WO2022034899A1 - 組成物、正極用組成物、正極用スラリー、正極、および二次電池 - Google Patents
組成物、正極用組成物、正極用スラリー、正極、および二次電池 Download PDFInfo
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- WO2022034899A1 WO2022034899A1 PCT/JP2021/029649 JP2021029649W WO2022034899A1 WO 2022034899 A1 WO2022034899 A1 WO 2022034899A1 JP 2021029649 W JP2021029649 W JP 2021029649W WO 2022034899 A1 WO2022034899 A1 WO 2022034899A1
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- positive electrode
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- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229940043265 methyl isobutyl ketone Drugs 0.000 description 1
- 229940017219 methyl propionate Drugs 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 150000002823 nitrates Chemical class 0.000 description 1
- LYGJENNIWJXYER-UHFFFAOYSA-N nitromethane Chemical compound C[N+]([O-])=O LYGJENNIWJXYER-UHFFFAOYSA-N 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 239000004767 olefin fiber Substances 0.000 description 1
- MHYFEEDKONKGEB-UHFFFAOYSA-N oxathiane 2,2-dioxide Chemical compound O=S1(=O)CCCCO1 MHYFEEDKONKGEB-UHFFFAOYSA-N 0.000 description 1
- PNJWIWWMYCMZRO-UHFFFAOYSA-N pent‐4‐en‐2‐one Natural products CC(=O)CC=C PNJWIWWMYCMZRO-UHFFFAOYSA-N 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000447 polyanionic polymer Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920000193 polymethacrylate Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- USHAGKDGDHPEEY-UHFFFAOYSA-L potassium persulfate Chemical compound [K+].[K+].[O-]S(=O)(=O)OOS([O-])(=O)=O USHAGKDGDHPEEY-UHFFFAOYSA-L 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- HNJBEVLQSNELDL-UHFFFAOYSA-N pyrrolidin-2-one Chemical compound O=C1CCCN1 HNJBEVLQSNELDL-UHFFFAOYSA-N 0.000 description 1
- 239000013557 residual solvent Substances 0.000 description 1
- 239000011342 resin composition Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 150000003462 sulfoxides Chemical class 0.000 description 1
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 150000007984 tetrahydrofuranes Chemical class 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F261/00—Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00
- C08F261/02—Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00 on to polymers of unsaturated alcohols
- C08F261/04—Macromolecular compounds obtained by polymerising monomers on to polymers of oxygen-containing monomers as defined in group C08F16/00 on to polymers of unsaturated alcohols on to polymers of vinyl alcohol
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/04—Acids; Metal salts or ammonium salts thereof
- C08F220/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
- C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
- C08F220/42—Nitriles
- C08F220/44—Acrylonitrile
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L29/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
- C08L29/02—Homopolymers or copolymers of unsaturated alcohols
- C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
- C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
-
- 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
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
-
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- 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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
- H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- 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
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/661—Metal or alloys, e.g. alloy coatings
-
- 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
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
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- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
-
- 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
Definitions
- the present invention relates to a composition, a positive electrode composition, a positive electrode slurry, a positive electrode, and a secondary battery.
- secondary batteries have been used as power sources for electronic devices such as notebook computers and mobile phones, and hybrid vehicles and electric vehicles that use secondary batteries as power sources are being developed for the purpose of reducing the environmental load. Secondary batteries with high energy density, high voltage, and high durability are required for these power sources. Lithium-ion secondary batteries are attracting attention as secondary batteries that can achieve high voltage and high energy density.
- the lithium ion secondary battery is composed of a positive electrode, a negative electrode, an electrolyte, and a separator member, and the positive electrode is composed of a positive electrode active material, a conductive auxiliary agent, a metal foil, and a binder (Patent Documents 1 to 3).
- a binder (graft copolymer) containing polyvinyl alcohol and polyacrylonitrile as main components is disclosed (Patent Document 4).
- a positive electrode binder for a lithium ion secondary battery a graft copolymer in which a monomer containing (meth) acrylonitrile and (meth) acrylic acid ester as main components is graft-copolymerized with a stem polymer having polyvinyl alcohol is contained.
- the composition to be used is disclosed (Patent Document 5).
- composition capable of obtaining a battery having an excellent balance between suppression of deterioration of battery performance with a high-capacity electrode, high-temperature storage characteristics, and DC resistance, a slurry for a positive electrode using the composition, a positive electrode, and a secondary battery Development was required.
- the present invention has been made in view of such problems, and uses a composition that serves as a binder having an excellent balance between suppression of deterioration of battery performance in a high-capacity electrode, high-temperature storage characteristics, and DC resistance. It provides a slurry for a positive electrode, a positive electrode, and a secondary battery.
- a composition containing a graft copolymer wherein the graft copolymer has a stem polymer and a branch polymer, the stem polymer contains a polyvinyl alcohol structure, and the branch polymer is , (Meta) acrylonitrile monomer unit and / or a first monomer unit containing (meth) acrylic acid monomer, the composition has a swelling rate of 105 to 15 days at 25 ° C. with respect to an electrolytic solution.
- the composition is 200%, and the swelling rate is the swelling rate after immersing the ethylene carbonate and diethyl carbonate in the electrolytic solution mixed at a volume ratio of 1: 2 for 15 days at 25 ° C.
- a first monomer which is a (meth) acrylonitrile monomer unit and / or a (meth) acrylic acid monomer unit is obtained with respect to a stem polymer having a polyvinyl alcohol structure.
- a graft copolymer having a graft-copolymerized structure is kept as a unit and keeping the swelling rate with respect to the electrolytic solution within a predetermined range at a predetermined temperature and time, deterioration of battery performance in a high-capacity electrode is suppressed.
- the present invention has been completed by finding that it is a binder having an excellent balance between high temperature storage characteristics and DC resistance.
- the composition further comprises a free polymer, the free polymer has no covalent bond with the graft copolymer, the free polymer is a polymer comprising a polyvinyl alcohol structure, and / or said first. Contains at least a polymer containing one monomeric unit.
- the graft copolymer further comprises a cross-linked portion derived from a cross-linking agent.
- the crosslinked portion comprises an ether structure.
- the composition contains 0.2 to 10 parts by mass of the structure derived from the cross-linking agent when the composition is 100 parts by mass.
- the composition is added to 300 ml of dimethyl sulfoxide, and the mixture is stirred at 60 ° C. for 15 hours to obtain No. 1 specified in JIS P 3801.
- the graft ratio of the graft copolymer is 40 to 3000%.
- the degree of saponification of the polyvinyl alcohol structure in the composition is 60 to 100 mol%.
- the polyvinyl alcohol structure in the composition has an average degree of polymerization of 300 to 4000.
- a positive electrode composition containing the above composition is preferable.
- a positive electrode slurry containing the positive electrode composition, a positive electrode active material and a conductive auxiliary agent.
- the conductive auxiliary agent is at least one selected from the group consisting of fibrous carbon, carbon black, and a carbon composite in which fibrous carbon and carbon black are interconnected.
- a metal foil and a positive electrode provided with a coating film of the above-mentioned positive electrode slurry formed on the metal foil.
- the secondary battery comprising the positive electrode described above, wherein the secondary battery is a lithium ion secondary battery, a sodium ion secondary battery, a magnesium ion secondary battery, or potassium.
- a secondary battery which is one or more selected from the group consisting of an ion secondary battery, is provided.
- the positive electrode active material is LiNi X Mn (2-X) O 4 (where 0 ⁇ X ⁇ 2), Li (Co X Ni Y Mn Z ) O 2 (where, where.
- the present invention provides a composition that serves as a binder that suppresses deterioration of battery performance with a high-capacity electrode, has excellent high-temperature storage characteristics, and has an excellent balance of DC resistance, a slurry for a positive electrode using the composition, a positive electrode, and a secondary battery. offer.
- composition according to one embodiment of the present invention can be used as a composition for a positive electrode.
- the positive electrode composition according to one embodiment of the present invention includes the composition according to one embodiment of the present invention, and preferably comprises the composition according to one embodiment of the present invention.
- the composition according to one embodiment of the present invention is a composition containing a graft copolymer, and the graft copolymer has a stem polymer and a branch polymer, preferably a stem polymer and a plurality of branch polymers. Have.
- the polymer may be referred to as a copolymer.
- the graft copolymer according to the embodiment of the present invention is synthesized by graft-copolymerizing at least the first monomer with the stem polymer.
- the branch polymer produced by the polymerization is grafted, that is, covalently bonded to the stem polymer.
- an ungrafted stem polymer or a polymer containing a first monomer that is not grafted to the stem polymer, that is, is not covalently bonded to the graft copolymer may be simultaneously produced as a free polymer. .. Therefore, the composition according to one embodiment of the present invention can include a graft copolymer and a free polymer.
- the graft copolymer according to the embodiment of the present invention can further contain a cross-linked portion derived from a cross-linking agent.
- the cross-linked portion means a structure derived from a cross-linking agent, which cross-links the branch polymers, cross-links the stem polymer and the branch polymer, or cross-links the stem polymers.
- at least the first monomer is graft-copolymerized with the stem polymer to crosslink either the stem polymer or the branch polymer with either the stem polymer or the branch polymer. By doing so, you can get it.
- the composition according to one embodiment of the present invention may also contain, as a free polymer, a polymer containing a structure derived from a cross-linking agent, in addition to the polymer containing the first monomer.
- the graft copolymer according to the embodiment of the present invention has a second monomer unit containing an ether structure, and a first monomer unit and a second monomer unit, as long as the effects of the present invention are not impaired. It may contain a monomer unit other than the above.
- the composition according to one embodiment of the present invention contains, as a free polymer, a polymer containing a second monomer unit, and a monomer unit other than the first monomer unit and the second monomer unit. It can also be a polymer.
- the graft ratio of the graft copolymer is preferably 40 to 1300%, more preferably 150 to 900%. From the viewpoint of solubility, the graft ratio is preferably in the above range. When the graft ratio is at least the above lower limit, the solubility in a solvent (for example, NMP (N-methyl-2-pyrrolidone)) is improved when the slurry is made, and when it is at least the above upper limit, the viscosity of the slurry is lowered. The fluidity of the slurry is improved.
- a solvent for example, NMP (N-methyl-2-pyrrolidone)
- the stem polymer has a polyvinyl alcohol structure.
- the polyvinyl alcohol structure is, for example, a structure derived from polyvinyl alcohol synthesized by saponifying polyvinyl acetate obtained by polymerizing a vinyl acetate monomer.
- the stem polymer is largely composed of a polyvinyl alcohol structure. More preferably, the stem polymer is polyvinyl alcohol.
- the average degree of polymerization of the polyvinyl alcohol structure in the composition is preferably 300 to 4000, and more preferably 500 to 2000.
- the stability of the slurry is particularly high. Further, it is preferably in the above range from the viewpoint of solubility, binding property, and viscosity of the binder.
- the average degree of polymerization is 300 or more, the binding property between the binder and the active material and the conductive auxiliary agent is improved, and the durability is improved.
- the average degree of polymerization is 4000 or less, the solubility is improved and the viscosity is lowered, so that the slurry for a positive electrode can be easily produced.
- the average degree of polymerization referred to here is a value measured by a method according to JIS K 6726.
- the degree of saponification of the polyvinyl alcohol structure in the composition is preferably 60 to 100 mol%, more preferably 80 to 100 mol%. When the saponification degree is in such a range, the stability of the slurry is particularly high.
- the degree of saponification referred to here is a value measured by a method according to JIS K 6726.
- the branch polymer contains at least the first monomeric unit. Further, the branch polymer may contain a second monomer unit and a monomer unit other than the first monomer unit and the second monomer unit as long as the effect of the present invention is not impaired.
- the first monomer unit and the second monomer unit are monomer units derived from the first monomer and the second monomer used in the synthesis of the graft copolymer, respectively.
- the graft copolymer according to the embodiment of the present invention may further contain a cross-linked portion.
- the cross-linking portion is a structure derived from a cross-linking agent, and connects the branch polymers of the graft copolymer to each other, the stem polymer to the branch polymer, or the stem polymers to each other.
- the cross-linking portion preferably cross-links the branch polymers of the graft copolymer.
- the crosslinked portion preferably contains an ether structure, more preferably contains an alkylene glycol repeating unit, and most preferably contains an ethylene glycol repeating unit.
- the cross-linking agent according to one embodiment of the present invention is a bifunctional or polyfunctional compound, preferably a compound soluble in a polar solvent, and preferably a compound soluble in a first monomer. Is preferable.
- the cross-linking agent is not particularly limited as long as the above requirements are satisfied, but ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, oligoethylene glycol di (meth) acrylate (polyethylene glycol di (meth) acrylate), Alcan polyol-poly (meth) acrylates such as trimethylolpropane di (meth) acrylates and trimethylolpropane tri (meth) acrylates, divinylbenzene can be mentioned.
- oligoethylene glycol di (meth) acrylate is preferable.
- the di (meth) acrylate represented by the following general formula (B) is preferable.
- R 21 and R 22 are hydrogen (H) or a methyl group.
- R 21 and R 22 may be the same or different.
- n is a number of 0 or more. n is preferably 1 or more. n is preferably 30 or less, more preferably 10 or less.
- the cross-linking agent preferably contains an ether structure and more preferably has an ethylene glycol repeating unit.
- the ethylene glycol repeating unit is preferably 2 or more and 20 or less, more preferably 5 or more and 15 or less, and for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 It may be within the range between any two of the numerical values exemplified here.
- the swelling of the binder with respect to the electrolytic solution can be controlled by adjusting the type and blending amount of the crosslinked portion.
- the composition according to one embodiment of the present invention may further contain a free polymer.
- the free polymer is a polymer that does not have a covalent bond with the graft copolymer, and includes at least a polymer containing a polyvinyl alcohol structure and / or a polymer containing the first monomer unit.
- the polymer having a polyvinyl alcohol structure mainly means a stem polymer that was not involved in graft copolymerization.
- the polymer containing the first monomer unit is a homopolymer of the first monomer, a copolymer containing the first monomer unit and the second monomer unit, the first monomer and the first monomer.
- the free polymer is preferably a polymer comprising substantially the first monomeric unit.
- the weight average molecular weight of a copolymer containing a free polymer other than the stem polymer is preferably 30,000 to 250,000, more preferably 40,000 to 200,000, and more preferably 50,000. ⁇ 150,000 is more preferable.
- the weight average molecular weight of the free polymer other than the stem polymer is preferably 300,000 or less, more preferably 200,000 or less, still more preferably 150,000 or less.
- the weight average molecular weight of the free polymer other than the stem polymer can be determined by GPC (gel permeation chromatography), and specifically, it can be measured by the method described later.
- the first monomer unit is a (meth) acrylonitrile monomer unit and / or a (meth) acrylic acid monomer unit.
- the first monomer unit is more preferably a (meth) acrylonitrile monomer unit, and still more preferably an acrylonitrile monomer unit. That is, the first monomer used in synthesizing the graft copolymer is preferably (meth) acrylonitrile and / or (meth) acrylic acid, more preferably (meth) acrylonitrile, and even more preferably. Acrylonitrile. Therefore, the first monomer unit has a structure derived from these.
- the second monomer unit is a structure unit containing an ether structure, and is a structure derived from a second monomer that is monofunctional.
- the second monomer unit is a monofunctional compound having an ether structure.
- the ether structure preferably has at least one selected from a linear polyether structure, a branched polyether structure, and a cyclic ether structure. More preferably, the ether structure has a polyethylene oxide structure.
- the second monomer unit preferably has a structure derived from a monomer which is a (meth) acrylic acid ester derivative, a styrene derivative, a polysubstituted ethylene, or a vinyl ether derivative.
- the second monomer used in synthesizing the graft polymer is a monomer having an ether structure, preferably a (meth) acrylic acid ester derivative having an ether structure, a styrene derivative having an ether structure, and the like. It is a monomer such as a polysubstituted ethylene derivative or a vinyl ether derivative. Among these, a (meth) acrylic acid ester derivative having an ether structure is preferable. Among the (meth) acrylic acid ester derivatives having an ether structure, the (meth) acrylic acid ester derivative represented by the following general formula (A) is preferable.
- Y is preferably ⁇ (AO) n—R.
- AO is an oxyalkylene group.
- the number of carbon atoms of the oxyalkylene group is preferably 1 to 18, and more preferably 2 to 10.
- As the oxyalkylene group one or more of an ethylene oxide group and a propylene oxide group is most preferable, and an ethylene oxide group is more preferable.
- n is a number of 0 or more.
- n is preferably 1 or more.
- n is preferably 30 or less, more preferably 10 or less.
- R 1 , R 2 , R 3 , and R are hydrogen (H), a hydrocarbon group which may be substituted, an ether group, or the like.
- the hydrocarbon group or ether group which may be substituted is a hydrocarbon group or an ether group having 1 to 20 carbon atoms.
- the ether group is a functional group having an ether bond, and for example, an alkyl ether group.
- R 1 , R 2 , R 3 , and R unsubstituted is preferable.
- R 1 , R 2 , R 3 , and R may be the same or different.
- R a hydrocarbon group is preferable.
- the hydrocarbon group one or more of a methyl group and an ethyl group are preferable.
- the (meth) acrylic acid ester derivative alkoxypolyalkylene glycol (meth) acrylate is preferable.
- the second monomer is more preferably one or more of (2- (2-ethoxy) ethoxy) ethyl (meth) acrylate and methoxydipropylene glycol (meth) acrylate, and most preferably (2-). It is (2-ethoxy) ethoxy) ethyl (meth) acrylate. Therefore, the second monomer unit has a structure derived from these.
- the positive electrode serves as a binder with an excellent balance of suppression of deterioration of battery performance in high-capacity electrodes, high-temperature storage characteristics (high-temperature storage characteristics), and DC resistance.
- Compositions for use may be provided.
- the content of the polyvinyl alcohol structure in the composition is preferably 5 to 70 parts by mass, and 10 to 60 parts by mass. It is more preferably 15 to 55 parts by mass, for example, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70 mass. It is a part, and may be within the range between any two of the numerical values exemplified here.
- the content is at least the above lower limit, a binder having binding property can be obtained, and when the content is not more than the above upper limit, oxidation resistance and flexibility can be maintained.
- the content of the polyvinyl alcohol structure in the composition is the total amount of the polyvinyl alcohol structure in the graft copolymer and the polyvinyl alcohol structure in the free polymer containing polyvinyl alcohol contained in the composition. Is shown.
- the composition according to the embodiment of the present invention preferably contains 3 to 80 parts by mass of the first monomer unit derived from the first monomer when the composition is 100 parts by mass. It is more preferably 5 to 70 parts by mass, for example, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80 parts by mass. It may be within the range between any two of the numerical values exemplified here.
- the content of the first monomer unit in the composition refers to the first monomer unit and the first monomer unit in the graft copolymer contained in the composition. The total amount of the first monomer unit in the containing free polymer is shown.
- the composition according to one embodiment of the present invention preferably contains 0.2 to 10 parts by mass, preferably 0.5 to 8 parts by mass, of a structure derived from a cross-linking agent when the composition is 100 parts by mass. It is more preferable, and it is particularly preferable to contain 1 to 5 parts by mass.
- the content of the structure derived from the cross-linking agent is, for example, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass. It may be in the range between any two of the exemplified values.
- the content of the structure derived from the cross-linking agent in the composition is the structure derived from the cross-linking agent bonded to the graft copolymer contained in the composition and the cross-linking in the free polymer.
- the total amount of the structure derived from the agent is shown.
- the composition according to the embodiment of the present invention preferably contains 0 to 20 parts by mass of the second monomer unit derived from the second monomer when the composition is 100 parts by mass. , 0 to 15 parts by mass, for example, 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, or 20 parts by mass, and the numerical values exemplified here are used. It may be within the range between any two.
- the composition according to one embodiment of the present invention may also be free of the second monomer unit. By setting the content of the second monomer unit within the above range, it is possible to obtain a binder having appropriate flexibility while controlling the swelling rate.
- the content of the second monomer unit in the composition refers to the second monomer unit and the second monomer unit in the graft copolymer contained in the composition. The total amount of the second monomer unit in the containing free polymer is shown.
- the composition according to the embodiment of the present invention preferably contains 0.1 to 20 parts by mass in total of the structure derived from the cross-linking agent and the second monomer unit when the composition is 100 parts by mass. , 0.1 to 15 parts by mass is more preferable.
- the total content of the structure derived from the cross-linking agent and the second monomer unit is, for example, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 , 12, 13, 14, 15, 16, 17, 18, 19, 20 parts by mass, and may be within the range between any two of the numerical values exemplified here.
- the composition according to one embodiment of the present invention has a swelling rate of 105 to 200%, preferably 105 to 180%, and more preferably 105 to 160% with respect to the electrolytic solution at 25 ° C. for 15 days. ..
- the swelling rate at 25 ° C. for 15 days with respect to the electrolytic solution means that the composition is immersed in an electrolytic solution in which ethylene carbonate and diethyl carbonate are mixed at a volume ratio of 1: 2 for 15 days at 25 ° C. It means the swelling rate after the swelling.
- composition according to one embodiment of the present invention by controlling the swelling rate within the above range, it is possible to maintain the pore volume, especially in the high rate region, while having appropriate flexibility. Therefore, it is presumed that it has high battery characteristics and can suppress a decrease in discharge capacity during high temperature storage.
- the composition according to the embodiment of the present invention has a swelling rate of 105 to 200%, preferably 110 to 180%, and more preferably 118 to 160% with respect to the electrolytic solution at 60 ° C. for 48 hours. be.
- the swelling of the composition is caused by the electrolytic solution being taken into the inside of the composition when the composition is immersed in the electrolytic solution, at least the affinity of the composition with the electrolytic solution and the structure retention of the composition are high. , It is thought that it affects the swelling rate.
- the PVA and the first monomer unit contained in the composition have a relatively low affinity with the electrolytic solution, while the ether bond that can be contained in the second monomer unit and the cross-linking agent is with the electrolytic solution. It is considered that the affinity of is relatively high.
- the structure retention of the composition is affected by the structure of the composition, specifically, the graft ratio and the degree of cross-linking.
- the swelling rate of the composition can be adjusted by controlling the content of PVA, the first monomer unit, the second monomer unit and the cross-linking agent and the structure of the composition, specifically. , The balance of the type and blending amount of the raw material of the composition, the conditions of graft copolymerization and the like can be adjusted.
- the composition according to one embodiment of the present invention preferably has a gel fraction of 30% or more, and in one embodiment, more preferably 50% or more, and most preferably 60% or more. It is even more preferable that it is 65% or more.
- the upper limit of the gel fraction can be, for example, 95%.
- the gel fraction is, for example, 30, 40, 50, 60, 65, 70, 80, 90, 95%, and may be in the range between any two of the numerical values exemplified here. According to the composition according to the embodiment of the present invention, by controlling the gel fraction within the above range, it is possible to maintain the pore volume while appropriately controlling the electrolytic solution that enters the inside of the composition. Therefore, it is presumed that it has high battery characteristics and can suppress a decrease in discharge capacity during high temperature storage.
- the swelling rate of the composition with respect to the electrolytic solution indicates the mass change before and after the film made of the composition is immersed in the electrolytic solution for a predetermined time and at a predetermined temperature.
- the swelling rate can be determined by, for example, the following method.
- the obtained composition is dissolved in NMP to prepare a 4% by mass NMP solution.
- 5.6 g of the obtained solution is added to a petri dish of PTFE (tetrafluoroethylene) and dried in a blower dryer at 105 ° C. for 8 hours to obtain a film having a thickness of 250 ⁇ m.
- the central portion of the obtained film is cut into a size of 5 mm ⁇ 5 mm to obtain a test film.
- the obtained test film is weighed and then immersed in an electrolytic solution in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed at a volume ratio of 1: 2.
- EC ethylene carbonate
- DEC diethyl carbonate
- the liquid on the film surface is wiped off, and the mass after immersion is measured.
- the swelling rate is calculated using the following formula.
- WA Mass before immersion
- WB Mass after immersion
- the swelling rate under different conditions can be obtained. For example, by setting the immersion condition in the electrolytic solution to 60 ° C. for 48 hours, the swelling rate when immersed in the electrolytic solution at 60 ° C. for 48 hours can be obtained, and the swelling rate can be evaluated in a short time.
- the gel fraction of the composition is evaluated by the insoluble fraction in the mixture in which the composition is dissolved in DMSO and stirred at a predetermined temperature and time.
- the gel fraction of the composition can be evaluated by the following method. To a 500 ml beaker, 1 g of the obtained composition and 300 ml of DMSO are added, and the mixture is stirred at 60 ° C. for 15 hours. Then, the obtained mixture was subjected to No. 2 specified in JIS P 3801. Using 5C filter paper, filter with a Kiriyama funnel, and the residue remaining on the filter paper is used as the insoluble part (gel part), and the filtrate is used as the soluble part.
- the composition according to one embodiment of the present invention contains a component derived from PVA and a component derived from the first monomer, and optionally, a component derived from the second monomer and / or a cross-linking agent. Contains ingredients derived from.
- the content of each component in the composition can be estimated from the amount charged for graft polymerization.
- the content of each component can be calculated more accurately by obtaining the reaction rate of each component by the following method. Further, the content of each component can also be calculated from the integral ratio by NMR of the obtained composition.
- the reaction rate of polyvinyl alcohol can be determined by the following method. First, the concentration of PVA in the raw material solution is determined by the absorbance. Next, a polymerization reaction is carried out to obtain a polymerization reaction solution, and 50 g of the obtained polymerization reaction solution is centrifuged at 3000 G for 30 minutes to obtain a supernatant. The absorbance in the supernatant is measured and the PVA concentration is measured. The reaction rate (%) of PVA is determined by ⁇ 1- (concentration of PVA in the supernatant) / (concentration of PVA at the time of preparation) ⁇ ⁇ 100. The reaction rate of the first monomer, the second monomer and the cross-linking agent can be determined by the following method.
- composition of each component is calculated from the intensity of the signal corresponding to PVA, the first monomer, the second monomer, and the cross-linking agent in the obtained spectrum with PVA as a reference. Comparing the composition calculated from NMR with the composition of each component at the time of charging, how much of the charged first monomer, second monomer and cross-linking agent, the first monomer and the second The reaction rate indicating whether the monomer and the cross-linking agent are contained in the composition is calculated.
- a free polymer containing at least one of the group consisting of a first monomer, a second monomer, and a cross-linking agent may be produced.
- the calculation of the graft ratio requires a step of separating the free polymer from the graft copolymer.
- the free polymer is soluble in dimethylformamide (hereinafter abbreviated as DMF), but PVA and graft copolymers are insoluble in DMF. By utilizing this difference in solubility, the free polymer can be separated by an operation such as centrifugation.
- the GPC measurement can be performed under the following conditions, for example.
- Method for producing a composition containing a graft copolymer The method for producing a composition containing a graft copolymer according to an embodiment of the present invention is not particularly limited, but the method for producing a composition according to an embodiment of the present invention is at least. It is preferable to include a graft copolymerization step in which a raw material containing polyvinyl alcohol and a first monomer is graft-copolymerized. That is, the composition according to one embodiment of the present invention is preferably obtained by a production method including a graft copolymerization step of graft-polymerizing a raw material containing at least polyvinyl alcohol and a first monomer.
- the production method according to the embodiment of the present invention further comprises a vinyl acetate polymerization step of polymerizing vinyl acetate to obtain polyvinyl acetate, and a saponification step of saponifying the obtained polyvinyl acetate to obtain polyvinyl alcohol. It is preferable to include it.
- Method for producing polyvinyl alcohol (PVA) As a method for polymerizing polyvinyl acetate, any known method such as bulk polymerization or solution polymerization can be used.
- Examples of the initiator used for the polymerization of polyvinyl acetate include azo-based initiators such as azobisisobutyronitrile, and organic peroxides such as benzoyl peroxide and bis (4-t-butylcyclohexyl) peroxydicarbonate. Things etc. can be mentioned.
- the saponification reaction of polyvinyl acetate can be carried out, for example, by a method of saponification in an organic solvent in the presence of a saponification catalyst.
- organic solvent examples include methanol, ethanol, propanol, ethylene glycol, methyl acetate, ethyl acetate, acetone, methyl ethyl ketone, benzene, toluene and the like. One or more of these may be used. Of these, methanol is preferred.
- the saponification catalyst examples include basic catalysts such as sodium hydroxide, potassium hydroxide and sodium alkoxide, and acidic catalysts such as sulfuric acid and hydrochloric acid. Of these, sodium hydroxide is preferred from the viewpoint of saponification rate.
- the degree of polymerization of polyvinyl alcohol can be controlled by adjusting the type and amount of the initiator and the temperature and time at the time of polymerization, and the type and amount of the saponification catalyst and the temperature and time at the time of saponification can be adjusted. Allows the degree of saponification of polyvinyl alcohol to be controlled. It is preferable to adjust the degree of polymerization and the degree of saponification of polyvinyl alcohol within the above ranges.
- the production method according to the embodiment of the present invention preferably includes a step of graft-copolymerizing a raw material containing at least polyvinyl alcohol and the first monomer, and the raw material containing at least polyvinyl alcohol and the first monomer. Can further include a cross-linking agent. Further, the raw material containing at least polyvinyl alcohol and the first monomer can further contain the second monomer.
- the swelling rate with respect to the electrolytic solution at 25 ° C. for 15 days is within the above range by adjusting the type and amount of the raw material to be used at the time of graft copolymerization, the polymerization conditions and the like. Adjust to.
- the polyvinyl alcohol used during the graft copolymerization preferably has the above-mentioned degree of polymerization and sacrifice degree, and the first monomer, the second monomer, and the cross-linking agent used during the graft copolymerization are the first unit of the above-mentioned type. It is preferably a polymer, a second monomer, or a cross-linking agent.
- the blending amount at the time of graft copolymerization is preferably adjusted so that the content of each component in the composition of the graft copolymer satisfies the requirement of the content of each component in the above-mentioned composition.
- the raw material to be subjected to graft copolymerization when the raw material to be subjected to graft copolymerization is 100 parts by mass, the raw material to be subjected to graft copolymerization preferably contains 0.2 to 10 parts by mass of a cross-linking agent, and more preferably 0.5 to 8 parts by mass. It is preferable to contain 1 to 5 parts by mass, and it is particularly preferable to contain 1 to 5 parts by mass.
- the content of the cross-linking agent in the raw material to be subjected to the graft copolymerization is, for example, 0.2, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 parts by mass. Yes, it may be within the range between any two of the numerical values exemplified here.
- a solution polymerization method As a method of graft-copolymerizing a monomer to polyvinyl alcohol, for example, a solution polymerization method can be mentioned.
- the solvent used include water, dimethyl sulfoxide, N-methylpyrrolidone and the like.
- Peroxide is preferable as the initiator used for graft copolymerization.
- the peroxide include organic peroxides such as benzoyl peroxide and inorganic peroxides.
- organic peroxides such as benzoyl peroxide and inorganic peroxides.
- inorganic peroxides are preferable.
- potassium persulfate, ammonium persulfate and the like can be used.
- ammonium persulfate is preferable.
- the graft copolymer according to the embodiment of the present invention can be used by dissolving it in a solvent.
- the solvent include dimethyl sulfoxide and N-methylpyrrolidone. These solvents may be contained in the composition and the slurry for the positive electrode described later.
- Compositions according to one embodiment of the present invention may contain other components, for example, resins and the like, as long as the effects of the present invention are not impaired.
- resins include fluororesins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene, styrene-butadiene-based copolymers (styrene-butadiene rubber and the like), acrylic-based copolymers and the like.
- PVDF polyvinylidene fluoride
- styrene-butadiene-based copolymers styrene-butadiene rubber and the like
- acrylic-based copolymers and the like acrylic-based copolymers and the like.
- a fluororesin, particularly polyvinylidene fluoride is preferable from the viewpoint of stability.
- the slurry for positive electrode according to the embodiment of the present invention contains the above composition and is excellent in stability. Further, the slurry for a positive electrode according to an embodiment of the present invention contains the above composition, and a positive electrode having excellent rate characteristics can be produced.
- the positive electrode slurry may contain a composition and a conductive auxiliary agent, or may contain a composition, a positive electrode active material and a conductive auxiliary agent.
- the positive electrode slurry according to the embodiment of the present invention preferably has a solid content of 0.1 to 20% by mass based on the total solid content in the positive electrode slurry. It is preferable, and it is more preferable that it is 1 to 10% by mass.
- Lithium-ion secondary battery As the battery provided with the positive electrode according to the embodiment of the present invention, a secondary battery is preferable. As the secondary battery, one or more selected from a lithium ion secondary battery, a sodium ion secondary battery, a magnesium ion secondary battery, and a potassium ion secondary battery are preferable, and a lithium ion secondary battery is more preferable.
- the positive electrode according to the embodiment of the present invention and the lithium ion secondary battery provided with the positive electrode can be produced by using a positive electrode slurry containing the above composition. It is preferably composed of the above-mentioned positive electrode, negative electrode, separator, and electrolyte solution (hereinafter, may be referred to as an electrolyte or an electrolytic solution).
- the positive electrode according to the embodiment of the present invention is formed by applying a positive electrode slurry containing a composition, a conductive auxiliary agent, and a positive electrode active material to be used as needed on a current collector such as an aluminum foil. It can be produced by removing the solvent contained in the slurry by heating and further pressurizing the current collector and the electrode mixture layer with a roll press or the like to bring them into close contact with each other. That is, a positive electrode having a metal foil and a coating film of a slurry for a positive electrode formed on the metal foil can be obtained.
- the conductive auxiliary agent is preferably at least one selected from the group consisting of (i) fibrous carbon, (ii) carbon black and (iii) a carbon composite in which fibrous carbon and carbon black are interconnected.
- fibrous carbon include gas-phase grown carbon fibers, carbon nanotubes, carbon nanofibers and the like.
- carbon black include acetylene black, furnace black and Ketjen black (registered trademark).
- These conductive auxiliaries may be used alone or in combination of two or more. Among these, one or more selected from acetylene black, carbon nanotubes and carbon nanofibers is preferable from the viewpoint of having a high effect of improving the dispersibility of the conductive auxiliary agent.
- the positive electrode slurry according to the embodiment of the present invention preferably has a solid content of 0.01 to 20% by mass of the conductive auxiliary agent with respect to the total solid content in the positive electrode slurry, and is 0. .1 to 10% by mass is more preferable.
- a positive electrode active material may be used.
- the positive electrode active material is preferably a positive electrode active material capable of reversibly occluding and releasing cations.
- the positive electrode active material is preferably a lithium-containing composite oxide containing Mn having a volume resistivity of 1 ⁇ 10 4 ⁇ ⁇ cm or more, or a lithium-containing polyanion compound.
- Examples thereof include Al Z ) O 2 and XLi 2 MnO 3- (1-X) LiMO 2 .
- X in LiNi X Mn (2-X) O 4 satisfies the relationship of 0 ⁇ X ⁇ 2, and is in Li (Co X Ni Y Mn Z ) O 2 or Li (Ni X Co Y Al Z ) O 2 X
- LiMO 2 satisfies the relationship 0 ⁇ X ⁇ 1, and M in LiMPO 4 , Li 2 MSiO 4 or XLi 2 MnO 3- (1-X) LiMO 2 is Fe, Co, Ni, Mn. It is preferable that it is one or more of the elements selected from.
- the positive electrode slurry according to the embodiment of the present invention preferably has a solid content of 50 to 99.8% by mass, preferably 80 to 99.8% by mass, based on the total solid content in the positive electrode slurry. It is more preferably to 99.5% by mass, and most preferably 95 to 99.0% by mass.
- the negative electrode used in the lithium ion secondary battery according to the embodiment of the present invention is not particularly limited, but can be manufactured by using a negative electrode slurry containing a negative electrode active material.
- This negative electrode can be manufactured by using, for example, a metal foil for a negative electrode and a slurry for a negative electrode provided on the metal foil.
- the negative electrode slurry preferably contains a negative electrode binder (negative electrode composition), a negative electrode active material, and the above-mentioned conductive auxiliary agent.
- the binder for the negative electrode is not particularly limited, and for example, polyvinylidene fluoride, polytetrafluoroethylene, a styrene-butadiene copolymer (styrene butadiene rubber, etc.), an acrylic copolymer, and the like can be used.
- a fluororesin is preferable.
- the fluororesin one or more of the group consisting of polyvinylidene fluoride and polytetrafluoroethylene is more preferable, and polyvinylidene fluoride is most preferable.
- Examples of the negative electrode active material used for the negative electrode include carbon materials such as graphite, polyacene, carbon nanotubes, and carbon nanofibers, alloy materials such as tin and silicon, and oxidation of tin oxide, silicon oxide, lithium titanate, and the like. Materials and the like can be mentioned. One or more of these may be used.
- As the metal foil for the negative electrode foil-shaped copper is preferably used, and the thickness is preferably 5 to 30 ⁇ m from the viewpoint of processability.
- the negative electrode can be manufactured by using the slurry for the negative electrode and the metal foil for the negative electrode by the method according to the method for manufacturing the positive electrode described above.
- any one having sufficient strength such as an electrically insulating porous film, a net, a non-woven fabric, and a fiber, can be used.
- a solution having low resistance to ion transfer of the electrolytic solution and having excellent solution retention is preferable.
- the material is not particularly limited, and examples thereof include inorganic fibers such as glass fibers or organic fibers, olefins such as polyethylene and polypropylene, synthetic resins such as polyester, polytetrafluoroethylene and polyflon, and layered composites thereof. From the viewpoint of binding and stability, olefins or layered complexes thereof are preferable.
- the olefin one or more of the group consisting of polyethylene and polypropylene is preferable.
- Electrodes Any known lithium salt can be used as the electrolyte, for example, LiClO 4 , LiBF 4 , LiBF 6 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiB 10 Cl 10 , LiAlCl.
- LiCl, LiBr, LiI, LiB (C 2 H 5 ) 4 LiCF 3 SO 3 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN ( Examples thereof include C 2 F 5 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , and lower fatty acid lithium carboxylate.
- the electrolytic solution for dissolving the electrolyte is not particularly limited.
- the electrolytic solution include carbonates such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate, lactones such as ⁇ -butyrolactone, trimethoxymethane, 1,2-dimethoxyethane, diethyl ether and 2 -Esters such as ethoxyethane, tetrahydrofuran and 2-methyltetra, sulfoxides such as dimethylsulfoxide, oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane, acetonitrile, nitromethane and N-methyl- Nitrogen-containing compounds such as 2-pyrrolidone, esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethy
- Acid esters such as dimethylformamide and dimethylacetamide, glyme such as diglyme, triglime and tetraglyme, ketones such as acetone, diethylketone, methylethylketone and methylisobutylketone, sulfolanes such as sulfolane, 3-methyl- Examples thereof include oxazolidinones such as 2-oxazolidinone, and sulton species such as 1,3-propanesartone, 4-butanesultone and naphthalosulton.
- the electrolytic solution preferably contains carbonates, and more preferably contains ethylene carbonate and diethyl carbonate.
- an electrolyte solution in which LiPF 6 is dissolved in carbonates is preferable, an electrolyte solution in which LiPF 6 is dissolved in a mixed solution containing ethylene carbonate and diethyl carbonate is more preferable, and LiPF 6 is referred to as ethylene carbonate.
- An electrolyte solution prepared by dissolving diethyl carbonate in a mixed solution in which a volume ratio of 1: 2 is mixed is even more preferable.
- the concentration of the electrolyte in the solution varies depending on the electrode used and the electrolytic solution, but is preferably 0.5 to 3 mol / L.
- the application of the lithium ion secondary battery according to the embodiment of the present invention is not particularly limited, but for example, a digital camera, a video camera, a portable audio player, a portable AV device such as a portable LCD TV, a notebook computer, a smartphone, and a mobile PC.
- a digital camera a digital camera
- a video camera a portable audio player
- a portable AV device such as a portable LCD TV
- a notebook computer a notebook computer
- smartphone a smartphone
- a mobile PC a mobile PC.
- mobile information terminals such as mobile information terminals, portable game devices, electric tools, electric bicycles, hybrid vehicles, electric vehicles, and power storage systems.
- Example 1 ⁇ Polyvinyl alcohol (PVA)> As PVA, PVA (B-17) manufactured by Denka Co., Ltd. was used. Table 1 shows the average degree of polymerization and the degree of saponification of the obtained PVA. The average degree of polymerization and saponification of PVA were measured based on JIS K 6726.
- composition > 1804 parts by mass of pure water is charged in a reaction vessel, nitrogen gas is bubbled to deoxidize, and then 100 parts by mass of partially saponified PVA (saponification degree 85.6%, polymerization degree 1700) is charged at room temperature and the temperature rises to 90 ° C. Dissolved by warming.
- the reaction vessel was adjusted to 60 ° C., and 170 parts by mass of a 10% ammonium persulfate aqueous solution deoxidized by bubbling nitrogen gas was added in a batch, and 96 parts by mass of acrylonitrile and the cross-linking agent oligoethylene glycol diacrylate (general formula (B)) were added.
- Ethylene glycol repeats n 9, R 21 , and R 22 are hydrogen.
- Table 1 shows the composition and the like of the composition containing the obtained graft copolymer.
- composition ratio of each component was calculated based on the reaction rate of Example 2 described later.
- the composition ratio includes a free polymer (homoPAN) which is a homopolymer of the first monomer. The results are shown in Table 1.
- NMP N-methyl-2-pyrrolidone
- the prepared slurry for positive electrode was applied to an aluminum foil having a thickness of 20 ⁇ m at 140 g / m 2 with an automatic coating machine, and pre-dried at 105 ° C. for 30 minutes. Next, it was pressed with a roll press machine at a linear pressure of 0.1 to 3.0 ton / cm, and the thickness of the positive electrode plate was adjusted to 75 ⁇ m. Further, the positive electrode plate was punched into a circle of 13 ⁇ mm. In order to completely remove volatile components such as residual solvent and adsorbed water, the product was dried at 170 ° C. for 6 hours to obtain a positive electrode.
- the electrode area density was 29.0 mg / cm 2 , and the volume density was 3.4 g / cm 3 .
- a 2032 type coin cell was produced by using the obtained positive electrode and metallic lithium as a counter electrode.
- a 15 ⁇ mm olefin fiber non-woven fabric was used as a separator for electrically separating these.
- the battery performance of the produced lithium-ion secondary battery was evaluated by the following method.
- ⁇ DC resistance> A current of 0.2, 0.4, 0.6, 0.8, 1.0 mmA was applied to a ⁇ 13 mm ⁇ 75 ⁇ m electrode manufactured in the same manner as the above positive electrode, and the voltage after 10 seconds was read. The resistance value was calculated from Ohm's law.
- ⁇ Equivalent to a lithium secondary battery using PVDF as a positive electrode binder
- ⁇ Compared with a lithium secondary battery using PVDF as a positive electrode binder, the high temperature storage characteristics are lower, and the difference is within 5%.
- X Compared with a lithium secondary battery using PVDF as a binder for a positive electrode, the high temperature storage characteristic is low, and the difference is more than 5% and within 15%.
- Example 2 ⁇ Preparation of polyvinyl alcohol (PVA)> As PVA, PVA (B-24) manufactured by Denka Co., Ltd. was used. Table 1 shows the average degree of polymerization and saponification of PVA.
- reaction rate and composition ratio For the obtained composition, the reaction rate of each raw material and the composition ratio of each component were calculated.
- the reaction rate of polyvinyl alcohol was determined by the following method. First, the concentration of PVA in the raw material solution was determined by the absorbance. Next, 50 g of the polymerization reaction solution obtained by the polymerization reaction was centrifuged at 3000 G for 30 minutes to obtain a supernatant. The absorbance in the supernatant was measured and the PVA concentration was measured. The reaction rate (%) of PVA was determined by ⁇ 1- (concentration of PVA in the supernatant) / (concentration of PVA at the time of preparation) ⁇ ⁇ 100. The reaction rate of PVA was 93%.
- the reaction rate of the first monomer and the cross-linking agent was determined by the following method. After completion of the polymerization, methanol was precipitated, and the dried product was dissolved in heavy DMSO, and 1 H-NMR was measured. The composition of each component was calculated from the intensity of the signal corresponding to PVA, the first monomer, and the cross-linking agent in the obtained spectrum with PVA as a reference. Signals derived from PVA at 1 to 1.7 ppm, PAN and vinyl acetate at 1.7 to 2.3 ppm, PAN at 3 to 3.2 ppm, and a cross-linking agent at 3.5 to 3.7 ppm are observed. The reaction rate was calculated by comparing the composition calculated from NMR with the composition of each component at the time of charging. The reaction rate indicates how much of the charged first monomer and cross-linking agent is contained in the composition. The reaction rate of the first monomer was 98%, and the reaction rate of the cross-linking agent was 100%.
- composition ratio of each component of the composition according to Example 2 was calculated from the reaction rate.
- the content of the polyvinyl alcohol structure is 47.7 parts by mass
- the content of the first monomer unit is 48.2 parts by mass
- the content of the structure derived from the cross-linking agent is 4. It was .2 parts by mass.
- the composition ratio includes a free polymer which is a homopolymer of the first monomer.
- composition was obtained in the same manner as in Example 1 except that the blending amounts of acrylonitrile, a cross-linking agent, and (2- (2-ethoxy) ethoxy) ethyl acrylate added to PVA were as shown in Table 1.
- the monomer unit represents the monomer from which the monomer unit is derived.
- AN Acrylonitrile
- EEEA 2- (2-ethoxyethoxy) ethyl acrylate
- OEG Oligoethylene glycol diacrylate
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Abstract
Description
好ましくは、前記組成物は、遊離ポリマーを更に含み、前記遊離ポリマーは、前記グラフト共重合体と共有結合を有さず、前記遊離ポリマーは、ポリビニルアルコール構造を含むポリマー、および/または、前記第1単量体単位を含むポリマーを少なくとも含む。
好ましくは、前記グラフト共重合体は、架橋剤に由来する架橋部を更に含む。
好ましくは、前記架橋部は、エーテル構造を含む。
好ましくは、前記組成物は、前記組成物を100質量部としたとき、前記架橋剤に由来する構造を0.2~10質量部含む。
好ましくは、前記組成物1gをジメチルスルホキシド300mlに加え、60℃で15時間撹拌し、JIS P 3801に規定されるNo.5Cのろ紙で濾過し、ろ紙上に残渣として残る不溶分をAgとしたとき、ゲル分率%=A×100/1で表されるゲル分率が、30%以上である。
好ましくは、前記グラフト共重合体のグラフト率は、40~3000%である。
好ましくは、前記組成物中のポリビニルアルコール構造の鹸化度は、60~100mol%である。
好ましくは、前記組成物中のポリビニルアルコール構造の平均重合度は、300~4000である。
好ましくは、前記組成物を含有する正極用組成物である。
好ましくは、前記正極用スラリー中の固形分総量を100質量%としたとき、前記正極用組成物の固形分含有量が1~20質量%である。
好ましくは、前記導電助剤が、繊維状炭素、カーボンブラック、繊維状炭素とカーボンブラックとが相互に連結した炭素複合体からなる群から選択される1種以上である。
本発明の別の観点によれば、金属箔および、前記金属箔上に形成された前記に記載の正極用スラリーの塗膜を備える正極が提供される。
本発明の別の観点によれば、前記に記載の正極を備える二次電池であって、前記二次電池は、リチウムイオン二次電池、ナトリウムイオン二次電池、マグネシウムイオン二次電池、またはカリウムイオン二次電池からなる群から選択される1種以上である二次電池が提供される。
本発明の別の観点によれば、前記正極活物質が、LiNiXMn(2-X)O4(但し、0<X<2)、Li(CoXNiYMnZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)、およびLi(NiXCoYAlZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)から選択される少なくとも1種以上を含み、かつ、二次電池がリチウムイオン二次電池である二次電池が提供される。
本発明の一実施形態に係る組成物は、正極用組成物として使用できる。
本発明の一実施形態に係る正極用組成物は、本発明の一実施形態に係る組成物を含み、好ましくは、本発明の一実施形態に係る組成物から成る。
本発明の一実施形態に係る組成物は、グラフト共重合体を含有する組成物であり、グラフト共重合体は、幹ポリマーおよび枝ポリマーを有し、好ましくは、幹ポリマーおよび複数の枝ポリマーを有する。以下、重合体を、共重合体ということもある。
本発明の一実施形態に係るグラフト共重合体は、幹ポリマーに対し、少なくとも第1単量体をグラフト共重合させることにより合成される。重合により生成した枝ポリマーは、幹ポリマーにグラフト、すなわち共有結合している。この際、グラフトされていない幹ポリマーや、幹ポリマーにグラフトしていない、すなわちグラフト共重合体に共有結合していない第1単量体を含む重合体が、遊離ポリマーとして同時に生成することがある。従って、本発明の一実施形態に係る組成物は、グラフト共重合体および遊離ポリマーを含むことができる。
幹ポリマーは、ポリビニルアルコール構造を有する。ここで、ポリビニルアルコール構造は、例えば、酢酸ビニルモノマーを重合したポリ酢酸ビニルを鹸化して合成されるポリビニルアルコールに由来する構造である。好ましくは、幹ポリマーは、大部分がポリビニルアルコール構造によって構成されている。より好ましくは、幹ポリマーは、ポリビニルアルコールである。
組成物中のポリビニルアルコール構造の鹸化度は、好ましくは60~100mol%であり、より好ましくは80~100mol%である。当該鹸化度が、このような範囲にある場合にスラリーの安定性が特に高い。ここでいう鹸化度は、JIS K 6726に準ずる方法で測定される値である。
枝ポリマーは、少なくとも第1単量体単位を含む。また、枝ポリマーは、本発明の効果を損なわない範囲で、第2単量体単位、並びに、第1単量体単位および第2単量体単位以外の単量体単位を含んでも良い。ここで、第1単量体単位、第2単量体単位とは、それぞれグラフト共重合体の合成に用いた第1単量体、第2単量体に由来する単量体単位である。
本発明の一実施形態に係るグラフト共重合体は、架橋部を更に含んでいてもよい。架橋部は、架橋剤に由来する構造であって、グラフト共重合体の、枝ポリマー同士、幹ポリマーと枝ポリマー、または幹ポリマー同士を連結する。架橋部は、好ましくは、グラフト共重合体の、枝ポリマー同士を架橋する。架橋部は、エーテル構造を含むことが好ましく、アルキレングリコール繰り返し単位を含むことがより好ましくは、エチレングリコール繰り返し単位を含むことが最も好ましい。
架橋剤としては、上記要件を満たせば特に制限はないが、エチレングリコールジ(メタ)アクリレート、ブチレングリコールジ(メタ)アクリレート、オリゴエチレングリコールジ(メタ)アクリレート(ポリエチレングリコールジ(メタ)アクリレート)、トリメチロールプロパンジ(メタ)アクリレート、トリメチロールプロパントリ(メタ)アクリレートのようなアルカンポリオール-ポリ(メタ)アクリレート、ジビニルベンゼンを挙げることができる。この中でも、オリゴエチレングリコールジ(メタ)アクリレートが好ましい。
オリゴエチレングリコールジ(メタ)アクリレートの中では、下記の一般式(B)で表されるジ(メタ)アクリレートが好ましい。
H2C=CR21-COO-(-CH2CH2O-)n-CO-CR22=CH2 (B)
一般式(B)において、R21、R22は、水素(H)またはメチル基である。R21、R22は、同一でも異なっても良い。nは0以上の数である。nは1以上が好ましい。nは30以下が好ましく、10以下がより好ましい。
架橋剤は、エーテル構造を含むことが好ましく、エチレングリコール繰り返し単位を有することがより好ましい。エチレングリコール繰り返し単位は、好ましくは2以上20以下であり、より好ましくは、5以上、15以下であり、例えば、5、6、7、8、9、10、11、12、13、14、15であり、ここで例示した数値の何れか2つの間の範囲内であってもよい。
本発明の一実施形態に係るグラフト共重合体は、架橋部の種類および配合量を調整することによって、バインダーの電解液に対する膨潤を制御することができる。
本発明の一実施形態に係る組成物は、遊離ポリマーを更に含んでいてもよい。遊離ポリマーは、前記グラフト共重合体と共有結合を有しないポリマーであり、ポリビニルアルコール構造を含むポリマー、および/または、前記第1単量体単位を含むポリマーを少なくとも含む。ポリビニルアルコール構造を有するポリマーとは、主にグラフト共重合に関与しなかった幹ポリマーを意味する。また、第1単量体単位を含むポリマーとは、第1単量体の単独重合体、第1単量体単位および第2単量体単位を含む共重合体、第1単量体並びに第1単量体単位および第2単量体単位以外の単量体単位を含む共重合体、または、第1単量体および架橋剤由来の構造を含む共重合体を含むポリマーであって、グラフト共重合体(すなわち、幹ポリマー)に共重合していないものを意味する。また、本発明の効果を損なわない範囲で、遊離ポリマーには、ポリビニルアルコール構造を有するポリマーおよび第1単量体単位を含むポリマー以外のポリマー、例えば、第2単量体の単独重合体、第1単量体および第2単量体以外の単量体の単独重合体、架橋剤由来の構造を含むポリマーであって、グラフト共重合体(すなわち、幹ポリマー)に共重合していないものが含まれていてもよい。遊離ポリマーは、好ましくは実質的に第1単量体単位を含むポリマーである。
第1単量体単位は、(メタ)アクリロニトリル単量体単位および/または(メタ)アクリル酸単量体単位である。第1単量体単位は、より好ましくは(メタ)アクリロニトリル単量体単位であり、更に好ましくはアクリロニトリル単量体単位である。
すなわち、グラフト共重合体を合成する際に用いる第1単量体は、好ましくは、(メタ)アクリロニトリルおよび/または(メタ)アクリル酸であり、より好ましくは(メタ)アクリロニトリルであり、更に好ましくはアクリロニトリルである。よって、第1単量体単位はこれらに由来する構造を有する。
第2単量体単位は、エーテル構造を含む構造体単位であり、単官能である第2単量体由来の構造である。
第2単量体単位は、エーテル構造を有する単官能の化合物である。エーテル構造は、好ましくは、直鎖状ポリエーテル構造、分岐状ポリエーテル構造、および環状エーテル構造から選ばれる少なくとも1つを有する。より好ましくは、エーテル構造が、ポリエチレンオキサイド構造を有する。
また、第2単量体単位は、好ましくは、(メタ)アクリル酸エステル誘導体、スチレン誘導体、多置換エチレン、またはビニルエーテル誘導体である単量体由来の構造を有する。
これらの中では、エーテル構造を有する(メタ)アクリル酸エステル誘導体が好ましい。エーテル構造を有する(メタ)アクリル酸エステル誘導体の中では、下記の一般式(A)で表される(メタ)アクリル酸エステル誘導体が好ましい。
また、R1、R2、R3、Rは、水素(H)、置換されていてもよい炭化水素基またはエーテル基等である。好ましくは、置換されていてもよい炭化水素基またはエーテル基が、炭素数1~20の炭化水素基またはエーテル基である。ここで、エーテル基とは、エーテル結合を有する官能基であり、例えば、アルキルエーテル基をいう。R1、R2、R3、Rとしては、非置換が好ましい。R1、R2、R3、Rは、同一でも異なっても良い。Rとしては、炭化水素基が好ましい。炭化水素基としては、メチル基、エチル基のうちの1種以上が好ましい。
(メタ)アクリル酸エステル誘導体としては、アルコキシポリアルキレングリコール(メタ)アクリレートが好ましい。アルコキシポリアルキレングリコール(メタ)アクリレートの中では、アルコキシポリエチレングリコール(メタ)アクリレート、アルコキシポリプロピレングリコール(メタ)アクリレートのうちの1種以上が好ましい。より具体的には、(2-(2-エトキシ)エトキシ)エチル(メタ)アクリレート、メトキシポリエチレングリコール(メタ)アクリレート(poly:n=23)、メトキシジプロピレングリコール(メタ)アクリレートのうちの1種以上が好ましい。第2単量体は、より好ましくは、(2-(2-エトキシ)エトキシ)エチル(メタ)アクリレート、メトキシジプロピレングリコール(メタ)アクリレートのうちの1種以上であり、最も好ましくは(2-(2-エトキシ)エトキシ)エチル(メタ)アクリレートである。よって、第2単量体単位はこれらに由来する構造を有する。
また、各成分の含有量および特性について以下の要件を満たすことが好ましい。各成分の含有量および特性が以下のような範囲にある場合に、高容量電極での電池性能の低下の抑制、高温保管特性(高温保存特性)、直流抵抗のバランスに優れたバインダーとなる正極用組成物を提供し得る。
(膨潤率)
本発明の一実施形態に係る組成物は、電解液に対する25℃、15日間の膨潤率が105~200%であり、好ましくは、105~180%であり、より好ましくは105~160%である。ここで、電解液に対する25℃、15日間の膨潤率とは、組成物を、エチレンカーボネートとジエチルカーボネートとを体積比で1対2の比率で混合した電解液に、25℃で15日間浸漬させた後の膨潤率を意味する。組成物を、電解液に25℃で15日間浸漬した際の膨潤率は、例えば、105、110、115、120、125、130、135、140、145、150、155、160、170、180%のいずれかであり、ここで例示した数値の何れか2つの間の範囲内であってもよい。
本発明の一実施形態に係る組成物によれば、膨潤率を上記範囲内に制御することによって、適度に柔軟性を有しつつ、特に高レート領域において、空孔体積を維持することができるため、高い電池特性を有し、かつ、高温保管時の放電容量の低下を抑制することができると推測される。
本発明の一実施形態に係る組成物は、電解液に対す60℃、48時間の膨潤率が105~200%であり、好ましくは、110~180%であり、より好ましくは118~160%である。
ここで、組成物に含まれるPVAおよび第1単量体単位は、電解液との親和性が比較的低く、一方、第2単量体単位および架橋剤が含み得るエーテル結合は、電解液との親和性が比較的高いと考えられる。また、組成物の構造保持性には、組成物の構造、具体的には、グラフト率や、架橋度が影響を及ぼし、例えば、架橋部が多いほど、膨潤を抑制する傾向にあるものと考えられる。
したがって、組成物の膨潤率は、PVA、第1単量体単位、第2単量体単位および架橋剤の含有量および組成物の構造を制御することによって調整することができ、具体的には、組成物の原料の種類および配合量のバランス、並びにグラフト共重合の条件等を調整することにより制御することができる。
本発明の一実施形態に係る組成物は、ゲル分率が30%以上であることが好ましく、一態様においては、50%以上であることがより好ましく、60%以上であることが最も好ましく、65%以上であることが尚更好ましい。ゲル分率の上限は、例えば、95%とすることができる。ゲル分率は、例えば30、40、50、60、65、70、80、90、95%のいずれかであり、ここで例示した数値の何れか2つの間の範囲内であってもよい。
本発明の一実施形態に係る組成物によれば、ゲル分率を上記範囲内に制御することによって、組成物の内部に入り込む電解液を適度に制御しつつ、空孔体積を維持することができるため、高い電池特性を有し、かつ、高温保管時の放電容量の低下を抑制することができると推測される。
(組成物の膨潤率(25℃、15日))
組成物の電解液に対する膨潤率は、組成物からなるフィルムを、所定の時間かつ所定の温度で電解液に浸漬した前後の質量変化を示す。膨潤率は、例えば、以下の方法で求めることができる。
得られた組成物をNMPに溶解し、4質量%NMP溶液を作成する。得られた溶液5.6gを、PTFE(テトラフルオロエチレン)のシャーレに加え、送風乾燥機で105℃、8h乾燥して厚み250μmのフィルムを得る。得られたフィルムの中央部分を5mm×5mmにカットし、試験用フィルムとする。得られた試験用フィルムは、質量を測定してから、エチレンカーボネート(EC)とジエチルカーボネート(DEC)とを体積比で1対2の比率で混合した電解液に浸漬させる。25℃で、15日間静置した後、フィルム表面の液をふき取り、浸漬後の質量を測定する。浸漬前後の質量の変化から、以下の式を用いて膨潤率を算出する。膨潤率は、浸漬前の質量をWA(g)、浸漬後の質量をWB(g)とし、以下の式から算出する。
膨潤率(25℃、15日)(%) = WB×100/WA・・・式(1)
WA:浸漬前の質量(g)
WB:浸漬後の質量(g)
組成物のゲル分率は、組成物をDMSOに溶解し、所定の温度および時間で撹拌した混合物中の不溶分で評価する。組成物のゲル分率は、具体的には以下の方法で評価できる。
500mlビーカーに、得られた組成物1gと、DMSO300mlを加え、60℃で15時間撹拌する。その後、得られた混合物を、JIS P 3801に規定されるNo.5Cのろ紙を用いて、桐山ロートで濾過し、ろ紙上に残った残渣を不溶部(ゲル分)、ろ液を可溶部とする。不溶部(ゲル分)を、100℃で、24時間真空乾燥し、秤量する。不溶分をAgとし、ゲル分率(%)=A×100/1を算出する。
本発明の一実施形態に係る組成物は、PVAに由来する成分と第1単量体に由来する成分を含み、任意選択で、第2単量体に由来する成分、および/または、架橋剤に由来する成分を含む。組成物中の各成分の含有量は、グラフト重合の仕込み量から概算することができる。各成分の含有量は、より正確には、以下の方法によって各成分の反応率を求めることによって、算出することができる。また、各成分の含有量は、得られた組成物のNMRによる積分比から算出することもできる。
第1単量体、第2単量体、架橋剤の反応率は以下の方法で求めることができる。重合終了後、メタノール析出し、乾燥した生成物を重DMSOに溶解させ、1H―NMRを測定する。得られたスペクトルの、PVA、第一単量体、第二単量体、架橋剤に対応するシグナルの強度から、PVAを基準として、各成分の組成を算出する。NMRから算出された組成と、仕込み時の各成分の組成とを比較して、仕込んだ第一単量体、第二単量体、架橋剤のうち、どの程度第一単量体、第二単量体、架橋剤が組成物に含まれるかを示す反応率を算出する。
グラフト共重合体を生成する際(グラフト共重合時)には、第1単量体、第2単量体、架橋剤からなる群の少なくともいずれかを含む遊離ポリマーが生成することがある。グラフト率の計算には、グラフト共重合体から遊離ポリマーを分離する工程が必要となる。遊離ポリマーはジメチルホルムアミド(以下、DMFと略すことがある。)には溶解するが、PVAおよびグラフト共重合体はDMFに溶解しない。この溶解性の差を利用し、遊離ポリマーを遠心分離等の操作により分離できる。
ここで、
F:DMFに溶解した成分の質量(g)
G:試験に使用した組成物の質量(g)
H:組成物中の第1単量体単位および第2単量体単位の合計含有量(質量%)
とすると、グラフト率は以下の式(2)で求められる。
[(G-F)/(G×(100-H)/100)]×100 ・・・式(2)
組成物を1.00g正秤し、これを特級DMF(国産化学株式会社製)50ccに添加し、80℃にて24時間1000rpmで撹拌する。次に、これを株式会社コクサン製の遠心分離機(型式:H2000B、ローター:H)にて回転数10000rpmで30分間遠心分離する。ろ液(DMF可溶分)を注意深く分離後、メタノール1000mlに投入し、析出物を得る。析出物を80℃にて24時間真空乾燥し、GPCにて標準ポリスチレン換算の重量平均分子量を測定する。GPCの測定は例えば以下の条件とできる。
カラム:GPC LF-804、φ8.0×300mm(昭和電工株式会社製)を2本直列に繋いで用いた。
カラム温度:40℃
溶媒:20mM-LiBr/DMF
本発明の一実施形態に係るグラフト共重合体を含む組成物の製造方法については特に制限されないが、本発明の一実施形態に係る製造方法は、少なくともポリビニルアルコールと第1単量体とを含む原料をグラフト共重合させるグラフト共重合工程を含むことが好ましい。すなわち、本発明の一実施形態に係る組成物は、少なくともポリビニルアルコールと第1単量体とを含む原料をグラフト共重合させるグラフト共重合工程を含む製造方法によって得られるものであることが好ましい。また、本発明の一実施形態に係る製造方法は、酢酸ビニルを重合してポリ酢酸ビニルを得る酢酸ビニル重合工程、および、得られたポリ酢酸ビニルを鹸化してポリビニルアルコールを得る鹸化工程を更に含むことが好ましい。
ポリ酢酸ビニルを重合する方法については、塊状重合、溶液重合等公知の任意の方法を用いることができる。
開始剤の種類および量、並びに重合時の温度および時間を調整することよって、ポリビニルアルコールの重合度を制御することができ、鹸化触媒の種類および量、並びに鹸化時の温度および時間を調整することによって、ポリビニルアルコールの鹸化度を制御することができる。ポリビニルアルコールの重合度および鹸化度は上記した範囲内に調整することが好ましい。
本発明の一実施形態に係る製造方法は、少なくともポリビニルアルコールと第1単量体とを含む原料をグラフト共重合させる工程を含むことが好ましく、少なくともポリビニルアルコールと第一単量体とを含む原料は、さらに、架橋剤を含むことができる。また、少なくともポリビニルアルコールと第一単量体とを含む原料は、さらに、第2単量体を含むことができる。
本発明の一実施形態に係る製造方法においては、グラフト共重合時に供する原料の種類および量並びに重合条件等を調整することによって、電解液に対する25℃、15日間の膨潤率を、上記した範囲内に調整する。
グラフト共重合時に供するポリビニルアルコールは、上記した重合度および鹸化度を有することが好ましく、グラフト共重合時に供する第1単量体、第2単量体、架橋剤は、上記した種類の第1単量体、第2単量体、架橋剤であることが好ましい。
グラフト共重合時の配合量は、グラフト共重合の組成物中の各成分の含有量が、上記した組成物中の各成分の含有量の要件を満たすように調整されることが好ましい。例えば、グラフト共重合に供する原料を100質量部としたとき、グラフト共重合に供する原料は、架橋剤を0.2~10質量部含むことが好ましく、0.5~8質量部含むことがより好ましく、1~5質量部含むことが特により好ましい。グラフト共重合に供する原料中の架橋剤の含有量は、例えば、0.2、0.5、1、2、3、4、5、6、7、8、9、10質量部のいずれかであり、ここで例示した数値の何れか2つの間の範囲内であってもよい。
本発明の一実施形態に係る組成物は、本発明の効果を損なわない範囲であれば、その他の成分、例えば、樹脂等を含んでいてもよい。そのような樹脂としては、ポリフッ化ビニリデン(PVDF)、ポリテトラフルオロエチレン等のフッ素系樹脂、スチレン-ブタジエン系共重合体(スチレンブタジエンゴム等)およびアクリル系共重合体等が挙げられる。中でも、安定性の観点からフッ素系樹脂、特にポリフッ化ビニリデンが好ましい。
本発明の一実施形態に係る正極用スラリーは、上記組成物を含み、安定性に優れる。また、本発明の一実施形態に係る正極用スラリーは、上記組成物を含み、レート特性に優れた正極を作製できる。正極用スラリーは、組成物および導電助剤を含有してもよく、また組成物、正極活物質および導電助剤を含有してもよい。
本発明の一実施形態に係る正極を備える電池として、二次電池が好ましい。二次電池としては、リチウムイオン二次電池、ナトリウムイオン二次電池、マグネシウムイオン二次電池、カリウムイオン二次電池から選択される1種以上が好ましく、リチウムイオン二次電池がより好ましい。
本発明の一実施形態に係る正極、および当該正極を備えるリチウムイオン二次電池は、上記組成物を含む正極用スラリーを用いて作製できる。好適には、上記の正極、負極、セパレータ、並びに、電解質溶液(以下、電解質、電解液と称することもある。)を含んで構成される。
本発明の一実施形態に係る正極は、組成物と、導電助剤と、必要に応じて使用する正極活物質とを含む正極用スラリーを、アルミニウム箔等の集電体上に塗布した後、加熱によりスラリーに含まれる溶剤を除去し、更に集電体と電極合剤層をロールプレス等により加圧して密着させることにより、作製できる。すなわち、金属箔と、当該金属箔上に形成された正極用スラリーの塗膜を備える正極が得られる。
導電助剤は、(i)繊維状炭素、(ii)カーボンブラックおよび(iii)繊維状炭素とカーボンブラックとが相互に連結した炭素複合体からなる群から選択される少なくとも1種以上が好ましい。繊維状炭素としては、気相成長炭素繊維、カーボンナノチューブおよびカーボンナノファイバー等が挙げられる。カーボンブラックとしては、アセチレンブラック、ファーネスブラックおよびケッチェンブラック(登録商標)等が挙げられる。これらの導電助剤は単体で用いてもよく、2種以上を併用してもよい。これらの中では、導電助剤の分散性を向上させる効果が高い観点から、アセチレンブラック、カーボンナノチューブおよびカーボンナノファイバーから選択される1種以上が好ましい。
本発明の一実施形態に係る正極用スラリーは、好ましくは、正極用スラリー中の固形分総量に対し、導電助剤の固形分含有量が0.01~20質量%であることが好ましく、0.1~10質量%であることがより好ましい。
必要に応じて正極活物質を使用してもよい。正極活物質は、カチオンを可逆的に吸蔵放出可能な正極活物質が好ましい。正極活物質は、体積抵抗率1×104Ω・cm以上のMnを含むリチウム含有複合酸化物またはリチウム含有ポリアニオン化合物が好ましい。例えば、LiCoO2、LiMn2O4、LiNiO2、LiMPO4、Li2MSiO4、LiNiXMn(2-X)O4、Li(CoXNiYMnZ)O2、Li(NiXCoYAlZ)O2またはXLi2MnO3-(1-X)LiMO2等が挙げられる。但し、LiNiXMn(2-X)O4中のXは0<X<2という関係を満たし、Li(CoXNiYMnZ)O2中またはLi(NiXCoYAlZ)O2中のX、YおよびZは、X+Y+Z=1という関係を満たし、かつ0<X<1、0<Y<1、0<Z<1という関係を満たし、XLi2MnO3-(1-X)LiMO2中のXは0<X<1という関係を満たし、更にLiMPO4中、Li2MSiO4中またはXLi2MnO3-(1-X)LiMO2中のMはFe、Co、Ni、Mnから選ばれる元素の1種以上であることが好ましい。
正極活物質の中では、LiNiXMn(2-X)O4(但し、0<X<2)、Li(CoXNiYMnZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)およびLi(NiXCoYAlZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)から選択される1種以上が好ましく、LiNiXMn(2-X)O4(但し、0<X<2)およびLi(CoXNiYMnZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)から選択される1種以上がより好ましい。
本発明の一実施形態に係る正極用スラリーは、好ましくは、正極用スラリー中の固形分総量に対し、正極活物質の固形分含有量が50~99.8質量%であることが好ましく、80~99.5質量%であることがより好ましく、95~99.0質量%であることが最も好ましい。
本発明の一実施形態に係るリチウムイオン二次電池に用いられる負極は、特に限定されないが、負極活物質を含む負極用スラリーを用いて製造できる。この負極は、例えば、負極用金属箔と、その金属箔上に設けられる負極用スラリーとを用いて製造できる。負極用スラリーは、負極用バインダー(負極用組成物)と、負極活物質と、前述の導電助剤とを含むことが好ましい。負極用バインダーとしては、特に限定されないが、例えば、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、スチレン-ブタジエン系共重合体(スチレンブタジエンゴム等)およびアクリル系共重合体等を用いることができる。負極用バインダーとしては、フッ素系樹脂が好ましい。フッ素系樹脂としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレンからなる群の1種以上がより好ましく、ポリフッ化ビニリデンが最も好ましい。
負極用の金属箔としては、箔状の銅を用いることが好ましく、厚さは、加工性の観点から、5~30μmが好ましい。負極は、前述の正極の製造方法に準じた方法にて、負極用スラリーおよび負極用金属箔を用いて製造できる。
セパレータには、電気絶縁性の多孔質膜、網、不織布、繊維等、充分な強度を有するものであれば使用できる。特に、電解液のイオン移動に対して低抵抗であり、かつ、溶液保持に優れたものを使用するとよい。材質は特に限定しないが、ガラス繊維等の無機物繊維または有機物繊維、ポリエチレン、ポリプロピレン等のオレフィン、ポリエステル、ポリテトラフルオロエチレン、ポリフロン等の合成樹脂またはこれらの層状複合体等を挙げることができる。結着性および安定性の観点から、オレフィンまたはこれらの層状複合体が好ましい。オレフィンとしては、ポリエチレン、ポリプロピレンからなる群の1種以上が好ましい。
電解質としては、公知のリチウム塩が何れも使用でき、例えば、LiClO4、LiBF4、LiBF6、LiPF6、LiCF3SO3、LiCF3CO2、LiAsF6、LiSbF6、LiB10Cl10、LiAlCl4、LiCl、LiBr、LiI、LiB(C2H5)4、LiCF3SO3、LiCH3SO3、LiCF3SO3、LiC4F9SO3、LiN(CF3SO2)2、LiN(C2F5SO2)2、LiC(CF3SO2)3、低級脂肪酸カルボン酸リチウム等が挙げられる。
上記電解質を溶解させる電解液は、特に限定されない。電解液としては、例えば、プロピレンカーボネート、エチレンカーボネート、ジメチルカーボネート、ジエチルカーボネートおよびメチルエチルカーボネート等のカーボネート類、γ-ブチロラクトン等のラクトン類、トリメトキシメタン、1,2-ジメトキシエタン、ジエチルエーテル、2-エトキシエタン、テトラヒドロフランおよび2-メチルテトラヒドロフラン等のエーテル類、ジメチルスルホキシド等のスルホキシド類、1,3-ジオキソランおよび4-メチル-1,3-ジオキソラン等のオキソラン類、アセトニトリル、ニトロメタンおよびN-メチル-2-ピロリドン等の含窒素化合物類、ギ酸メチル、酢酸メチル、酢酸エチル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチルおよびリン酸トリエステル等のエステル類、硫酸エステル、硝酸エステルおよび塩酸エステル等の無機酸エステル類、ジメチルホルムアミドおよびジメチルアセトアミド等のアミド類、ジグライム、トリグライムおよびテトラグライム等のグライム類、アセトン、ジエチルケトン、メチルエチルケトンおよびメチルイソブチルケトン等のケトン類、スルホラン等のスルホラン類、3-メチル-2-オキサゾリジノン等のオキサゾリジノン類、並びに、1,3-プロパンサルトン、4-ブタンスルトンおよびナフタスルトン等のスルトン類等が挙げられる。これらの電解液の中から選択される1種以上を使用できる。電解液は、好ましくは、カーボネート類を含み、さらに好ましくはエチレンカーボネート、ジエチルカーボネートを含む。
<ポリビニルアルコール(PVA)>
PVAとして、デンカ株式会社製、PVA(B-17)を用いた。得られたPVAの平均重合度、鹸化度を表1に示す。
PVAの平均重合度および鹸化度は、JIS K 6726に基づき測定した。
反応容器に純水1804質量部を仕込み、窒素ガスをバブリングして脱酸素した後、部分けん化PVA(けん化度85.6%、重合度1700)100質量部を室温下で仕込み、90℃まで昇温することで溶解した。反応容器を60℃に調整し、別途窒素ガスをバブリングして脱酸素した10%過硫酸アンモニウム水溶液170質量部を一括添加し、アクリロニトリル96質量部と架橋剤オリゴエチレングリコールジアクリレート(一般式(B)のエチレングリコール繰り返し数n=9、R21、R22は、水素である。)(新中村化学工業製、商品名:A-400)8質量部の混合液を5時間かけて添加し、重合した。得られた重合液100質量部を300質量部のメタノール中に添加し、析出物を減圧ろ過して40℃で12時間乾燥させて樹脂組成物を得た。
得られたグラフト共重合体を含む組成物の組成等については表1に示す。
得られた組成物について、後述の実施例2の反応率に基づき、各成分の組成比を算出した。なお、この組成比には、第一単量体のホモポリマーである遊離ポリマー(homoPAN)が含まれる。結果を表1に示す。
(DMSO不溶分(ゲル分率))
500mlビーカーに、得られた組成物1gと、DMSO300mlを加え、60℃で15時間撹拌した。その後、得られた混合物を、JIS P 3801に規定されるNo.5Cのろ紙を用いて、桐山ロートで濾過し、ろ紙上に残った残渣を不溶部(ゲル分)、ろ液を可溶部とした。不溶部(ゲル分)を、100℃で、24時間真空乾燥し、秤量した。不溶分をAgとし、ゲル分率(%)=A×100/1を算出した。
得られたグラフト共重合体を含む組成物を1.00g正秤し、これを特級DMF(国産化学株式会社製)50ccに添加し、80℃にて24時間1000rpmで撹拌した。次に、これを株式会社コクサン製の遠心分離機(型式:H2000B、ローター:H)にて回転数10000rpmで30分間遠心分離した。ろ液(DMF可溶分)を注意深く分離後、DMF不溶分を100℃にて24時間真空乾燥し、以下の式を用いグラフト率を計算した。
[(G-F)/(G×(100-H)/100)]×100・・・式(3)
F:DMFに溶解した成分の質量(g)
G:試験に使用した組成物の質量(g)
H:組成物中の第1単量体単位および第2単量体単位の合計含有量(質量%)
得られた組成物をNMPに溶解し、4質量%NMPを作成した。得られた溶液5.6gを、PTFE(テトラフルオロエチレン)のシャーレに加え、送風乾燥機で105℃、8h乾燥して厚み250μmのフィルムを得た。得られたフィルムの中央部分を5mm×5mmにカットし、試験用フィルムとした。得られた試験用フィルムは、質量を測定してから、エチレンカーボネート(EC)とジエチルカーボネート(DEC)とを体積比で1対2の比率で混合した電解液に浸漬させた。25℃、で、15日間静置した後、フィルム表面の液をふき取り、浸漬後の質量を測定した。浸漬前後の質量の変化から、以下の式を用いて膨潤率を算出した。膨潤率は、浸漬前の質量をWA(g)、浸漬後の質量をWB(g)とし、以下の式から算出した。
膨潤率(25℃、15日)(%) = WB×100/WA・・・式(4)
WA:浸漬前の質量(g)
WB:浸漬後の質量(g)
電解液への浸漬条件を、60℃、48時間とした以外は、(組成物の膨潤率(25℃、15日))と同様に、60℃、48時間電解液に浸漬した場合の膨潤率を求めた。
得られたバインダー1質量部、アセチレンブラック(デンカ株式会社製、デンカブラック(登録商標)「Li435」)2質量部、NMC532(LiNi0.5Mn0.3Co0.2O2、ユミコア社、TX-10)97質量部を、N-メチル-2-ピロリドン(以下、NMPと略す)66質量部に溶解させて、正極形成用スラリーとした。
厚み20μmのアルミニウム箔に、調製した正極用スラリーを、自動塗工機で140g/m2となるように塗布し、105℃で30分間予備乾燥した。次に、ロールプレス機にて0.1~3.0ton/cmの線圧でプレスし、正極板の厚さが75μmになるように調製した。更に正極板を13Φmmの円形に打ち抜いた。残留溶媒や吸着水分といった揮発成分を完全に除去するため、170℃で6時間乾燥して正極を得た。電極面積密度は、29.0mg/cm2、体積密度は、3.4g/cm3であった。
得られた正極と、対極として金属リチウムとを用い、2032型コインセルを作製した。電解質としてLiPF6を1mol/Lの濃度で溶解した電解液(エチレンカーボネート/ジエチルカーボネート=1/2(体積比)混合液)を用いた。これらを電気的に隔離するセパレータとして15Φmmのオレフィン繊維製不織布を用いた。作製したリチウムイオン二次電池について、以下の方法により電池性能を評価した。
得られた電池の電池特性を下記の測定条件で評価した。
充電条件:CC-CV方式、CC電流=0.2C、CV電圧=4.2V、カットオフ電流=1/20C
放電条件:CC方式、CC電流=0.2,0.5,1.0,2.0,2.8C、カットオフ電圧=3.0V
温度条件:25℃
電池を初充電後、充放電効率が100%近傍になることを確認後、0.20mA/cm2の電流密度にて定電流放電を3.0Vまで行った際の放電容量を測定し、正極活物質量で除した容量密度(mAh/g)を算出した。この容量(mAh)を1時間で充放電可能な電流値を「1C」とした。
上記の正極と同様に作製したφ13mm×75μmの電極に対して、0.2,0.4,0.6,0.8,1.0mmAの電流を印加し、10秒後の電圧を読み取り、オームの法則より抵抗値を求めた。
体積抵抗率(Ω・cm)は二端子法により測定した。電位差をV、断面積をS、電流値をI(A)、電極厚みをL(cm)とすると、以下の式で表すことができる。
体積抵抗率(Ω・cm) = (V×S)/(I×L)・・・式(3)
得られたリチウム二次電池を、0.2Cの定電流で4.3Vまで充電した(満充電)。これを60℃の環境試験器に入れ、30日間保存した。30日経過後25℃において0.2Cの定電流で3.0Vまで放電させ、以下の式を用いて、高温保存特性を求めた。
(高温保存特性(%))=[(保存後放電容量)÷(保存前充電容量)]×100を求めた。
また、得られた高温保存特性を、後述の参考例1に係る、正極用バインダーとしてPVDFを用いたリチウム二次電池の高温保存特性と比較して、以下の基準で評価した。結果を表1に示す。
○:正極用バインダーとしてPVDFを用いたリチウム二次電池と同等
△:正極用バインダーとしてPVDFを用いたリチウム二次電池に比べ、高温保存特性が低く、その差は5%以内である。
X:正極用バインダーとしてPVDFを用いたリチウム二次電池に比べ、高温保存特性が低く、その差は5%超、15%以内である。
<ポリビニルアルコール(PVA)の調製>
PVAとして、デンカ株式会社製、PVA(B-24)を用いた。PVAの平均重合度、鹸化度を表1に示す。
配合量を表1に示すとおりとした以外は、実施例1と同様の方法で組成物を得た。結果を表1に示す。
得られた組成物について、各原料の反応率と各成分の組成比を算出した。
ポリビニルアルコールの反応率は以下の方法で求めた。まず、原料溶液中のPVAの濃度を、吸光度により求めた。次に、重合反応で得た重合反応液50gを3000Gで30分間遠心分離して上澄みを得た。上澄み中の吸光度を測定し、PVA濃度を測定した。PVAの反応率(%)を、{1-(上澄み中のPVA濃度)/(仕込み時のPVAの濃度)}×100で求めた。PVAの反応率は、93%であった。
<ポリビニルアルコール(PVA)の調製>
PVAとして、デンカ株式会社製、PVA(F-12)を用いた。PVAの平均重合度、鹸化度を表1に示す。
PVAに対して添加するアクリロニトリル、架橋剤、(2-(2-エトキシ)エトキシ)エチルアクリレートの配合量を表1に記載の通りとした以外は実施例1と同様に、組成物を得た。
実施例2と同様の方法で各原料の反応率と各成分の組成比を算出した。なお、比較例3、4の組成比の算出には、実施例2のOEGの反応率、比較例2のAN、EEEAの反応率を用いた。結果を表1に示す。
正極用組成物としてポリフッ化ビニリデン樹脂(HSV900:アルケマ社製)を用いた。結果を表1に示す。
AN:アクリロニトリル
EEEA:2-(2-エトキシエトキシ)エチルアクリレート
OEG:オリゴエチレングリコールジアクリレート
Claims (16)
- グラフト共重合体を含有する組成物であって、
前記グラフト共重合体は、幹ポリマーおよび枝ポリマーを有し、
前記幹ポリマーは、ポリビニルアルコール構造を含み、
前記枝ポリマーは、(メタ)アクリロニトリル単量体単位および/または(メタ)アクリル酸単量体を含む第1単量体単位を含み、
前記組成物は、電解液に対する25℃、15日間の膨潤率が105~200%であり、
前記膨潤率は、エチレンカーボネートとジエチルカーボネートとを、体積比で1対2の比率で混合した前記電解液に、25℃で15日間浸漬させた後の膨潤率である組成物。 - 前記組成物は、遊離ポリマーを更に含み、
前記遊離ポリマーは、前記グラフト共重合体と共有結合を有さず、
前記遊離ポリマーは、ポリビニルアルコール構造を含むポリマー、および/または、前記第1単量体単位を含むポリマーを少なくとも含む、
請求項1に記載の組成物。 - 前記グラフト共重合体は、架橋剤に由来する架橋部を更に含む、請求項1または請求項2に記載の組成物。
- 前記架橋部は、エーテル構造を含む、請求項3に記載の組成物。
- 前記組成物は、前記組成物を100質量部としたとき、前記架橋剤に由来する構造を0.2~10質量部含む、請求項3または請求項4のいずれかに記載の組成物。
- 前記組成物1gをジメチルスルホキシド300mlに加え、60℃で15時間撹拌し、JIS P 3801に規定されるNo.5Cのろ紙で濾過し、前記ろ紙上に残渣として残る不溶分をAgとしたとき、ゲル分率%=A×100/1で表されるゲル分率が、30%以上である、請求項1~請求項5のいずれかに記載の組成物。
- 前記グラフト共重合体のグラフト率は、40~3000%である、請求項1~請求項6のいずれかに記載の組成物。
- 前記組成物中のポリビニルアルコール構造の鹸化度は、60~100mol%である、請求項1~請求項7のいずれかに記載の組成物。
- 前記組成物中のポリビニルアルコール構造の平均重合度は、300~4000である、請求項1~請求項8のいずれかに記載の組成物。
- 請求項1~請求項9のいずれかに記載の組成物を含有する正極用組成物。
- 請求項10に記載の正極用組成物、正極活物質および導電助剤を含有する、正極用スラリー。
- 前記正極用スラリー中の固形分総量を100質量%としたとき、前記正極用組成物の固形分含有量が1~20質量%である、請求項11に記載の正極用スラリー。
- 前記導電助剤が、繊維状炭素、カーボンブラック、繊維状炭素とカーボンブラックとが相互に連結した炭素複合体からなる群から選択される1種以上である、請求項11または請求項12のいずれかに記載の正極用スラリー。
- 金属箔および、前記金属箔上に形成された請求項11~13の何れか一項に記載の正極用スラリーの塗膜を備える正極。
- 請求項14に記載の正極を備える二次電池であって、前記二次電池は、リチウムイオン二次電池、ナトリウムイオン二次電池、マグネシウムイオン二次電池、またはカリウムイオン二次電池からなる群から選択される1種以上である、二次電池。
- 前記正極活物質が、LiNiXMn(2-X)O4(但し、0<X<2)、Li(CoXNiYMnZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)、およびLi(NiXCoYAlZ)O2(但し、0<X<1、0<Y<1、0<Z<1、且つX+Y+Z=1)から選択される少なくとも1種以上を含み、かつ、二次電池がリチウムイオン二次電池である請求項15に記載の二次電池。
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Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06172452A (ja) | 1992-12-02 | 1994-06-21 | Kureha Chem Ind Co Ltd | フッ化ビニリデン系共重合体 |
JPH06506252A (ja) * | 1991-03-19 | 1994-07-14 | ザ・ダウ・ケミカル・カンパニー | 吸収速度の速い高度に有効な表面積を有するしわのある吸収剤粒子 |
JP2000095823A (ja) * | 1998-09-22 | 2000-04-04 | Osaka Organic Chem Ind Ltd | 吸水性ゲル溶液の製法 |
JP2001256980A (ja) * | 2000-03-09 | 2001-09-21 | Nippon Zeon Co Ltd | リチウムイオン二次電池電極用バインダーおよびその利用 |
JP2004227974A (ja) * | 2003-01-24 | 2004-08-12 | Nippon Zeon Co Ltd | 電極用スラリー組成物、電極および二次電池 |
JP2010521798A (ja) * | 2008-03-18 | 2010-06-24 | チャンゾウ ゾンケ ライファン パワー サイエンス アンド テクノロジー カンパニー リミテッド | リチウムイオン電池用水性接着剤およびその製造方法、並びにリチウムイオン電池正極シート |
JP2013048043A (ja) * | 2011-08-29 | 2013-03-07 | Dainichiseika Color & Chem Mfg Co Ltd | 塗工液、導電性塗工膜、蓄電装置用電極板及び蓄電装置 |
JP2013084351A (ja) | 2011-10-06 | 2013-05-09 | Nippon Zeon Co Ltd | 電気化学素子電極用複合粒子、電気化学素子電極材料、及び電気化学素子電極 |
JP2013098123A (ja) | 2011-11-04 | 2013-05-20 | Jsr Corp | 電極用バインダー組成物、電極用スラリー、電極、および蓄電デバイス |
WO2015053224A1 (ja) | 2013-10-09 | 2015-04-16 | 電気化学工業株式会社 | 正極用バインダー組成物、正極用スラリー、正極及びリチウムイオン二次電池 |
WO2016024525A1 (ja) * | 2014-08-11 | 2016-02-18 | 電気化学工業株式会社 | 電極用導電性組成物、それを用いた電極及びリチウムイオン二次電池 |
WO2017154949A1 (ja) * | 2016-03-08 | 2017-09-14 | デンカ株式会社 | 負極用バインダー組成物、負極用スラリー、負極及びリチウムイオン二次電池 |
WO2018230599A1 (ja) | 2017-06-13 | 2018-12-20 | デンカ株式会社 | 組成物、正極用バインダー組成物 |
WO2020162503A1 (ja) * | 2019-02-06 | 2020-08-13 | デンカ株式会社 | 組成物、正極用スラリー及び電池 |
WO2020162505A1 (ja) * | 2019-02-06 | 2020-08-13 | デンカ株式会社 | 組成物、正極用スラリー及び電池 |
WO2020209260A1 (ja) * | 2019-04-09 | 2020-10-15 | デンカ株式会社 | 組成物 |
-
2021
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- 2021-08-11 WO PCT/JP2021/029649 patent/WO2022034899A1/ja unknown
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- 2021-08-11 EP EP21855978.9A patent/EP4198086A4/en active Pending
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Patent Citations (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH06506252A (ja) * | 1991-03-19 | 1994-07-14 | ザ・ダウ・ケミカル・カンパニー | 吸収速度の速い高度に有効な表面積を有するしわのある吸収剤粒子 |
JPH06172452A (ja) | 1992-12-02 | 1994-06-21 | Kureha Chem Ind Co Ltd | フッ化ビニリデン系共重合体 |
JP2000095823A (ja) * | 1998-09-22 | 2000-04-04 | Osaka Organic Chem Ind Ltd | 吸水性ゲル溶液の製法 |
JP2001256980A (ja) * | 2000-03-09 | 2001-09-21 | Nippon Zeon Co Ltd | リチウムイオン二次電池電極用バインダーおよびその利用 |
JP2004227974A (ja) * | 2003-01-24 | 2004-08-12 | Nippon Zeon Co Ltd | 電極用スラリー組成物、電極および二次電池 |
JP2010521798A (ja) * | 2008-03-18 | 2010-06-24 | チャンゾウ ゾンケ ライファン パワー サイエンス アンド テクノロジー カンパニー リミテッド | リチウムイオン電池用水性接着剤およびその製造方法、並びにリチウムイオン電池正極シート |
JP2013048043A (ja) * | 2011-08-29 | 2013-03-07 | Dainichiseika Color & Chem Mfg Co Ltd | 塗工液、導電性塗工膜、蓄電装置用電極板及び蓄電装置 |
JP2013084351A (ja) | 2011-10-06 | 2013-05-09 | Nippon Zeon Co Ltd | 電気化学素子電極用複合粒子、電気化学素子電極材料、及び電気化学素子電極 |
JP2013098123A (ja) | 2011-11-04 | 2013-05-20 | Jsr Corp | 電極用バインダー組成物、電極用スラリー、電極、および蓄電デバイス |
WO2015053224A1 (ja) | 2013-10-09 | 2015-04-16 | 電気化学工業株式会社 | 正極用バインダー組成物、正極用スラリー、正極及びリチウムイオン二次電池 |
WO2016024525A1 (ja) * | 2014-08-11 | 2016-02-18 | 電気化学工業株式会社 | 電極用導電性組成物、それを用いた電極及びリチウムイオン二次電池 |
WO2017154949A1 (ja) * | 2016-03-08 | 2017-09-14 | デンカ株式会社 | 負極用バインダー組成物、負極用スラリー、負極及びリチウムイオン二次電池 |
WO2018230599A1 (ja) | 2017-06-13 | 2018-12-20 | デンカ株式会社 | 組成物、正極用バインダー組成物 |
WO2020162503A1 (ja) * | 2019-02-06 | 2020-08-13 | デンカ株式会社 | 組成物、正極用スラリー及び電池 |
WO2020162505A1 (ja) * | 2019-02-06 | 2020-08-13 | デンカ株式会社 | 組成物、正極用スラリー及び電池 |
WO2020209260A1 (ja) * | 2019-04-09 | 2020-10-15 | デンカ株式会社 | 組成物 |
Non-Patent Citations (1)
Title |
---|
See also references of EP4198086A4 |
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