Patent Application
20210257666
This disclosure relates generally to batteries, and, more particularly, to lithium-ion batteries that can compensate for operational cycle losses.
Recent developments in batteries allow consumers to use electronic devices in many new applications. However, further improvements in battery technology are desirable.
This Summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.
One innovative aspect of the subject matter described in this disclosure may be implemented as a lithium-sulfur electrochemical cell including a cathode and an anode positioned opposite to the cathode. The cathode may include various regions, where each region may be defined by two or more core-shell structures adjacent to and in contact with each other. The lithium-sulfur electrochemical cell may include an electrolyte with a ternary solvent package. In one implementation, the electrolyte may include the ternary solvent package and 4,4′-thiobisbenzenethiol (TBT). Alternatively, in another implementation, the electrolyte may include the ternary solvent package and 2-mercaptobenzothiazole (MBT). The electrolyte may be interspersed throughout the cathode and in contact with the anode.
In one implementation, the ternary solvent package may include 1,2-Dimethoxyethane (DME), 1,3-Dioxolane (DOL), tetraethylene glycol dimethyl ether (TEGDME), and or one or more additives, which may include lithium nitrate (LiNO3). For example, in one implementation, the ternary solvent package may be prepared with 5,800 microliters (μL) of DME, 2,900 microliters (μL) of DOL, and 1,300 microliters (μL) of TEGDME and include approximately 0.01 mol of dissolved lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The ternary solvent package may be prepared at a first approximate dilution level of 1 molar (M) LiTFSI in a mixture of DME:DOL:TEGDME. The ternary solvent package may be prepared at a second approximate dilution level of approximately 1 M LiTFSI in DME:DOL:TEGDME at a volume ratio of volume:volume:volume=58:29:13 including 2 weight percent (wt. %) lithium nitrate.
Alternatively, in another implementation, the ternary solvent package may be prepared with 2,000 microliters (μL) of DME, 8,000 microliters (μL) of DOL, and 2,000 microliters (μL) of TEGDME and include approximately 0.01 mol of dissolved lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The ternary solvent package may be prepared at a first approximate dilution level of 1 molar (M) LiTFSI in a mixture of DME:DOL:TEGDME. The ternary solvent package may be prepared at a second approximate dilution level of approximately 1 M LiTFSI in DME:DOL:TEGDME at an approximate volume ratio of volume:volume:volume=1:4:1 and include either an addition of 5M TBT solution or an addition of 5M MBT solution.
In various implementations, each core-shell structure may be a carbon nano-onion (CNO), which may include a relatively high-density outer shell region and a relatively low-density core region. In some aspects, the core region may be positioned within an interior region of the outer shell region. The outer shell region may have a first carbon density, such as between approximately 2.0 grams per cubic centimeter (g/cc) and 2.3 g/cc. The core region may have a second carbon density that is lower than the first carbon density. For example, the second carbon density may be between approximately 0.0 g/cc and 2.0 g/cc.
The regions of the cathode may include microporous channels, mesoporous channels, and macroporous channels. In one implementation, at least some of the microporous channels, the mesoporous channels, and the macroporous channels may connect with each other and form a porous network that may extend from the outer shell region to the core region. For example, the porous network may include pores that each have a principal dimension of approximately 1.5 nm.
In various implementations, the regions of the cathode may temporarily microconfine an elemental sulfur. In some aspects, the ternary solvent package may have a tunable polarity, a tunable solubility, and include ions. For example, the ternary solvent package, in some aspects, may provide a soluble medium through which lithium ions may flow during battery cycling. Similarly, the ternary solvent package may at least temporarily suspend polysulfides (PS) during charge-discharge cycles of the lithium-sulfur electrochemical cell.
The anode of the lithium-sulfur electrochemical cell may, in some aspects, be a graphitic scaffold, which may include graphene sheets stacked vertically. In one implementation, at least some adjacent graphene sheets may intercalate lithium ions, which may chemically react with carbon provided by exposed surfaces of the corresponding graphene sheets. Lithium, provided by the lithium ions, and carbon provided by the adjacent graphene sheets, may chemically react with each other to produce lithiated or lithium-intercalated graphite (LiC6). As a result, in this implementation, the graphitic scaffold may at least partially convert to lithium-intercalated graphite.
In various implementations, the regions of the cathode may include, such as by pre-loading prior to battery cycling, elemental sulfur. The elemental sulfur may chemically react with available lithium in the electrolyte, during battery cycling, to generate poly sulfides, which may be suspended within the electrolyte and confined to the regions. The cathode, which may include flexure points that encompass several of the regions, may volumetrically expand to accommodate these trapped polysulfides while continuing to permit lithium ions in the electrolyte flow freely, resulting in improved performance and cyclability of the lithium-sulfur electrochemical cell.
In some implementations, a separator may be positioned between the cathode and the anode. For example, in one implementation, the separator may be coated with one or more of a ceramic-containing compound or an aluminum fluoride containing mixture. In some aspects, the separator may be porous to allow lithium ions to flow through the separator. As a result, the lithium ions may flow from or to the anode and/or the cathode depending on charge or discharge cycling operations of the lithium-sulfur electrochemical cell. In addition, an artificial solid-electrolyte interphase may be formed on the anode in response to battery cycling of the lithium-sulfur electrochemical cell. In some aspects, a barrier layer including a mechanical strength enhancer may be coated on the anode.
Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.
Like reference numbers and designations in the various drawings indicate like elements.
The following description is directed to some example implementations for the purposes of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in any type of electrochemical cell, battery, or battery pack, and can be used to compensate for electrolyte performance deficiencies. As such, the disclosed implementations are not to be limited by the examples provided herein, but rather encompass all implementations contemplated by the attached claims. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.
Batteries typically include several electrochemical cells, which can be connected to each other to provide electric power to a wide variety of devices such as (but not limited to) mobile phones, laptops, electric vehicles (EVs), factories, and buildings. Certain types of batteries, such as lithium-ion or lithium-sulfur batteries, may be limited in performance by the type of electrolyte used. Optimization of the electrolyte may improve the cyclability, the rate capability, the safety, and the lifespan of a respective battery. For example, electrolytes may be tuned to meet certain battery usage requirements. In a new or “fresh” battery, lithium ions flow freely from the anode to the cathode during a discharge cycle. During a battery charge cycle, lithium ions are forced to migrate back from their electrochemically favored positions in the cathode to the anode, where they can be stored for subsequent use. Lithium-containing polysulfide intermediates are generated upon interaction of lithium ions with sulfur pre-loaded in the cathode for lithium-sulfur batteries during battery charge-discharge cycling. These intermediates are soluble in the electrolyte and therefore diffuse throughout the cell during battery cycling, impeding the free travel of lithium ions as required for optimal battery performance. Excessive generation of polysulfide intermediates can result in capacity decay and cell failure during battery cycling.
Lithium polysulfide intermediates participate in the formation of inorganic layers in a solid electrolyte interphase (SEI), which may form on the anode. The anode may be protected by a stable inorganic layer formed in the electrolyte containing 0.020 M Li2S5 (0.10 M sulfur) and 5.0 wt % LiNO3. The anode with a lithium fluoride and lithium polysulfide intermediates (LiF—Li2Sx) may enrich the SEI and result in a stable Coulombic efficiency of 95% after 233 cycles for Li—Cu half cells, while preventing formation of lithium dendrites. However, when lithium-containing polysulfide intermediates (also referred to as “polysulfides”) are generated (such as during demanding discharge or charge cycling rates and/or extended usage over many cycles) at certain concentrations (such as greater than 0.50 M sulfur), formation of the SEI may be hindered. As a result, lithium metal from the anode may be etched. This type of unwanted deterioration (etching) of the anode due to a relatively high concentration of polysulfide intermediates indicates that polysulfide dissolution and diffusion may need to be regulated to optimize battery performance.
The cathode porosity may be controlled or adjusted to optimize lithium-sulfur battery energy density. While relatively high sulfur areal pre-loading has been pursued, less attention has been paid to cathode porosity. For example, cathode porosity may be higher in sulfur and carbon composite cathodes compared to traditional lithium-ion battery electrodes. Denser electrodes with relatively low porosity may minimize electrolyte intake, parasitic weight, and cost. Sulfur utilization may be limited by the solubility of polysulfide intermediates and conversion from those intermediates to lithium disulfide (Li2S). The conversion of polysulfide intermediates may be based on the accessible surface area of the porous carbon cathode. As a result, cathode porosity may also be optimized in view of electrolyte constituent material selection to maximize battery volumetric energy density.
Various aspects of the subject matter disclosed herein relate to a lithium-sulfur battery including an electrolyte, which may include a ternary solvent package and one or more additives. In accordance with various implementations of the subject matter disclosed herein, the lithium-sulfur battery may include a cathode, an anode positioned opposite to the cathode, and the electrolyte. The cathode may include several regions, where each region may be defined by two or more core-shell structures adjacent to and in contact with each other. In some instances, the electrolyte may include the ternary solvent package, be interspersed throughout the cathode and be in contact with the anode. In one implementation, the electrolyte may include the ternary solvent package and 4,4′-thiobisbenzenethiol (TBT). In another implementation, the electrolyte may include the ternary solvent package and 2-mercaptobenzothiazole (MBT).
In some aspects, the ternary solvent package may include 1,2-Dimethoxyethane (DME), 1,3-Dioxolane (DOL), tetraethylene glycol dimethyl ether (TEGDME), and one or more additives, which may include a lithium nitrate (LiNO3), all which may be in a liquid-phase. In one implementation, the ternary solvent package may be prepared by mixing together approximately 5,800 microliters (μL) of DME, 2,900 microliters (μL) of DOL, and 1,300 microliters (μL) of TEGDME to create a mixture. Approximately 0.01 mol of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) may be dissolved into ternary solvent package to produce an approximate dilution level of 1 M LiTFSI in DME:DOL:TEGDME at a volume ratio of volume:volume:volume=58:29:13 including approximately 2 weight percent (wt. %) lithium nitrate.
Alternatively, in another implementation, the ternary solvent package may be prepared with 2,000 microliters (μL) of DME, 8,000 microliters (μL) of DOL, and 2,000 microliters (μL) of TEGDME and include approximately 0.01 mol of dissolved lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The ternary solvent package may be prepared at a first approximate dilution level of 1 molar (M) LiTFSI in a mixture of DME:DOL:TEGDME. The ternary solvent package may be prepared at a second approximate dilution level of approximately 1 M LiTFSI in DME:DOL:TEGDME at an approximate volume ratio of volume:volume:volume=1:4:1 and include either an addition of 5M TBT solution or an addition of 5M MBT solution, or an addition of other additives and/or chemical substances.
In various implementations, each core-shell structure may be a carbon nano-onion (CNO), which may include a relatively high-density outer shell region and a relatively low-density core region. In some aspects, the core region may be positioned within an interior region of the outer shell region. The outer shell region may have a first carbon density, such as between approximately 1.0 grams per cubic centimeter (g/cc) and 2.3 g/cc. The core region may have a second carbon density that is lower than the first carbon density. For example, the second carbon density may be between approximately 0.0 g/cc and 1.0 g/cc.
The regions of the cathode may include microporous channels, mesoporous channels, and macroporous channels. In one implementation, at least some of the microporous channels, the mesoporous channels, and the macroporous channels may connect with each other and form a porous network that may extend from the outer shell region to the core region. For example, the porous network may include pores that each have a principal dimension of approximately 1.5 nm.
In various implementations, the regions of the cathode may temporarily microconfine an elemental sulfur. In some aspects, the ternary solvent package may have a tunable polarity, a tunable solubility, and include lithium ions. For example, the ternary solvent package, in some aspects, may provide a soluble medium through which lithium ions may flow during battery cycling. Similarly, the ternary solvent package may at least temporarily suspend polysulfides (PS) during charge-discharge cycles of the lithium-sulfur electrochemical cell.
Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more potential advantages. In some implementations, the porous network formed by connection of some of the micro-, meso-, and macroporous channels of the cathode may include several pore types including a first, second, and third pore type. The first pore type may be microporous, such as having a pore size of approximately less than 5 nm. The second pore type may be mesoporous, such as having a pore size between approximately 5 to 50 nm. The third pore type may be macroporous, such as having a pore size greater than approximately 50 nm. In some implementations, the three pore types may work independently or in unison to mitigate unwanted shuttle of polysulfide intermediates within the electrolyte. Since polysulfide shuttle interferes with transport of lithium ions in the electrolyte, control, and reduction of such unwanted shuttle, such as by the three pore types, results in noticeable battery performance improvement (e.g., measured in energy storage capacity and/or power delivery).
In some instances, a first type of pore may have a pore size of approximately 1.5 nm, for example, to microconfine elemental sulfur (S8) pre-loaded into the cathode. TBT or MBT, when complexing with sulfur ions generated during battery cycling, may partially block movement of long-chain polysulfide containing intermediates within, for example, the second pore type pores. As a result, cathodes including the first, second and third pore types may volumetrically expand to retain the intermediates and thereby minimize the polysulfide shuttle effect. Accordingly, lithium ions may continue to flow freely (such as through a “cascade” effect and/or due to differences in electrochemical potential between the anode and the cathode) in the electrolyte without being blocked or impeded by the polysulfide intermediates. The free flow of lithium ions throughout the electrolyte (such as without interference by the polysulfides) can increase battery performance. As further described below, specific combinations of pore sizes created by, for example, adjacent core-shell structures, matched with unique electrolyte formulations can reduce or mitigate the harmful effects of unwanted polysulfide diffusion even further to produce even greater battery performance improvements.
Although not shown for simplicity, in one implementation, a lithium layer may be electrodeposited on one or more exposed carbon surfaces of the anode 120. In some instances, the lithium layer may include elemental lithium provided by the ex-situ lithium electrodeposition onto exposed surfaces of the anode 120. In addition, or in the alternative, the lithium layer may include lithium, calcium potassium, magnesium, sodium, and/or cesium, where each metal may be ex-situ deposited onto exposed carbon surfaces of the anode 120. The lithium layer may provide lithium ions available for transport to-and-from the cathode 110 during operational cycling of the battery 100. As a result, in this implementation, no additional lithium source is required in the cathode 110, such as lithium disulfide (LiS2), a common electroactive material that may be used in other lithium-sulfur electrochemical cell and/or battery configurations. Instead of using lithium disulfide, elemental sulfur (S8) may be pre-loaded (e.g., referring to shipment of the battery 100 prior to activation of the battery 100) in pores (such as those shown in
In some implementations, the battery 100 may include a solid-electrolyte interphase layer 140. The solid-electrolyte interphase layer 140 may, in some instances, be formed artificially on the anode 120 during battery cycling of the battery 100. In such instances, the solid-electrolyte interphase layer 140 may also be referred to as an artificial solid-electrolyte interphase, or A-SEI. The solid-electrolyte interphase layer 160, when formed as an A-SEI, may include tin, manganese, molybdenum, and/or fluorine compounds. The molybdenum may provide cations, and the fluorine compounds may provide anions. The cations and anions may produce salts such as tin fluoride, manganese fluoride, silicon nitride, lithium nitride, lithium nitrate, lithium phosphate, manganese oxide, lithium lanthanum zirconium oxide (LLZO, Li7La3Zr2O12), etc. In some instances, the A-SEI may be formed in response to exposure of lithium ions 125 to the electrolyte 130, which may include solvent-based solutions including tin and/or fluorine.
In various implementations, the solid-electrolyte interphase layer 140 may be artificially provided on the anode 120 prior to activation of the battery 100. Alternatively, in one implementation, the solid-electrolyte interphase layer 140 may form naturally, e.g., during operational cycling of the battery 100, on the anode 120. In some instances, the solid-electrolyte interphase layer 140 may provide a passivation layer including an outer layer of shielding material that can be applied to the anode 120 as a micro-coating. In this way, formation of the solid-electrolyte interphase layer 140 on the anode 120 facing the electrolyte 130 may reduce decomposition of the electrolyte 130.
In some implementations, the battery 100 may include a barrier layer 142. The barrier layer 142 may include a mechanical strength enhancer 144 coated and/or deposited on the anode 120. In some aspects, the mechanical strength enhancer 144 may provide structural support for the battery 100, may prevent lithium dendrite formation from the anode 120, and/or may prevent dispersion of lithium dendrite throughout the battery 100. In some implementations, the mechanical strength enhancer 144 may be formed as a protective coating over the anode 120, and may include one or more carbon allotropes, carbon nano-onions (CNOs), nanotubes (CNTs), reduced graphene oxide, graphene oxide (GO), and/or carbon nano-diamonds. In some instances, the solid-electrolyte interphase layer 140 may be formed within the mechanical strength enhancer 144.
In implementations for which the lithium layer includes elemental lithium, the elemental lithium may dissociate and/or separate into lithium ions 125 and electrons 174 during a discharge cycle of the battery 100. The lithium ions 125 (such as provided by the lithium layer, not shown for simplicity) may move from the anode 120 towards the cathode 110 through the electrolyte 130 to their electrochemically favored positions within the cathode 110, as shown in the example of
In some implementations, each of the first substrate 101 and the second substrate 102 may be a current collector, such as a solid aluminum or copper metal foil. In some instances, the first and second substrates 101 and 102 may be a solid copper metal foil. The first and second substrates 101 and 102 may influence the energy capacity, rate capability, lifespan, and long-term stability of the battery 100. The first and second substrates 101 and 102 may be subject to etching, carbon coating, or other suitable treatment to increase electrochemical stability and/or electrical conductivity of the battery 100.
In other implementations, the first substrate 101 and/or the second substrate 102 may include or may be formed from aluminum, copper, nickel, titanium, stainless steel and/or carbonaceous materials (such as depending on end-use applications and/or performance requirements of the battery 100). For example, the first substrate 101 and/or the second substrate 102 may be individually tuned or tailored such that the battery meets one or more performance requirements or metrics.
In some aspects, the first substrate 101 and/or the second substrate 102 may be at least partially foam-based or foam-derived and can be selected from any one or more of metal foam, metal web, metal screen, perforated metal, or a sheet-based 3D structure. In other aspects, the first substrate 101 and/or the second substrate 102 may be a metal fiber mat, metal nanowire mat, conductive polymer nanofiber mat, conductive polymer foam, conductive polymer-coated fiber foam, carbon foam, graphite foam, or carbon aerogel. In some other aspects, the first substrate 101 and/or second substrate 102 may be carbon xerogel, graphene foam, graphene oxide foam, reduced graphene oxide foam, carbon fiber foam, graphite fiber foam, exfoliated graphite foam, or combinations thereof.
Energy density gains associated with various cathode materials may be based on whether lithium metal is used in the anode 220. For example, high-capacity cathodes may need thicker or denser anodes in order to supply the increased quantities of lithium consumed by the high-capacity cathodes. Anodes hosted by structures such as the host structure 138 of
In one implementation, a void space intended to replace the anode 220 may be formed within the battery 200. Operational cycling of the battery 200 in this implementation may result in the deposition of lithium, such as provided by lithium disulfide pre-loaded onto exposed carbon surfaces of the cathode 210 and/or lithium ions 260 prevalent in the electrolyte 230, into the void spade. As a result, the void space may transform into a lithium-containing region (such as a solid lithium metal layer) and function as the anode 220. In some aspects, the void space may be created in response to chemical reactions between a metal-containing electrically inactive component and a graphene-containing component. Specifically, the graphene-containing component may chemically react with lithium deposited into the void space during operational cycling and produce lithiated graphite (LiC6) or a patterned lithium metal. The lithiated graphite produced by the chemical reactions may generate or lead to the generation and/or liberation of lithium ions and/or electrons that can be used to carry electric charge or a “current” between the anode 120 and the cathode 110 during discharge cycles of the battery 200. And, where the anode 220 is a solid lithium metal layer, the battery 200 may be able to hold more electroactive material and/or lithium per unit volume. That is, compared to batteries with scaffolded carbon and/or intercalated lithiated graphite anodes, the anode 220, when prepared as a solid lithium metal layer, may result in the battery 200 having a higher energy density and/or specific capacity, resulting in longer discharge cycle times and additional power output per unit time.
In some aspects, the electrode 300 may be porous and receptive of a liquid-phase electrolyte, such as the electrolyte 130 of
The electrode 300 may include a body region 301 defined by a width 305 and may include a first thin film 310 and a second thin film 320. The first film 310 may include a plurality of first aggregates 312 that join together to form the first porous structure 316 of the electrode 300. In some instances, the first porous structure 316 may have an electrical conductivity between approximately 0 and 500 S/m. In other instances, the first electrical conductivity may be between approximately 500 and 1,000 S/m. In some other instances, the first electrical conductivity may be greater than 1,000 S/m. In some aspects, the first aggregates 312 may include carbon nano-tubes (CNTs), carbon nano-onions (CNOs, such as those shown in
In some implementations, the first aggregates 312 may be decorated with a plurality of first nanoparticles 314. In some instances, the first nanoparticles 314 may include tin, lithium alloy, iron, silver, cobalt, semiconducting materials and/or metals such as silicon and/or the like. In some aspects, CNTs, due to their ability to provide high exposed surface areas per unit volume and stability at relatively high temperatures (such as above 77° F. or 25° C.), may be used as a support material for the first nanoparticles 314. For example, the first nanoparticles 314 may be immobilized (such as by decoration, deposition, surface modification or the like) onto exposed surfaces of CNTs and/or other carbonaceous materials. The first nanoparticles 314 may react with chemically available carbon on exposed surfaces of the CNTs and/or other carbonaceous materials, for example, as shown by the cobalt-decorated carbon-growths shown in
The second thin film 320 may include a plurality of second aggregates 322 that join together to form a second porous structure 326. In some instances, the electrical conductivities of the first and second porous structures 316 and/or 326 may be between approximately 0 S/m and 250 S/m. In instances for which the first porous structure 316 includes a higher concentration of aggregates than the second porous structure 326, the first porous structure 316 may have a higher electrical conductivity than the second porous structure 326. In one implementation, the first electrical conductivity may be between approximately 250 S/m and 500 S/m, while the second electrical conductivity may be between approximately 100 S/m and 250 S/m. In another implementation, the second electrical conductivity may be between approximately 250 S/m and 500 S/m. In yet another implementation, the second electrical conductivity may be greater than 500 S/m. In some aspects, the second aggregates 322 may include CNTs, CNOs, flaky graphene, crinkled graphene, graphene grown on carbonaceous materials, and/or graphene grown on graphene.
The second aggregates 322 may be decorated with a plurality of second nanoparticles 324. In some implementations, the second nanoparticles 324 may include iron, silver, cobalt, semiconducting materials and/or metals such as silicon and/or the like. In some instances, CNTs may also be used as a support material for the second nanoparticles 324. For example, the second nanoparticles 324 may be immobilized (such as by decoration, deposition, surface modification or the like) onto exposed surfaces of CNTs and/or other carbonaceous materials. The second nanoparticles 324 may react with chemically available carbon on exposed surfaces of the CNTs and/or other carbonaceous materials, for example, as shown by the cobalt-decorated carbon-growths depicted in
In various implementations, the first aggregates 312 and/or the second aggregates 322 may be a relatively large particle formed by many relatively small particles bonded or fused together. As a result, the external surface area of the relatively large particle may be significantly smaller than combined surface areas of the many relatively small particles. The forces holding an aggregate together may be, for example, covalent, ionic bonds, or other types of chemical bonds resulting from the sintering or complex physical entanglement of former primary particles.
As discussed above, the first aggregates 312 may join together to form the first porous structure 316, and the second aggregates 322 may join together to form the second porous structure 326. The electrical conductivity of the first porous structure 316 may be associated with the concentration level of the first aggregates 312 within the first porous structure 316, and the electrical conductivity of the second porous structure 326 may be associated with the concentration level of the second aggregates 322 the second porous structure 326. For example, the concentration level of the first aggregates 312 may cause the first porous structure 316 to have a relatively high electrical conductivity, and the concentration level of the second aggregates 322 may cause the second porous structure 326 to have a relatively low electrical conductivity (such that the first porous structure 316 has a greater electrical conductivity than the second porous structure 326). The resulting differences in electrical conductivities of the first and second porous structures 316 and 326 may create an electrical conductivity gradient across the electrode 300. In some implementations, the electrical conductivity gradient may be used to control or adjust electrical conduction throughout the electrode 300 and/or one or more operations of the battery 100 of
As used herein, aggregates may be referred to as “secondary particles,” and the original source particles may be referred to as “primary particles.” As shown in
The surface area and/or porosity of these innate particles may be imparted by secondary processes, such as carbon-activation by thermal processes, carbon dioxide (CO2) treatment, and/or hydrogen gas (H2) treatment. In some implementations, the first porous structure 316 and/or the second porous structure 326 may be derived from a carbon-containing gaseous species that can be controlled by gas-solid reactions under non-equilibrium conditions. Deriving the first porous structure 316 and/or the second porous structure 326 in this manner may involve recombination of carbon-containing radicals formed from the controlled cooling of carbon-containing plasma species (which can be generated by excitement or compaction of feedstock carbon-containing gaseous and/or plasma species in a suitable chemical reactor).
In some implementations, the first aggregates 312 and/or the second aggregates 322 may have a percentage of carbon to other elements, except hydrogen, within each respective aggregate of greater than 99%. In some instances, a median size of each aggregate may be between approximately 0.1 microns and 50 microns. The first aggregates 312 and/or the second aggregates 322 may also include metal organic frameworks (MOFs).
In some aspects, the first thin film 310 and/or the second thin film 320 (as well as any additional thin films disposed on their respective immediately preceding thin film) may be created as a layer of material and/or aggregates. The layer may range from fractions of a nanometer (in instances of a monolayer) to several microns in thickness, such as between approximately 0 and 5 microns, between approximately 5 and 10 microns, between approximately 10 and 15 microns, or greater than 15 microns. Any of the materials and/or aggregates disclosed herein, such as CNOs, may be incorporated into the first thin film 310 and/or the second thin film 320 to result in the described thickness levels.
In some implementations, the first thin film 310 may be deposited onto the second substrate 102 of
In some implementations, the first porous structure 316 and second porous structure 326 may collectively define a host structure 328, for example, as shown in
The host structure 328, when provided within the electrode 300 as shown in
In some aspects, each of the first porous structure 316 and/or the second porous structure 326 may have a porosity created by one or more of a thermal process, a carbon dioxide (CO2) gas treatment, or a hydrogen gas (H2) treatment. Specifically, the micro, meso, and macro porous pathways of the host structure 328 of the electrode 300 may include macroporous pathways, mesoporous pathways, and/or microporous pathways, for example, in which the macroporous pathways have a principal dimension greater than 50 nm, the mesoporous pathways have a principal dimension between approximately 20 nm and 50 nm, and the microporous pathways have a principal dimension less than 4 nm. As such, the macroporous pathways and mesoporous pathways can provide tunable conduits for transporting lithium ions 125, and the microporous pathways may confine active materials within the electrode 300.
In some implementations, the electrode 300 may include more than two thin films such as one or more additional thin films. Each of the one or more additional thin films may include individual aggregates interconnected with each other across different thin films, with at least some of the thin films having different concentration levels of aggregates. As a result, the concentration levels of any thin film may be varied (such as by gradation) to achieve particular electrical resistance (or conductance) values. For example, in some implementations, the concentration levels of aggregates may progressively decline between the first thin film 310 and the last thin film (such as in a direction from the second substrate 102 toward the separator 150 and the first substrate 101 of the battery 100 of
The host structure 328 may be prepared with multiple active sites on exposed surfaces of the first aggregates 312 and/or the second aggregates 322. These active sites, as well as the exposed surfaces of the first aggregates 312 and/or the second aggregates 322, may be configured for ex-situ electrodeposition, such as electroplating, prior to incorporation of the electrode 300 into the battery 100. Electroplating is a process that creates a lithium layer 330 (including lithium on exposed surfaces of the host structure 328) through chemical reduction of metal cations by application of a direct current. In implementations where the electrode 300 is configured to serve as the anode 120 of the battery 100 in
In various implementations, excess lithium provided by the lithium layer 330 may increase the number of lithium ions 125 available for transporting in the battery 100, thereby increasing the storage capacity, longevity, and performance of the battery 100 (as compared with traditional lithium-ion and/or lithium-sulfur batteries).
In some aspects, the lithium layer 330 may be configured to produce lithium-intercalated graphite (LiC6) and/or lithiated graphite based on chemical reactions with the first aggregates 312 and/or the second aggregates 322. Lithium intercalated between alternating graphene layers may migrate or be transported within the electrode 300 due to differences in electrochemical gradients during operational cycling of the battery 100, which in turn may increase the energy storage and power delivery of the battery 100.
In some instances, the graphene 400 may be stacked on top of itself to form a bulk material, such as graphite including multiple discrete graphene stacked parallel to each other in a three dimensional, crystalline, long-range order. The number of discrete graphene in the resulting bulk material may depend on one or more properties of the material. In the case of layers of the graphene 400, each layer of the graphene 400 may be a 2D material including up to 10 layers. In some implementations, the graphene 400 shown in
The secondary layer 720 may be disposed on the primary layer 710 and may include a non-concentric co-planar junction 722. In some aspects, the non-concentric co-planar junction 722 may include a first layer of platelets 724 joined together. Each platelet 724 may be, for example, the graphene nanoplatelet 500 and/or the aggregate 600 and may have similar dimensionality to adjacent platelets connected together (such as to form the first layer of platelets 524) at respective non-concentration co-planar junctions 722. Each platelet of the first layer of platelets 724 may be oriented to other platelets at a first angle 726. In addition, a second layer of platelets 728 may extend from the first layer of platelets 724 at respective non-concentric co-planar junctions 722 at a second angle 730. In some aspects, the second angle 730 may be different than the first angle 726. In addition, or in the alternative, the primary layer 710 may be rotated relative to the secondary layer 720 by approximately 90 degrees.
The carbon-based scaffold 802 shown in
In some aspects, the carbon-based scaffold 802 may include CNO oxides organized as a monolithic and/or interconnected growth and be produced in a thermal reactor. The carbon-based scaffold 802 may be decorated with cobalt nanoparticles 804 according to the following example recipe: cobalt(II) acetate (C4H6CoO4), the cobalt salt of acetic acid (often found as tetrahydrate Co(CH3CO2)2.4H2O, which may be abbreviated as Co(OAc)2.4H2O, may be flowed into the thermal reactor at a ratio of approximately 59.60 wt % corresponding to 40.40 wt % carbon (referring to carbon in CNO form), resulting in the functionalization of active sites on the CNO oxides with cobalt, showing cobalt-decorated CNOs at a 15,000× level, respectively. In some implementations, suitable gas mixtures used to produce Carbon #29 and/or the cobalt-decorated CNOs may include the following steps:
In some implementations, each pore may have a width or dimension between approximately 0.0 nm and 0.5 nm, between approximately 0.0 and 0.1 nm, between approximately 0.0 and 6.0 nm, or between approximately 0.0 and 35 nm. Each CNO of the plurality of CNOs 1002 may also have a second concentration 1012 at the core region 1006 of interconnected carbons. The second concentration 1012 may include a plurality of relatively lower-density regions arranged concentrically. The second concentration 1012 may be lower than the first concentration 1010 between approximately 0.0 g/cc and 1.0 g/cc or between approximately 1.0 g/cc and 1.5 g/cc. The relationship between the first concentration 1010 and the second concentration 1012 may increase the ability to enclose and/or confine sulfur or lithium polysulfides (PS). For example, sulfur and/or lithium polysulfides may travel through the first concentration 1010 and be at least temporarily confined within and/or interspersed throughout the second concentration 1012 during operational cycling of a lithium-sulfur battery.
Pros for DOL include reducing viscosity of the electrolyte 130. Lower viscosity levels of the electrolyte 130 may permit easier flow of ions, such as lithium ions, to and from the cathode and anode. Other example pros of DOL include improvements in formation of shorter polysulfides during battery cycling. The shorter polysulfides may be easier to confine within specific regions of the electrode 300 and/or the cathode 110 relative to their long-chain polysulfide counterparts, thereby improving overall performance of the battery 100. DOL also imparts stability to solid lithium metal anodes, such as the anode 220 of the battery 200 of
Pros for DME include providing relatively high solubility to elemental sulfur. DME may also, due to its chemical structure and/or other properties, provide stability to polysulfides suspended in DME. However, DME also presents several cons, including having a relatively high viscosity and raising interfacial resistance, which may prevent facile ionic flow.
Pros for TEGDME include providing solvation capabilities for lithium salts, thereby allowing for free formation and flow of lithium ions. TEGDME also provides a lower discharge voltage plateau, but suffers from a high viscosity, which may impede ionic flow. In some implementations, various dilution ratios, concentrations, and volumes of DOL, DME, and/or TEGDME may be mixed together, in liquid-phase, at room temperature to produce any of the presently disclosed mixtures or compositions.
As shown in the graph 1200, the new solvent package demonstrates an approximate 22% performance improvement in ionic conductivity measured in milli-siemens per centimeter (mS/cm). The new electrolyte demonstrates an approximate 21% performance improvement in ionic conductivity measured in mS/cm. The new electrolyte may be used in any of the presently disclosed battery and/or electrochemical cell implementations, such as with the electrode 300 of
In some implementations, the complex 1900, with an approximate maximum dimension of 2 nm, may be used to bind to polysulfide intermediates, such the polysulfide intermediate 1920, which may be created during battery cycling of the battery 100 of
In some implementations, formed complexes between the MBT 2410 and the sulfur ions 2420, such as a first complex 2430 and a second complex 2440, may experience decreased solubility and diffusion in the MBT-containing electrolytes due to the larger molecular size of the complexes relative to the sulfur ion 2420. As a result, these larger sized complexes may become trapped in regions and/or pores of the electrode 300. The entrapment of these larger sized complexes within the cathode 110 may result in fewer complexes moving within the electrolyte 130, thereby failing to impede movement of the lithium ions 125. As a result, the entrapment of larger sized complexes within the cathode 110 increases the speed, rate, and amount of lithium ions 125 that can be transported from the anode 120 through the electrolyte 130 towards the cathode 110. Increasing the amount of freely movable and/or transportable lithium ions unimpeded by lithium-containing polysulfide intermediates in the cathode 110 may increase the energy capacity and improve electric power delivery efficiency of the battery 100.
The sulfur vulcanization accelerators 2500 may be further classified as “primary accelerators” or “secondary accelerators.” Primary accelerators may include thiazones and sulfenamides. In some aspects, thioreas and dicarbamates can function as both primary and secondary accelerators. In one implementation, electrolyte solutions may contain both primary and secondary accelerators. In this implementation, secondary accelerators may be used to activate primary accelerators. That is, the process 2300 of
In some implementations, additional chemical molecules (not shown in
The core-shell structures may join together in, for example, the electrode 300 when configured as the cathode 110, to create any of the porosity types shown in the schematic diagram 3000. For example, the electrode 300 may include any of a porosity type 13010, a porosity type II 2030, and a porosity type III 3030. In some implementations, the porosity type 13010 may include a first pore 3011, a second pore 3012, and a third pore 3013, all sized with a principal dimension of less than 5 nm to retain polysulfides Some polysulfides may grow in size upon forming larger complexes and become immovably lodged within, for example, pores of the porosity type I 3010. In addition, or the alternative, aggregates may be joined together to create pores of the porosity type II 3020 and/or of the porosity type III 3030 to correspondingly retain polysulfides and/or polysulfides complexed with other chemical molecules as may be needed to mitigate polysulfide shuttling for larger polysulfides and/or complexes.
As used herein, a phrase referring to “at least one of” or “one or more of” a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c.
The various illustrative components, logic, logical blocks, modules, circuits, operations, and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or combinations of hardware, firmware, or software, including the structures disclosed in this specification and the structural equivalents thereof. The interchangeability of hardware, firmware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described above. Whether such functionality is implemented in hardware, firmware or software depends upon the application and design constraints imposed on the overall system.
Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.
Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above in combination with one another, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single product or packaged into multiple products.
This Patent Application is a continuation-in-part application and claims priority to U.S. patent application Ser. No. 17/209,038 entitled “CARBON COMPOSITE ANODE WITH EX-SITU ELECTRODEPOSITED LITHIUM” filed on Mar. 22, 2021, which is a continuation-in-part application and claims priority to U.S. patent application Ser. No. 16/942,229 entitled “CARBON-BASED STRUCTURES FOR INCORPORATION INTO LITHIUM (LI) ION BATTERY ELECTRODES filed on Jul. 29, 2020, which is a continuation-in-part application of and claims priority to U.S. patent application Ser. No. 16/785,020 entitled “3D SELF-ASSEMBLED MULTI-MODAL CARBON BASED PARTICLE” filed on Feb. 7, 2020 and to U.S. patent application Ser. No. 16/785,076 entitled “3D SELF-ASSEMBLED MULTI-MODAL CARBON BASED PARTICLES INTEGRATED INTO A CONTINUOUS FILM LAYER” filed on Feb. 7, 2020, both of which claim priority to U.S. Provisional Patent Application No. 62/942,103 entitled “3D HIERARCHICAL MESOPOROUS CARBON-BASED PARTICLES INTEGRATED INTO A CONTINUOUS ELECTRODE FILM LAYER” filed on Nov. 30, 2019 and to U.S. Provisional Patent Application No. 62/926,225 entitled “3D HIERARCHICAL MESOPOROUS CARBON-BASED PARTICLES INTEGRATED INTO A CONTINUOUS ELECTRODE FILM LAYER” filed on Oct. 25, 2019, and this Patent application claims the benefit of priority to U.S. Provisional Patent Application No. 63/019,145, entitled “RUBBER VULCANIZATION ACCELERATORS AS ELECTROLYTE ADDITIVES” filed on May 1, 2020, and to U.S. Provisional Patent Application No. 63/018,930, entitled “PREVENTING POLYSULFIDE MIGRATION” filed on May 1, 2020, all of which are assigned to the assignee hereof. The disclosures of all prior Applications are considered part of and are incorporated by reference in this Patent Application in their respective entireties.
| Number | Date | Country | |
|---|---|---|---|
| 62942103 | Nov 2019 | US | |
| 62926225 | Oct 2019 | US | |
| 63018930 | May 2020 | US | |
| 63019145 | May 2020 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17209038 | Mar 2021 | US |
| Child | 17236291 | US | |
| Parent | 16942229 | Jul 2020 | US |
| Child | 17209038 | US | |
| Parent | 16785020 | Feb 2020 | US |
| Child | 16942229 | US | |
| Parent | 16785076 | Feb 2020 | US |
| Child | 16785020 | US |
