Patent Application
20130089769
This disclosure is generally directed to electrochemical energy cells.
The operation of a battery can be based on electrochemical reactions in which electrons are produced. The electrons can flow from the negative terminal of the battery to the positive terminal through a load connected between the positive and negative terminals, forming an electrical current produced by the battery.
Aspects of this disclosure relate to an electrochemical energy cell that includes at least one galvanic cell including: an anode electrode unit; a cathode electrode unit; an electrolyte body between the anode and cathode electrode units and contacting both the anode and cathode electrode units; and a separator layer including the electrolyte body and placed within the cell to contact both the anode and cathode electrode units to bring the anode and cathode electrode units in contact with the electrolyte body. The cathode electrode unit includes a cathode material comprising a powder mixture of a powder of hydrated ruthenium oxide and one or more additives. The anode electrode unit includes a structure formed of an oxidizable metal. The separator layer includes a material that is porous to ions in liquid and is electrically non-conductive.
One or more optional features may be included or involved with the electrochemical energy cell. The separator layer can include a permeable, electrically insulating separator layer saturated with the electrolyte body. The one or more additives can include activated carbon. The cathode material can be configured to enable the cell to have one or more properties including a first property of having an increased level of conductivity in the cell, a second property to increase a level of a rate of chemical and electrochemical reactions related to an operation of a battery, or a third property to suppress one or more reactions that are harmful to the battery. The electrochemical energy cell can include a cathode current collector structure, where the cathode material is suspended in the electrolyte body and spread over the cathode current collector structure. The cathode electrode unit can include a coating of the cathode material on an electrically conductive, chemically inert material that serves as a cathode current collector. The coating of the cathode material can be a product of at least one of a Langmuir-Blodgett-based coating, a screen printing, an inkjet printing, an aerosol-based printing, a gravure coating, a reverse gravure coating, and a deposition. The structure of the anode electrode unit can be formed of the oxidizable metal and additives to contribute to one or more properties of the cell, the one or more properties can include: a property related to increasing a level of a conductivity in the cell, a property related to increasing a rate of a chemical reaction or an electrochemical reaction related to a battery performance, a property related to desecrating a rate of reactions in the cell that are detrimental to a battery performance. An entirety of the anode electrode unit can be formed as an anode current collector from a form of the oxidizable metal. The cell can have electrical contact, where the electrical contact can have the oxidizable metal or another conductive material. A part of the anode electrode unit can be formed as an anode current collector, where in some cases, only a part of the entirety of the anode electrode unit can be formed as an anode current collector. The anode current collector can be covered, coated or in contact with a form of the oxidizable metal or another conductive metal as an electrical contact. The electrolyte body can include a solvent and solutes that affect chemical and electrochemical reactions related to a battery. The electrochemical energy cell can be configured to operate as a battery. The cathode material can have an effective surface area over which a battery operation occurs, where the effective surface area of the cathode material affects a level of a performance of the battery, and where the effective surface area can be larger than a footprint of the cell. The electrochemical energy cell can be configured to operate as a battery, where the battery can be a folded design structure and/or has the cathode electrode unit or the anode electrode unit substantially positioned within a pocket structure of the battery. The electrochemical energy cell can be configured to operate as a battery, where the cathode material can have an effective surface area that affects a level of a performance of the battery, and a size of the effective surface area can be determined as a function of at least one of the following: material properties of the cathode material, a porosity of hydrated ruthenium oxide particles, a porosity of activated carbon particles, sizes of the hydrated ruthenium oxide and activated carbon particles, or a mixing method involving placing the cell in a sonic bath. The cathode electrode unit can include a cathode current collector and a paste of the cathode material spread on the cathode current collector. The cathode electrode unit can also include additives suspended in an electrolyte spread on the cathode current collector. The cathode electrode unit can include a cathode current collector comprising a mesh with holes, where the cathode electrode unit can include additives pressed through the mesh of the cathode current collector. The cathode electrode unit can include a cathode current collector coated by the cathode material. The cathode electrode unit can include a cathode current collector, where the cathode current collector can include a material that is electrically conductive and chemically inactive in regards to a battery operation. The material for the cathode current collector can include at least one of graphite or carbon cloth. The additives can include one or more of agar, sucrose, sorbitol, platinum, palladium, iridium oxide, indium oxide, magnetite, Nafion™, metal-functionalized carbon nanotubes, nickel-plated carbon nanotubes, titanium dioxide, tungsten carbide, sodium chloride, and polyethylene glycols. The cathode material can include another material configured to receive electrons from a circuit and ions from the electrolyte body, and configured to facilitate a plurality of oxidation states. The structure for the anode electrode unit can be in a form of a layer, a sheet, a foil or a mesh. The oxidizable metal can be at least one of zinc, aluminum, tin or lead. The anode electrode unit can include a layer of an active anode material, including a powder of the oxidizable metal, and where the layer of the active anode material can be coated on an electrically-conductive, chemically inactive anode current collector. The separator layer can be electrically insulating and able to be permeated with the electrolyte body to allow movement of ions between the anode and the cathode electrode units. The separator layer can include at least one of a glass, a fiber material, a filter paper or paper, or an electrically isolating and permeable material. The electrolyte body can include a liquid solution or a gel that is configured to permit a movement of ions between the anode and the cathode electrode units, accept ions for a battery from the anode electrode unit and/or supply ions to the cathode electrode unit. The electrolyte body can be configured to increase a level of a capacity of the cell by having a property that affects a rate of electron acceptance from an external circuit by having the cathode material of at least the powder of hydrated ruthenium oxide in the cell. The electrolyte body can include a composition that is configured to increase a level of a cell cycle lifetime of the cell by supporting cathode reactions that are reversible. The electrolyte body can include an aqueous solution of salts, organic acids, inorganic acids, and other additives. The electrolyte body can include a solution of an organic solvent and salts, additives, organic acids, and inorganic acids. The electrolyte body can be in a gel form, where the gel form can include gelling agents. The gelling agents can include at least one of agar or carboxymethyl cellulose.
Other aspects of the disclosure describe a device comprising an electrochemical cell, the electrochemical cell comprising: an anode electrode unit; a cathode electrode unit; and a first electrolyte body sandwiched between the anode and the electrode units. The cathode electrode unit includes a cathode material having at least a powder mixture of a powder of ruthenium oxide with activated carbon (AC) particles suspended in a second electrolyte body. The electrochemical cell is bendable and twistable to form a non-planar shape. The electrochemical cell is configured for a reduction-oxidation (redox) reaction to generate power at a surface of one or both of the electrode units.
Other aspects of the disclosure describe a method of fabricating a flexible electrochemical cell. The method includes: forming a backing layer of predetermined dimensions; identifying a predetermined active area on a surface of the backing layer; mixing a powder mixture from a powder of hydrated ruthenium oxide and a powder of activated carbon; preparing a paste from the powder mixture and an electrolyte; depositing the paste on the active area on the backing layer; applying the paste into the backing layer, thereby forming a cathode electrode unit, wherein the backing layer serves as a current collector; forming a metal anode electrode unit; forming a separator layer of predetermined dimensions from a permeable electrically insulating material; positioning the separator layer on the cathode electrode unit contiguous to the paste dispersed on the active area; impregnating the separator layer with the electrolyte; and attaching the metal anode electrode unit to the cathode electrode unit with the separator layer sandwiched therebetween.
One or more optional features may be included or involved with the electrochemical cell. The formation of the backing layer can include forming the backing layer of predetermined dimensions from a flexible metal, Mylar, plastic mesh or foil coated with an electrically conductive, chemically isolating polymer comprising polyaniline or polypyrrole. The application of the paste can include applying the paste into the active area on the backing foil, thereby forming the cathode electrode unit. The formation of the backing layer can involve forming the backing layer of predetermined dimensions from a flexible graphite mesh or carbon cloth. The metal anode electrode unit can be formed from a flexible sheet or foil of an oxidizable metal or the metal anode electrode unit can be formed from a flexible mesh of an oxidizable metal.
The details of one or more implementations are set further in the accompanying drawings and the description below. Other features will be apparent from the description and the drawings, and from the claims.
FIGS. 5A-5H-B illustrate a sequence of operations of an example method of manufacturing a prototype of one variant design of the electrochemical energy cell.
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various example embodiments. It will be apparent, however, that some of these embodiments may be practiced without these specific details. The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and aspects are apparent from the description and drawings, and from the claims.
A battery can “hold” energy for a long period of time when in a dormant state until electrons flow from the negative to the positive terminal. The chemical reaction can be launched once an electric load is created between the positive and negative terminals. In some batteries, an electrical current can be created when one material oxidizes, or gives up electrons, while another material immersed in an electrolyte becomes reduced, or gains electrons. In the reverse process, when a rechargeable battery is connected to an electrical power source, the flow of electrons can be opposite, so that the material that oxidizes during discharge gains electrons, while the other material gives up electrons. A non-rechargeable (single-use) battery is sometimes called a “primary battery.”
A capacitor can refer to a passive electronic component that stores energy in the form of an electrostatic field. In one form, for example, the capacitor can include a pair of conducting plates separated by an insulating material, e.g., a dielectric. The capacitance can be directly proportional to the surface area of the plates, and can be inversely proportional to the separation between the plates. The capacitance of a capacitor also depends on the dielectric constant of the substance separating the plates. Some capacitors rely on a phenomenon known as double-layer capacitance, where the positive and negative charges are collected on a particulate surface and the electrolyte it is immersed in, or on a phenomenon known as pseudocapacitance, where some electrode systems behave like capacitors in the sense that the potential they display is proportional to the amount of charge passed to or taken from the electrode.
Some embodiments may involve batteries, or galvanic cells, with all or some of the features described throughout this disclosure, which are designed and operated to be rechargeable. In some embodiments, these batteries may require low (e.g., below 1.5 volts) charge voltages, and may be safe in use. Some embodiments may involve batteries, or electrochemical energy cells, with all or some of the features described throughout this disclosure, which are designed and operated as primary (non-rechargeable) batteries. These batteries may be safe in use.
The described embodiments herein may have different physical designs for the battery. For example, there can be designs that use different current collector structures as a part of the anode or the cathode electrode unit, where numerous alternative physical structures can serve as an anode current collector that goes into the construction of the anode or as a cathode current collector that goes into the construction of the cathode.
The described embodiments herein may have various physical shapes for the battery. For example, one design results in a sandwich-like, single-layer battery; another design results in a “cathode-in-pocket” battery that effectively puts the cathode in a pocket made of the anode; another design results in an “anode-in-pocket” battery that effectively puts the anode in a pocket made of the cathode; and another design results in a “folded” battery that effectively folds the anode and cathode “around” each other in an interlocking manner. Other designs or combinations of these designs are within the scope of this disclosure.
The described embodiments herein may have a coated structure as a combined cathode current collector and cathode material (e.g., the coated structure by itself may be the entire cathode electrode unit). The described embodiments herein may have a coated structure as a combined anode current collector and cathode material (e.g., the coated structure by itself may be the entire anode electrode unit). Other coated structures may be within the scope of this disclosure.
The described embodiments herein may have different chemical designs and compositions for the battery. For example, there may be various additives (or combinations of the various additives) to the cathode material, anode material, and/or the electrolyte material.
The terms for “electrochemical energy cell,” “electrochemical cell,” “galvanic cell,” or “battery,” for example, can be used interchangeably. In some embodiments, an “electrochemical cell” or “electrochemical energy cell” can also imply “hybrid battery/capacitor cell.”
Referring to
In various embodiments, the electrochemical energy cell can include, for example, the following components.
a. A cathode electrode unit 20, comprising either:
b. A separator unit 70;
c. An electrolyte body 60, comprising an electrolyte material 62 and possibly electrolyte additives as described in Table 1.
d. An anode electrode unit 40, comprising either:
e. A cathode contact unit 80 and an anode contact unit 90,
f. A sealing and packaging unit or method 100.
The formation of these components shall be described in detail in this Section. It should be understood that any variants of the cathode electrode unit 20, separator unit 70, electrolyte body 60 and anode electrode unit 40 may be used in any combination to form the thin electrochemical cell 10. The fabrication methods to obtain batteries with different form factors are also described in this section. It should be understood that any variants of the cathode electrode unit 20, separator unit 70, electrolyte body 60 and anode electrode unit 40 may be used in any combination in the fabrication of any of the form factors described.
The thin electrochemical energy cell can include, for example, one or more of the following features:
a. The cathode active material 22 may be formed by the compounding of activated carbon (abbreviation: AC, chemical composition: C) particles with hydrated ruthenium oxide particles. Additionally, the cathode active material 22 may be formed by the compounding of carbon nanotube (abbreviation: CNT, chemical composition: C) or graphene particles with hydrated ruthenium oxide particles. Note that the chemical composition RuO2.xH2O, can refers to “ruthenium oxide hydrate” or “hydrated ruthenium oxide”. Further, note that from here on, the term “particles” may mean “particles or nanoparticles”. The volume ratios of the materials in either the AC:RuO2.xH2O mixture or the CNT:RuO2.xH2O mixture may vary from 0%:100% to 100%:0%, depending on the requirements for the battery. For one embodiment, for example, this ratio may be 50%:50% for either mixture. Additionally, it is possible to form the cathode active material 22 by compounding both AC and CNT with RuO2.xH2O, or by compounding any other conductivity-enhancing additive with RuO2.xH2O.
b. The cathode material additives 28 may include Nafion™, iridium oxide, indium oxide, sodium chloride, platinum black, palladium, Agar, metal functionalized carbon-nanotubes (Ni-plated carbon nanotubes for example), titanium dioxide, tungsten carbide, or other materials. When Nafion™ is utilized, for example, it may be used in the form of a solution where the concentration may be 5% by weight or less. If iridium oxide, indium oxide, sodium chloride or similar materials are used, for example, the amount used may be 10 mg or less per each cm2 of active battery area.
c. The cathode current collector structure 24 may include one or more of the following structures and/or materials:
d. If the coated cathode structure 30 is used in the battery construction, it may be prepared in one of the following structures:
e. The electrolyte material 62 may be a mixture including ethylene glycol, glycerol, boric acid, citric acid, hydrochloric acid, other weak or strong acids, sodium citrate, zinc chloride, zinc acetate, zinc perchlorate, ammonium chloride, ammonium hydroxide, sodium chloride, or other salts. Not all of these components may be present in the particular electrolyte composition that is implemented. The mixture can be in the range of pH 0 to pH 7 (i.e. acidic). The mixture can be in the range of pH 7 to pH 14 (i.e. basic). As an example, the citric acid may be prepared with 400 mg of citric acid crystals dissolved in 100 cm3 of water, or with 10 g of citric acid crystals dissolved in 100 cm3 of water, or with 50 g of citric acid crystals dissolved in 100 cm3 of water. The boric acid may be prepared with 5 grams or less of boric acid crystals dissolved in 100 cm3 of water. The hydrochloric acid may be 37% by weight hydrochloric acid. An example embodiment of the electrolyte may be prepared with the following volume percentages: 25% hydrochloric acid (at 37% by weight concentration), 33.75% ethylene glycol, 27.75% boric acid and 13.5% citric acid. Other embodiments may be selected from among the electrolyte composition options described herein. A few drops of hydrochloric acid can be added to adjust the pH to more acidic values. A few drops of ammonium hydroxide can be added to adjust the pH to less acidic values.
f. The electrolyte additives 68 may be amounts of polyaniline, polypyrrole, zinc oxide, indium oxide, iridium oxide, various other metal oxides, sodium chloride, sodium citrate, sodium phosphate, potassium phosphate, various other salts, agar, sucrose, glucose, low-molecular-weight polyethylene glycol, or Nafion™, among others.
g. The electrolyte may be present in the form of a gel, the gelled electrolyte material 64, created from an electrolyte material 62 as the liquid base and gelling agents 68. The gelling agent 68 may be one or a mixture of any of the following materials: Agar, cellulose, carboxymethyl cellulose, methyl cellulose, pectin, gelatin, sorbitol, glycerol, carrageenan, polyethylene glycol and other materials with thickening or colloid properties. Surfactants may be included to aid with the formation of a flat, thin gel and for better connection between the gel and electrode surfaces.
h. The separator unit or separator layer 70 may comprise of a thin, flexible sheet, made of any material, referred to as the separator material 72, that is electrically insulating, porous enough to allow for ion transport, and is capable of absorbing, or being impregnated by, the electrolyte material 62 without being damaged by the electrolyte material. In some embodiments, for example, the following materials may be used as separator material 72: Glass fiber filter paper, Nafion™ in sheet form, separators available from Celgard™, separators available from AMS™, separators from other separator suppliers, tissue paper, and cheesecloth. The separator material 72 may also be made of the gelled electrolyte material 64 itself as described above if that option is exercised, produced for instance by mixing any gelling agent 66 listed above or others with water, electrolyte material 62, ethylene glycol or glycerol, or any mixture of these liquids. In this case, the separator unit 70 is made of a thin slice of the gel electrolyte material 64. The separator unit 70 may also be a combination of alternating layers of the gelled electrolyte material 64 and separator material 72, where both the gelled electrolyte material 64 and the separator material 72 may be chosen from the options described herein.
i. The anode active material 42 may include:
j. The anode current collector structure if in use, for example, may include:
k. When used, the sealing unit 100 can be made of several parts, from an electrically insulating and chemically isolating material, such as a thin plastic foil, or a sheet of laminating material or a sheet of plastic foil treated for gas and liquid impermeability, which may be self-adhesive on one side for ease of battery fabrication.
The thin electrochemical energy cell can be fabricated in several form factors (as described herein) using any of the possible combinations of cathode electrode unit 20, anode electrode unit 40, separator unit 70, and electrolyte body 60, along with (if necessary; cathode and anode contact units 80 and 90 respectively, and a sealing unit 100 if necessitated by the structure.
Referring to
a. the coated cathode structure 30 as the cathode electrode unit 20,
b. a foil of the anode material 42 as the anode electrode unit 40, and
c. a layer of filter paper as the separator unit 70.
It should be understood that a method similar to those shown in
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FIGS. 5A-5H-B illustrate an example of a method for the assemblage of the electrochemical energy cell 10. This example, in particular, is for the assemblage of the type “anode-in-pocket cell” 16, using at least the following:
It should be understood that a method similar to those shown in
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It should be understood that a similar and parallel method of fabrication may be used to construct the “cathode-in-pocket” cell 14, swapping the anode and cathode current collectors and materials in the techniques described above in FIGS. 5A through 5H-B.
Another alternative method of constructing a cell, called a “folded cell” 18, involves forming a multiple-layered battery structure by folding anode electrode units 40 and cathode electrode units around each other, and separating them with one or more separator structures 70, as shown schematically in the example of
Other example embodiments may include one or more of the other listed features in Table 1.
In some embodiments, a multiple-layer cathode structure (e.g., folded mesh, carbon veil, or layers of the same, as well as multiple-layer coatings on a single cathode current collector) can add capacity with layer thickness. This multiple-layer cathode structure can lead to extremely high capacities.
The described features may also be implemented in one or more combinations of the following embodiments.
Some battery and capacitor designs might incorporate a structure serving as a “current collector.” The anode and cathode electrode units have separate current collectors, as the anode current collector and cathode current collector, respectively. This structure can to be electrically conductive, and it may be chemically inert for the purposes of the battery operation. In the battery, this structure can be in electrical contact with a separate anode or cathode material as applicable to collect electrons from the battery operation and conduct them to the outside load (in the case of an anode current collector) or supply electrons from the outside to the battery operation (in the case of a cathode current collector). Also, positive and negative lead contacts can be electrically connected to the cathode electrode unit and the anode electrode unit, respectively.
Some embodiments may relate to a high capacitance battery or electrochemical energy cell, in which the battery or cell can include, as a cathode material, a powdery mixture of hydrated ruthenium oxide particles and/or activated carbon particles and possibly further conductivity-enhancing additives suspended in an electrolyte. In some embodiments, this cathode material may be spread over the cathode current collector. In some embodiments, this cathode material may be coated over the cathode current collector. The cathode current collector may take the form of a thin, conductive sheet or thin, conductive mesh.
Some embodiments involve an electrochemical energy cell that has at least one battery cell including: an anode electrode unit; a cathode electrode unit; and a first electrolyte body sandwiched between the anode and cathode electrode units; in which the first electrolyte body may be permeating a separator material; in which the cathode electrode unit includes a cathode material having a powder mixture of a powder of hydrated ruthenium oxide (chemical formula RuO2.xH2O) with activated carbon (AC, chemical formula C) particles and possibly conductivity-enhancing additives suspended in a second electrolyte body. A variety of carbon additives can be used in the battery on the RuO2.xH2O side, such as activated carbon, carbon nanotubes, graphene, carbon nanofoam, and carbon fiber, carbon black.
Some embodiments involve an electrochemical energy cell that has the anode electrode unit placed in a pocket made of a separator unit, which itself is imbued with an electrolyte body, and all of this wrapped in a cathode electrode unit, in which the cathode electrode unit includes a cathode material having a powder mixture of a powder of hydrated ruthenium oxide (RuO2.xH2O) with activated carbon (AC) particles and possibly conductivity-enhancing additives suspended in a second electrolyte body. Such embodiments are said to be constructed with the pocket method with the anode inside.
Some embodiments involve an electrochemical energy cell that has the cathode electrode unit placed in a pocket made of a separator unit, which itself is imbued with an electrolyte body, and all of this wrapped in an anode electrode unit, in which the cathode electrode unit includes a cathode material having a powder mixture of a powder of hydrated ruthenium oxide (RuO2.xH2O) with activated carbon (AC) particles and possibly conductivity-enhancing additives suspended in a second electrolyte body. Such embodiments are said to be constructed with the pocket method with the cathode inside.
Some embodiments involve an electrochemical energy cell that has an anode electrode unit; a cathode electrode unit; and a first electrolyte body sandwiched between the anode and cathode electrode units, and the full ensemble is folded in two, three, four or more folds, in order to reduce the outer physical surface area of the cell while keeping the effective cathode and anode active areas internal to the cell the same, in which the cathode electrode unit includes a cathode material having a powder mixture of a powder of hydrated ruthenium oxide (RuO2.xH2O) with activated carbon (AC) particles and possibly conductivity-enhancing additives suspended in a second electrolyte body. Some of these structures, for example, may resemble an accordion-fold type design.
Some aspects of some embodiments may involve a thin flexible battery with high capacity that can have a maximized active surface for efficient electrochemical reactions in the cell, which can be attained by using a powdered mixture of hydrated ruthenium oxide particles and activated carbon particles or other types of carbon additives suspended in an electrolyte.
Some aspects of some embodiments may involve the use of one or more additives to the cathode material or to the electrolyte to enhance conductivity and facilitate the chemical reactions that form the basis of the cathode action, or to prevent chemical reactions that are harmful to the cathode action. Some aspects of some embodiments may involve the use of one or more additives in the electrolyte to enhance the ionic conductivity of the electrolyte. Some aspects of some embodiments may involve the use of one or more additives in the electrolyte to prevent the formation of unwanted parasitic structures with use which degrade the performance and capacity of the battery. For example, one such parasitic structure may be dendrite formation, which may degrade battery performance in terms of the number of charge/discharge cycles in a rechargeable embodiment. Some aspects of some embodiments may involve the use of one or more additives in the electrolyte or on the anode structure to enhance conductivity and facilitate the chemical reactions that form the basis of the anode action, or to prevent chemical reactions that are harmful to the anode action. Some aspects of some embodiments may involve the use of one or more additives to the cathode material, anode material, or the electrolyte to improve the rechargeability performance of the battery.
Some aspects of some embodiments may involve an electrochemical energy cell that may include at least one rechargeable or one primary thin flexible battery unit, which can have any number of the flexible thin battery cells stacked on each other or included in the same physical packaging by another arrangement, and connected in series or parallel. The connections in such a stack or combination may be internal or external to the packaging.
Some embodiments of the thin anode electrode unit can include a layer of an oxidizable metal, such as zinc, aluminum, lead, tin, or combinations thereof, for example. The oxidizable metal can be either a sheet of the oxidizable metal or may include a sputter-coated metal powder on a flexible backing material. Some embodiments of the thin anode electrode unit can be constructed from a powder of an oxidizable metal, such as zinc or tin, or their mixtures, formed into a paste or suspended in an electrolyte and either spread or coated over an anode current collector, which can be a sheet, mesh, wire, or rod structure. The coating technique may be sputtercoating, thermal spray deposition, airbrushing, ink-jetting, aerosol-based coating, screen-printing, gravure printing, reverse gravure printing, or any other coating, painting or printing technique. Some embodiments of the thin anode electrode unit can be constructed by pressing the powder of an oxidizable metal, plus optional additive(s), into a slab or patty under high pressure exceeding 10000 psi.
Some embodiments of the cathode electrode unit can include a cathode material having a powder mixture of a powder of hydrated ruthenium oxide particles with activated carbon particles mixed in a volumetric ratio. The powder mixture may be suspended in an electrolyte body to form a paste to be spread over a cathode current collector, which can be a sheet, mesh, wire or rod structure. The powder mixture may also be coated over the aforementioned cathode current collector. The coating method may involve a technique based on Langmuir-Blodgett coating, airbrushing, aerosol-coating, painting, gravure printing, reverse gravure printing, ink-jetting, screen-printing, or any other coating, painting or printing technique that would serve. The powder mixture may vary over a wide range of volume ratios between the powder of hydrated ruthenium oxide and the powder of activated carbon, or (an)other conductivity-enhancing additive(s), depending on the individual application. In some embodiments, the volume ratio of the powder of RuO2.xH2O and powder of, for instance, AC in said powder mixture can vary in a range from 0%:100% volume ratio to 100%:0% volume ratio. In some embodiments, the volume ratio can be approximately 50%:50%.
A range of a thickness of the rechargeable electrochemical energy cell can be 1 cm or less. If the aforementioned pocket or folded designs are used, a range of a thickness of the rechargeable or primary electrochemical energy cell can be 1 cm or less per each fold or pocket face. Some embodiments may be 1 mm or less per each fold, or even 100 μm or less per each fold.
Some embodiments of the electrolyte body in contact with both the anode electrode and the cathode electrode unit, as well as the electrolyte body in which the powder mixture for the cathode and/or anode materials may be suspended, may include materials from a group of materials, in which some embodiments may include water, ethylene glycol, propylene glycol, glycerol, boric acid, citric acid, hydrochloric acid, sulfuric acid, acetic acid, perchloric acid, orthophosphoric acid, or other weak or strong acids, zinc chloride, sodium chloride, sodium phosphate, sodium citrate, zinc acetate, zinc perchlorate, ammonium chloride, ammonium sulfate and other salts, tetramethylammonium chloride, and other tetraalkylammonium salts, or sodium hydroxide, potassium hydroxide, or other bases, as well as further electrolyte additives to enhance conductivity, or to assist processes beneficial to the battery operation, or to prevent processes harmful to the battery operation.
Some embodiments of the electrolyte may include additives. In some embodiments, these additives may be differing amounts of sodium chloride, indium oxide, iridium oxide, sodium citrate, sodium phosphate, potassium phosphate, zinc oxide, Nafion™, agar, sugar, or other additives.
Some embodiments may include a permeable electrically insulating separator layer saturated with the electrolyte, and sandwiched between the anode and cathode electrode units contiguous to the cathode material on one side and to the anode material on the other. The separator layer can be a material that is porous to ions in liquid and is electrically non-conductive, i.e. an ionic conductor and electronic insulator material. The separator layer may be formed from a number of materials, including glass fiber filter paper, cleanroom-grade tissue paper, styrene-grafted fluorinated ethylene polypropylene, Celgard™ separator, AMC™ separator, a sheet of gelatin or other gelled material prepared with water, or glycerol, or one of the electrolyte liquids described above, or other materials that may serve the same purpose, e.g., other commercial separators, glass beads of various sizes (ranging from tens of nanometers to tens of microns or more), Nafion™ or other ionically-conductive membranes.
Some embodiments of the structure may include a flexible backing layer of conductive graphite, which backs the cathode material spread thereon in a predetermined active area. This layer may serve as a cathode current collector as well as mechanical support and backing for the cathode material. The surface of the graphite foil may have corrugations, serrations, grooves, holes, etc., to further expand and maximize the active area of the electrochemical cell. Some embodiments of the structure may replace the conductive graphite backing layer with a layer of carbon cloth, mesh, carbon nanofoam, carbon-based inks coated on a variety of substrates, or carbon additives, with the cathode material pressed into the mesh holes where present and spread over the active area. Some embodiments of the structure may replace the conductive graphite backing layer (or other forms of carbon) with a layer of metal (e.g., copper, aluminum, gold or any other metal) mesh or foil (or nanotubes, nanowires, foam, porous metal, or a sheet) coated with an electrically conductive, chemically non-reactive polymer such as polyaniline or polypyrrole, with the cathode material being spread over the active area and pressed into the mesh holes where these holes are present in the cathode current collector. Some embodiments of the structure may replace the conductive graphite backing layer with a layer of metal foil coated with an electrically conductive, chemically non-reactive (or non-soluble in the electrolyte being used) polymer such as described above. Some embodiments of the structure may replace the conductive graphite backing layer with a layer of Mylar (or other plastic material), or other non-electrically conductive materials including cloth fibers, plastics, semiconductors, in any form (such as mesh, foil, or rod) coated with an electrically conductive, chemically non-reactive polymer such as described above. All these variants of this structure may act as a cathode current collector.
Some aspects of some embodiments may involve a method of fabricating a flexible, thin, rechargeable or primary electrochemical cell. The method may involve forming a graphite backing layer of predetermined dimensions from a flexible graphite foil (e.g., corrugations may be applied on the surface of the graphite foil), identifying a predetermined active area on a respective surface of the graphite layer, and mixing a powder mixture from a predetermined quantity of a powder of hydrated ruthenium oxide and a powder of activated carbon. The method may involve, for example, preparing a paste from the powder mixture and an electrolyte, depositing the paste onto the active area on the backing graphite layer, thereby forming a cathode electrode unit. In this case, the graphite backing layer is acting as a current collector. The method may involve forming a metal anode electrode unit, forming a separator layer of predetermined dimensions from a permeable electrically insulating material, positioning the separator layer on the cathode electrode unit contiguous to the paste dispersed on the active area, impregnating the separator layer with the electrolyte, and attaching the metal anode electrode unit to the cathode electrode unit with the separator layer sandwiched between.
Some aspects of some embodiments may involve a method of fabricating a flexible, thin, rechargeable or primary electrochemical cell. The method may involve forming a backing layer of predetermined dimensions from a flexible graphite mesh or carbon cloth, identifying a predetermined active area on a respective surface of the graphite mesh, and mixing a powder mixture from a predetermined quantity of a powder of hydrated ruthenium oxide and a powder of activated carbon. The method may involve preparing a paste from the powder mixture and an electrolyte, depositing the paste on the active area on the backing graphite mesh and pressing it into the space between the threads of the mesh, thereby forming a cathode electrode unit. In this case, for example, the mesh or cloth is acting as a current collector. The method may involve forming a metal anode electrode unit. This metal anode electrode layer may be formed from a flexible thin sheet or foil of an oxidizable metal, or from a flexible thin mesh of an oxidizable metal. The method may involve forming a separator layer of predetermined dimensions from a permeable electrically insulating material, positioning the separator layer on the cathode electrode unit contiguous to the paste dispersed on the active area, impregnating the separator layer with the electrolyte, and attaching the metal anode electrode unit to the cathode electrode unit with the separator layer sandwiched between.
Some aspects of some embodiments may involve a method of fabricating a flexible, thin, rechargeable or primary electrochemical cell. The method may involve forming a backing layer of predetermined dimensions from a flexible, thin metal or Mylar (or other similar) plastic mesh or foil coated with an electrically conductive, chemically inert polymer such as polyaniline or polypyrrole, identifying a predetermined active area on a respective surface of the mesh or foil, and mixing a powder mixture from a predetermined quantity of a powder of hydrated ruthenium oxide and a powder of activated carbon. The method may involve preparing a paste from the powder mixture and an electrolyte, depositing the paste on the active area on the backing mesh and pressing it into the space between the threads of the mesh, or spreading the paste on the active area on the backing foil, thereby forming a cathode electrode unit. In this case, the backing mesh or foil is acting as a current collector. The method may involve forming a metal anode electrode unit. The method may involve forming a separator layer of predetermined dimensions from a permeable electrically insulating material, positioning the separator layer on the cathode electrode unit contiguous to the paste dispersed on the active area, impregnating the separator layer with the electrolyte, and attaching the metal anode electrode unit to the cathode electrode unit with the separator layer sandwiched therebetween.
Some aspects of some embodiments may involve a method of fabricating a flexible, thin, rechargeable or primary electrochemical cell. This method may proceed as above, but utilizing a cathode electrode unit constructed by coating a thin chemically inactive material with a cathode material formed of nanoparticles as described above. This coating technique may be Langmuir-Blodgett-based coating, screen-printing, inkjet printing, aerosol-based printing, airbrushing, thermal spray deposition, gravure coating, reverse gravure coating, or any other technique that would serve. The method may involve forming a metal anode electrode unit. The method may involve forming a separator layer of predetermined dimensions from a permeable electrically insulating material, positioning the separator layer on the cathode electrode unit contiguous to the paste dispersed on the active area, impregnating the separator layer with the electrolyte, and attaching the metal anode electrode unit to the cathode electrode unit with the separator layer sandwiched between.
Some aspects of some embodiments may involve a method of fabricating a flexible, thin, rechargeable or primary electrochemical cell. This method may proceed as described above for the preparation of the cathode electrode unit, with the use of any of the methods and cathode current collectors described, and for the preparations of the separator and the electrolyte. The method may involve the preparation of an anode electrode unit with the use of an anode current collector and an anode material. The anode current collector may be formed from a thin flexible layer of metal coated by an electrically conductive, chemically insulating polymer such as polypyrrole or polyaniline. In other embodiments, the anode current collector may be formed from a thin, flexible layer or sheet of Mylar, or other plastic material, coated by an electrically conductive, chemically inert polymer such as polypyrrole or polyaniline. In other embodiments, the anode current collector may be formed from a thin, flexible mesh of metal coated by an electrically conductive, chemically inert polymer such as polypyrrole or polyaniline, or of a thin flexible layer of such a polymer by itself. The method may involve the preparation of the anode material from a powder of an oxidizable metallic material such as zinc or aluminum, with the possible inclusion of additives to increase conductivity and improve paste formation. A paste may be prepared from this powder mixture and the electrolyte, and spread onto the anode current collector to prepare the anode electrode unit. In other embodiments, the powder mixture may be pressed, under high pressure (exceeding 10000 psi), into a thin slab or patty, which may be placed on a backing to form the anode electrode unit, or serve as the entire anode electrode unit by itself. In other embodiments, a layer of oxidizable metal serving as the anode material may be coated over an anode current collector, chosen from the described options above, by using sputter coating, thermal spray coating, airbrushing, aerosol-based coating, or any other coating, painting or printing technique that would serve. In other embodiments, the anode current collector and anode material may be one and the same structure, a thin flexible foil or mesh formed from the anode metal, forming the anode electrode unit by itself. The battery assembly may be concluded with the placement of the separator layer between the cathode electrode unit and the anode electrode unit.
Some aspects of some embodiments may involve a first contact strip attached between the bottom of the cathode current collector and the bottom seal layer, with an end of the first contact strip extending beyond an edge thereof. A second contact strip can be attached between a top seal layer and the metal anode electrode layer, or the anode current collector when the appropriate assembly method is used, with an end of the second contact strip extending beyond an edge of the top seal layer. The top and bottom seal layers can be adhered each to the other, using chemical, thermal or mechanical adhesion techniques, laser-welding, ultrasonic welding, or a combination of these methods at the perimeter of the cell, thus forming a sealing package enveloping the cell.
Some aspects of some embodiments that are constructed using either of the pocket methods described above may involve a contact strip being attached to the electrode unit that is placed inside the pocket and reaching outwards through the mouth of the packet. The second contact may be formed by directly contacting the electrode unit that forms the outside of the pocket. The edges of the outside pocket electrode may be sealed to each other, and a seal may be formed at the opening or mouth of the pocket in an electrically insulating manner to separate the contact strip from the inside electrode from the outside electrode, thereby forming a sealed package enveloping the cell.
For some embodiments, the electrochemical cell is configured for a reduction-oxidation (redox) reaction to generate power at the electrolyte/electrode interface surface of one or both of the electrode layers.
In some embodiments, the electrochemical cell may be less than 1 mm in thickness, and weigh less than 5 grams. The electrode body may be weakly or strongly acidic. The electrode body may be weakly or strongly basic. Some embodiments may involve electrochemical energy cells that are environmentally safe, thin, and with a charge voltage at 1.5 V or below in case they are designed and operated as rechargeable batteries.
One or more of the embodiments described herein may include the following features.
Some aspects of some embodiments may involve a flexible (e.g., bendable, twistable), rechargeable or primary battery, or electrochemical cell. The electrochemical cell can be bendable and twistable to form a non-planar shape. This battery may be integrated in a flexible electronics matrix. It may be applicable for powering devices which are distributed network nodes, or medical devices, or other portable or personal electronics devices, or miniature electronic devices. In some embodiments, potential applications can be used as “skin” for prosthetics, or as aircraft fuselage or wing “skin”, or as a tent lining, for example.
Some aspects of some embodiments may include a rechargeable or primary, flexible electrochemical cell that can have a simple manufacturing process and can be highly efficient in operation.
In some embodiments, an electrochemical energy cell can have at least one galvanic cell including:
The cathode electrode unit can include a cathode material comprising a powder mixture of a powder of hydrated ruthenium oxide and one or more additives to increase conductivity and/or to enhance chemical and electrochemical reactions beneficial to the battery action or to suppress reactions harmful to the battery action, suspended in the electrolyte body and spread over a cathode current collector structure. The cathode unit can (alternatively) have a coating of the cathode material on an electrically conductive, chemically inert thin material acting as the cathode current collector. The anode electrode unit can include a structure formed of an oxidizable metal, optionally with additives to increase conductivity and/or to enhance chemical or electrochemical reactions beneficial to the battery action or to suppress reactions harmful to the battery action, where this structure may comprise the entire anode electrode unit by itself or the anode electrode unit may be constructed from an anode current collector and some form of the oxidizable metal as the anode active material in electrical contact. The separator layer can include a material that is porous to ions in liquid and is electrically non-conductive,
In some of these embodiments of the electrochemical energy cell the separator layer includes a glass fiber filter paper, cleanroom-grade tissue paper, styrene-grafted fluorinated ethylene propylene, a type of commercially-available separator or membrane materials such as Celgard™ or AMC™, a thin layer of gelled material prepared with glycerol or any other gelling and thickening agent such as agar, carboxymethyl cellulose, pectin, carrageenan, or a photo-polymerized acrylic hydrogel, or any other thin structure that may be formed to meet the qualifications of the cell. The separator layer can be treated with a surfactant or other methods to enhance the properties of the cell and to prevent battery performance degradation by way of dendrite formation. The separator layer includes a gel made with a gelling agent and electrolyte additives using one electrolyte variant or another liquid so as to yield an ionically conductive, electrically insulating gel. This option may embody the electrolyte body in with the gel separator body as well, although extra electrolyte can still be used. The materials used to construct the electrolyte variants and obtain a gel from the electrolyte liquid are referred to herein. The aforementioned additives can increase conductivity on either the cathode or anode side and may be particles of activated carbon, carbon nanotubes, graphene, other carbon-based particles, or of a commercially available battery additive. For the cathode-side conductivity-enhancing additives, the volume ratio of conductive additive to hydrated ruthenium oxide in the cathode material can vary between 0%:100% to 100%:0%. The cathode-side conductivity-enhancing additives may include non-oxidizing metals, such as gold, and the anode-side conductivity-enhancing additives may also include gold, aluminum, nickel, tin, and other oxidizing or non-oxidizing metals. The volume ratio of conductivity-enhancing additive to hydrated ruthenium oxide in the cathode material can be 50%:50%. The aforementioned additives to the cathode material to enhance chemical and electrochemical reactions can be beneficial to battery action or to suppress reactions harmful to battery action and may be agar, sucrose, sorbitol, platinum, palladium, iridium oxide, indium oxide, magnetite, Nafion™, metal-functionalized carbon nanotubes (e.g. nickel-plated carbon nanotubes), titanium dioxide, tungsten carbide, sodium chloride or other materials, and low-molecular weight or high-molecular weight polyethylene glycols. The amount of Nafion™ included may vary between 1 mL/cm2 of active area to 5 mL/cm2 of active area, and the composition of Nafion™ in solution may vary between 0.05% to 4% by volume. The aforementioned additives to the anode material to enhance chemical and electrochemical reactions beneficial to battery action or to suppress reactions harmful to battery action can be indium oxide, iridium oxide, zinc oxide, polyaniline, polypyrrole, crystalline boric acid, citric acid, acetic acid or other anhydrous acid materials, various surfactants such as sodium dodecyl sulfate, dodecyltrimethylammonium chloride or bromide, or polyethylene glycol, or other materials.
In some embodiments of the electrochemical energy cell, the cathode or anode current collector structure may include the following:
The cathode or anode current collector structure may be in any form factor including sheet (planar), block, rod, etc. The surface of the cathode or anode current collector may be modified to obtain corrugations, serrations, grooves, or holes to expand and maximize the active surface area of the battery by expanding the contact area between the anode/cathode current collectors and the anode/cathode active materials.
In some embodiments of the electrochemical energy cell, the cathode unit is made of the following:
The coating may be multiple layers of coating, such as one or more layers of cathode active material mixed with additives, or one or more layers of cathode active material followed by one or more layers of cathode additives followed by one or more layers of cathode active material, or any conceivable combination of layer order and numbers. In some embodiments, each layer of coating may be less than 10 mil (250 μm) thick.
The cathode electrode unit can have a coating that is optionally treated by annealing the coating by the method of heating the coating to a temperature between 100° C. and 300° C. for a period of time between 0.5 hours and 3 hours, and/or the cathode electrode unit can have a coating that is top-coated with a thin layer of conductive additive prior to the electrochemical cell construction.
In some aspects of some embodiments, the electrochemical energy cell can have the electrolyte body to be acidic with a pH lower than 7, or the electrolyte body can be basic with a pH higher than 8. The electrolyte body can include materials from ethylene glycol, glycerol, propylene glycol, distilled (deionized) water, boric acid, citric acid, tartaric acid, acetic acid, other organic acids, hydrochloric acid, sulfuric acid, perchloric acid, nitric acid, orthophosphoric acid, boric acid, or other inorganic acids, zinc chloride, zinc nitrate, zinc acetate, zinc perchlorate, sodium chloride, ammonium sulfate, ammonium chloride, other metal salts, tetramethylammonium chloride, tetraethylammonium chloride, tetrabutylammonium chloride, or other quaternary ammonium salts, ammonium hydroxide, sodium hydroxide, potassium hydroxide or other bases, and other solvents, acids, bases and salts.
In some aspects of some embodiments, the electrolyte body includes additives from sodium chloride, potassium chloride, sodium citrate, sodium phosphate, potassium phosphate, zinc oxide, zinc citrate, sucrose or glucose, sorbitol, zinc oxide, indium oxide, iridium oxide, platinum, palladium, titanium dioxide, tungsten carbide, or metal-enhanced carbon nanotubes (such as nickel plated carbon nanotubes), polyethylene glycol, and other materials, and other additives. These additives may serve to increase the ionic conductivity of the electrolyte, and/or to enhance chemical or electrochemical reactions beneficial to the battery action, performance and energy generation, and/or to inhibit chemical or electrochemical reactions harmful to the battery action, performance and energy generation, or these additives can serve as surfactants to enhance the contact between the electrolyte body and the anode and cathode electrode units. These additives may also serve to prevent the formation of parasitic structures, such as dendrites, which may affect battery performance. The electrolyte body may include a gel made with a gelling agent (cellulose, methyl cellulose, hydroxyethyl cellulose, agar, pectin, gelatin, carboxymethyl cellulose, or other gelling agents and optional thickening agents and surfactants) and the electrolyte liquid formed as described above.
In some aspects of some embodiments, the anode electrode unit is a thin layer, sheet, foil or mesh of oxidizable metal, and the oxidizable metal may be chosen from zinc (Zn), aluminum (Al), tin (Sb) or lead (Pb), or another metal that will be able to supply electrons for the anode action. In some embodiments, the anode electrode unit is made from an anode current collector and a paste of an oxidizable metal and other additives suspended in electrolyte and spread on or pressed through the anode current collector, or the anode electrode unit is made from an anode current collector coated with an oxidizable metal and optional additives, where the coating is obtained by sputtercoating, thermal spray deposition, airbrushing, other aerosol-based methods, Langmuir-Blodgett-based coating, gravure or reverse gravure printing, inkjet printing, screen-printing, or any other coating, deposition, painting or printing methods that would serve for coating. The coating may be multiple layers of coating, for instance one or more layers of oxidizable metal mixed with additives or other metals, or one or more layers of oxidizable metal followed by one or more layers of anode additives or other metals followed by one or more layers of oxidizable metal, or any conceivable combination of layer order and numbers. Each layer of coating may be less than 10 mil (250 μm) thick. The anode electrode unit can be made from a slab or patty made by pressing a powder of an oxidizable metal and, optionally, additives, under high pressure exceeding 10000 psi.
In some aspects of some embodiments, the anode current collector can include the following:
The ratio of powder of oxidizable metal and additives may vary between 100%:0% and 0%:100%. The additives can be chosen from zinc oxide, agar, indium oxide, iridium oxide, sucrose, glucose, boric acid, other weak organic acids, polyaniline, polypyrrole, various surfactants, or other materials.
In some aspects of some embodiments, the electrochemical energy cell can include a positive lead structure (positive contact) and a negative lead structure (negative contact), allowing the transfer of electrical current into and out of the electrochemical energy cell, each electrically connected to one of the cathode electrode unit and anode electrode unit respectively.
In some aspects of some embodiments, the electrochemical energy cell can include a packaging/sealing structure chemically isolating the other battery parts from the ambient and electrically insulating the other battery parts, except the positive and negative lead contacts, from the ambient, for which the structure is formed of an electrically insulating and chemically isolating, thin and optionally flexible material such as Mylar or other types of plastic, which may or may not feature self-adhesive properties.
In some aspects of some embodiments, the isolation properties of the packaging structure can be generated by:
Some aspects of some embodiments, involve a method of manufacturing a thin flexible electrochemical energy cell that involves forming at least one battery by an anode-center pocket battery method. The anode electrode unit, cathode electrode unit(s), electrolyte body or bodies, and packaging comprise of any of the alternative structures described herein. The anode electrode unit can be placed in a pocket made of a separator unit that is imbued with an electrolyte body and wrapped in a cathode electrode unit, or covered on both sides by a gel-type separator and wrapped in a cathode electrode unit.
Some aspects of some embodiments involve a method of manufacturing a thin flexible rechargeable electrochemical energy cell, where the method involves forming at least one battery by a cathode-center pocket battery method. For this method, the cathode electrode unit, anode electrode unit(s), electrolyte body or bodies, and packaging can be of any of the alternative structures described herein. The cathode electrode unit is placed in a pocket made of a separator unit that is imbued with an electrolyte body and wrapped in an anode electrode unit, or covered on both sides by a gel-type separator and wrapped in an anode electrode unit.
Some aspects of some embodiments relate to an electrochemical energy cell that has an anode electrode unit, a cathode electrode unit and a first electrolyte body sandwiched between the anode and cathode electrode units. The cell can be folded in two, three, four or more folds to reduce a physical surface area of the cell while keeping an effective active area the same, where the cathode electrode unit can include a cathode material having a powder mixture of a powder of hydrated ruthenium oxide (RuO2.xH2O) with activated carbon (AC) particles. The cell can resemble an accordion-fold type design.
Some aspects of some embodiments describe a method of manufacturing the electrochemical energy cell, comprising forming at least one battery by a pocket or folded battery method, where the cathode electrode unit(s), anode electrode unit(s), electrolyte body or bodies, and packaging can be any of the alternative structures described herein.
If pocket or folded designs are implemented in a structure of the battery, for example, a range of the thickness of the electrochemical energy cell can be the following:
In some aspects of some embodiments, an electrochemical energy cell includes the following:
In some aspects of some embodiments, the electrochemical energy cell can include a thin, flexible battery with a high capacity that has an active surface for electrochemical reactions in the cell, where the high capacity is attained by maximizing the active surface area by means of using, for instance, a powdered mixture of hydrated ruthenium oxide particles and activated carbon particles, or other additives described herein, suspended in an electrolyte, and the particles of RuO2.xH2O and activated carbon (or other conductivity-enhancing additive) may have been pre-processed to obtain particles with higher porosity and surface area per unit weight.
In some aspects of some embodiments, the embodiments can involve at least one thin flexible battery unit, and any number of the flexible thin battery cells stacked on each other within a single package or packaged individually, or combined in another geometric arrangement within a single package, and connected in series or parallel, with the connections being formed either within the packaging, or outside the packaging, or a combination of both approaches. In some embodiments of the electrochemical energy cell, the thin anode electrode unit includes:
In some aspects of some embodiments, the electrochemical energy cell, the cathode electrode unit includes a cathode material containing a powder mixture of hydrated ruthenium oxide particles and activated carbon particles (or another conductivity-enhancing material, as described herein), mixed in a volumetric relationship, where the powder mixture is suspended in an electrolyte body to form a paste, and where the powder mixture is variable over a range of volume ratios between the powder of hydrated ruthenium oxide and the powder of activated carbon. In some embodiments, the volume ratio of the powder of RuO2.xH2O and powder of activated carbon in the powder mixture is variable in a range from 0%:100% volume ratio to 100%:0% volume ratio. In some embodiments, one electrolyte body is in contact with the anode electrode unit, the cathode electrode unit, and another electrolyte body in which the powder mixture is suspended, in which the electrolyte bodies include the following:
The solution in the electrochemical energy cell can include:
In the solution, the “boric acid” may be prepared by dissolving 5 g or less of boric acid crystals in 100 mL of water, the “citric acid” may be prepared by dissolving 50 g or less of citric acid crystals in 100 mL of water, with drops of added hydrochloric acid to adjust acidity (optional), or other compositions. In the electrochemical energy cell, the electrolyte can include additives with differing amounts of sodium chloride, indium oxide, iridium oxide, sodium citrate, sodium phosphate, potassium phosphate, zinc oxide, Nafion™, agar, sucrose or glucose, polyethylene glycol (PEG 200, 400, 1000, 3350, or 6000), or other additives. Also, in the electrochemical energy cell, the solution can include a strong base and one or more salts, dissolved in de-ionized water, where examples include, but are not limited to the following:
In some aspects of some embodiments, a method of fabricating a flexible thin electrochemical cell involves the following:
In some aspects of some embodiments, a method involves fabricating a flexible thin electrochemical cell that utilizes a cathode electrode unit constructed by coating a thin, conductive, chemically inactive material with a cathode material formed of particles, where the coating includes Langmuir-Blodgett-based coating, screen printing, inkjet printing, aerosol-based printing, gravure coating, or reverse gravure coating. This method further involves:
In some aspects of some embodiments, a method involves fabricating the anode electrode unit of a flexible thin electrochemical cell, the method involves the following:
Some aspects of some embodiments involve a method of fabricating an electrochemical energy cell, where the method involves placing a bottom seal layer on the surface of the cathode current collector facing outward, that is to say, the surface which is not in contact with the separator and the electrolyte body, such that the edges of the bottom seal layer extend beyond the cathode current collector edges and beyond the separator edges. The method involves placing a first contact strip attached between a bottom of a cathode current collector and a bottom seal layer, with an end of the first contact strip extending beyond an edge of the bottom seal layer thereof, or opening up a hole in the bottom seal layer somewhere over the cathode current collector surface and filling this hole with an electrically conductive material such as conductive epoxy, and attaching a contact strip to this material to form the positive contact. The method also involves placing a top seal layer on the surface of the anode current collector or metal anode electrode layer facing away from the separator and the electrode body, such that the edges of the top seal layer extend beyond the anode electrode unit edges and beyond the separator edges, or opening up a hole in the bottom seal layer somewhere over the anode electrode unit surface and filling this hole with an electrically conductive material such as conductive epoxy, and attaching a contact strip to this material to form the negative contact. The top and bottom seal layers are adhered each to the other at a perimeter of the cell, thus forming a sealing package enveloping the cell. In the case of a folded or pocket structure, the method involves using a contact strip attached to the electrode unit that is placed inside a pocket and reaching outwards through the mouth of the packet, where the second contact is formed by directly contacting the electrode unit that forms an outside of the pocket, and the edges of the outside pocket electrode are sealed to each other, and a seal is formed at the opening or mouth of the pocket in an electrically insulating manner to separate at least one of the contact strips from the inside of the electrode unit from the outside of the electrode unit, thereby forming the sealed package enveloping the cell. The electrochemical cell is bendable and twistable to form a non-planar shape.
In some aspects of some embodiments, the electrochemical energy cell is configured for a reduction-oxidation (redox) reaction to generate power at the interface(s) of one (or both) of the electrode layer(s) and the electrolyte body. The electrochemical cell can be less than 1 mm in thickness, and weighs less than 5 grams, and the cell can be environmentally safe and non-toxic. The cell thickness can be less than 1 mm per number of cathode/electrolyte surfaces present in its structure, and the cell weight can be less than 5 grams per number of cathode/electrolyte surfaces present in its structure.
In some aspects of some embodiments, the thin, flexible battery cell, or an electrochemical energy cell can be comprised of thin, flexible battery cells packaged together, which can be integrated into a flexible electronics system, device or matrix, and which may be the battery or electrochemical energy cell described herein. Some embodiments have a thin, flexible battery, applicable for powering distributed network node devices, or medical devices, or portable or personal electronics, and which may be the battery or electrochemical energy cell described herein. Some embodiments can have a thin battery or electrochemical cell which may be rechargeable and require a low charge voltage, in which the low voltage is below 1.5 volts, and which may be the battery or electrochemical energy cell described herein. In some embodiments, the electrochemical energy cell can have a high capacity where the charge capacity meets or exceeds 1 mAh/cm2 of active area or where the charge capacity meets or exceeds 10 mAh/cm2 of active area.
In some aspects of some embodiments, an electrochemical energy cell can include the following:
The electrolyte body has compositions for the electrochemical cell that may be configured with and for one or more properties, including the following properties:
a. it may be designed to enhance cell capacity, for instance by enabling higher rates and net amount of electron acceptance from the outside circuit by the hydrated ruthenium oxide active cathode material,
b. it may be designed to enhance cell cycle lifetime, for instance by enabling and enhancing the cathode reactions that are easily reversible,
c. it may be an aqueous solution comprising various salts, additives, and organic and inorganic acids as described elsewhere in this application,
d. it may be a solution of an organic solvent and various salts, additives, and organic and inorganic acids as described elsewhere in this application, and/or
e. it may be prepared in the form of a gel by the addition of gelling agents such as agar, carboxymethyl cellulose, or other gelling agents as mentioned elsewhere in this disclosure.
The descriptions above are intended to illustrate possible implementations and are not restrictive. Many variations, modifications and alternatives will become apparent. For example, method steps equivalent to those shown and described may be substituted therefore, elements and methods individually described may be combined, and methodologies described as discrete may be distributed across many algorithm techniques. While this disclosure contains many specifics, these should not be construed as limitations or of what may be claimed, but rather as descriptions of features specific to particular embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations 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 sub-combination or variation of a sub-combination. 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. The scope of the disclosure should therefore be determined not with reference to only the particular descriptions above, but also with reference to the appended claims, along with their full range of equivalence.
This application claims the benefit of priority to U.S. Provisional Patent Application No. 61/328,751, entitled “Thin Flexible Rechargeable Electrochemical Energy Cell with Enhanced Capacity,” filed on Apr. 28, 2010, the disclosure of which is incorporated by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2011/034314 | 4/28/2011 | WO | 00 | 12/19/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61328751 | Apr 2010 | US |
