Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
• • H01M2/166—
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
  • H01G11/52—Separators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
  • H01G9/004—Details
  • H01G9/02—Diaphragms; Separators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M4/00—Electrodes
  • H01M4/02—Electrodes composed of, or comprising, active material
  • H01M4/36—Selection of substances as active materials, active masses, active liquids
  • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
  • H01M4/381—Alkaline or alkaline earth metals elements
  • H01M4/382—Lithium
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/417—Polyolefins
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/426—Fluorocarbon polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/431—Inorganic material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
  • H01M50/491—Porosity
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/13—Energy storage using capacitors
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/249921—Web or sheet containing structurally defined element or component
  • Y10T428/249953—Composite having voids in a component [e.g., porous, cellular, etc.]
  • Y10T428/249978—Voids specified as micro

Definitions

• the present invention relates generally to the field of porous membranes and to the fields of electric current producing cells and of separators for use in electric current producing cells. More particularly, this invention pertains to a porous separator membrane comprising an aluminum oxide and an organic polymer where the aluminum oxide has been surface modified by treatment with an organic acid to provide dispersibility in aprotic organic solvents. Also, the present invention pertains to electric current producing cells, such as lithium ion cells and capacitors, comprising such porous separators.
• An electroactive material that has been fabricated into a structure for use in an electrochemical cell is referred to as an electrode.
• the electrode on the electrochemically higher potential side is referred to as the positive electrode or the cathode, while the electrode on the electrochemically lower potential side is referred to as the negative electrode, or the anode.
• a battery may contain one or more electrochemical cells.
• an electrolyte element is interposed between the cathode and the anode.
• This electrolyte element must be electronically non-conductive to prevent short circuits, but must permit the transport of ions between the anode and the cathode.
• the electrolyte element should also be stable electrochemically and chemically toward both the anode and the cathode.
• the electrolyte element contains a porous material, referred to as a separator (since it separates or insulates the anode and the cathode from each other), and an aqueous or non-aqueous electrolyte, that usually comprises an ionic electrolyte salt and ionically conductive material, in the pores of the separator.
• a separator since it separates or insulates the anode and the cathode from each other
• an aqueous or non-aqueous electrolyte that usually comprises an ionic electrolyte salt and ionically conductive material, in the pores of the separator.
• porous separator materials include polyolefins such as polyethylenes and polypropylenes, glass fiber filter papers, and ceramic materials. Usually these separator materials are supplied as porous free-standing membranes that are interleaved with the anodes and the cathodes in the fabrication of electrochemical cells.
• a liquid organic electrolyte containing organic solvents and lithium salts is typically used as the electrolyte in the pores of the separator in the electrolyte element for rechargeable or secondary lithium ion and non-rechargeable or primary lithium electrochemical cells.
• a gel or solid polymer electrolyte containing an ionically conductive polymer and lithium salts, and optionally organic solvents, might be utilized instead of the liquid organic electrolyte.
• the separator In addition to being porous and chemically stable to the other materials of the electric current producing cell, the separator should be flexible, thin, economical in cost, and have good mechanical strength and safety properties.
• High porosity in the separator is important for obtaining the high ionic conductivity needed for effective performance in most batteries, except, for example, those batteries operating at relatively low charge and discharge rates, and for efficiency in capacitors, such as supercapacitors. It is desirable for the separator to have a porosity of at least 30 percent, and preferably 40 percent or higher, in lithium ion batteries.
• Another highly desirable feature of the separator in the electrolyte element is that it is readily wetted by the electrolyte materials that provide the ionic conductivity.
• the separator material is a polyolefin material that has non-polar surface properties
• the electrolyte materials (which typically have highly polar properties) often poorly wet the separator material. This results in longer times to fill the battery with electrolyte and potentially in low capacities in the battery due to a non-uniform distribution of electrolyte materials in the electrolyte element.
• the separators used for lithium ion batteries are typically polyolefin separators, which melt at below 200° C. and are very flammable.
• the lithium ion batteries, as well as lithium primary batteries and some capacitors, utilize highly flammable organic solvents in their electrolytes.
• a non-melting and flame retardant separator would help prevent the spread of any burning of the organic electrolyte, caused by an internal short circuit, thermal runaway, or other unsafe condition, that might spread into a larger area of the battery or capacitor and cause a major explosion.
• As lithium ion batteries are increasingly utilized for high power applications, such as for electric vehicles, the need for improved safety is greatly increased because of the very large size and high power rates of these vehicle batteries.
• the present invention utilizes non-flammable inorganic oxides, such as aluminum oxides, and preferably non-flammable organic polymers having fluorinated groups in the separators.
• This invention utilizes various inorganic oxide particle pretreatment, mixing, coating, drying, and delaminating methods for preparing such separators.
• One aspect of the present invention pertains to a separator for an electric current producing cell, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the organic acid is a sulfonic acid, preferably an aryl sulfonic acid, and more preferably a toluenesulfonic acid.
• the organic acid is a carboxylic acid.
• the aluminum oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O, wherein x is in the range of 1.0 to 1.5, and wherein the hydrated aluminum oxide is surface modified by treatment with an organic acid to form a modified hydrated aluminum oxide.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 50 to 85% by weight.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 65 to 80% by weight.
• the separator comprises 60 to 90% by weight of the modified aluminum oxide.
• the separator comprises 70 to 85% by weight of the modified aluminum oxide.
• the microporous layer is a xerogel layer.
• the organic polymer comprises a polyvinylidene fluoride polymer.
• the separator comprises a copolymer of a first fluorinated organic monomer and a second organic monomer.
• the second organic monomer is a second fluorinated organic monomer.
• the electric current producing cell is a secondary lithium ion cell. In one embodiment, the electric current producing cell is a primary lithium cell. In one embodiment, the electric current producing cell is a capacitor. In one embodiment, the separator does not melt at temperatures lower than 300° C. In one embodiment, the separator is a flame retardant separator.
• an electrochemical cell comprising an anode, a cathode, an organic electrolyte comprising a lithium salt, and a separator interposed between the anode and the cathode, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid.
• the organic acid is a sulfonic acid, preferably an aryl sulfonic acid, and more preferably a toluenesulfonic acid.
• the organic acid is a carboxylic acid.
• the aluminum oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O, wherein x is in the range of 1.0 to 1.5, and wherein the hydrated aluminum oxide is surface modified by treatment with an organic acid to form a modified hydrated aluminum oxide.
• the microporous layer is a xerogel layer.
• the anode active material of the anode is lithium.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 50 to 85% by weight. In one embodiment, the modified aluminum oxide has an Al 2 O 3 content in the range of 65 to 80% by weight.
• the organic polymer comprises a polyvinylidene fluoride polymer. In one embodiment, the organic polymer comprises a copolymer of a first fluorinated organic monomer and a second organic monomer. In one embodiment, the second organic monomer is a second fluorinated organic monomer. In one embodiment, the lithium salt is lithium hexafluorophosphate.
• a capacitor comprising two electrodes, an organic electrolyte comprising a tetraalkyl ammonium salt, and a separator interposed between the two electrodes, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the inorganic oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O wherein x is in the range of 1.0 to 1.5, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the organic acid is a sulfonic acid.
• the microporous layer is a xerogel layer.
• the organic polymer comprises a polyvinylidene fluoride polymer.
• the organic polymer comprises a copolymer of a first fluorinated organic monomer and a second organic monomer.
• the separators of the present invention provide superior safety and other key performance properties for use in electric current producing cells, including, but not limited to, lithium batteries and capacitors.
• Methods of preparing microporous xerogel separators for electrochemical cells are described in U.S. Pat. Nos. 6,153,337 and 6,306,545, and in U.S. Pat. Application 20020092155, all to Carlson et al.
• the liquid mixture described in these references for coating xerogel separators comprises an inorganic oxide, an organic binder, and typically water as the volatile liquid in the mixture.
• the liquid mixture comprises organic solvents, preferably protic organic solvents. Examples of protic organic solvents are alcohols and glycols.
• xerogel layer and “xerogel structure,” as used herein, is meant, respectively, a layer of a coating or the structure of a coating layer in which the layer and structure were formed by drying a liquid sol or sol-gel mixture to form a solid gel matrix as, for example, described in Chem. Mater ., Vol. 9, pages 1296 to 1298 (1997) by Ichinose et al.
• the microporous xerogel layers of this invention comprise a dried microporous three-dimensional solid network with pores which are interconnected in a substantially continuous fashion from one outermost surface of the layer through to the other outermost surface of the layer.
• a continuous xerogel coating layer has the materials of the xerogel in a continuous structure in the coating layer, i.e., the materials, such as inorganic oxide particles, are in contact and do not have discontinuities in the structure, such as a discontinuous layer of solid pigment particles that are separated from each other.
• xerogel pigment particles may be formed by a xerogel process involving drying a liquid solution of a suitable precursor to the pigment to form a dried mass of xerogel pigment particles, which is typically then ground to a fine powder to provide xerogel pigment particles.
• the microporous inorganic oxide layers of this invention may be, but are not limited to, xerogel layers.
• the inorganic oxide layers of the present invention may also be discontinuous layers of solid pigment particles that are not a xerogel coating layer and have discontinuities of solid pigment particles that are separated from each other in the structure of the discontinuous layer. This separation typically involves organic polymer interposed between the pigment particles.
• xerogel coating and “xerogel coating layer,” as used herein, are synonymous with the term “xerogel layer.”
• microporous describes the material of a layer or coating, in which the material possesses pores of a diameter of about 1 micron or less.
• nanoporous describes the material of a layer or coating, in which the material possesses pores of a diameter of about 100 nanometers or less.
• these pores are connected in a substantially continuous fashion from one outermost surface of the microporous layer through to the other outermost surface of the layer.
• This substantially continuous 3-dimensional microporous inorganic oxide network is efficient in allowing the diffusion of ions, such as lithium ions, through the separator during the charging and discharging of the electric current producing cell.
• the amount of the pores in the separator may be characterized by the percent porosity or percent pore volume, which is the cubic centimeters of pores per cubic centimeters of the separator.
• the porosity may be measured by filling the pores with a relatively non-volatile liquid having a known density and then calculated by the increase in weight of the separator with the liquid present divided by the known density of the liquid and then dividing this quotient by the volume of the separator, as calculated from the area and average thickness of the separator.
• the average pore diameter of the microporous inorganic oxide layer is from 2 nm to 70 nm. Typically, the average pore diameter of the microporous inorganic oxide layer is from 30 to 50 nm.
• the pore sizes of the separators of this invention may provide ion transport and conductivity with lithium ion battery electrolytes that is at least equal to that of polyolefin separators.
• the inorganic oxide is an aluminum oxide.
• Other inorganic oxides such as zirconium oxides and silicas, as known in the art of electrolyte elements and separators for electrochemical cells, may be utilized alone or in combination with other inorganic oxides including aluminum oxides.
• Preferred aluminum oxides are aluminum boehmites.
• the term “pseudo-boehmite,” as used herein, pertains to hydrated aluminum oxides having the chemical formula, Al 2 O 3 ⁇ xH 2 O, wherein x is in the range of 1.0 to 1.5.
• pseudo-boehmite include “aluminum boehmite,” “boehmite,” “AlOOH,” and “hydrated alumina.”
• the materials referred to herein as “pseudo-boehmite” are distinct from anhydrous aluminum oxides or aluminas (Al 2 O 3 such as alpha-alumina or gamma-alumina) and hydrated aluminum oxides of the formula Al 2 O 3 ⁇ xH 2 O wherein x is less than 1.0 or greater than 1.5.
• the weight percent of the aluminum oxide in the separator is greater than 50%. This loading of the aluminum oxide helps to provide the porosity of the separator that is needed for conductivity and for rapid wetting by the electrolyte when manufacturing the electric current producing cell.
• One aspect of the present invention pertains to a separator for an electric current producing cell, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the separator may contain only the microporous layer of this invention or may contain additional microporous layers, such as porous polyolefin layers as typically used in lithium ion batteries.
• the microporous layer of the present invention may be coated on one or both sides of a microporous polyolefin layer, such as Celgard 2500, the trade name for a polyolefin separator membrane available from Polypore, Inc., of Charlotte, N.C..
• a thickness of 5 to 20 microns is typical for the separators of this invention that contain only the microporous layers of this invention
• the thickness of a coating of the microporous layer of this invention onto a polyolefin microporous separator is typically in, but not limited to, the range of 1 to 4 microns.
• the organic acid is a sulfonic acid, preferably an aryl sulfonic acid, and more preferably a toluenesulfonic acid.
• the organic acid is a carboxylic acid.
• One purpose of the surface modification of the aluminum oxide is to make the aluminum oxide particles dispersible in organic solvents, especially in aprotic organic solvents. This broader scope of dispersibility is advantageous in enabling a wider range of organic polymers that are soluble in aprotic organic solvents, but not in water and alcohols, to be used.
• Other types of surface modification of inorganic oxides as known in the art of surface modification of inorganic oxides for excellent dispersibility in aprotic organic solvents may be utilized in the present invention.
• the aluminum oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O, wherein x is in the range of 1.0 to 1.5, and wherein the hydrated aluminum oxide is surface modified by treatment with an organic acid to form a modified hydrated aluminum oxide.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 50 to 85% by weight.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 65 to 80% by weight.
• the separator comprises 60 to 90% by weight of the modified aluminum oxide.
• the separator comprises 70 to 85% by weight of the modified aluminum oxide.
• the microporous layer is a xerogel layer.
• the organic polymer comprises a polyvinylidene fluoride (PVDF) polymer, such as KYNAR HSV 900, the trade name for a PVDF polymer for lithium battery and other applications available from Arkema, Inc.
• the separator comprises a copolymer of a first fluorinated organic monomer and a second organic monomer.
• the second organic monomer is a second fluorinated organic monomer.
• the electric current producing cell is a secondary lithium ion cell. In one embodiment, the electric current producing cell is a primary lithium cell. In one embodiment, the electric current producing cell is a capacitor. In one embodiment, the separator does not melt at temperatures lower than 300° C. The aluminum oxide or other inorganic oxide material is primarily responsible for providing this non-melting and dimensionally stable property at high temperatures. In one embodiment, the separator is a flame retardant separator. The aluminum oxide or other inorganic oxide is a flame retardant material and, in combination with a highly fluorinated organic polymer which is also flame retardant, provides a flame retardant separator.
• an electrochemical cell comprising an anode, a cathode, an organic electrolyte comprising a lithium salt, and a separator interposed between the anode and the cathode, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid.
• the organic acid is a sulfonic acid, preferably an aryl sulfonic acid, and more preferably a toluenesulfonic acid.
• the organic acid is a carboxylic acid.
• the aluminum oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O, wherein x is in the range of 1.0 to 1.5, and wherein the hydrated aluminum oxide is surface modified by treatment with an organic acid to form a modified hydrated aluminum oxide.
• the microporous layer is a xerogel layer.
• the anode active material of the anode is lithium.
• the modified aluminum oxide has an Al 2 O 3 content in the range of 50 to 85% by weight. In one embodiment, the modified aluminum oxide has an Al 2 O 3 content in the range of 65 to 80% by weight.
• the organic polymer comprises a polyvinylidene fluoride polymer. In one embodiment, the organic polymer comprises a copolymer of a first fluorinated organic monomer and a second organic monomer. In one embodiment, the second organic monomer is a second fluorinated organic monomer. In one embodiment, the lithium salt is lithium hexafluorophosphate.
• a capacitor comprising two electrodes, an organic electrolyte comprising a tetraalkyl ammonium salt, and a separator interposed between the two electrodes, wherein the separator comprises a microporous layer comprising (a) at least 50% by weight of an aluminum oxide and (b) an organic polymer, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the inorganic oxide comprises a hydrated aluminum oxide of the formula Al 2 O 3 ⁇ xH 2 O wherein x is in the range of 1.0 to 1.5, wherein the aluminum oxide is surface modified by treatment with an organic acid to form a modified aluminum oxide.
• the organic acid is a sulfonic acid.
• the microporous layer is a xerogel layer.
• the organic polymer comprises a polyvinylidene fluoride polymer.
• the organic polymer comprises a copolymer of a first fluorinated organic monomer and a second organic monomer.
• a 20% by weight dispersion of DISPAL 10SR the trade name for a surface-modified aluminum oxide available from SASOL North America, Houston, Tex., in methyl ethyl ketone was prepared.
• MSDS Material Safety Data Sheet
• the aluminum oxide is an aluminum boehmite
• the surface modification comprises p-toluenesulfonic acid (PTSA).
• PTSA p-toluenesulfonic acid
• NMP N-methyl pyrrolidone
• the aluminum oxide dispersion was added to the stirred fluoropolymer solution to prepare a dispersion containing the aluminum oxide and fluoropolymer in a dry weight ratio of 5:1. The % solids of this dispersion was about 17%.
• This dispersion was coated onto a 3 mil thick silicone treated polyester (PET) film on the silicone release side to give a dry coating thickness of about 20 microns and then delaminated from the release substrate to provide a free standing aluminum oxide microporous separator with a porosity of about 43%.
• PET silicone treated polyester
• the aluminum oxide separator did not melt at temperatures below 300° C. and was flame retardant, as shown by not burning when exposed to an open flame.
• Example 1 The aluminum oxide and fluoropolymer dispersion of Example 1 was coated onto a 20 micron thick polyolefin separator from Ube and dried at 90° C. to avoid shrinkage and melting of the polyolefin separator. The thickness of the coating was varied from 1 to 4 microns dry and coated on one or both sides of the polyolefin separator. Button cells as described in Example 1 were prepared with a 2 micron thick aluminum oxide microporous coating on one or both sides of the polyolefin separator and gave comparable stability at 55° C., cycling, and conductivity to control button cells with the polyolefin separator only.
• DISPAL 10F4 the trade name for a surface-modified aluminum boehmite available from SASOL North America, Houston, Tex., in methyl ethyl ketone was mixed at 2200 rpm stirring for 40 minutes. No satisfactory dispersion was obtained, and nearly all of the pigment settled to the bottom of the mix container.
• MSDS Material Safety Data Sheet
• the surface modification comprises formic acid.
• a 10% by weight solution of KYNAR HSV 900 in NMP was prepared.
• the non-dispersed DISPAL 10F4 mix in methyl ethyl ketone was added to the stirred fluoropolymer solution at a dry weight ratio of 3:1 of the aluminum boehmite and fluoropolymer with continued stirring at 2200 rpm for 40 minutes. No satisfactory dispersion was obtained, and nearly all of the pigment settled to the bottom of the mix container. The mix was not suitable for coating a separator layer on a release substrate.
• a 7.5% by weight solution of KYNAR HSV 900 in NMP was prepared.
• DISPAL 10F4 in a dry weight ratio of 5:1 of the aluminum boehmite and fluoropolymer was added slowly with continued stirring at 2200 rpm for 40 minutes. No satisfactory dispersion was obtained, and nearly all of the pigment settled to the bottom of the mix container. The mix was not suitable for coating a separator layer on a release substrate.
• Comparative Examples 1 and 2 show that surface modification of an aluminum oxide with formic acid does not provide dispersibility in aprotic solvents as represented by NMP and methyl ethyl ketone and consequently is not suitable for coating separators with polyvinylidene fluoride (PVdF) and other fluoropolymers that require aprotic solvents such as NMP for solubility and for use in coatings, such as a separator or battery electrode coating.
• PVdF polyvinylidene fluoride

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• 2011
  • 2011-07-18 EP EP11761412.3A patent/EP2596538B1/en active Active
  • 2011-07-18 PL PL11761412T patent/PL2596538T3/pl unknown
  • 2011-07-18 EP EP18198974.0A patent/EP3444867B1/en active Active
  • 2011-07-18 KR KR1020137003965A patent/KR20140018171A/ko not_active Application Discontinuation
  • 2011-07-18 JP JP2013520699A patent/JP5990804B2/ja active Active
  • 2011-07-18 ES ES11761412T patent/ES2713517T3/es active Active
  • 2011-07-18 WO PCT/US2011/001274 patent/WO2012011944A2/en active Application Filing
  • 2011-07-18 CN CN201710017940.5A patent/CN106784556A/zh active Pending
  • 2011-07-18 DK DK11761412.3T patent/DK2596538T3/en active
  • 2011-07-18 CN CN201180035701.3A patent/CN103283060B/zh active Active
• 2013
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• 2016
  • 2016-07-21 JP JP2016143054A patent/JP6505052B2/ja active Active
• 2017
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• 2020
  • 2020-11-03 US US17/088,351 patent/US11728544B2/en active Active
• 2023
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