connected to the bottom of the cylindrical cell and cathode current collector foils being connected to the top of the cylindrical cell or vice versa). Such a design may suffer from the need to have numerous strips to be welded to a tab to minimize electrical resistance and enable higher-power cells with low electrical and thermal resistance. More recently, so-called “tabless” designs (e.g., 4680 cells) were introduced in wound cylindrical cells where current collectors on each side are cut and bent to connect to the case. However, such a design is not compatible with stacked cylindrical cells (or stacked prismatic cells where the stacking is perpendicular to the prismatic cell orientation). Yet, stacked cell designs may be attractive as these may, for example, reduce the resistances even further. Stack cell designs may also facilitate increases to electrode thickness or may provide other mechanical or electrical benefits. In some designs, stack cell designs may facilitate fast changes to cell chemistry and areal capacity loadings on the same production equipment. Stack cell designs may also enhance safety. Stack cell designs may also offer improved precision and (in some designs) cell manufacturing speed, especially for large diameter cylindrical cells. One or more embodiments of the disclosure are directed to (in some designs, effectively tabless) stack cell design solution, which may particularly benefit from having integrated separators within electrode(s). In some designs, the current collector(s) of an anode in a stacked cell may form electrical contact(s) with one (first) part of an electrically conductive (e.g., metal) case (e.g., a bottom part) (e.g., along some or all area of the circumference) (e.g., in some designs, by a physical touch) while being electrically insulated from anode (second) part of the electrically conductive (e.g., metal) case (e.g., a top part); and while the current collectors of a cathode in a stacked cell may form electrical contact(s) with another (second) part of a metal case (e.g., a top part) (e.g., through the inner electrically conductive, for example, metallic rod (or needle or tube or plate, etc.) which is being electrically connected to this second case part (e.g., a top part)) while remaining electrically insulated from the first part of the metal case (e.g., a bottom part). In other designs, both parts (e.g., the top and bottom part) of the case are electrically connected to each other and to the current collectors of one of the electrode (e.g., anode), while the current collectors of the other electrode (e.g., cathode) are electrically connected to an electrically conductive (e.g., metallic) rod (or needle or tube or plate, etc.) (which is electrically insulated from both parts of the case) and electrically insulated from both parts of the case. An electric contact between the conductive rod (or needle or tube or plate, etc.) and one of the electrodes (e.g., cathode) may be established by having the (e.g., cathode) current collectors touch the rod (or needle or tube or plate, etc.), while ensuring that such (e.g., cathode) current collectors remain electrically insulated from the (e.g., anode) current collectors (and, e.g., anode) (e.g., by having a sufficient space and/or an additional insulative material in between; note that such an insulative material may comprise small electrically insulative wires, in some designs). In some designs, both the anodes and the cathodes of the stacked cell may have aligned holes, through which the electrically conductive metal rod (or needle or plate or sheet or tube, etc.) is penetrating, but only one polarity (e.g., only the cathode) current collectors electrically connect (e.g., touch) with such a rod (or a needle or a tube or a plate, etc.), while the other (e.g., anode) current collectors remain electrically insulated from the rod (or a needle or a tube or a plate, etc.). In some designs, the rod (or a needle or a tube or a plate, etc.) may propagate through the center of the cell; in other designs—be near or at the edge of the cell; in yet other designs—anywhere other than the edge or the center. In some designs, the top and bottom part of the case may be crimped together. In some designs, the top and bottom part of the case may be sealed by other means.
In some designs, the stacked cell designs may offer enhanced safety. For example, (i) the conductive current collectors and/or (ii) the conductive rod and/or (iii) the conductive connection between the conductive rod and a terminal or a top of the case and/or (iv) the conductive surface layer on the interior of the case (e.g., bottom part of the case, etc.) and/or (v) other electrical connections between the individually stacked electrodes or the whole electrode stack and the corresponding negative or positive terminals may become disrupted (e.g., by being pulverized or by having rapidly lost electrical connectivity) upon heating above a predetermined temperature (a temperature within, for example, about 200- about 450° C. or, in other designs, slightly lower or, in other designs, higher). Such a disruption, for example, may be achieved by using a polymer-metal composite or polymer-metal laminar or other designs that rely on the use of a polymer or a phase transition, where the thermal expansion or melting of the polymer or a phase transition induces rapid disruption of the electrical conductivity paths. For example, instead of using metal foil current collectors, in some designs one may use metal film-coated polymer sheets, where melting the polymer induces electrical disconnects within the current collectors. In some designs, for example, the inner area of the case may be coated with a polymer film and further coated with a metal film, where the melting of the polymer film induces electrical disconnects within the film conductivity. In some designs, for example, the conductive rod may be composed of a polymer rod coated with a metal film, where melting of the polymer core induces electrical disconnects within the metal film.
In some applications, the use of the various small wire comprising composites (particularly those described herein) in the form of fibers, nanofibers, threads, ropes, and fabrics may be advantageous. Such fibers may be produced, for example, by spinning, melt-spinning or electrospinning, extrusion, or other suitable methods of composite fiber fabrications.
In some applications, the use of small oxide (e.g., aluminum oxide, magnesium oxide, or other oxide) and ceramic wires and oxide (e.g., aluminum oxide or other oxide) and ceramic membranes, particularly those produced according to the methods herein, in small wire/ceramic composites is advantageous.
In some applications, the use of metal (such as aluminum, magnesium, titanium, etc.) oxyhydroxides, hydroxides, and oxides in the form of small wires (particularly those described herein, including porous small wires) or in the form of porous membranes as fillers in asphalts and concretes (including asphalt concretes) may be advantageous in terms of increasing strength, toughness, fatigue resistance, improving dynamic modulus, moisture susceptibility, creep compliance, rutting resistance and freeze-thaw resistance, reducing manufacturing time and energy consumption, and providing other benefits compared to the use of regular (small wire-free) asphalt, brick (and other masonry structures), or concrete compositions. Furthermore, the application of such small wires may provide better durability and properties when compared to more traditional fiber-reinforced concretes with typical polypropylene fibers, polyester fibers, asbestos fibers, cellulose fibers, carbon fibers, glass fibers, and nylon fibers. In some applications, it may be advantageous to use metal (such as aluminum, magnesium, titanium, and other metal) oxyhydroxides, hydroxides, and oxides in the form of small wires (particularly those described herein, including porous small wires) or in the form of porous membranes in combination with polymer (e.g., polypropylene, polyester, cellulose, nylon), mineral (e.g., asbestos), carbon, or glass fibers. The suitable mass fraction of small wires in asphalts and concretes may range from around 0.001 wt. % to around 40 wt. %. In some applications, it may be advantageous to use small wire/polymer composites or porous membranes/polymer composites (such as aluminum) oxide/polymer composites, particularly those described herein, including porous small wires) (for example, in the form of fibers, timber structures, rods, etc.) as reinforcements in structural applications (such as concretes, asphalts, buildings, etc.).
In some applications, the use of aluminum oxide (and other oxide) and other ceramic (e.g., carbide) small wires (particularly those described herein) as fillers in various metals and metallic alloys may be highly advantageous in terms of increasing hardness, strength (and specific strength), fatigue resistance, elastic modulus, wear resistance, scratch resistance, thermal stability, creep resistance, fracture toughness, manufacturability in thin foil states, and other important properties of metals and metal alloys. The applications of such small wire/metal composites may include cases for a broad range of devices, sporting goods, various medical tools, various cutting tools (including cutting blades), various components of electronic devices, various conductive small wires, jewelry, various components of transportation devices (including but not limited to land, sea, and air and space transportation), various constructions and load-bearing applications, various energy storage devices, various protection devices, and various engines and turbines, to name a few. Examples of suitable lightweight metals and metal alloys include, but are not limited to, aluminum and various aluminum alloys, magnesium and various magnesium alloys, titanium and various titanium alloys, and beryllium and various beryllium alloys. Examples of suitable structural (including piping, plumbing, gearing, valves, engines, turbines, etc.) metals and metal alloys include, but are not limited to, iron and iron alloys (e.g., various steels, including carbon steel and stainless steel, among others), copper and copper alloys, aluminum and aluminum alloys, magnesium and various magnesium alloys, zinc and zinc alloys (e.g., for soldering or surface coatings), tin and tin alloys (e.g., for soldering), lead and lead alloys (e.g., for soldering), vanadium and vanadium alloys (mostly as components of other alloys), chromium and chromium alloys (mostly as components of other alloys), tungsten and tungsten alloys (e.g., in armor, in gas turbines, etc.), and nickel and nickel alloys. Examples of suitable metal and metal alloys for use in current collectors and conductive small wires and other applications requiring high electrical conductivity include, but are not limited to, gold and gold alloys, silver and silver alloys, aluminum and aluminum alloys, copper and copper alloys, platinum and platinum alloys, molybdenum and molybdenum alloys, zinc and zinc alloys, lithium and lithium alloys, tungsten and tungsten alloys, brass, nickel and nickel alloys, titanium and titanium alloys, and palladium and palladium alloys, to name a few. Examples of suitable metal and metal alloys for use in jewelry and jewelry-related (e.g., watches and portable and wearable electronic devices) applications include, but are not limited to, gold and gold alloys (e.g., 10 karat, 12 karat, 14 karat, 18 karat, 22 karat, 24 karat, etc., various types of white gold and rose gold alloys, etc.), platinum and platinum alloys, silver and silver alloys, various nickel alloys (e.g., so-called “nickel-silver,” which comprises Ni, Cu, and Zn), palladium and palladium alloys, rhodium and rhodium alloys, tungsten and tungsten alloys, titanium and titanium alloys, various stainless steels, and copper and copper alloys (including brass), to name a few. Examples of suitable high temperature corrosion resistant alloys include, but are not limited to, various nickel-based super-alloys, molybdenum alloys, tungsten and tungsten alloys, stainless steels, and tantalum alloys and titanium alloys, to name a few examples. Examples of other suitable metal and metal alloys include, but are not limited to, metals and alloys comprising at least one of the following elements: Cr, Mn, Co, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Ga, Sn, Hf, Ta, Re, Os, Ir, Hg, Rf, Db, Sg, Bh, Hs, Mt, La and various elements in the lanthanide series, Ac and various elements in the actinide series, and various shape memory alloys, to name a few. The suitable mass fraction of small wires in metal-wire composites may range from around 0.002 wt. % to around 85 wt. %.
In some applications, it may be advantageous to add a particular color to oxide small wire/metal composites to modify the otherwise “regular metallic” color. For example, it may be advantageous (or desirable) for “colored” (e.g., black, white, blue, red, green, velvet, yellow, gold, silver, or other color) cases and frames of various electronic devices (laptops, ultrabooks, tablets, electronic books, televisions, credit card terminals, cameras, microscopes, spectroscopes and other research tools, monitors of various other electronic devices or components of devices, etc.), cases of watches and other wearable devices, furniture, frames of reading glasses, components of automotive, aerospace, ship and other transport devices (cars, buses, planes, ships, spacecraft, drones, etc.), components of various appliances (oven doors, cook tops, etc.), tableware glass, jewelry, components of various protection equipment (safety screens, helmets, personal protection equipment, etc.), various sporting goods, various interior design and furniture (mirrors, partitions, balustrades, tables, shelves, lighting) and other devices where it is desirable to not reveal scratches. In some designs, it may be desirable for the metals and small wire/metal composites to exhibit a uniform color throughout the metal (small wire/metal, porous oxide-metal) part(s) or at least through a sufficiently thick surface layer (e.g., at least about 1 micron or more, preferably about 10 microns or more) instead of introducing the metals and small wire/metal composites to a thin layer on the surface (e.g., by anodization) or using a relatively soft polymer-based paint on the surface. Conventionally, various dyes are difficult to introduce (without damage to the dyes) and distribute uniformly within a metal (particularly without reducing metal mechanical properties). One or more embodiments of the present disclosure overcome this limitation. For example, in some applications, suitable dyes or quantum dots may be attached to the surface of the oxide small wires or be infiltrated into the pores (if present in small wires) prior to the formation of the small wire/metal composites. In some applications, it may be advantageous to seal these pores in order to reduce or prevent direct contact between the dyes (or quantum dots) and metal. In some applications, the sealing material may be a glass (e.g., oxide) or a ceramic (e.g., an oxide, a nitride, or a carbide, to provide a few examples). In some applications, porous oxides of not elongated shape (not small wires) and other porous materials may be utilized for the purpose of introducing a color to a metal or metal-ceramic composite. In some applications, instead of dyes, particles or coatings may be utilized (e.g., carbon particles or carbon coating for “black” color).
Examples of suitable methods for the formation of small wire (e.g., aluminum oxide small wire, among other oxides and other ceramic small wire)/metal composites include, but are not limited to, plating and electroplating (e.g., through small wire-comprising or small wire-based membranes or small wire-based porous bulk samples), melt-infiltration (e.g., into small wire-comprising or small wire-based membranes or small wire-based porous bulk samples), physical vapor deposition (sputtering, pulse-laser deposition, etc.), chemical vapor deposition, various mechanical alloying methods (e.g., ball milling, friction stir, etc.), various powder metallurgy methods (including, but not limited to, various sintering methods, such as spark plasma and plasma-activated sintering and magnetic-field-assisted sintering, pulsed current hot pressing, hot isostatic pressing, hot pressing, etc.), various casting methods (e.g., pressure casting, hot pressing including vacuum hot pressing, squeeze casting, etc.), sheath rolling, and ultrasonic consolidation, to name a few. As mentioned above, in order to tune the small wire/metal interface strength, in order to improve wetting of metals on the small wire surface, or in order to tune other properties of the small wire/metal interface (or interphase), it may be advantageous to pre-coat the small wire surface with coatings of other materials (e.g., by carbon, by ceramic—e.g., carbides (such as boron carbide, aluminum carbon, etc.) or by metals (e.g., by metals other than the “main” metal of the small wire-metal composites)).
In some applications, it may be advantageous to utilize some of the above-described lightweight small wire (e.g., aluminum oxide small wire, among other oxides and other ceramic small wire)/metal composites in ballistic protection applications (e.g., in bulletproof or stab-protective wests or bulletproof structural materials, such as plates, etc.). Lightweight alloys (such as aluminum alloys, magnesium alloys, titanium alloys, beryllium alloys, their combinations, etc.) and (in the case of plates) steel may be particularly advantageous for use in such composites. As mentioned above, it may be advantageous to pre-coat the small wire surface with coatings of other materials (e.g., by carbides (such as boron carbide, silicon carbide, aluminum carbon, among others), borides, etc.), by metals (e.g., by metals other than the “main” metal of the small wire/metal composites), or by polymers) in order to optimize mechanical properties of the small wire/metal composites and improve wetting of metals on the small wire surface. In some ballistic applications, polymers may be used instead of metals in such composites. Examples of suitable polymers include, but are not limited to, nylon, polyethylene, polyacrylonitrile (PAN), aramids (such as poly(p-phenylene terephthalamides) (PPTA)), polybenzoxazole, poly(pyridobisimidazole) (PIPD) (such as commercially available KEVLAR® (e.g., Kevlar 49, 149, etc.), ZYLON® HM, M5® (PIPD), TWARON®, TECHNORA®, ZYLON®, etc.), silk, spider silk, among others. In some ballistic applications, ceramic, carbon, and glass may be used instead of metals in such composites. In some applications, the small wire-comprising composites may be in the form of fibers or fabrics. In some ballistic applications, silicon carbide, boron carbide, or carbon small wires or platelets (or plates) as well as aluminum oxide platelets (or plates) may be utilized in addition to aluminum oxide small wires in such composites. The suitable mass and volume fractions of the small wires in ballistic protection composites may range from around 0.01 vol. % (and around 0.01 wt. %) to around 80 vol. % (and around 80 wt. %).
In some applications, the use of aluminum oxide (or other oxides and other ceramic) small wires (particularly those described herein) or porous bodies or porous membranes in catalyst applications may be advantageous. The use of oxide or ceramic small wires in combination with carbon particles (such as carbon nanotubes, exfoliated graphite, graphene, porous carbon particles, carbon nanoparticles, etc.) or carbon coatings may be advantageous.
In some applications, it may be advantageous to use aluminum oxide (and other oxide as well as other suitable ceramic) small wires (particularly those described herein) or porous bodies or porous membranes as substrates for catalysts utilized for the photodegradation of toxic organic pollutants. Benefiting from the high surface area, good dispersion, and chemical stability of these oxide small wires, the catalysts (e.g., TiO2, ZnO, Bi2O3, BiVO4, etc.) may exhibit high and stable photocatalytic activity for the degradation and mineralization of various toxic organic pollutants. Good mechanical stability, thermal stability, high porosity, and high permeability of the small oxide wires-based porous substrates (e.g., membranes) make them particularly attractive for such applications.
In some applications, some or all of the pores in the porous ceramic (e.g., oxide) small wires may be infiltrated with functional fillers for improved performance in various applications. Examples of useful functional fillers may include: (i) magnetic (e.g., ferrimagnetic materials, ferromagnetic materials, etc.) materials, (ii) superconductive materials, (iii) piezoelectric materials, (iv) ferroelectric materials (including pyroelectric materials), (v) various other markers or sensing materials (detectors), (vi) various optical materials, (vii) strong dielectrics, and others. Magnetic fillers may be used to orient the small wires along the desired direction by application of a magnetic field (which may be advantageous, e.g., in making improved composites or during the operation of the materials or devices, or both). Magnetic fillers may make it easier to assemble cells with ceramic small wire-based separators. Porous wires filled with magnetic materials and thus attaining magnetic properties may be used as soft or hard magnets (depending on the filler) and be used in corresponding applications (e.g., transformers, inductors, electric machines, electromagnet cores, relays, magnetic recording heads, magnetic amplifiers, filters, etc., for soft magnets or magnetic recording (storage) media, permanent magnets (e.g., integrated in multifunctional materials), loudspeakers and headphones, phone receivers, starter motors, servo motors, stepper and other motors, Magnetic Resonance Imaging (MRI) scanners, etc., for hard magnets). Superconductive materials (e.g., filled within interconnected pores of the, e.g., small oxide wires or other ceramic wires or metal organic wires or metallic wires) may allow these to attain superconductive properties (e.g., below a critical temperature or below a critical magnetic field) and used in functional (or multifunctional) devices. Confinement of the superconductive materials within the (nano)pores of the small wires may provide additional performance (or stability) advantages and improve the mechanical (or other) properties of the superconductors. The produced filled porous wire composites may be parts of other materials or devices. Piezoelectric fillers may make the wires attain piezoelectric properties. Porous wires filled with piezoelectric materials and thus attaining piezoelectric properties may also be used, e.g., in piezoelectric transducers, crystal oscillators, delay lines, filters, accelerometers, earphones, speakers, microphones, and spark generators, to name a few. The confinement of the piezoelectric materials into the pores (e.g., interconnected pores) of the wires may enhance their performance or stability, or allow formation of 1D (wire-shaped) piezoelectric materials or 2D (membrane-shaped) ferroelectric materials, or may allow attaining multifunctional properties. Ferroelectric fillers may make the wires attain ferroelectric properties. These properties may help to orient the wires along the desired direction(s) by applying an electric field (which may be advantageous, e.g., in making improved composites or during the operation of the materials or devices, or both). Porous wires filled with ferroelectric materials and thus attaining ferroelectric properties may also be used, e.g., in electronic circuits, electro-optic modulators, high-k-dielectrics, capacitors (e.g., with tunable or non-tunable capacitance), ferroelectric random-access memory, ferroelectric tunnel junction devices, sensors, multiferroics, fire (or heat) sensors, sonar, vibration sensors, fuel injectors, etc. Pyroelectric fillers are a sub-class of the ferroelectric fillers, in which the dipole moment depends on temperature. These are particularly useful as radiation or heat detectors. The confinement of the ferroelectric materials into the pores (e.g., interconnected pores) of the small porous wires may enhance their performance or stability, or allow formation of 1D (wire-shaped) ferroelectric materials or 2D (membrane-shaped) ferroelectric materials, or may allow attaining multifunctional properties.
In some designs, it may be advantageous for the small oxide wires (including the small wires produced according to the disclosed methods) to be processed into thermally stable (e.g., to above about 1200° C.) and ultra-strong yards, ropes, sheets, and fabrics (e.g., based on Al2O3, ZrO2, or MgO small wires).
In the detailed description above it can be seen that different features are grouped together in examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are explicitly mentioned in each clause. Rather, the various aspects of the disclosure may include fewer than all features of an individual example clause disclosed. Therefore, the following clauses should hereby be deemed to be incorporated in the description, wherein each clause by itself can stand as a separate example. Although each dependent clause can refer in the clauses to a specific combination with one of the other clauses, the aspect(s) of that dependent clause are not limited to the specific combination. It will be appreciated that other example clauses can also include a combination of the dependent clause aspect(s) with the subject matter of any other dependent clause or independent clause or a combination of any feature with other dependent and independent clauses. The various aspects disclosed herein expressly include these combinations, unless it is explicitly expressed or can be readily inferred that a specific combination is not intended (e.g., contradictory aspects, such as defining an element as both an electrical insulator and an electrical conductor). Furthermore, it is also intended that aspects of a clause can be included in any other independent clause, even if the clause is not directly dependent on the independent clause.
Implementation examples are described in the following numbered clauses:
Clause 1. An integrated electrode-separator component, comprising: an electrode substrate; and a separator comprising a first layer, the first layer comprising small wires, the first layer being directly deposited on the electrode substrate, wherein: a total thickness of the separator ranges between about 0.5 μm and about 10 μm; and the small wires exhibit diameters in the range of about 2 nm to about 10 μm and diameter-to-length aspect ratios in the range of about 1:4 to about 1:10,000,000.
Clause 2. The integrated electrode-separator component of clause 1, wherein: the small wires exhibit diameters in a range of about 3 nm to about 2 μm.
Clause 3. The integrated electrode-separator component of any of clauses 1 to 2, wherein: the small wires exhibit diameter-to-length aspect ratios in a range of about 1:20 to about 1:100,000.
Clause 4. The integrated electrode-separator component of any of clauses 1 to 3, wherein: the small wires in the first layer are preferentially aligned in a first direction.
Clause 5. The integrated electrode-separator component of any of clauses 1 to 4, wherein: the separator comprises a second layer of the separator directly on the first layer of the separator.
Clause 6. The integrated electrode-separator component of clause 5, wherein: the second layer comprises an adhesive.
Clause 7. The integrated electrode-separator component of any of clauses 5 to 6, wherein: the small wires in the first layer are first small wires; and the second layer of the separator comprises second small wires.
Clause 8. The integrated electrode-separator component of clause 7, wherein: the second small wires in the second layer are preferentially aligned in a second direction.
Clause 9. The integrated electrode-separator component of any of clauses 1 to 8, wherein: the total thickness of the separator ranges between about 0.5 μm and about 5 μm.
Clause 10. The integrated electrode-separator component of any of clauses 1 to 9, wherein: the separator further comprises a polymer at a weight fraction of the separator in a range of about 0.1 wt. % to about 90 wt. %.
Clause 11. The integrated electrode-separator component of clause 10, wherein: the polymer comprises a thermoplastic with a melting point in a range of about 70 to about 150° C.
Clause 12. The integrated electrode-separator component of any of clauses 1 to 11, wherein: a porosity of the separator is in a range of about 30 vol. % to about 95 vol. 0.
Clause 13. The integrated electrode-separator component of clause 12, wherein: the porosity of the separator is in a range of about 50 vol. % to about 70 vol. %.
Clause 14. The integrated electrode-separator component of any of clauses 12 to 13, wherein: the porosity of the separator is in a range of about 30 vol. % to about 50 vol. %.
Clause 15. The integrated electrode-separator component of any of clauses 1 to 14, wherein: the small wires comprise one or more of the following materials: a metal alkoxide, a metal hydroxide, a metal oxyhydroxide, and a metal oxide.
Clause 16. The integrated electrode-separator component of any of clauses 1 to 15, wherein: the small wires comprise one or more of the following materials: aluminum alkoxide, aluminum hydroxide, aluminum oxyhydroxide, aluminum oxide, magnesium alkoxide, magnesium hydroxide, magnesium oxyhydroxide, magnesium oxide, a mixture thereof, an alloy thereof.
Clause 17. The integrated electrode-separator component of any of clauses 1 to 16, wherein at least one of the one or more materials in the small wires is doped.
Clause 18. The integrated electrode-separator component of any of clauses 1 to 17, wherein: the small wires exhibit lengths in a range of about 50 nm to about 50 mm.
Clause 19. The integrated electrode-separator component of any of clauses 1 to 18, wherein: the small wires comprise a functional surface coating that exhibits surface layer thicknesses in a range of about 0.3 nm to about 30 nm.
Clause 20. The integrated electrode-separator component of any of clauses 1 to 19, wherein: at least some of the small wires are bundled.
Clause 21. The integrated electrode-separator component of any of clauses 1 to 20, wherein: the integrated electrode-separator component is of a non-rectangular shape when the integrated electrode-separator component is viewed in a plan view.
Clause 22. The integrated electrode-separator component of any of clauses 1 to 21, wherein: the integrated electrode-separator component is of an L-like shape, a non-rectangular polygonal shape, a round shape, or a truncated round shape, when the integrated electrode-separator component is viewed in a plan view.
Clause 23. The integrated electrode-separator component of any of clauses 1 to 22, wherein: the integrated electrode-separator component comprises a hole penetrating therethrough.
Clause 24. The integrated electrode-separator component of any of clauses 1 to 23, wherein: an outer periphery of the integrated electrode-separator component comprises an edge region; the separator is present in the edge region; and the edge region is devoid of an electrode.
Clause 25. The integrated electrode-separator component of any of clauses 1 to 24, wherein the electrode substrate comprises a current collector and a first electrode attached to or deposited onto a first side of the current collector.
Clause 26. The integrated electrode-separator component of clause 25, wherein: the separator is a first separator; the electrode substrate further comprises a second electrode on a second side of the current collector opposite the first side; and the integrated electrode-separator component further comprises a second separator deposited directly on the second electrode.
Clause 27. The integrated electrode-separator component of clause 26, wherein: the first separator and the second separator are discontiguous.
Clause 28. A battery component stack, comprising: the integrated electrode-separator component of clause 1; and an opposite electrode substrate disposed adjacent to the integrated electrode-separator component, the opposite electrode substrate comprising an opposite current collector and an opposite electrode on a first side of the opposite current collector, wherein: the opposite electrode substrate and the integrated electrode-separator component are aligned to each other; and the opposite electrode and the separator of the integrated electrode-separator component are in contact with each other.
Clause 29. The battery component stack of clause 28, wherein: the opposite electrode and the separator of the integrated electrode-separator component are laminated to each other by an adhesive.
Clause 30. A battery cell, comprising: the battery component stack of clause 28; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the opposite electrode substrate and the electrode substrate of the integrated electrode-separator component are configured to be of opposite polarity to each other.
Clause 31. A battery component stack, comprising: a first instantiation of the integrated electrode-separator component of clause 1, configured as a first integrated electrode-separator component; a second instantiation of the integrated electrode-separator component of clause 1 configured as a second integrated electrode-separator component and disposed adjacent to the first integrated electrode-separator component, wherein: the first integrated electrode-separator component and the second integrated electrode-separator component are aligned to each other; and the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component are in contact with each other.
Clause 32. The battery component stack of clause 31, wherein: the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component are laminated to each other by an adhesive.
Clause 33. The battery component stack of any of clauses 31 to 32, wherein: the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component satisfy one or more of the following: a material composition of the separator of the first integrated electrode-separator component differs from a material composition the separator of the second integrated electrode-separator component; a thickness of the separator of the first integrated electrode-separator component differs from a thickness of the separator of the second integrated electrode-separator component; a density of the separator of the first integrated electrode-separator component differs from a density of the separator of the second integrated electrode-separator component; a porosity of the separator of the first integrated electrode-separator component differs from a porosity of the separator of the second integrated electrode-separator component; and the small wires of the first layer of the separator of the first integrated electrode-separator component are preferentially aligned in a first direction, and the small wires of the first layer of separator of the second integrated electrode-separator component are preferentially aligned in a second direction different from the first direction.
Clause 34. A battery cell, comprising: the battery component stack of clause 31; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the electrode substrate of the first integrated electrode-separator component and the electrode substrate of the second integrated electrode-separator component are of opposite polarity to each other.
Clause 35. A battery component stack, comprising: an opposite electrode substrate comprising an opposite current collector and a respective opposite electrode on each side of the opposite current collector; and a plurality of instantiations of the integrated electrode-separator component of clause 1, including a first integrated electrode-separator component and a second integrated electrode-separator component, the opposite electrode substrate being positioned between the first integrated electrode-separator component and the second integrated electrode-separator component, wherein: the first integrated electrode-separator component, the second integrated electrode-separator component, and the opposite electrode substrate are aligned to each other; the separator of the first integrated electrode-separator component and the opposite electrode on one of the sides of the opposite current collector are in contact with each other; and the separator of the second integrated electrode-separator component and the opposite electrode on another one of the sides of the opposite current collector are in contact with each other.
Clause 36. The battery component stack of clause 35, wherein: the first integrated electrode-separator component is characterized by a first outer periphery; the second integrated electrode-separator component is characterized by a second outer periphery; the first outer periphery and the second outer periphery differ from each other in at least one lateral dimension of the first and the second integrated electrode-separator components.
Clause 37. The battery component stack of clause 36, wherein: the opposite electrode substrate is a first opposite electrode substrate; the battery component stack comprises a second opposite electrode substrate comprising a second opposite current collector and a respective opposite electrode on each side of the second opposite current collector; the plurality of instantiations includes a third integrated electrode-separator component, the second opposite electrode substrate being positioned between the second integrated electrode-separator component and the third integrated electrode-separator component; the third integrated electrode-separator component is characterized by a third outer periphery; and the third outer periphery differs from the first outer periphery and/or the second outer periphery in the at least one lateral dimension.
Clause 38. The battery component stack of clause 37, wherein: the third outer periphery is greater than the second outer periphery in the at least one lateral dimension; and the second outer periphery is greater than the first outer periphery in the at least one lateral dimension.
Clause 39. The battery component stack of any of clauses 35 to 38, wherein: each of the first and the second integrated electrode-separator components comprises a respective strip extending from the respective current collector thereof; and the respective separator of each of the first and the second integrated electrode-separator components covers at least a portion of each of the respective strips.
Clause 40. A battery cell, comprising: the battery component stack of clause 35; and an electrolyte, wherein: the electrolyte infiltrates the battery component stack; and the opposite electrode substrate is configured to be of opposite polarity to the electrode substrates of the first and the second integrated electrode-separator components.
Clause 41. A method of making an integrated electrode-separator component, the method comprising: providing a suspension comprising small wires; forming a separator directly on an electrode substrate; and fashioning the integrated electrode-separator component from the electrode substrate having the separator deposited thereon, wherein: the forming of the separator comprises depositing the suspension directly on the electrode substrate to form a first layer of the separator; a total thickness of the separator ranges between about 0.5 μm and about 10 μm; and the small wires exhibit diameters in a range of about 2 nm to about 10 μm and diameter-to-length aspect ratios in a range of about 1:4 to about 1:10,000,000.
Clause 42. The method of clause 41, wherein: the small wires exhibit diameters in a range of about 3 nm to about 2 μm.
Clause 43. The method of any of clauses 41 to 42, wherein: the small wires exhibit diameter-to-length aspect ratios in a range of about 1:20 to about 1:100,000.
Clause 44. The method of any of clauses 41 to 43, wherein: the small wires in the first layer are preferentially aligned in a first direction.
Clause 45. The method of any of clauses 41 to 44, wherein: the forming of the separator comprises forming a second layer of the separator directly on the first layer of the separator.
Clause 46. The method of clause 45, wherein: the second layer comprises an adhesive.
Clause 47. The method of any of clauses 45 to 46, wherein: the suspension is a first suspension; the small wires are first small wires; the method further comprises providing a second suspension comprising second small wires; and the forming of the second layer of the separator comprises depositing the second suspension directly on the first layer of the separator to form the second layer of the separator.
Clause 48. The method of clause 47, wherein: the second small wires in the second layer are preferentially aligned in a second direction.
Clause 49. The method of any of clauses 41 to 48, further comprising: heat-treating at least the separator.
Clause 50. The method of any of clauses 41 to 49, further comprising: compacting at least the separator.
Clause 51. The method of any of clauses 41 to 50, wherein: the total thickness of the separator ranges between about 0.5 μm and about 5 μm.
Clause 52. The method of any of clauses 41 to 51, wherein: the separator further comprises a polymer at a weight fraction of the separator in a range of about 0.1 wt. % to about 90 wt. %.
Clause 53. The method of clause 52, wherein: the polymer comprises a thermoplastic with a melting point in a range of about 70 to about 150° C.
Clause 54. The method of any of clauses 41 to 53, wherein: a porosity of the separator is in a range of about 30 vol. % to about 95 vol. %.
Clause 55. The method of clause 54, wherein: the porosity of the separator is in a range of about 50 vol. % to about 70%.
Clause 56. The method of any of clauses 54 to 55, wherein: the porosity of the separator is in a range of about 30 vol. % to about 50 vol. %.
Clause 57. The method of any of clauses 41 to 56, wherein: the small wires comprise one or more of the following materials: a metal alkoxide, a metal hydroxide, a metal oxyhydroxide, and a metal oxide.
Clause 58. The method of any of clauses 41 to 57, wherein: the small wires comprise one or more of the following materials: aluminum alkoxide, aluminum hydroxide, aluminum oxyhydroxide, aluminum oxide, magnesium alkoxide, magnesium hydroxide, magnesium oxyhydroxide, magnesium oxide, a mixture thereof, or an alloy thereof.
Clause 59. The method of clause 58, wherein at least one of the one or more materials in the small wires is doped.
Clause 60. The method of any of clauses 41 to 59, wherein: the small wires exhibit lengths in a range of about 50 nm to about 50 mm.
Clause 61. The method of any of clauses 41 to 60, further comprising: depositing a functional surface coating on the small wires that exhibits surface layer thicknesses in a range of about 0.3 nm to about 30 nm.
Clause 62. The method of any of clauses 41 to 61, wherein: the suspension is a liquid suspension.
Clause 63. The method of any of clauses 41 to 62, wherein: at least some of the small wires are bundled.
Clause 64. The method of any of clauses 41 to 63, wherein: the depositing of the suspension is carried out by casting, spray deposition, field-assisted deposition, and/or dip coating.
Clause 65. The method of any of clauses 41 to 64, wherein: the fashioning of the integrated electrode-separator component comprises segmenting a portion of the electrode substrate having the separator deposited thereon to form the integrated electrode-separator component.
Clause 66. The method of clause 65, wherein: the segmented portion is of a non-rectangular shape when the segmented portion is viewed in a plan view.
Clause 67. The method of any of clauses 65 to 66, wherein: the segmented portion is of an L-like shape, a non-rectangular polygonal shape, a round shape, or a truncated round shape, when the segmented portion is viewed in a plan view.
Clause 68. The method of any of clauses 65 to 67, wherein: the segmented portion comprises a hole penetrating through the integrated electrode-separator component.
Clause 69. The method of any of clauses 65 to 68, wherein: the segmenting comprises cutting the electrode substrate at at least one edge region; wherein: the separator is present in the edge region; and the edge region is devoid of an electrode part of the electrode substrate.
Clause 70. The method of any of clauses 41 to 69, wherein the electrode substrate comprises a current collector and a first electrode attached to or deposited onto a first side of the current collector.
Clause 71. The method of clause 70, wherein: the current collector is in a form of a roll.
Clause 72. The method of any of clauses 70 to 71, wherein: the separator is a first separator; the electrode substrate comprises at least a second electrode on a second side of the current collector opposite the first side; and the method further comprises forming a second separator directly on the electrode substrate, the second separator being formed on the second electrode.
Clause 73. A method of making a battery component stack, comprising: making a first instantiation of the integrated electrode-separator component according to the method of clause 41, configured as a first integrated electrode-separator component; making a second instantiation of the integrated electrode-separator component according to the method of clause 41, configured as a second integrated electrode-separator component; and disposing the second integrated electrode-separator component adjacent to the first integrated electrode-separator component to form a battery component stack, wherein: the disposing comprises aligning the first integrated electrode-separator component and the second integrated electrode-separator component to each other; and the disposing comprises contacting the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component to each other.
Clause 74. The method of clause 73, wherein: the disposing comprises laminating the separator of the first integrated electrode-separator component and the separator of the second integrated electrode-separator component to each other by an adhesive.
Clause 75. A method of making a battery cell, comprising: making a battery component stack according to the method of clause 73; infiltrating an electrolyte into the battery component stack; and configuring the electrode substrate of the first integrated electrode-separator component and the electrode substrate of the second integrated electrode-separator component to be of opposite polarity to each other to form the battery cell.
Clause 76. A method of making a battery component stack, comprising: making the integrated electrode-separator component according to the method of clause 40; and disposing an opposite electrode substrate adjacent to the integrated electrode-separator component to form a battery component stack, the opposite electrode substrate comprising an opposite current collector and an opposite electrode on a first side of the opposite current collector, wherein: the disposing comprises aligning the opposite electrode substrate and the integrated electrode-separator component to each other; and the disposing comprises contacting the opposite electrode and the separator of the integrated electrode-separator component to each other.
Clause 77. The method of clause 76, wherein: the disposing comprises laminating the opposite electrode and the separator of the integrated electrode-separator component to each other by an adhesive.
Clause 78. A method of making a battery cell, comprising: making a battery component stack according to the method of clause 76; infiltrating an electrolyte into the battery component stack; and configuring the opposite electrode substrate and the electrode substrate of the integrated electrode-separator component to be of opposite polarity to each other to form the battery cell.
The foregoing description is provided to enable any person skilled in the art to make or use embodiments of the present invention. It will be appreciated, however, that the present invention is not limited to the particular formulations, process steps, and materials disclosed herein, as various modifications to these embodiments will be readily apparent to those skilled in the art. That is, the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention.
The present application for patent is a Continuation-in-Part of U.S. patent application Ser. No. 17/656,844 entitled “Formation and Modifications of Ceramic Nanowires and Their Use in Functional Materials” filed Mar. 28, 2022, which is a Continuation of U.S. patent application Ser. No. 16/005,400 entitled “Formation and Modifications of Ceramic Nanowires and Their Use in Functional Materials” filed Jun. 11, 2018, which is a Continuation of U.S. patent application Ser. No. 15/395,930 entitled “Formation and Modifications of Ceramic Nanowires and Their Use in Functional Materials” filed Dec. 30, 2016, which claims the benefit of U.S. Provisional Application No. 62/307,864, entitled “Formation and Modifications of Ceramic Nanowires and their use in Functional Materials,” filed Mar. 14, 2016, and U.S. Provisional Application No. 62/295,989, entitled “Low Cost, Aluminum Oxide Nanowires for a Safer, Higher Power, and Energy Dense All-Ceramic Li-Ion Battery Separator,” filed Feb. 16, 2016, each of which is expressly incorporated herein by reference in its entirety.
This invention was made with government support under Award ID DMR0954925 awarded by the National Science Foundation (NSF). The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 62307864 | Mar 2016 | US | |
| 62295989 | Feb 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16005400 | Jun 2018 | US |
| Child | 17656844 | US | |
| Parent | 15395930 | Dec 2016 | US |
| Child | 16005400 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17656844 | Mar 2022 | US |
| Child | 18318694 | US |
