WO2013105623A1 - 二次電池電極用バインダ樹脂組成物、二次電池電極用スラリー、二次電池用電極、リチウムイオン二次電池 - Google Patents
二次電池電極用バインダ樹脂組成物、二次電池電極用スラリー、二次電池用電極、リチウムイオン二次電池 Download PDFInfo
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- WO2013105623A1 WO2013105623A1 PCT/JP2013/050358 JP2013050358W WO2013105623A1 WO 2013105623 A1 WO2013105623 A1 WO 2013105623A1 JP 2013050358 W JP2013050358 W JP 2013050358W WO 2013105623 A1 WO2013105623 A1 WO 2013105623A1
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- electrode
- secondary battery
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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
- H01M4/04—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
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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
- 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
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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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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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
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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
- H01M4/623—Binders being polymers fluorinated polymers
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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
- H01M2004/021—Physical characteristics, e.g. porosity, surface area
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- 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 binder resin composition for a secondary battery electrode, a slurry for a secondary battery electrode, an electrode for a secondary battery, and a lithium ion secondary battery.
- lithium ion secondary batteries have been used as storage batteries for portable devices such as mobile phones, video cameras, laptop computers, hybrid vehicles, and electric vehicles.
- Electrodes for lithium ion secondary batteries are usually mixed with a mixture of a powdered electrode active material (active material) and an appropriate amount of a binder (binder) to form a slurry for the electrode. It is obtained by applying an electrode layer to the body after applying and drying.
- the binder a material that satisfies the solvent resistance to the organic solvent used in the electrolyte of the secondary battery, the oxidation resistance and the reduction resistance within the driving voltage, and the like is used.
- PVDF polyvinylidene fluoride
- amides such as N-methyl-2-pyrrolidone (hereinafter abbreviated as “NMP”) and nitrogen-containing organic solvents such as ureas Is used.
- NMP N-methyl-2-pyrrolidone
- nitrogen-containing organic solvents such as NMP have problems such as solvent recovery costs and high environmental load.
- NMP has a high boiling point of 204 ° C., and thus has a problem of requiring a lot of energy during drying and solvent recovery and purification.
- Patent Document 1 discloses a binder containing carboxymethyl cellulose and a polymer latex.
- a binder containing carboxymethyl cellulose and a polymer latex is excellent in dispersion stability and coatability, and an electrode layer having good adhesion to a current collector can be obtained.
- carboxymethyl cellulose is derived from a natural product, the quality of each supply lot is difficult to stabilize, and there are problems such as poor storage stability.
- Patent Document 2 discloses a positive paste for a non-aqueous battery containing poly N-vinylacetamide as a polymer containing a repeating structural unit having an amide structure.
- Poly N-vinylacetamide is said to be able to improve the required performance in secondary batteries (especially non-aqueous secondary batteries) such as paste stability, binding properties, and electrochemical stability.
- Patent Document 3 discloses a resin component containing poly N-vinylacetamide and a copolymer of ethylene oxide (EO) and propylene oxide (PO) as a binder. According to this binder, it is said that it has excellent binding properties and battery characteristics from low temperature to room temperature.
- EO ethylene oxide
- PO propylene oxide
- an electrode using poly N-vinylacetamide composed only of repeating structural units having an amide structure as a binder is inferior in flexibility (flexibility).
- poly N-vinylacetamide is used as the binder for the negative electrode, the stability of the slurry for the electrode (slurry stability) and the battery characteristics of the resulting battery are likely to deteriorate.
- a conductive assistant such as acetylene black for imparting conductivity is often added to the positive electrode.
- This conductive auxiliary agent also has an effect of imparting thixotropy to the electrode slurry because of its small particle size. Therefore, the positive electrode slurry (positive electrode slurry) is less likely to settle the active material or the like in a stationary state, and the slurry is highly stable over time.
- a carbon-based material is frequently used as an active material in the negative electrode and conductivity is ensured, a conductive auxiliary agent is often not added.
- the electrode slurry for the negative electrode (negative electrode slurry) has low thixotropy and the active material tends to settle immediately in a stationary state, resulting in poor stability.
- this negative electrode slurry is applied to the current collector, the active material settles before drying, and the binder is unevenly distributed at the top, resulting in inferior battery characteristics, particularly long-term cycle characteristics.
- the present invention has been made in view of the above circumstances, and can form an electrode having excellent flexibility, a battery having excellent battery characteristics, particularly long-term cycle characteristics, and a secondary battery electrode having excellent binding properties.
- An object of the present invention is to provide a binder resin composition for use, a slurry for a secondary battery electrode, an electrode for a secondary battery, and a lithium ion secondary battery including the same.
- the present invention provides a slurry for an electrode having excellent stability even when used for a negative electrode, can form an electrode in which uneven distribution of an active material and a binder is suppressed, and provides a battery having excellent battery characteristics, particularly long-term cycle characteristics. It is an object of the present invention to provide a secondary battery electrode binder resin composition, a secondary battery electrode slurry, a secondary battery electrode, and a lithium ion secondary battery including the same.
- the inventors of the present invention have improved binding properties and a flexible electrode by using a polymer having an amide structural unit as a binder and a particulate polymer insoluble in water. It was found that a battery excellent in battery characteristics could be obtained, and the present invention was completed.
- the present inventors have used a polymer having an amide structural unit as a binder and a water-soluble polymer (polymer) having an acidic group or / and a salt thereof in combination.
- a highly stable slurry can be obtained, an electrode with less uneven distribution of an active material and a binder can be formed, and a battery excellent in battery characteristics can be obtained.
- the present invention has been completed.
- R 1 and R 2 are each independently a hydrogen atom or an alkyl group.
- ⁇ 2> The binder resin composition for a secondary battery electrode according to ⁇ 1>, wherein the polymer (B-1) has an average particle size of 10 to 1000 nm.
- the mass ratio of the polymer (A) to the polymer (B-1) (polymer (A) / polymer (B-1)) is 5/95 to 95/5, ⁇ 1> Or the binder resin composition for secondary battery electrodes as described in ⁇ 2>.
- the binder resin composition for secondary battery electrodes and water are kneaded. An active material is added thereto and kneaded. Further, when the electrode is a positive electrode, a conductive additive is added and kneaded, and then the viscosity is adjusted with water to obtain a slurry for an electrode.
- a compounding quantity makes 2 mass parts of binder resin compositions for secondary battery electrodes with respect to 100 mass parts of active materials, and makes a conductive support agent 5 mass parts.
- the obtained electrode slurry is applied to a current collector and dried to obtain an electrode in which an electrode layer having a thickness of 20 to 200 ⁇ m is formed on the current collector. The obtained electrode is cut into 3 cm width and 5 cm length to obtain a test piece.
- the acidic group or / and salt thereof is at least one selected from the group consisting of a carboxyl group, a carboxyl group salt, a sulfonic acid group, a sulfonic acid group salt, a phosphoric acid group, and a phosphoric acid group salt.
- the binder resin composition for secondary battery electrodes according to ⁇ 1>.
- the mass ratio of the polymer (A) to the polymer (B-2) (polymer (A) / polymer (B-2)) is 5/95 to 99.5 / 0.5.
- the binder resin composition for secondary battery electrodes is 5/95 to 99.5 / 0.5.
- the viscosity ( ⁇ ) of a 1% by mass aqueous solution of the polymer (A) and the polymer (B-2) in the aqueous solution are 10 parts by mass with respect to 100 parts by mass of the polymer (A).
- the binder resin composition for a secondary battery electrode according to any one of ⁇ 1>, ⁇ 5>, and ⁇ 6>, wherein the ratio ( ⁇ / ⁇ ) to the viscosity ( ⁇ ) of the solution added to is 5 or more object.
- a secondary battery electrode slurry comprising the binder resin composition for a secondary battery electrode according to any one of ⁇ 1> to ⁇ 7>, an active material, and a solvent.
- a lithium ion secondary battery comprising the secondary battery electrode according to ⁇ 9>.
- ⁇ 11> A current collector and an electrode layer provided on the current collector, wherein the electrode layer is applied with the slurry for a secondary battery electrode according to ⁇ 8> on the current collector and dried.
- An electrode for a secondary battery obtained by ⁇ 12> A lithium ion secondary battery comprising the secondary battery electrode according to ⁇ 11>.
- an electrode having excellent flexibility can be formed, a battery having excellent battery characteristics, particularly long-term cycle characteristics, and a binder resin composition for a secondary battery electrode having excellent binding properties, a secondary battery A battery electrode slurry, a secondary battery electrode, and a lithium ion secondary battery including the same can be provided.
- an electrode slurry excellent in stability can be obtained even when used for a negative electrode, an electrode in which uneven distribution of an active material and a binder is suppressed can be formed, and battery characteristics, particularly long-term cycle characteristics are excellent.
- a binder resin composition for a secondary battery electrode from which a battery is obtained, a slurry for a secondary battery electrode, an electrode for a secondary battery, and a lithium ion secondary battery including the same can be provided.
- the binder resin composition for secondary battery electrodes of the first aspect of the present invention includes the following polymer (A) and polymer (B-1).
- a polymer (A) is a polymer containing the structural unit represented by following General formula (1), and is a component which provides binding property to a resin composition.
- R 1 and R 2 are each independently a hydrogen atom or an alkyl group.
- the alkyl group is preferably a linear or branched alkyl group having 1 to 5 carbon atoms.
- the content of the structural unit represented by the general formula (1) in the polymer (A) is 1 to 100 mol%. It is preferably 60 to 100 mol%. In particular, when the content of the structural unit represented by the general formula (1) is 60 mol% or more, the water solubility and thickening of the resulting polymer (A) are improved. In addition, as the content of the structural unit represented by the general formula (1) increases, the binding property of the electrode layer to the current collector tends to increase. Strong binding properties.
- Examples of the monomer (hereinafter referred to as “monomer (a)”) from which the structural unit represented by the general formula (1) is derived include N-vinylformamide and N-vinylacetamide. .
- the polymer (A) may contain units (arbitrary units) other than the structural unit represented by the general formula (1) as necessary. By including an arbitrary unit, mechanical properties such as rigidity and bending strength of the electrode layer described later are improved.
- the monomer that is the source of the arbitrary unit (hereinafter referred to as “optional monomer”) is not particularly limited as long as it is copolymerizable with the monomer (a), and examples thereof include acrylonitrile, methacrylonitrile, Vinyl cyanide monomers such as ⁇ -cyanoacrylate, dicyanovinylidene, and fumaronitrile; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate and the like ( (Meth) acrylates; carboxyl group-containing monomers such as (meth) acrylic acid, itaconic acid, crotonic acid, maleic acid,
- the mass average molecular weight of the polymer (A) is preferably 5,000 to 10,000,000, more preferably 10,000 to 7.5 million.
- the mass average molecular weight of the polymer (A) can be measured using gel permeation chromatography (GPC). For example, it can be determined as a molecular weight in terms of polystyrene using a solvent such as tetrahydrofuran or water as an eluent.
- the viscosity average molecular weight of the polymer (A) is preferably 10,000 to 10,000,000, more preferably 100,000 to 8,000,000. If the viscosity average molecular weight of the polymer (A) is not less than the above lower limit value, the binding property will be further increased, and if it is not more than the above upper limit value, the water solubility will be increased, and the dispersibility of the conductive additive will be improved.
- the viscosity average molecular weight of the polymer (A) is calculated from the viscosity of the aqueous solution of the polymer (A) as a viscosity converted molecular weight using poly N-vinylformamide (hereinafter referred to as PNVF) as a standard substance.
- PNVF poly N-vinylformamide
- “C” is the concentration (g / dL) of the polymer (A) in the aqueous solution of the polymer (A).
- the measuring method of the reduced viscosity of the aqueous solution of the polymer (A) will be described later.
- Method for measuring reduced viscosity First, the polymer (A) is dissolved in 1N saline so that the concentration of the polymer (A) is 0.1% by mass to obtain an aqueous solution of the polymer (A). The aqueous solution of the resulting polymer (A), using a Ostwald viscometer to measure the flow time at 25 °C (t 1). Separately, the flow time (t 0 ) at 25 ° C. is measured using a Oswald viscometer for 1N saline as a blank. From the obtained flow-down time, the reduced viscosity is calculated by the following formula (i).
- C is the concentration (g / dL) of the polymer (A) in the aqueous solution of the polymer (A).
- the polymer (A) can be obtained by polymerizing the above-described monomer (a) alone or copolymerizing the monomer (a) and an arbitrary monomer.
- the polymerization method is not particularly limited, and methods such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and photopolymerization may be employed depending on the monomers used as raw materials and the solubility of the polymer to be generated. .
- Use radical polymerization initiators such as a water-soluble azo compound, an organic peroxide, a water-soluble mineralization oxide, a redox-type polymerization initiator. Can do.
- water-soluble azo compounds examples include 4,4′-azobis (4-cyanovaleric acid), 2,2′-bis (2-imidazolin-2-yl) [2,2′-azobispropane] dihydrochloride Salt, 2,2′-bis (2-imidazolin-2-yl) [2,2′-azobispropane] disulfate dihydrate, 2,2′-azobis (2-amidinopropane) dihydrochloride 2,2′-azobis (2- (N- (2-carboxyethyl) amidino) propane), 2,2′-azobis (2- (2-imidazolin-2-yl) propane), 2,2′- Azobis (2-methyl-N- (1,1-bis (hydroxymethyl) -2-hydroxyethyl) propionamide), 2,2′-azobis [N- (2-hydroxyethyl) -2-methylpropanamide] Etc.
- 4,4′-azobis (4-cyanovaleric acid 2,2′-bis (2-imidazolin-2-y
- the organic peroxide is preferably a water-soluble peroxide, such as tert-butyl hydroperoxide.
- water-soluble inorganic peroxide include persulfates such as potassium persulfate, ammonium persulfate, and sodium persulfate, and hydrogen peroxide.
- An oxidizing agent such as persulfate can also be used as a redox initiator in combination with a reducing agent such as sodium bisulfite, sodium thiosulfate, or hydrosulfite, and a polymerization accelerator such as iron sulfate.
- a chain transfer agent may be used for the purpose of adjusting the molecular weight or a dispersant may be used for the purpose of improving dispersibility.
- examples of the chain transfer agent include mercaptan compounds, thioglycol, carbon tetrachloride, and ⁇ -methylstyrene dimer.
- dispersant examples include water-soluble cellulose resins such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose, polyvinyl alcohols, polyethylene glycol, polyvinyl pyrrolidone polyacrylamide, polystyrene sulfonate organic substances, inorganic substances such as calcium phosphate and calcium carbonate.
- water-soluble cellulose resins such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl cellulose
- polyvinyl alcohols polyethylene glycol
- polyvinyl pyrrolidone polyacrylamide polystyrene sulfonate organic substances
- inorganic substances such as calcium phosphate and calcium carbonate.
- the polymerization solvent used for the polymerization of the polymer (A) is not particularly limited.
- water, methanol, ethanol, isopropanol, hexane, cyclohexane, benzene, toluene, xylene, acetone, methyl ethyl ketone, dimethoxyethane, tetrahydrofuran, chloroform four Examples thereof include carbon chloride, ethylene dichloride, ethyl acetate, N-methylpyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide and the like.
- These polymerization solvents may be used alone or in combination of two or more.
- the polymer (B-1) is a particulate polymer that is substantially insoluble in water, and is a component that imparts flexibility to the electrode and imparts battery characteristics, particularly long-term cycle characteristics, to the battery.
- substantially insoluble in water means that the solubility in 100 g of water at 25 ° C. (that is, the limit of solubility in 100 g of water at 25 ° C.) is less than 0.5 g.
- the solubility is preferably 0.1 g or less.
- Examples of such a polymer (B-1) include aromatic vinyl compounds such as styrene, ⁇ -methylstyrene and p-methylstyrene, conjugated diolefins such as butadiene, and chlorine-containing compounds such as vinyl chloride and vinylidene chloride.
- particles obtained by polymerizing a polymer obtained by solution polymerization, bulk polymerization, or other methods For example, it is possible to use particles obtained by dispersing polyacrylonitrile powder obtained by suspension polymerization in water and forcibly emulsifying with a wet atomizer.
- vinyl styrene such as styrene, (meth) acrylate, or acrylonitrile in the presence of rubber such as conjugated diene such as polybutadiene, poly (meth) acrylate, or polyorganosiloxane is used.
- rubber such as conjugated diene such as polybutadiene, poly (meth) acrylate, or polyorganosiloxane is used.
- the rubber it is also possible to use a composite rubber comprising an acrylic ester or methacrylic ester component and a polyorganosiloxane component.
- the rubber content in the graft copolymer is preferably 40 to 90% by mass, more preferably 50 to 90% by mass.
- the polymer (B-1) is preferably a polymer of aromatic vinyl compounds, fluorine-containing vinyl compounds or unsaturated nitrile compounds, or a graft copolymer. Among them, polyvinylidene fluoride, polyacrylonitrile or graft copolymer Coalescence is more preferred.
- the average particle size of the polymer (B-1) is preferably 10 to 1000 nm, more preferably 50 to 500 nm, and further preferably 70 to 300 nm. If the average particle diameter of the polymer (B-1) is within the above range, the polymer (B-1) may precipitate when the resin composition is used as a binder in the production of an electrode as described in detail later. A stable resin composition capable of suppressing aggregation is obtained.
- the average particle size of the polymer (B-1) is a volume average primary particle size measured using a laser diffraction / scattering particle size distribution analyzer.
- the mass ratio of the polymer (A) to the polymer (B-1) is calculated in terms of solid content. 5/95 to 95/5 is preferable, 25/75 to 75/25 is more preferable, and 25/75 to 50/50 is particularly preferable.
- an electrode slurry (secondary battery electrode slurry) is prepared using the resin composition to produce an electrode. Furthermore, the handleability of the electrode slurry and the coating property to the current collector are improved. In addition, the uniformity inside the electrode layer formed from the electrode slurry is increased.
- the resin composition can be obtained, for example, by mixing the polymer (A) and the polymer (B-1). As will be described in detail later, the polymer (A), the polymer (B-1), the active material, and the like may be dispersed in a solvent at the timing of preparing the electrode slurry.
- the resin composition may be composed of the polymer (A) and the polymer (B-1), but may contain a polymer (B-2) described later.
- the resin composition of the first aspect of the present invention contains the polymer (A) and the polymer (B-1), it has excellent binding properties. Moreover, the electrode produced using the resin composition containing the polymer (A) and the polymer (B-1) is excellent in flexibility, and the battery equipped with the electrode has battery characteristics (particularly long-term cycle characteristics). Excellent. Therefore, the resin composition of the first aspect of the present invention can form an electrode excellent in binding properties and flexibility, and a battery excellent in battery characteristics (particularly long-term cycle characteristics) can be obtained. Specifically, an electrode having no change in the electrode layer can be formed when the flexibility of the electrode is evaluated by the following flexibility test.
- “no change in the electrode layer” means that the electrode layer does not show any changes such as cracks and chips when observed with an optical microscope at a magnification of 60 times.
- the binder resin composition for secondary battery electrodes and water are kneaded. An active material is added thereto and kneaded. Further, when the electrode is a positive electrode, a conductive additive is added and kneaded, and then the viscosity is adjusted with water to obtain a slurry for an electrode.
- a compounding quantity makes 2 mass parts of binder resin compositions for secondary battery electrodes with respect to 100 mass parts of active materials, and makes a conductive support agent 5 mass parts.
- the obtained electrode slurry is applied to a current collector and dried to obtain an electrode in which an electrode layer having a thickness of 20 to 200 ⁇ m is formed on the current collector. The obtained electrode is cut into 3 cm width and 5 cm length to obtain a test piece.
- the resin composition of the first aspect of the present invention is suitable as a binder for both the positive electrode and the negative electrode of a lithium ion secondary battery.
- the slurry for secondary battery electrodes of the first aspect of the present invention contains the above-described resin composition of the first aspect of the present invention, an active material, and a solvent. To do.
- the electrode slurry contains a binder resin (other binder resin) other than the polymer (A) and the polymer (B-1), a viscosity modifier, a binding improver, a dispersant and the like. Also good.
- a slurry for electrodes when using the slurry for electrodes as an object for positive electrodes, you may make a slurry for electrodes contain a conductive support agent.
- the resin composition used for the electrode slurry of the first aspect of the present invention is the above-described resin composition of the first aspect of the present invention, and a detailed description thereof is omitted here.
- the ratio of the resin composition in the electrode slurry (that is, the total of the polymer (A) and the polymer (B-1)) is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the active material. 0.2 to 5 parts by mass is more preferable. If the ratio of a resin composition is 0.1 mass part or more, the adhesiveness to an electrical power collector and the binding property between active materials will become favorable. On the other hand, if the ratio of the resin composition is 10 parts by mass or less, the resistance in the electrode can be prevented from deteriorating.
- the active material used for the electrode slurry only needs to have a different potential between the positive electrode and the negative electrode.
- the positive electrode active material include at least one metal selected from iron, cobalt, nickel, and manganese, and a lithium-containing metal composite oxide containing lithium.
- the active material for the negative electrode for example, carbon materials such as graphite, amorphous carbon, carbon fiber, coke and activated carbon; the carbon materials and metals such as silicon, tin and silver, or these Examples include composites with oxides.
- a positive electrode active material and a negative electrode active material may be used individually by 1 type, and may use 2 or more types together.
- binder resins examples include acrylic acid-modified SBR resin (SBR latex) and acrylic rubber latex.
- SBR latex acrylic acid-modified SBR resin
- acrylic rubber latex acrylic rubber latex
- a polymer that is substantially insoluble in water and not in the form of particles such as vinyl acetate copolymer, styrene butadiene block copolymer (SBR), polyvinylidene fluoride (PVDF), or the like is used. You can also.
- the viscosity modifier examples include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose, and ammonium salts thereof; poly (meth) acrylates such as sodium poly (meth) acrylate; polyvinyl alcohol, polyethylene oxide, Polyvinylpyrrolidone, acrylic acid or acrylate and vinyl alcohol copolymer, maleic anhydride, maleic acid or fumaric acid and vinyl alcohol copolymer, modified polyvinyl alcohol, modified polyacrylic acid, polyethylene glycol, polycarboxylic acid, etc. Is mentioned.
- the viscosity modifier can also be used as other binder resins.
- Examples of the conductive assistant include graphite, carbon black, carbon nanotube, carbon nanofiber, acetylene black, and conductive polymer. These conductive assistants may be used alone or in combination of two or more.
- the solvent examples include water; one or more of water, NMP, N, N-dimethylformamide, tetrahydrofuran, dimethylacetamide, dimethylsulfoxide, hexamethylsulfuramide, tetramethylurea, acetone, methyl ethyl ketone, and N-methylpyrrolidone;
- Examples thereof include mixed solvents of ester solvents (ethyl acetate, n-butyl acetate, butyl cellosolve acetate, butyl carbitol acetate, etc.); mixed solvents of NMP and glyme solvents (diglyme, triglyme, tetraglyme, etc.).
- water is preferable from the viewpoint of reducing energy for recovering the solvent, environmental load, and drying.
- These solvents may be used alone or in combination of two or more.
- the slurry for electrodes according to the first aspect of the present invention described above includes the resin composition according to the first aspect of the present invention, an electrode having excellent binding properties and excellent flexibility can be formed. A battery having excellent characteristics (particularly long-term cycle characteristics) can be obtained.
- the electrode for secondary batteries (hereinafter referred to as “electrode”) according to the first aspect of the present invention includes a current collector and an electrode layer provided on the current collector.
- the electrode layer is a layer containing at least the active material and the resin composition of the first aspect of the present invention as a binder, and if necessary, other than the polymer (A) and the polymer (B-1) It may contain known additives such as binder resins (other binder resins), viscosity modifiers, binding improvers, and dispersants.
- binder resins other binder resins
- viscosity modifiers examples include the active material, other binder resin, and viscosity modifier exemplified above in the description of the electrode slurry according to the first aspect of the present invention.
- the electrode layer of a positive electrode may contain a conductive support agent.
- Battery performance can be improved more by containing a conductive support agent.
- a conductive support agent the conductive support agent illustrated previously in description of the slurry for electrodes of the 1st aspect of this invention is mentioned.
- the electrode layer is, for example, a layer formed on at least one surface of a plate-like current collector, and the thickness is preferably 0.1 to 500 ⁇ m, but is not limited thereto. Note that since the positive electrode has a smaller active material capacity than the negative electrode, the positive electrode layer is preferably thicker than the negative electrode layer.
- any material having conductivity can be used, and a metal can be used.
- a metal a metal that is difficult to be alloyed with lithium is preferable. Specific examples include aluminum, copper, nickel, iron, titanium, vanadium, chromium, manganese, and alloys thereof.
- the shape of the current collector include a thin film shape, a net shape, and a fiber shape. Among these, a thin film is preferable.
- the thickness of the current collector is preferably 5 to 30 ⁇ m, more preferably 8 to 25 ⁇ m.
- the electrode of the first aspect of the present invention can be manufactured using a known method.
- the secondary battery is obtained by dispersing the resin composition of the first aspect of the present invention, the active material, and, if necessary, other binder resins, additives such as a viscosity adjusting agent and a conductive assistant in a solvent.
- the electrode slurry (electrode slurry) is prepared (slurry preparation step), the electrode slurry is applied to the current collector (application step), the solvent is removed (solvent removal step), and the first of the present invention
- An electrode in which a layer (electrode layer) holding an active material or the like with the resin composition of the aspect is formed on a current collector is obtained.
- the resin composition of the first aspect of the present invention, the active material, and, if necessary, other binder resins, additives such as a viscosity modifier and a conductive aid are dispersed in a solvent.
- the polymer (A) and the polymer (B-1) described above may be mixed in advance to form a resin composition, or the polymer (A) and the polymer (B-1) in the slurry preparation step. May be dispersed in a solvent together with the active material and the timing of dispersion of the polymer (A), the polymer (B-1), the active material and the like in the solvent is not particularly limited.
- an electrode slurry may be prepared by mixing an aqueous solution in which the polymer (A) is dissolved in water, a dispersion in which the polymer (B-1) is dispersed in a solvent, and an active material.
- the aqueous solution of the polymer (A) and the dispersion of the polymer (B-1) may be mixed in advance, and these and the active material may be mixed, or the aqueous solution of the polymer (A) and the active material may be mixed.
- the dispersion of polymer (B-1) may be mixed, but the polymer (A-1) can be prepared in that the active material is well dispersed and a homogeneous electrode slurry can be prepared. It is preferable to mix the dispersion of polymer (B-1) after mixing the aqueous solution of) and the active material.
- the ratio of the resin composition of the first aspect of the present invention (that is, the total of the polymer (A) and the polymer (B-1)) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the active material. Is preferable, and 0.2 to 5 parts by mass is more preferable. If the ratio of a resin composition is 0.1 mass part or more, the adhesiveness to an electrical power collector and the binding property between active materials will become favorable. On the other hand, if the ratio of the resin composition is 10 parts by mass or less, the resistance in the electrode can be prevented from deteriorating.
- Examples of the solvent used in the slurry preparation step include the solvents exemplified above in the description of the electrode slurry according to the first aspect of the present invention.
- the electrode slurry is obtained by kneading at least the resin composition of the first aspect of the present invention and the active material in the presence of a solvent.
- the kneading method is not particularly limited as long as the resin composition and the active material can be sufficiently kneaded.
- the kneading is carried out by various dispersing machines such as a revolving stirrer, a planetary mixer, a homogenizer, a ball mill, a sand mill, and a roll mill. A method is mentioned.
- the application step is a step of applying the electrode slurry obtained in the slurry preparation step to the current collector.
- the application method is not particularly limited as long as the electrode slurry can be applied to the current collector so that the thickness of the electrode layer is 0.1 to 500 ⁇ m. Examples thereof include a bar coating method, a doctor blade method, a knife method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a curtain method, a dipping method, and a brush coating method.
- a solvent removal process is a process of removing the solvent in the slurry for electrodes apply
- a removal method a generally adopted method can be used as long as the solvent can be removed.
- the removal conditions are not particularly limited as long as the solvent can be sufficiently removed and the polymer (A) and the polymer (B-1) are not decomposed, but are 40 to 120 ° C., preferably 60 to 100 ° C.
- Heat treatment is preferably performed for 1 minute to 10 hours. Under these conditions, the polymer (A) and the polymer (B-1) can be provided with high adhesion between the active material and the current collector or the active material without being decomposed. Further, the current collector is not easily corroded.
- the electrode layer may be pressed as necessary (pressing step).
- pressing step the area of the electrode layer can be expanded and adjusted to an arbitrary thickness, and the smoothness and electric density of the electrode layer surface can be increased.
- the pressing method include a mold press and a roll press. Furthermore, you may cut
- the electrode of the first aspect of the present invention uses the resin composition of the first aspect of the present invention as a binder, the electrode layer has a high binding property to the current collector, and Excellent flexibility. In addition, since the active material is not easily lost, the discharge capacity can be maintained high over a long period of time.
- the electrode of the first aspect of the present invention is suitable as an electrode for a lithium ion secondary battery.
- the lithium ion secondary battery according to the first aspect of the present invention includes the electrode according to the first aspect of the present invention.
- a lithium ion secondary battery for example, a positive electrode and a negative electrode are arranged with a permeable separator (for example, a porous film made of polyethylene or polypropylene) interposed therebetween, and this is impregnated with a non-aqueous electrolyte.
- a permeable separator for example, a porous film made of polyethylene or polypropylene
- Non-aqueous secondary battery negative electrode / separator / electrode body formed on both sides of current collector, and positive electrode / separator layered on both sides of current collector in a roll shape (spiral shape) Examples thereof include a cylindrical non-aqueous secondary battery in which a wound wound body is housed in a bottomed metal casing together with an electrolytic solution.
- an electrolytic solution in which a lithium salt as an electrolyte is dissolved in a non-aqueous organic solvent at a concentration of about 1M is used.
- the lithium salt LiClO 4, LiBF 4, LiI, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, LiCH 3 SO 3, LiC 4 F 9 SO 3, Li (CF 3 SO 2) 2 N, Li [(CO 2) 2] such as 2 B and the like.
- non-aqueous organic solvents carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; lactones such as ⁇ -butyrolactone; trimethoxymethane, 1,2-dimethoxyethane Ethers such as diethyl ether, 2-ethoxyethane, tetrahydrofuran and 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide; oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane; acetonitrile, nitromethane , Nitrogen-containing compounds such as NMP; esters such as methyl formate, methyl acetate, butyl acetate, methyl propionate, ethyl propionate, phosphate triester; diglyme, triglyme, Gly
- a lithium ion secondary battery is obtained, for example, by disposing a positive electrode and a negative electrode with a permeable separator interposed therebetween, and impregnating the non-aqueous electrolyte solution with the separator.
- a laminate composed of a negative electrode / separator / positive electrode / separator having an electrode layer formed on both sides of a current collector is wound into a roll (spiral shape). Let it be the body.
- the obtained wound body is accommodated in a bottomed metal casing (battery can), and the negative electrode is connected to the negative electrode terminal and the positive electrode is connected to the positive electrode terminal.
- the metal casing is sealed to obtain a cylindrical lithium ion secondary battery.
- the thus obtained lithium ion secondary battery according to the first aspect of the present invention is provided with an electrode using the resin composition according to the first aspect of the present invention as a binder, and thus has excellent battery performance.
- the battery performance is excellent because the electrode is excellent in flexibility, so even if stress is applied, the electrode is difficult to break, and the electrode layer has a high binding property to the current collector.
- the resin composition hardly swells and can maintain a high discharge capacity over a long period of time.
- the binder resin composition for secondary battery electrodes of the second aspect of the present invention includes the following polymer (A) and polymer (B-2).
- a polymer (A) is a polymer containing the structural unit represented by the said General formula (1).
- the polymer (A) used in the resin composition of the second aspect of the present invention is the same as the polymer (A) used in the resin composition of the first aspect of the present invention, and the detailed description here is Omitted.
- the polymer (B-2) is a substantially water-soluble polymer (polymer) and has an acidic group or / and a salt thereof.
- the polymer (B-2) is a component that imparts an appropriate viscosity to the secondary battery electrode slurry (electrode slurry) and imparts stability and battery characteristics, particularly long-term cycle characteristics, of the electrode slurry.
- substantially soluble in water means that the solubility in 100 g of water at 25 ° C. (that is, the limit of solubility in 100 g of water at 25 ° C.) is 0.5 g or more.
- the solubility is preferably 1 g or more.
- the acidic group or / and salt thereof possessed by the polymer (B-2) is preferably a carboxyl group, a carboxyl group salt, a sulfonic acid group, a sulfonic acid group salt, a phosphoric acid group, or a phosphoric acid group salt.
- the polymer (B-2) may contain one of these alone or in a mixture of two or more.
- the acid group salt include an alkali metal salt, an alkaline earth metal salt, an ammonium salt, and a substituted ammonium salt.
- the alkali metal include lithium, sodium, and potassium.
- Examples of the alkaline earth metal include magnesium and calcium.
- substituted ammonium include alicyclic ammoniums, cyclic saturated ammoniums, and cyclic unsaturated ammoniums.
- Examples of such a polymer (B-2) include carboxymethyl cellulose, polyacrylic acid, polymethacrylic acid, polyitaconic acid, polyfumaric acid, polycrotonic acid, polymaleic acid, (meth) acrylic acid-itaconic acid copolymer, Carboxyl group-containing polymers such as (meth) acrylic acid- (anhydrous) maleic acid copolymer and salts thereof; poly (meth) allylsulfonic acid, poly (meth) allyloxybenzenesulfonic acid, polystyrenesulfonic acid, 2- Sulfonic acid group-containing polymers such as acrylamido-2-methylpropanesulfonic acid polymer and salts thereof; 2- (meth) acryloyloxyethyl acid phosphate polymer, 2- (meth) acryloyloxyethyl acid phosphate monoethanolamine Polymer, diphenyl ((meth) acrylo Ruoxyethyl) phosphate
- R 3 is one group selected from the group consisting of a sulfonic acid group, a carboxyl group, and alkali metal salts, alkaline earth metal salts, ammonium salts and substituted ammonium salts thereof; 4 is a methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, tert-butyl group, dodecyl group, tetracosyl group, methoxy group, ethoxy group, n-propoxy group, n-butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, pentoxy group, hexoxy group, octoxy group, dodecoxy group, tetradecoxy group, fluoro group, chloro group and bromo group 1 represents a group selected from the group, x represents an arbitrary number of 0
- polyethylene dioxythiophene polystyrene sulfate may be used as the polymer (B-2).
- the polymer has a structure in which polystyrene sulfonic acid is added as a dopant although a sulfonic acid group is not introduced into the polymer skeleton.
- polymer (B-2) these may be used alone or in combination of two or more.
- the mass ratio of the polymer (A) to the polymer (B-2) is calculated in terms of solid content. 5/95 to 99.5 / 0.5 is preferable, 50/50 to 99/1 is more preferable, 60/40 to 99/1 is further preferable, and 80/20 to 99/1 is particularly preferable. If the mass ratio of the polymer (A) and the polymer (B-2) is within the above range, the stability of the electrode slurry is improved, and the electrode is prepared by preparing the electrode slurry using the resin composition. In this case, the handleability of the electrode slurry and the coating property to the current collector are improved. In addition, the uniformity inside the electrode layer formed from the electrode slurry is increased.
- the viscosity ( ⁇ ) of a 1% by mass aqueous solution of the polymer (A) and the polymer (B-2) in the aqueous solution are added to 100 parts by mass of the polymer (A).
- the ratio ( ⁇ / ⁇ ) to the viscosity ( ⁇ ) of the solution added so as to be 10 parts by mass is preferably 5 or more, and more preferably 7 or more. If ⁇ / ⁇ is 5 or more, the stability of the electrode slurry is improved, and the coating property to the current collector and the adhesion of the electrode layer to the current collector are increased.
- About the upper limit of (beta) / (alpha) 1000 or less are preferable and 700 or less are more preferable at the point from which the handleability of the slurry for electrodes becomes favorable.
- the viscosity ( ⁇ ) can be determined by measuring the viscosity of a 1% by mass aqueous solution of the polymer (A) as follows. First, the polymer (A) is dissolved in ion-exchanged water so that the concentration of the polymer (A) is 1% by mass to obtain a 1% by mass aqueous solution of the polymer (A). About the 1 mass% aqueous solution of the obtained polymer (A), the viscosity in 25 degreeC is measured using a B-type viscosity meter. The rotor to be used and the number of rotations may be determined in consideration of the measurable viscosity range.
- the viscosity ( ⁇ ) is obtained by measuring the viscosity of a solution obtained by adding the polymer (B-2) to a 1% by mass aqueous solution of the polymer (A) as follows.
- the polymer (A) is dissolved in ion-exchanged water so that the concentration of the polymer (A) is 1% by mass to obtain a 1% by mass aqueous solution of the polymer (A).
- the polymer (B-2) is added so as to be 10 parts by mass with respect to 100 parts by mass of the polymer (A) to obtain a solution.
- a viscosity is measured like the 1 mass% aqueous solution of a polymer (A).
- the resin composition can be obtained, for example, by mixing the polymer (A) and the polymer (B-2). As will be described in detail later, the polymer (A), the polymer (B-2), the active material, and the like may be dispersed in a solvent at the timing of preparing the electrode slurry.
- the resin composition may be composed of the polymer (A) and the polymer (B-2), but may contain the polymer (B-1) described above.
- the resin composition according to the second aspect of the present invention contains the polymer (A) and the polymer (B-2), the slurry can be separated even when the electrode slurry for the negative electrode is prepared.
- the viscosity is such that precipitation of the active material hardly occurs, an electrode slurry having excellent stability can be obtained.
- an electrode produced using a resin composition containing the polymer (A) and the polymer (B-2) has little active material and binder unevenly distributed, the battery equipped with the electrode has battery characteristics (especially long-term performance). Excellent cycle characteristics.
- an electrode slurry excellent in stability can be obtained, and an electrode including an electrode layer excellent in uniformity with less uneven distribution of active material and binder can be formed.
- a battery having excellent long-term cycle characteristics can be obtained.
- the resin composition of the second aspect of the present invention is suitable as a binder for both the positive electrode and the negative electrode of a lithium ion secondary battery.
- the slurry for secondary battery electrodes of the second aspect of the present invention contains the above-described resin composition of the second aspect of the present invention, an active material, and a solvent. To do. Further, the electrode slurry contains a binder resin (other binder resin) other than the polymer (A) and the polymer (B-2), a viscosity modifier, a binding improver, a dispersant and the like. Also good. Moreover, when using the slurry for electrodes as an object for positive electrodes, you may make a slurry for electrodes contain a conductive support agent.
- the resin composition used for the electrode slurry according to the second aspect of the present invention is the above-described resin composition according to the second aspect of the present invention, and a detailed description thereof is omitted here.
- the ratio of the resin composition in the electrode slurry (that is, the total of the polymer (A) and the polymer (B-2)) is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the active material. 0.2 to 5 parts by mass is more preferable. If the ratio of a resin composition is 0.1 mass part or more, the adhesiveness to an electrical power collector and the binding property between active materials will become favorable. On the other hand, if the ratio of the resin composition is 10 parts by mass or less, the resistance in the electrode can be prevented from deteriorating.
- Examples of the active material, conductive additive, and solvent used in the electrode slurry include the active material, conductive aid, and solvent exemplified above in the description of the electrode slurry according to the first aspect of the present invention.
- binder resins examples include acrylic acid-modified SBR resin (SBR latex) and acrylic rubber latex.
- the viscosity modifier examples include cellulose polymers such as methyl cellulose and hydroxypropyl cellulose and ammonium salts thereof; polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, acrylic acid or a copolymer of acrylate and vinyl alcohol, maleic anhydride Examples thereof include a copolymer of acid, maleic acid or fumaric acid and vinyl alcohol, modified polyvinyl alcohol, modified polyacrylic acid, and polyethylene glycol.
- the viscosity modifier can also be used as other binder resins.
- the slurry for electrodes according to the second aspect of the present invention described above contains the resin composition according to the second aspect of the present invention, it has excellent stability even when used for the negative electrode, and suppresses the uneven distribution of the active material and binder.
- An electrode can be formed, and a battery excellent in battery characteristics, particularly in long-term cycle characteristics can be obtained.
- the electrode for secondary batteries (hereinafter referred to as “electrode”) according to the second aspect of the present invention includes a current collector and an electrode layer provided on the current collector.
- the electrode layer is a layer containing at least the active material and the resin composition of the second aspect of the present invention as a binder, and if necessary, other than the polymer (A) and the polymer (B-2) It may contain known additives such as binder resins (other binder resins), viscosity modifiers, binding improvers, and dispersants.
- binder resins other binder resins
- viscosity modifiers include the other binder resins and viscosity modifiers exemplified above in the description of the electrode slurry of the second aspect of the present invention.
- the electrode layer of an electrode may contain a conductive support agent.
- Battery performance can be improved more by containing a conductive support agent.
- a conductive support agent the conductive support agent illustrated previously in description of the slurry for electrodes of the 1st aspect of this invention is mentioned.
- the electrode layer is, for example, a layer formed on at least one surface of a plate-like current collector, and the thickness is preferably 0.1 to 500 ⁇ m, but is not limited thereto. Note that since the positive electrode has a smaller active material capacity than the negative electrode, the positive electrode layer is preferably thicker than the negative electrode layer.
- any material having conductivity can be used, and a metal can be used.
- a metal a metal that is difficult to be alloyed with lithium is preferable. Specific examples include aluminum, copper, nickel, iron, titanium, vanadium, chromium, manganese, and alloys thereof.
- the shape of the current collector include a thin film shape, a net shape, and a fiber shape. Among these, a thin film is preferable.
- the thickness of the current collector is preferably 5 to 30 ⁇ m, more preferably 8 to 25 ⁇ m.
- the electrode of the second aspect of the present invention can be manufactured using a known method.
- a secondary battery in which the resin composition according to the second aspect of the present invention, an active material, and other binder resin, an additive such as a viscosity modifier and a conductive auxiliary agent are dispersed in a solvent as necessary.
- An electrode slurry (electrode slurry) is prepared (slurry preparation step), the electrode slurry is applied to a current collector (application step), the solvent is removed (solvent removal step), and the second of the present invention
- An electrode in which a layer (electrode layer) holding an active material or the like with the resin composition of the aspect is formed on a current collector is obtained.
- the resin composition of the second aspect of the present invention, the active material, and, if necessary, other binder resins, additives such as a viscosity modifier and a conductive aid are dispersed in a solvent.
- the polymer (A) and the polymer (B-2) described above may be mixed in advance to form a resin composition, or the polymer (A) and the polymer (B-2) in the slurry preparation step. May be dispersed in a solvent together with the active material and the timing of dispersion of the polymer (A), the polymer (B-2), the active material and the like in the solvent is not particularly limited.
- the ratio of the resin composition of the second aspect of the present invention (that is, the total of the polymer (A) and the polymer (B-2)) is 0.1 to 10 parts by mass with respect to 100 parts by mass of the active material. Is preferable, and 0.2 to 5 parts by mass is more preferable. If the ratio of a resin composition is 0.1 mass part or more, the adhesiveness to an electrical power collector and the binding property between active materials will become favorable. On the other hand, if the ratio of the resin composition is 10 parts by mass or less, the resistance in the electrode can be prevented from deteriorating.
- Examples of the solvent used in the slurry preparation step include the solvents exemplified above in the description of the electrode slurry according to the first aspect of the present invention.
- the electrode slurry is obtained by kneading at least the resin composition of the second aspect of the present invention and the active material in the presence of a solvent.
- the kneading method is not particularly limited as long as the resin composition and the active material can be sufficiently kneaded.
- the kneading is carried out by various dispersing machines such as a revolving stirrer, a planetary mixer, a homogenizer, a ball mill, a sand mill, and a roll mill. A method is mentioned.
- the application step is a step of applying the electrode slurry obtained in the slurry preparation step to the current collector.
- the application method is not particularly limited as long as the electrode slurry can be applied to the current collector so that the thickness of the electrode layer is 0.1 to 500 ⁇ m. Examples thereof include a bar coating method, a doctor blade method, a knife method, a dipping method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a curtain method, a dipping method, and a brush coating method.
- a solvent removal process is a process of removing the solvent in the slurry for electrodes apply
- a removal method a generally adopted method can be used as long as the solvent can be removed.
- the removal conditions are not particularly limited as long as the solvent can be sufficiently removed and the polymer (A) and the polymer (B-2) are not decomposed, but are 40 to 120 ° C., preferably 60 to 100 ° C.
- Heat treatment is preferably performed for 1 minute to 10 hours. Under these conditions, the polymer (A) and the polymer (B-2) can be provided with high adhesion between the active material and the current collector or the active material without being decomposed. Further, the current collector is not easily corroded.
- the electrode layer may be pressed as necessary (pressing step).
- pressing step the area of the electrode layer can be expanded and adjusted to an arbitrary thickness, and the smoothness and electric density of the electrode layer surface can be increased.
- the pressing method include a mold press and a roll press. Furthermore, you may cut
- the electrode of the present invention uses the resin composition of the second aspect of the present invention as a binder, even when preparing an electrode slurry for a negative electrode, the slurry is separated and the active material is precipitated. Therefore, it is manufactured using an electrode slurry having excellent stability. Therefore, the electrode according to the second aspect of the present invention includes an electrode layer with little uneven distribution of active material and binder and excellent uniformity, so that a battery capable of maintaining a high discharge capacity over a long period of time can be obtained.
- the electrode of the second aspect of the present invention is suitable as an electrode for a lithium ion secondary battery.
- the lithium ion secondary battery according to the second aspect of the present invention includes the electrode according to the second aspect of the present invention.
- a lithium ion secondary battery for example, a positive electrode and a negative electrode are arranged with a permeable separator (for example, a porous film made of polyethylene or polypropylene) interposed therebetween, and this is impregnated with a non-aqueous electrolyte.
- a permeable separator for example, a porous film made of polyethylene or polypropylene
- Non-aqueous secondary battery negative electrode / separator / electrode body formed on both sides of current collector, and positive electrode / separator layered on both sides of current collector in a roll shape (spiral shape) Examples thereof include a cylindrical non-aqueous secondary battery in which a wound wound body is housed in a bottomed metal casing together with an electrolytic solution.
- lithium ion secondary battery an electrolytic solution in which a lithium salt as an electrolyte is dissolved in a non-aqueous organic solvent at a concentration of about 1M is used.
- the lithium salt and non-aqueous organic solvent include the lithium salt and non-aqueous organic solvent exemplified above in the description of the lithium ion secondary battery according to the first aspect of the present invention.
- a lithium ion secondary battery is obtained, for example, by disposing a positive electrode and a negative electrode with a permeable separator interposed therebetween, and impregnating the non-aqueous electrolyte solution with the separator.
- a permeable separator interposed therebetween, and impregnating the non-aqueous electrolyte solution with the separator.
- it is obtained by the method exemplified above in the description of the lithium ion secondary battery according to the first aspect of the present invention.
- the thus obtained lithium ion secondary battery of the second aspect of the present invention is provided with an electrode using the resin composition of the second aspect of the present invention as a binder, and thus has excellent battery performance.
- the battery performance is excellent because the electrode slurry can be manufactured using the electrode slurry having excellent stability, so that the active material is not easily settled, the uniformity of the electrode layer is good, and the electrode is immersed in the electrolyte. This is because the resin composition hardly swells and can maintain a high discharge capacity over a long period of time.
- N-vinylacetamide polymer (A2) 30 parts by mass of a 75% by mass aqueous solution of N-vinylacetamide was added dropwise over 1 hour. After completion of the dropwise addition, the mixture was kept at 55 ° C. for 2 hours and then cooled to obtain a polymer suspension. The obtained polymer suspension was filtered, and the obtained solid was dried at 60 ° C. under vacuum to obtain an N-vinylacetamide polymer (A2).
- peeling strength was evaluated by the following method.
- the positive electrode or negative electrode of each example was cut out to a width of 2 cm, and a test piece 1 was obtained.
- the test piece 1 was attached to a polycarbonate plate (2.5 cm ⁇ 10 cm ⁇ thickness 1 mm) with a double-sided tape (manufactured by Sekisui Chemical Co., Ltd., “# 570”) to obtain a test piece for measurement.
- the positive electrode or the negative electrode was attached to the polycarbonate plate so that the electrode layer was in contact with the polycarbonate plate.
- the load when the current collector was peeled off from the measurement specimen was measured. Measurement was performed on five test pieces, and the average value was defined as the peel strength.
- the measurement conditions were a peeling rate of 10 mm / min, a peeling angle of 180 °, an environmental temperature of 23 ° C., and an environmental humidity of 40% RH. It means that the higher the peel strength, the stronger the electrode layer is bound by the current collector.
- the positive electrode or the negative electrode of each example was cut out to be 3 cm wide and 5 cm long to obtain a test piece 2.
- the test piece 2 was evaluated for flexibility with reference to the paint general test method flex resistance (cylindrical mandrel method) of JIS K-5600-5-1: 1999 (ISO 1519: 1973).
- flex resistance cylindrical mandrel method
- JIS K-5600-5-1 1999 (ISO 1519: 1973.
- the state of the electrode layer when the test piece 2 is bent so that the inside of the test piece 2 is bent is observed using a 60 ⁇ microscope (manufactured by Three R System Co., Ltd., “Wireless Digital Microscope”), and the following evaluation criteria are used.
- the flexibility of the positive electrode was evaluated.
- the evaluation was performed in the same manner as in the case of the positive electrode except that a mandrel having a diameter of 3 mm was applied to the current collector surface of the obtained test piece 2.
- ⁇ No changes such as cracks and chippings are observed in the electrode layer.
- X Changes such as cracks and chipping were observed in the electrode layer.
- the battery characteristics of the obtained electrode were evaluated by the following method.
- the positive electrode of each example and a commercially available metal lithium electrode (negative electrode), or the negative electrode of each example and a commercially available metal lithium electrode (positive electrode) were opposed to each other through a separator (Celguard # 2400).
- the obtained 2032 type coin battery was tested by a constant current method (current density: 0.6 mA / g-active material) at 60 ° C. with a charge / discharge rate of 0.5 C.
- Example 1-1> (Preparation of slurry for positive electrode)
- 50 parts by mass (2 parts by mass in terms of solid content) of a 4% by mass aqueous solution of N-vinylformamide polymer (A1) as polymer (A) and 40 parts by mass of deionized water are weighed.
- 100 parts by mass of lithium cobalt oxide (Nippon Chemical Industry Co., Ltd., “Cellseed C-5H”) and 5 parts by mass of acetylene black (Electrochemical Industry Co., Ltd.) were added. Kneading Awatori ”)) and kneading under the conditions of rotation of 1000 rpm and revolution of 2000 rpm.
- the obtained positive electrode slurry was applied onto a current collector (aluminum foil, 19 cm ⁇ 25 cm, thickness 20 ⁇ m) using a doctor blade, dried at 60 ° C. for 30 minutes in a circulating hot air dryer, and further into a vacuum dryer And dried under reduced pressure at 80 ° C. for 12 hours to obtain a positive electrode in which an electrode layer having a thickness of 80 ⁇ m was formed on a current collector (aluminum foil).
- peeling strength was measured and the softness
- Example 1 except that 25 parts by mass (1 part by mass in terms of solid content) of a 4% by mass aqueous solution of N-vinylformamide polymer (A1) and 40 parts by mass of deionized water were weighed in an ointment container.
- a positive electrode slurry was prepared, a positive electrode was prepared, and various measurements and evaluations were performed.
- Table 1 shows the composition of the positive electrode slurry.
- Table 2 shows the evaluation measurements and results.
- Example 1-3 A positive electrode slurry was prepared in the same manner as in Example 1-1 except that the N-vinylacetamide polymer (A2) was used instead of the N-vinylformamide polymer (A1) as the polymer (A).
- a positive electrode was prepared and subjected to various measurements and evaluations. Table 1 shows the composition of the positive electrode slurry. The measurement / evaluation results are shown in Table 2.
- Example 1-4 Instead of polyvinylidene fluoride latex as polymer (B-1), an acrylic silicone latex (average particle size 166 nm, solid content) obtained by graft polymerization of methyl methacrylate to a composite rubber comprising a butyl acrylate component and a polyorganosiloxane component A positive electrode slurry was prepared in the same manner as in Example 1-1, except that 8 parts by mass (25 parts by mass) (2 parts by mass in terms of solid content) was used, and a positive electrode was prepared and subjected to various measurements and evaluations. . Table 1 shows the composition of the positive electrode slurry. The measurement / evaluation results are shown in Table 2.
- Example 1-5> instead of polyvinylidene fluoride latex as polymer (B-1), polyacrylonitrile latex obtained by dispersing polyacrylonitrile powder obtained by suspension polymerization in water and forcibly emulsifying with a wet atomizer A positive electrode slurry was prepared in the same manner as in Example 1-1, except that 27 parts by mass (average particle size: 400 nm, solid content: 7.5% by mass) was used (2 parts by mass in terms of solid content). It produced and performed various measurement and evaluation. Table 1 shows the composition of the positive electrode slurry. The measurement / evaluation results are shown in Table 2.
- Example 1-6 (Preparation of slurry for negative electrode) In an ointment container, 50 parts by mass (2 parts by mass in terms of solid content) of a 4% by mass aqueous solution of N-vinylformamide polymer (A1) as polymer (A) and 50 parts by mass of deionized water were weighed.
- a natural graphite-based negative electrode active material (manufactured by Mitsubishi Chemical Co., Ltd., “MPGC16”) is added, and using a revolving stirrer (manufactured by Thinky, “Nentaro Awatori”), a rotation speed of 1000 rpm, a revolving speed of 2000 rpm It knead
- Example 1-7 A negative electrode slurry was prepared in the same manner as in Example 1-6, except that the N-vinylacetamide polymer (A2) was used instead of the N-vinylformamide polymer (A1). Measurement and evaluation were performed. The composition of the negative electrode slurry is shown in Table 1. The measurement / evaluation results are shown in Table 2.
- Example 1-8> instead of polyvinylidene fluoride latex as polymer (B-1), an acrylic silicone latex (average particle size of 166 nm, solid content) obtained by graft polymerization of methyl methacrylate to a composite rubber comprising a butyl acrylate component and a polyorganosiloxane component
- a negative electrode slurry was prepared in the same manner as in Example 1-6 except that 8 parts by mass (25 parts by mass) (2 parts by mass in terms of solid content) was used, and a negative electrode was prepared and subjected to various measurements and evaluations. .
- the composition of the negative electrode slurry is shown in Table 1.
- the measurement / evaluation results are shown in Table 2.
- Example 1-9> instead of polyvinylidene fluoride latex as polymer (B-1), polyacrylonitrile latex obtained by dispersing polyacrylonitrile powder obtained by suspension polymerization in water and forcibly emulsifying with a wet atomizer A negative electrode slurry was prepared in the same manner as in Example 1-6 except that 27 parts by mass (average mass of 400 nm, solid content: 7.5% by mass) was used (2 parts by mass in terms of solid content). It produced and performed various measurement and evaluation. The composition of the negative electrode slurry is shown in Table 1. The measurement / evaluation results are shown in Table 2.
- Example 1-1 A positive electrode slurry was prepared in the same manner as in Example 1-1 except that the polyvinylidene fluoride latex was not used, a positive electrode was prepared, and various measurements and evaluations were performed. Table 1 shows the composition of the positive electrode slurry. The measurement / evaluation results are shown in Table 2.
- Example 1-1 ⁇ Comparative Example 1-2> Example 1-1, except that N-vinylacetamide polymer (A2) was used in place of N-vinylformamide polymer (A1) as polymer (A), and no polyvinylidene fluoride latex was used.
- N-vinylacetamide polymer (A2) was used in place of N-vinylformamide polymer (A1) as polymer (A)
- no polyvinylidene fluoride latex was used.
- Table 1 shows the composition of the positive electrode slurry. The measurement / evaluation results are shown in Table 2.
- Example 1-6 ⁇ Comparative Example 1-4> Example 1-6, except that N-vinylacetamide polymer (A2) was used in place of N-vinylformamide polymer (A1) as polymer (A), and polyvinylidene fluoride latex was not used.
- N-vinylacetamide polymer (A2) was used in place of N-vinylformamide polymer (A1) as polymer (A)
- polyvinylidene fluoride latex was not used.
- a negative electrode slurry was prepared, a negative electrode was prepared, and various measurements and evaluations were performed.
- the composition of the negative electrode slurry is shown in Table 1.
- the measurement / evaluation results are shown in Table 2.
- Table 1 The abbreviations in Table 1 are as follows.
- “parts” refers to parts by mass, and the amounts of the polymer (A) and the polymer (B-1) are amounts in terms of solid content.
- PVDF-Em polyvinylidene fluoride latex (manufactured by Arkema, average particle size 127 nm, solid content 49.6% by mass).
- Acrylic silicone Acrylic silicone latex obtained in Example 1-4 (average particle size 166 nm, solid content 25% by mass).
- PAN-Em polyacrylonitrile latex obtained in Example 1-5 (average particle size 400 nm, solid content 7.5% by mass).
- LCO lithium cobalt oxide (manufactured by Nippon Chemical Industry Co., Ltd., “Cell Seed C-5H”).
- MPGC16 natural graphite-based negative electrode active material (manufactured by Mitsubishi Chemical Corporation, “MPGC16”).
- ⁇ AB Acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.)
- the negative electrode had high peel strength and was excellent in the binding property of the electrode layer to the current collector. These electrodes were also excellent in flexibility. Furthermore, the battery provided with these electrodes maintained the battery capacity at the 50th cycle at 80% or more of the battery capacity at the first cycle, and was excellent in battery characteristics.
- the polymer (A) was dissolved in ion-exchanged water so that the concentration of the polymer (A) was 1% by mass to obtain a 1% by mass aqueous solution of the polymer (A).
- the viscosity in 25 degreeC was measured using the B-type viscosity meter, and the value was made into the viscosity ((alpha)).
- the polymer (A) was dissolved in ion-exchanged water so that the concentration of the polymer (A) was 1% by mass to obtain a 1% by mass aqueous solution of the polymer (A).
- the polymer (B-2) was added in an amount of 10 parts by mass with respect to 100 parts by mass of the polymer (A) to obtain a solution.
- the viscosity was measured like the 1 mass% aqueous solution of a polymer (A), and the value was made into the viscosity ((beta)).
- the ratio ( ⁇ / ⁇ ) between the viscosity ( ⁇ ) and the viscosity ( ⁇ ) measured by the above method was calculated.
- Example 2-1> (Preparation of resin composition)
- polymer (A) 2 parts by mass of N-vinylformamide polymer (A1) and as polymer (B-2) an aqueous poly (2-sulfo-5-methoxy-1,4-iminophenylene) solution (solid content 5) (Mass%) 4 parts by mass (0.2 parts by mass in terms of solid content) and 94 parts by mass of deionized water were weighed and sufficiently dissolved to obtain an aqueous solution of the resin composition.
- the viscosity of the aqueous solution of the obtained resin composition was measured.
- the rotor used was M4, and the viscosity at a rotational speed of 3 rpm was read. Also, the viscosity ratio was calculated. Table 3 shows the measurement results.
- Example 2-2 As polymer (A), 2 parts by mass of N-vinylformamide polymer (A1) and as polymer (B-2) sodium polystyrenesulfonate aqueous solution (manufactured by Tosoh Organic Chemical Co., Ltd., “Polynas PS-5”, solid content 20 parts by mass) 1 part by mass (0.2 parts by mass in terms of solid content) and 97 parts by mass of deionized water were weighed and sufficiently dissolved to obtain an aqueous solution of the resin composition. The viscosity of the aqueous solution of the obtained resin composition was measured. The rotor used was M4, and the viscosity at a rotational speed of 6 rpm was read. Also, the viscosity ratio was calculated. Table 3 shows the measurement results.
- Example 2-3 As polymer (A), 2 parts by mass of N-vinylformamide polymer (A1) and as polymer (B-2) sodium polyacrylate aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solid content 4 mass) %) 5 parts by mass (0.2 parts by mass in terms of solid content) and 93 parts by mass of deionized water were weighed and sufficiently dissolved to obtain an aqueous solution of the resin composition. The viscosity of the aqueous solution of the obtained resin composition was measured. The rotor used was M4, and the viscosity at a rotational speed of 6 rpm was read. Also, the viscosity ratio was calculated. Table 3 shows the measurement results.
- Example 2-4 2 parts by mass of N-vinylformamide polymer (A1) as polymer (A) and lithium polyacrylate aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solid content 4 mass) as polymer (B-2) %) 5 parts by mass (0.2 parts by mass in terms of solid content) and 93 parts by mass of deionized water were weighed and sufficiently dissolved to obtain an aqueous solution of the resin composition. The viscosity of the aqueous solution of the obtained resin composition was measured. The rotor used was M4, and the viscosity at a rotational speed of 6 rpm was read. Also, the viscosity ratio was calculated. Table 3 shows the measurement results.
- Example 2-5> (Preparation of slurry for negative electrode)
- 50 parts by mass (2 parts by mass in terms of solid content) of a 4% by mass aqueous solution of N-vinylformamide polymer (A1) as polymer (A) and poly (2 -Sulfo-5-methoxy-1,4-iminophenylene) aqueous solution (5 mass% solid content) 4 parts by mass (0.2 mass parts in terms of solid content) and 40 parts by mass of deionized water were weighed.
- Example 2-6 As the polymer (B-2), 1 part by weight of sodium polystyrenesulfonate aqueous solution (Tosoh Organic Chemical Co., Ltd., “Polynas PS-5”, solid content 20% by mass) (0.2 mass part in terms of solid content) is used. Except for the above, a negative electrode slurry was prepared in the same manner as in Example 2-5, a negative electrode was prepared, and various measurements and evaluations were performed. Table 4 shows the composition of the negative electrode slurry. Table 5 shows the measurement / evaluation results.
- sodium polystyrenesulfonate aqueous solution Tosoh Organic Chemical Co., Ltd., “Polynas PS-5”, solid content 20% by mass
- Table 4 shows the composition of the negative electrode slurry.
- Table 5 shows the measurement / evaluation results.
- Example 2-7 As polymer (B-2), 5 parts by weight (0.2 parts by weight in terms of solids) of sodium polyacrylate aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solids 4% by weight) is used. Except that 1 part by mass of acetylene black was used as an auxiliary agent, a negative electrode slurry was prepared in the same manner as in Example 2-5, a negative electrode was prepared, and various measurements and evaluations were performed. Table 4 shows the composition of the negative electrode slurry. Table 5 shows the measurement / evaluation results.
- Example 2-8 As polymer (B-2), 5 parts by weight (0.2 parts by weight in terms of solids) of an aqueous lithium polyacrylate solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solids 4% by weight) is used. Except that 1 part by mass of acetylene black was used as an auxiliary agent, a negative electrode slurry was prepared in the same manner as in Example 2-5, a negative electrode was prepared, and various measurements and evaluations were performed. Table 4 shows the composition of the negative electrode slurry. Table 5 shows the measurement / evaluation results.
- an aqueous lithium polyacrylate solution manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solids 4% by weight
- Example 2-2 A negative electrode slurry was prepared in the same manner as in Example 2-5, except that no polyaniline sulfonic acid aqueous solution was used as the polymer (B-2). A negative electrode was prepared, and various measurements and evaluations were performed. Table 4 shows the composition of the negative electrode slurry. Table 5 shows the measurement / evaluation results.
- Table 4 The abbreviations in Table 4 are as follows. Further, “parts” in Table 4 means parts by mass, and the amounts of the polymer (A) and the polymer (B-2) are amounts in terms of solid content.
- MPGC16 natural graphite-based negative electrode active material (manufactured by Mitsubishi Chemical Corporation, “MPGC16”).
- ⁇ AB Acetylene black (manufactured by Electrochemical Industry Co., Ltd.)
- Examples 2-1 to 2-4 using the polymer (A) and the polymer (B-2) were similar to Comparative Example 2-1 using only the polymer (A).
- the viscosity of the aqueous solution of the resin composition is high.
- This increase in the viscosity of the aqueous solution also affects the increase in the viscosity of the electrode slurry.
- the viscosity of the aqueous solution increases, so that the viscosity of the electrode slurry increases, and the stability of the electrode slurry is likely to be improved. This is also clear from the evaluation results of slurry stability in Table 5.
- the aqueous solution of the polymer (A) which is Comparative Example 2-1 is known to have a viscosity close to a Newtonian fluid whose viscosity does not depend on the shear rate when the concentration is about 2% by mass. Even when the rotation speed is changed from 3 rpm to 6 rpm, it is considered that a viscosity equivalent to 20 rpm is shown as a measured value.
- Example 3-1> (Preparation of slurry for positive electrode)
- a sodium aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solid content 4% by mass) was weighed 5 parts by mass (0.2 parts by mass in terms of solid content) and 40 parts by mass of deionized water.
- the obtained positive electrode slurry was applied onto a current collector (aluminum foil, 19 cm ⁇ 25 cm, thickness 20 ⁇ m) using a doctor blade, dried at 60 ° C. for 30 minutes in a circulating hot air dryer, and further into a vacuum dryer And dried under reduced pressure at 80 ° C. for 12 hours to obtain a positive electrode in which an electrode layer having a thickness of 80 ⁇ m was formed on a current collector (aluminum foil).
- peeling strength was measured and the softness
- Example 3-2> (Preparation of slurry for negative electrode)
- a sodium aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1 million, solid content 4% by mass) was weighed 5 parts by mass (0.2 parts by mass in terms of solid content) and 40 parts by mass of deionized water.
- Example 3-1 A positive electrode slurry was prepared in the same manner as in Example 3-1, except that the sodium polyacrylate aqueous solution and the polyvinylidene fluoride latex were not used. A positive electrode was prepared, and various measurements and evaluations were performed. Table 6 shows the composition of the positive electrode slurry. Table 7 shows the measurement / evaluation results.
- Table 6 The abbreviations in Table 6 are as follows. In Table 6, “parts” means parts by mass, and the amounts of the polymer (A), the polymer (B-1), and the polymer (B-2) are amounts in terms of solid content.
- PVDF-Em polyvinylidene fluoride latex (manufactured by Arkema, average particle size 127 nm, solid content 49.6% by mass).
- LCO lithium cobalt oxide (manufactured by Nippon Chemical Industry Co., Ltd., “Cell Seed C-5H”).
- MPGC16 natural graphite-based negative electrode active material (manufactured by Mitsubishi Chemical Corporation, “MPGC16”).
- ⁇ AB Acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd.)
- an electrode excellent in flexibility can be formed, a battery excellent in battery characteristics, particularly in long-term cycle characteristics, and binding can be obtained. Excellent in properties.
- the slurry for secondary battery electrodes according to the first aspect of the present invention is obtained using the binder resin composition for secondary battery electrodes according to the first aspect, and can form an electrode having excellent flexibility.
- a battery having excellent characteristics, particularly long-term cycle characteristics, can be obtained.
- the electrode for a secondary battery according to the first aspect of the present invention is excellent in flexibility. Therefore, the lithium ion secondary battery provided with the electrode is excellent in battery characteristics, particularly in long-term cycle characteristics.
- the binder resin composition for a secondary battery electrode of the second aspect of the present invention an electrode slurry excellent in stability can be obtained even when used for a negative electrode, and the uneven distribution of the active material and binder is suppressed.
- the slurry for the secondary battery electrode of the second aspect of the present invention is obtained using the binder resin composition for the secondary battery electrode of the second aspect, and is excellent in stability and active even when used for the negative electrode.
- An electrode that suppresses uneven distribution of substances and binders can be formed, and a battery having excellent battery characteristics, particularly long-term cycle characteristics, can be obtained.
- the active material and the binder are hardly unevenly distributed. Therefore, the lithium ion secondary battery provided with the electrode is excellent in battery characteristics, particularly in long-term cycle characteristics.
Abstract
Description
本願は、2012年1月11日に、日本に出願された特願2012-3209号、および2012年1月17日に、日本に出願された特願2012-7441号、に基づき優先権を主張し、その内容をここに援用する。
リチウムイオン二次電池用電極は、通常、粉体状の電極活物質材料(活物質)に結着剤(バインダ)を適当量添加した混合物に溶媒を混ぜて電極用スラリーとし、これを集電体に塗布、乾燥後、圧着させて電極層を形成することで得られる。
一方、活物質やバインダ等の混合物をスラリーとするための溶媒としては、N-メチル-2-ピロリドン(以下、「NMP」と略記する。)等のアミド類、ウレア類といった含窒素系有機溶媒が用いられる。
しかし、NMP等の含窒素系有機溶媒は、溶媒回収コストや、環境に対する負荷が高い等の問題があった。また、例えばNMPは、沸点が204℃と高いため、乾燥時や溶媒回収精製時に多くのエネルギーを必要とするという問題があった。
例えば特許文献1には、カルボキシメチルセルロースと高分子ラテックスとを含有する結着剤が開示されている。カルボキシメチルセルロースと高分子ラテックスとを含有する結着剤は、分散安定性および塗工性に優れ、集電体に対して密着性良好な電極層が得られる。
しかし、カルボキシメチルセルロースは天然物由来であるため、供給ロット毎の品質が安定しにくく、また、貯蔵安定性に劣るなどの問題があった。
例えば特許文献2には、アミド構造を有する繰り返し構造単位を含む重合体として、ポリN-ビニルアセトアミドを含む非水電池用正極ペーストが開示されている。ポリN-ビニルアセトアミドは、ペースト安定性、結着性、電気化学的安定性など、二次電池(特に非水二次電池)における要求性能を改善できるとしている。
また特許文献3には、バインダとして、ポリN-ビニルアセトアミドと、エチレンオキサイド(EO)およびプロピレンオキサイド(PO)の共重合体とを含む樹脂成分が開示されている。このバインダによれば、結着性、低温から室温環境下での電池特性に優れるとしている。
一方、負極では活物質に炭素系物質が多用されており導電性が確保されているため、導電助剤が添加されない場合が多い。そのため、負極用の電極用スラリー(負極用スラリー)はチキソ性が低く静置状態で活物質がすぐに沈降しやすく、安定性が悪い。この負極スラリーを集電体に塗布すると乾燥までの間に活物質が沈降してバインダが上部に偏在化し、電池特性、特に長期のサイクル特性に劣るという問題があった。
<1> 下記一般式(1)で表される構造単位を有する重合体(A)と、水に不溶な粒子状の重合体(B-1)、または/および、水に可溶な重合体(B-2)とを含み、前記重合体(B-2)が酸性基または/およびその塩を有する、二次電池電極用バインダ樹脂組成物。
<3> 前記重合体(A)と重合体(B-1)との質量比(重合体(A)/重合体(B-1))が5/95~95/5である、<1>または<2>に記載の二次電池電極用バインダ樹脂組成物。
<4> 下記柔軟性試験により電極の柔軟性の評価を行ったときに、電極層に変化がない、<1>~<3>のいずれか一項に記載の二次電池電極用バインダ樹脂組成物。
(柔軟性試験)
当該二次電池電極用バインダ樹脂組成物と水とを混練する。これに活物質を加えて混練し、さらに電極が正極の場合には導電助剤を加えて混練した後、塗工可能な粘度まで水で調整して電極用スラリーを得る。配合量は、活物質100質量部に対して、二次電池電極用バインダ樹脂組成物を2質量部とし、導電助剤を5質量部とする。
得られた電極用スラリーを集電体に塗布し、乾燥して、膜厚20~200μmの電極層が集電体上に形成された電極を得る。
得られた電極を横3cm、縦5cmに切り出し、試験片とする。
得られた試験片の集電体面に直径5mmのマンドレルをあて、試験片の片側をテープで固定し、湿度10%以下の環境にて、集電体面が内側になるよう試験片を折り曲げたときの電極層の状態を観察し、電極の柔軟性を評価する。
<6> 前記重合体(A)と重合体(B-2)との質量比(重合体(A)/重合体(B-2))が5/95~99.5/0.5である、<1>または<5>に記載の二次電池電極用バインダ樹脂組成物。
<7> 前記重合体(A)の1質量%水溶液の粘度(α)と、該水溶液に前記重合体(B-2)を重合体(A)100質量部に対して10質量部となるように添加した溶液の粘度(β)との比(β/α)が5以上である、<1>、<5>、<6>のいずれか一項に記載の二次電池電極用バインダ樹脂組成物。
<9> 集電体と、該集電体上に設けられた電極層とを備え、前記電極層は、活物質と、<1>~<7>のいずれか一項に記載の二次電池電極用バインダ樹脂組成物とを含有する、二次電池用電極。
<10> <9>に記載の二次電池用電極を備える、リチウムイオン二次電池。
<11> 集電体と、該集電体上に設けられた電極層とを備え、前記電極層は、<8>に記載の二次電池電極用スラリーを集電体に塗布し、乾燥させて得られるものである、二次電池用電極。
<12> <11>に記載の二次電池用電極を備える、リチウムイオン二次電池。
「第一の態様」
<二次電池電極用バインダ樹脂組成物>
本発明の第一の態様の二次電池電極用バインダ樹脂組成物(以下、「樹脂組成物」という。)は、以下に示す重合体(A)と重合体(B-1)とを含む。
重合体(A)は、下記一般式(1)で表される構造単位を含む重合体であり、樹脂組成物に結着性を付与する成分である。
アルキル基としては、炭素数1~5の直鎖もしくは分岐のアルキル基が好ましく、例えばメチル基、エチル基、n-プロピル基、iso-プロピル基、n-ブチル基 、sec-ブチル基、tert-ブチル基、n-ペンチル基、1-メチルブチル基、2-メチルブチル基、3-メチルブチル基、1-エチルプロピル基、1,1-ジメチルプロピル基、1,2-ジメチルプロピル基、2,2-ジメチルプロピル基などが挙げられる。
得られる重合体(A)の溶解性、粘度特性、酸化安定性の観点から、R1およびR2としては、それぞれ独立して、水素原子またはメチル基が好ましい。
任意単位の由来源となる単量体(以下、「任意単量体」という。)としては、単量体(a)と共重合可能であれば特に限定されないが、例えばアクリロニトリル、メタクリロニトリル、α-シアノアクリレート、ジシアノビニリデン、フマロニトリル等のシアン化ビニル単量体;メチル(メタ)アクリレート、エチル(メタ)アクリレート、プロピル(メタ)アクリレート、ブチル(メタ)アクリレート、ヘキシル(メタ)アクリレート等の(メタ)アクリレート;(メタ)アクリル酸、イタコン酸、クロトン酸、マレイン酸、無水マレイン酸等のカルボキシル基含有単量体及びその塩;スチレン、α-メチルスチレン等の芳香族ビニル単量体;マレイミド、フェニルマレイミド等のマレイミド類;(メタ)アリルスルホン酸、(メタ)アリルオキシベンゼンスルホン酸、スチレンスルホン酸、2-アクリルアミド-2-メチルプロパンスルホン酸等のスルホン酸基含有ビニル単量体及びその塩;2-(メタ)アクリロイルオキシエチルアシッドホスフェート、2-(メタ)アクリロイルオキシエチルアシッドホスフェート・モノエタノールアミン塩、ジフェニル((メタ)アクリロイルオキシエチル)ホスフェート、(メタ)アクリロイルオキシプロピルアシッドホスフェート、3-クロロ-2-アシッド・ホスホオキシプロピル(メタ)アクリレート、アシッド・ホスホオキシポリオキシエチレングリコールモノ(メタ)アクリレート、アシッド・ホスホオキシポリオキシプロピレングリコール(メタ)アクリレート等のリン酸基を含有ビニル単量体及びその塩;ジメチルアミノエチル(メタ)アクリレート、ジメチルアミノプロピル(メタ)アクリルアミドの三級塩若しくは四級アンモニウム塩;(メタ)アクリルアミド、酢酸ビニル、N-ビニルピロリドンが挙げられる。
これら任意単量体は、1種単独で用いてもよいし、2種以上を併用してもよい。
重合体(A)の質量平均分子量は、ゲルパーミエーションクロマトグラフィー(GPC)を用いて測定することができる。例えば、テトラヒドロフランや水等の溶媒を溶離液とし、ポリスチレン換算分子量として求めることができる。
重合体(A)の粘度平均分子量は、重合体(A)の水溶液の粘度から、ポリN-ビニルホルムアミド(以下、PNVFという。)を標準物質とした粘度換算分子量として算出される。粘度平均分子量の算出方法の例を以下に示す。
重合体(A)の水溶液の還元粘度(ηsp/C)と、Hugginsの式(ηsp/C=[η]+K’[η]2C)とから、固有粘度[η]を算出する。なお、上記式中の「C」は、重合体(A)の水溶液における重合体(A)の濃度(g/dL)である。重合体(A)の水溶液の還元粘度の測定方法は、後述のものである。
得られた固有粘度[η]、およびMark-Houwinkの式([η]=KMa)から、粘度平均分子量(式中の「M」)を算出する。
なお、1N食塩水において、PNVFのパラメータは、K=8.31×10-5、a=0.76、K’=0.31である。
まず、重合体(A)の濃度が0.1質量%となるように、1N食塩水に重合体(A)を溶解して、重合体(A)の水溶液を得る。得られた重合体(A)の水溶液について、オスワルド粘度計を用いて、25℃での流下時間(t1)を測定する。
別途、ブランクとして、1N食塩水についてオスワルド粘度計を用いて、25℃での流下時間(t0)を測定する。
得られた流下時間から、下記式(i)により還元粘度を算出する。
ηsp/C={(t1/t0)-1}/C ・・・(i)
(式(i)中、Cは、重合体(A)の水溶液における重合体(A)の濃度(g/dL)である。)
重合方法は特に限定されず、原料として用いる単量体や生成する重合体の溶解性などに応じて、バルク重合、溶液重合、懸濁重合、乳化重合、光重合などの方法を採用すればよい。
水溶性アゾ化合物としては、例えば4,4’-アゾビス(4-シアノバレリックアシッド)、2,2’-ビス(2-イミダゾリン-2-イル)[2,2’-アゾビスプロパン]二塩酸塩、2,2’-ビス(2-イミダゾリン-2-イル)[2,2’-アゾビスプロパン]二硫酸塩二水和物、2,2’-アゾビス(2-アミジノプロパン)二塩酸塩、2,2’-アゾビス(2-(N-(2-カルボキシエチル)アミジノ)プロパン)、2,2’-アゾビス(2-(2-イミダゾリン-2-イル)プロパン)、2,2’-アゾビス(2-メチル-N-(1,1-ビス(ヒドロキシメチル)-2-ヒドロキシエチル)プロピオンアミド)、2,2’-アゾビス[N-(2-ヒドロキシエチル)-2-メチルプロパンアミド]等を挙げることができる。
有機過酸化物としては、水溶性の過酸化物が好ましく、例えばtert-ブチルハイドロパーオキサイド等が挙げられる。
水溶性無機過酸化物としては、例えば過硫酸カリウム、過硫酸アンモニウム、過硫酸ナトリウム等の過硫酸塩、過酸化水素等が挙げられる。
なお、過硫酸塩等の酸化剤は、亜硫酸水素ナトリウム、チオ硫酸ナトリウム、ハイドロサルファイト等の還元剤、硫酸鉄等の重合促進剤と組み合わせて、レドックス系開始剤として用いることもできる。
連鎖移動剤としては、例えばメルカプタン化合物、チオグリコール、四塩化炭素、α-メチルスチレンダイマーが挙げられる。
これら重合用溶媒は、1種を単独で用いてもよく、2種以上を併用してもよい。
重合体(B-1)は、実質的に水に不溶な粒子状の重合体であり、電極に柔軟性を付与し、電池に電池特性、特に長期のサイクル特性を付与する成分である。
なお、本発明において、「実質的に水に不溶」とは、25℃の水100gに対する溶解度(すなわち、25℃において水100gに対して溶解する限度)が0.5g未満のことをいう。溶解度は0.1g以下が好ましい。
グラフト共重合体中のゴム含有量は40~90質量%が好ましく、50~90質量%がより好ましい。
なお、重合体(B-1)の平均粒子径は、レーザ回折/散乱式粒度分布測定装置を用いて測定される体積平均1次粒子径である。
本発明の第一の態様の樹脂組成物における、重合体(A)と重合体(B-1)の質量比(重合体(A)/重合体(B-1))は、固形分換算で5/95~95/5が好ましく、25/75~75/25がより好ましく、25/75~50/50が特に好ましい。重合体(A)と重合体(B-1)の質量比が上記範囲内であれば、樹脂組成物を用いて電極用スラリー(二次電池電極用スラリー)を調製して電極を製造する際に、電極用スラリーの取り扱い性、集電体への塗工性が良好となる。加えて、電極用スラリーより形成される電極層内部の均一性が高まる。
また、樹脂組成物は、重合体(A)と重合体(B-1)とからなるものでもよいが、後述する重合体(B-2)を含んでいてもよい。
よって、本発明の第一の態様の樹脂組成物は、結着性に優れ、かつ、柔軟性に優れた電極を形成でき、電池特性(特に長期のサイクル特性)に優れた電池が得られる。具体的には、下記柔軟性試験により電極の柔軟性の評価を行ったときに、電極層に変化がない電極を形成できる。
ここで、「電極層に変化がない」とは、光学顕微鏡で60倍の倍率で観察したときに電極層に割れ、欠け等の変化が見られないことを意味する。
当該二次電池電極用バインダ樹脂組成物と水とを混練する。これに活物質を加えて混練し、さらに電極が正極の場合には導電助剤を加えて混練した後、塗工可能な粘度まで水で調整して電極用スラリーを得る。配合量は、活物質100質量部に対して、二次電池電極用バインダ樹脂組成物を2質量部とし、導電助剤を5質量部とする。
得られた電極用スラリーを集電体に塗布し、乾燥して、膜厚20~200μmの電極層が集電体上に形成された電極を得る。
得られた電極を横3cm、縦5cmに切り出し、試験片とする。
得られた試験片の集電体面に直径5mmのマンドレルをあて、試験片の片側をテープで固定し、湿度10%以下の環境にて、集電体面が内側になるよう試験片を折り曲げたときの電極層の状態を観察し、電極の柔軟性を評価する。
本発明の第一の態様の二次電池電極用スラリー(以下、「電極用スラリー」という。)は、上述した本発明の第一の態様の樹脂組成物と、活物質と、溶媒とを含有する。また、電極用スラリーは、重合体(A)および重合体(B-1)以外のバインダ樹脂(他のバインダ樹脂)や、粘度調整剤、結着性向上剤、分散剤等を含有していてもよい。また、電極用スラリーを正極用として用いる場合には、電極用スラリーに導電助剤を含有させてもよい。
電極用スラリー中の樹脂組成物の割合(すなわち、重合体(A)と重合体(B-1)の合計)は、活物質100質量部に対して、0.1~10質量部が好ましく、0.2~5質量部がより好ましい。樹脂組成物の割合が0.1質量部以上であれば、集電体への密着性、活物質間の結着性が良好となる。一方、樹脂組成物の割合が10質量部以下であれば、電極中の抵抗が悪化するのを抑制できる。
正極用の活物質(正極活物質)としては、例えば鉄、コバルト、ニッケル、マンガンから選ばれる少なくとも1種類以上の金属と、リチウムを含有するリチウム含有金属複合酸化物が挙げられる。
一方、負極用の活物質(負極活物質)としては、例えば黒鉛、非晶質炭素、炭素繊維、コークス、活性炭等の炭素材料;前記炭素材料とシリコン、錫、銀等の金属、またはこれらの酸化物との複合物が挙げられる。
正極活物質および負極活物質は、1種を単独で用いてもよく、2種以上を併用してもよい。
これら導電助剤は、1種を単独で用いてもよく、2種以上を併用してもよい。
これら溶媒は、1種を単独で用いてもよく、2種以上を併用してもよい。
本発明の第一の態様の二次電池用電極(以下、「電極」という。)は、集電体と、該集電体上に設けられた電極層とを備える。
電極層は、活物質と、バインダとして本発明の第一の態様の樹脂組成物とを少なくとも含有する層であり、必要に応じて、重合体(A)および重合体(B-1)以外のバインダ樹脂(他のバインダ樹脂)や、粘度調整剤、結着性向上剤、分散剤等の公知の添加剤を含有していてもよい。
活物質、他のバインダ樹脂、粘度調整剤としては、本発明の第一の態様の電極用スラリーの説明において先に例示した活物質、他のバインダ樹脂、粘度調整剤が挙げられる。
導電助剤としては、本発明の第一の態様の電極用スラリーの説明において先に例示した導電助剤が挙げられる。
集電体の形状としては、薄膜状、網状、繊維状が挙げられる。この中では、薄膜状が好ましい。集電体の厚みは、5~30μmが好ましく、8~25μmがより好ましい。
また、重合体(A)を水に溶解した水溶液と、重合体(B-1)を溶媒に分散した分散液と、活物質とを混合して電極用スラリーを調製してもよい。この際、重合体(A)の水溶液と重合体(B-1)の分散液を予め混合してから、これらと活物質とを混合してもよいし、重合体(A)の水溶液と活物質とを混合した後、重合体(B-1)の分散液を混合してもよいが、活物質の分散が良好となり均質な電極用スラリーを調製することができる点で、重合体(A)の水溶液と活物質とを混合した後、重合体(B-1)の分散液を混合する方が好ましい。
混錬方法としては、樹脂組成物と活物質とを十分に混練できる方法であれば特に限定されないが、例えば自公転攪拌機、プラネタリミキサ、ホモジナイザー、ボールミル、サンドミル、ロールミル等の各種分散機で混練する方法が挙げられる。
塗布方法は、電極層の厚みが0.1~500μmとなるように電極用スラリーを集電体に塗布できる方法であれば特に限定されない。例えばバーコート法、ドクターブレード法、ナイフ法、ディップ法、リバースロール法、ダイレクトロール法、グラビア法、エクストルージョン法、カーテン法、浸漬法、ハケ塗り法などが挙げられる。
除去方法としては、溶媒を除去できれば一般に採用されている方法を利用することができる。特に、熱風、真空、赤外線、遠赤外線、電子線および低温風を単独あるいは組み合わせて用いることが好ましい。
除去条件は、溶媒が十分に除去可能で、かつ重合体(A)および重合体(B-1)が分解しない条件であれば特に限定されないが、40~120℃、好ましくは60~100℃で、1分間~10時間、加熱処理することが好ましい。この条件であれば、重合体(A)および重合体(B-1)が分解することなく、活物質と集電体、あるいは活物質間の高い密着性を付与することができる。また、集電体が腐食しにくい。
さらに、必要に応じて、得られた電池用電極を任意の寸法に切断してもよい(スリット加工工程)。
本発明の第一の態様の電極は、リチウムイオン二次電池用の電極として好適である。
本発明の第一の態様のリチウムイオン二次電池は、本発明の第一の態様の電極を備える。
リチウムイオン二次電池としては、例えば、正極と負極とを、透過性のセパレータ(例えば、ポリエチレンあるいはポリプロピレン製の多孔性フィルム)を間に介して配置し、これに非水系の電解液を含浸させた非水系二次電池;集電体の両面に電極層が形成された負極/セパレータ/集電体の両面に電極層が形成された正極/セパレータからなる積層体をロール状(渦巻状)に巻回した巻回体が、電解液と共に有底の金属ケーシングに収容された筒状の非水系二次電池などが挙げられる。
リチウム塩としては、例えばLiClO4、LiBF4、LiI、LiPF6、LiCF3SO3、LiCF3CO2、LiAsF6、LiSbF6、LiAlCl4、LiCl、LiBr、LiB(C2H5)4、LiCH3SO3、LiC4F9SO3、Li(CF3SO2)2N、Li[(CO2)2]2Bなどが挙げられる。
一方、非水系有機溶媒としては、プロピレンカーボネート、エチレンカーボネート、ブ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、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、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、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、NMP等の含窒素類;ギ酸メチル、酢酸メチル、酢酸ブチル、プロピオン酸メチル、プロピオン酸エチル、リン酸トリエステル等のエステル類;ジグライム、トリグライム、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、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;1,3-プロパンスルトン、4-ブタンスルトン、ナフタスルトン等のスルトン類などが挙げられる。
電解液は、1種を単独で用いてもよく、2種以上を併用してもよい。
また、筒状の場合は以下のようにして得られる。
まず、集電体の両面に電極層が形成された負極/セパレータ/集電体の両面に電極層が形成された正極/セパレータからなる積層体をロール状(渦巻状)に巻回して巻回体とする。得られた巻回体を有底の金属ケーシング(電池缶)に収容し、負極を負極端子に、正極を正極端子に接続する。ついで、金属ケーシングに電解液を含浸させた後、金属ケーシングを封止することにより筒状のリチウムイオン二次電池とする。
<二次電池電極用バインダ樹脂組成物>
本発明の第二の態様の二次電池電極用バインダ樹脂組成物(以下、「樹脂組成物」という。)は、以下に示す重合体(A)と重合体(B-2)とを含む。
重合体(A)は、上記一般式(1)で表される構造単位を含む重合体である。
本発明の第二の態様の樹脂組成物に用いる重合体(A)は、本発明の第一の態様の樹脂組成物に用いる重合体(A)と同じであり、ここでの詳細な説明は省略する。
重合体(B-2)は、実質的に水に可溶な高分子体(重合体)であり、酸性基または/およびその塩を有するものである。重合体(B-2)は、二次電池電極用スラリー(電極用スラリー)に適度な粘度を付与し、電極用スラリーの安定性や電池特性、特に長期のサイクル特性を付与する成分である。
なお、本発明において、「実質的に水に可溶」とは、25℃の水100gに対する溶解度(すなわち、25℃において水100gに対して溶解する限度)が0.5g以上のことをいう。溶解度は1g以上が好ましい。
酸性基の塩としては、酸性基のアルカリ金属塩、アルカリ土類金属塩、アンモニウム塩、置換アンモニウム塩などが挙げられる。
アルカリ金属としては、例えばリチウム、ナトリウム、カリウムなどが挙げられる。
アルカリ土類金属としては、例えばマグネシウム、カルシウムなどが挙げられる。
置換アンモニウムとしては、例えば脂式アンモニウム類、環式飽和アンモニウム類、環式不飽和アンモニウム類などが挙げられる。
また、重合体(B-2)としては、下記一般式(2)で表される、スルホン酸基または/およびカルボキシル基を有するアニリン系ポリマーも好適に使用可能である。
本発明の第二の態様の樹脂組成物における、重合体(A)と重合体(B-2)の質量比(重合体(A)/重合体(B-2))は、固形分換算で5/95~99.5/0.5が好ましく、50/50~99/1がより好ましく、60/40~99/1がさらに好ましく、80/20~99/1が特に好ましい。重合体(A)と重合体(B-2)の質量比が上記範囲内であれば、電極用スラリーの安定性が向上し、樹脂組成物を用いて電極用スラリーを調製して電極を製造する際に、電極用スラリーの取り扱い性、集電体への塗工性が良好となる。加えて、電極用スラリーより形成される電極層内部の均一性が高まる。
本発明の第二の態様の樹脂組成物における、重合体(A)の1質量%水溶液の粘度(α)と、該水溶液に重合体(B-2)を重合体(A)100質量部に対して10質量部となるように添加した溶液の粘度(β)との比(β/α)は、5以上が好ましく、7以上が好ましい。β/αが5以上であれば、電極用スラリーの安定性が向上し、集電体への塗工性および集電体への電極層の密着性が高まる。β/αの上限値については、電極用スラリーの取り扱い性が良好となる点で、1000以下が好ましく、700以下がより好ましい。
まず、重合体(A)の濃度が1質量%となるように、イオン交換水に重合体(A)を溶解して、重合体(A)の1質量%水溶液を得る。得られた重合体(A)の1質量%水溶液について、B型粘度計を用いて、25℃での粘度を測定する。使用するローターおよび回転数は、測定可能な粘度範囲を考慮して決定すればよい。
まず、重合体(A)の濃度が1質量%となるように、イオン交換水に重合体(A)を溶解して、重合体(A)の1質量%水溶液を得る。この水溶液に、重合体(B-2)を重合体(A)100質量部に対して10質量部となるように添加して溶液を得る。得られた溶液について、重合体(A)の1質量%水溶液と同様にして粘度を測定する。
また、樹脂組成物は、重合体(A)と重合体(B-2)とからなるものでもよいが、上述した重合体(B-1)を含んでいてもよい。
よって、本発明の樹脂組成物を用いると、安定性に優れた電極用スラリーが得られ、活物質やバインダの偏在が少なく均一性に優れた電極層を備えた電極を形成でき、電池特性(特に長期のサイクル特性)に優れた電池が得られる。
本発明の第二の態様の二次電池電極用スラリー(以下、「電極用スラリー」という。)は、上述した本発明の第二の態様の樹脂組成物と、活物質と、溶媒とを含有する。また、電極用スラリーは、重合体(A)および重合体(B-2)以外のバインダ樹脂(他のバインダ樹脂)や、粘度調整剤、結着性向上剤、分散剤等を含有していてもよい。また、電極用スラリーを正極用として用いる場合には、電極用スラリーに導電助剤を含有させてもよい。
電極用スラリー中の樹脂組成物の割合(すなわち、重合体(A)と重合体(B-2)の合計)は、活物質100質量部に対して、0.1~10質量部が好ましく、0.2~5質量部がより好ましい。樹脂組成物の割合が0.1質量部以上であれば、集電体への密着性、活物質間の結着性が良好となる。一方、樹脂組成物の割合が10質量部以下であれば、電極中の抵抗が悪化するのを抑制できる。
本発明の第二の態様の二次電池用電極(以下、「電極」という。)は、集電体と、該集電体上に設けられた電極層とを備える。
電極層は、活物質と、バインダとして本発明の第二の態様の樹脂組成物とを少なくとも含有する層であり、必要に応じて、重合体(A)および重合体(B-2)以外のバインダ樹脂(他のバインダ樹脂)や、粘度調整剤、結着性向上剤、分散剤等の公知の添加剤を含有していてもよい。
活物質としては、本発明の第一の態様の電極用スラリーの説明において先に例示した活物質が挙げられる。
他のバインダ樹脂、粘度調整剤としては、本発明の第二の態様の電極用スラリーの説明において先に例示した他のバインダ樹脂、粘度調整剤が挙げられる。
導電助剤としては、本発明の第一の態様の電極用スラリーの説明において先に例示した導電助剤が挙げられる。
集電体の形状としては、薄膜状、網状、繊維状が挙げられる。この中では、薄膜状が好ましい。集電体の厚みは、5~30μmが好ましく、8~25μmがより好ましい。
混錬方法としては、樹脂組成物と活物質とを十分に混練できる方法であれば特に限定されないが、例えば自公転攪拌機、プラネタリミキサ、ホモジナイザー、ボールミル、サンドミル、ロールミル等の各種分散機で混練する方法が挙げられる。
塗布方法は、電極層の厚みが0.1~500μmとなるように電極用スラリーを集電体に塗布できる方法であれば特に限定されない。例えばバーコート法、ドクターブレード法、ナイフ法、ディップ法、リバースロール法、ダイレクトロール法、グラビア法、エクストルージョン法、カーテン法、浸漬法、ハケ塗り法などが挙げられる。
除去方法としては、溶媒を除去できれば一般に採用されている方法を利用することができる。特に、熱風、真空、赤外線、遠赤外線、電子線および低温風を単独あるいは組み合わせて用いることが好ましい。
除去条件は、溶媒が十分に除去可能で、かつ重合体(A)および重合体(B-2)が分解しない条件であれば特に限定されないが、40~120℃、好ましくは60~100℃で、1分間~10時間、加熱処理することが好ましい。この条件であれば、重合体(A)および重合体(B-2)が分解することなく、活物質と集電体、あるいは活物質間の高い密着性を付与することができる。また、集電体が腐食しにくい。
さらに、必要に応じて、得られた電極を任意の寸法に切断してもよい(スリット加工工程)。
本発明の第二の態様の電極は、リチウムイオン二次電池用の電極として好適である。
本発明の第二の態様のリチウムイオン二次電池は、本発明の第二の態様の電極を備える。
リチウムイオン二次電池としては、例えば、正極と負極とを、透過性のセパレータ(例えば、ポリエチレンあるいはポリプロピレン製の多孔性フィルム)を間に介して配置し、これに非水系の電解液を含浸させた非水系二次電池;集電体の両面に電極層が形成された負極/セパレータ/集電体の両面に電極層が形成された正極/セパレータからなる積層体をロール状(渦巻状)に巻回した巻回体が、電解液と共に有底の金属ケーシングに収容された筒状の非水系二次電池などが挙げられる。
リチウム塩、非水系有機溶媒としては、本発明の第一の態様のリチウムイオン二次電池の説明において、先に例示したリチウム塩、非水系有機溶媒が挙げられる。
また、筒状の場合は、本発明の第一の態様のリチウムイオン二次電池の説明において先に例示した方法により得られる。
<重合体(A)の製造>
(製造例1:N-ビニルホルムアミド重合体(A1)の製造)
脱イオン水70質量部に対し、N-ビニルホルムアミド30質量部を混合した単量体水溶液を、リン酸によりpH=6.3となるよう調節し、単量体調節液を得た。この単量体調節液を5℃まで冷却した後、温度計を取り付けた断熱反応容器に入れ、15分間窒素曝気を行った。その後、4、4’-アゾビス(4-シアノバレリックアシッド)(和光純薬工業株式会社製、「V-501」)12質量%水溶液を0.4質量部添加し、次いで、tert-ブチルハイドロパーオキサイド10質量%水溶液および亜硫酸水素ナトリウム10質量%水溶液をそれぞれ0.1質量部添加して重合を行った。内温がピークを超えた後さらに1時間熟成し、ゲルを取り出しミートチョッパーで粉砕した後、60℃で10時間乾燥し、得られた固体を粉砕し、N-ビニルホルムアミド重合体(A1)を得た。
シクロヘキサン95質量部、脱イオン水5質量部の溶液に対して、乳化剤としてポリオキシアルキレンアルキルエーテル1.5質量部を混合した水溶液を55℃に加温し、1時間窒素曝気を行った。その後、重合開始剤として4、4’-アゾビス(4-シアノバレリックアシッド)(和光純薬工業株式会社製、「V-501」)の12質量%水溶液0.8質量部を添加した。ついで、N-ビニルアセトアミド75質量%水溶液30質量部を1時間かけて滴下した。滴下終了後、55℃で2時間保温した後に冷却し、重合体懸濁液を得た。得られた重合体懸濁液をろ過し、得られた固体を真空下60℃で乾燥させ、N-ビニルアセトアミド重合体(A2)を得た。
(平均粒子径の測定)
レーザ回折/散乱式粒度分布測定装置を用いて重合体(B-1)の体積平均1次粒子径を測定し、これを重合体(B-1)の平均粒子径とした。
得られた電極について、以下の方法で剥離強度を評価した。
各例の正極または負極を幅2cmに切り出し、試験片1とした。この試験片1を両面テープ(積水化学工業株式会社製、「#570」)でポリカーボネート板(2.5cm×10cm×厚さ1mm)に貼着して、測定用試験片を得た。この際、電極層がポリカーボネート板に接するように、正極または負極をポリカーボネート板に貼着した。
テンシロン万能試験機(株式会社オリエンテック製、「RTC-1210A」)を用い、集電体を測定用試験片から剥離した際の荷重を測定した。5個の試験片について測定を行い、その平均値を剥離強度とした。測定条件は、剥離速度10mm/分、剥離角度180°、環境温度23℃、環境湿度40%RHとした。剥離強度が大きいほど、電極層が集電体により強固に結着していることを意味する。
得られた電極について、以下の方法で柔軟性を評価した。
各例の正極または負極を横3cm、縦5cmになるように切り出し、試験片2とした。この試験片2について、JIS K-5600-5-1:1999(ISO 1519:1973)の塗料一般試験方法耐屈曲性(円筒形マンドレル法)を参考にして柔軟性を評価した。
正極の柔軟性を評価する場合、得られた試験片2の集電体面に直径5mmのマンドレルをあて、試験片2の片側をテープで固定し、湿度10%以下の環境にて、集電体面が内側になるよう試験片2を折り曲げたときの電極層の状態を60倍のマイクロスコープ(スリー・アールシステム株式会社製、「ワイヤレスデジタル顕微鏡」)を用いて観察し、以下の評価基準にて正極の柔軟性を評価した。
負極の柔軟性を評価する場合、得られた試験片2の集電体面に直径3mmのマンドレルをあてた以外は、正極の場合と同様にして評価した。
○:電極層に割れ、欠け等の変化が見られない。
×:電極層に割れ、欠け等の変化が見られた。
得られた電極について、以下の方法で、電池特性を評価した。
各例の正極および市販の金属リチウム電極(負極)、または各例の負極および市販の金属リチウム電極(正極)を、セパレータ(セルガード♯2400)を介して対向させた。電解液として1Mの六フッ化リン酸リチウム(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))を用いて、2032型コイン電池を作製した。
得られた2032型コイン電池について、60℃で充放電レートを0.5Cとし、定電流法(電流密度:0.6mA/g-活物質)で試験した。
各例の正極を用いた2032型コイン電池の場合、4.2Vに充電し、3Vまで放電する充放電を50回繰り返し、50サイクル目の電池容量を測定した。
各例の負極を用いた2032型コイン電池の場合、3.0Vに充電し、0Vまで放電する充放電を50回繰り返し、50サイクル目の電池容量を測定した。
1サイクル目の電池容量に対する50サイクル目の電池容量の割合を百分率で表し、これを容量維持率とした。
(正極用スラリーの調製)
軟膏容器に、重合体(A)としてN-ビニルホルムアミド重合体(A1)の4質量%水溶液を50質量部(固形分換算で2質量部)と、脱イオン水40質量部とを計量し、これにコバルト酸リチウム(日本化学工業株式会社製、「セルシードC-5H」)100質量部と、アセチレンブラック(電気化学工業株式会社製)5質量部を加え、自公転攪拌機(Thinky社製、「泡とり練太郎」)を用い、自転1000rpm、公転2000rpmの条件にて混練した。十分に混錬した後、重合体(B-1)としてポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)を4質量部(固形分換算で2質量部)添加し、自公転攪拌機で攪拌しながら、塗工可能な粘度になるまで脱イオン水を用いて粘度調節し、正極用スラリーを得た。
正極用スラリーの配合組成を表1に示す。
得られた正極用スラリーを集電体(アルミニウム箔、19cm×25cm、厚み20μm)上にドクターブレードを用いて塗布し、循環式熱風乾燥機中60℃で30分間乾燥させ、さらに真空乾燥機にて80℃で12時間減圧乾燥させて、膜厚80μmの電極層が集電体(アルミニウム箔)上に形成された正極を得た。
得られた正極について、剥離強度を測定し、柔軟性および電池特性を評価した。結果を表2に示す。
軟膏容器に、N-ビニルホルムアミド重合体(A1)の4質量%水溶液を25質量部(固形分換算で1質量部)と、脱イオン水40質量部とを計量した以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。正極用スラリーの配合組成を表1に示す。また、評価測定・結果を表2に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)の代わりに、N-ビニルアセトアミド重合体(A2)を用いた以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。正極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(B-1)としてポリフッ化ビニリデンラテックスの代わりに、ブチルアクリレート成分およびポリオルガノシロキサン成分からなる複合ゴムに、メチルメタクリレートをグラフト重合して得られるアクリルシリコーンラテックス(平均粒子径166nm、固形分25質量%)を8質量部(固形分換算で2質量部)用いた以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。正極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(B-1)としてポリフッ化ビニリデンラテックスの代わりに、懸濁重合によって得られたポリアクリロニトリル粉体を水に分散させ、湿式微粒化装置によって強制的に乳化させて得られたポリアクリロニトリルラテックス(平均粒子径400nm、固形分7.5質量%)を27質量部(固形分換算で2質量部)用いた以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。正極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
(負極用スラリーの調製)
軟膏容器に、重合体(A)としてN-ビニルホルムアミド重合体(A1)の4質量%水溶液を50質量部(固形分換算で2質量部)と、脱イオン水50質量部とを計量し、これに天然の黒鉛系負極活物質(三菱化学株式会社製、「MPGC16」)100質量部を加え、自公転攪拌機(Thinky社製、「泡とり練太郎」)を用い、自転1000rpm、公転2000rpmの条件にて混練した。十分に混錬した後、重合体(B-1)としてポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)を4質量部(固形分換算で2質量部)添加し、自公転攪拌機で攪拌しながら、塗工可能な粘度になるまで脱イオン水を用いて粘度調節し、負極用スラリーを得た。
負極用スラリーの配合組成を表1に示す。
得られた負極用スラリーを集電体(銅箔、19cm×25cm、厚み18μm)上にドクターブレードを用いて塗布し、循環式熱風乾燥機中60℃で30分間乾燥させ、さらに真空乾燥機にて80℃で12時間減圧乾燥させて、膜厚80μmの電極層が集電体(銅箔)上に形成された負極を得た。
得られた負極について、剥離強度を測定し、柔軟性および電池特性を評価した。結果を表2に示す。
N-ビニルホルムアミド重合体(A1)の代わりに、N-ビニルアセトアミド重合体(A2)を用いた以外は、実施例1-6と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(B-1)としてポリフッ化ビニリデンラテックスの代わりに、ブチルアクリレート成分及びポリオルガノシロキサン成分からなる複合ゴムに、メチルメタクリレートをグラフト重合して得られるアクリルシリコーンラテックス(平均粒子径166nm、固形分25質量%)を8質量部(固形分換算で2質量部)用いた以外は、実施例1-6と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(B-1)としてポリフッ化ビニリデンラテックスの代わりに、懸濁重合によって得られたポリアクリロニトリル粉体を水に分散させ、湿式微粒化装置によって強制的に乳化させて得られたポリアクリロニトリルラテックス(平均粒子径400nm、固形分7.5質量%)を27質量部(固形分換算で2質量部)用いた以外は、実施例1-6と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
ポリフッ化ビニリデンラテックスを用いなかった以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。
正極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)の代わりに、N-ビニルアセトアミド重合体(A2)を用い、かつポリフッ化ビニリデンラテックスを用いなかった以外は、実施例1-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。
正極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
ポリフッ化ビニリデンラテックスを用いなかった以外は、実施例1-6と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)の代わりに、N-ビニルアセトアミド重合体(A2)を用い、かつポリフッ化ビニリデンラテックスを用いなかった以外は、実施例1-6と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表1に示す。また、測定・評価結果を表2に示す。
・PVDF-Em:ポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)。
・アクリルシリコーン:実施例1-4で得られたアクリルシリコーンラテックス(平均粒子径166nm、固形分25質量%)。
・PAN-Em:実施例1-5で得られたポリアクリロニトリルラテックス(平均粒子径400nm、固形分7.5質量%)。
・LCO:コバルト酸リチウム(日本化学工業株式会社製、「セルシードC-5H」)。
・MPGC16:天然の黒鉛系負極活物質(三菱化学株式会社製、「MPGC16」)。
・AB:アセチレンブラック(電気化学工業株式会社製)
また、比較例1-1の正極を備えた電池は実施例1-1、1-5に比べて、比較例1-2で得られた正極を備えた電池は実施例1-3に比べて、それぞれ容量維持率が低く、電池特性に劣っていた。比較例1-3の負極を備えた電池は実施例1-6、1-8、1-9に比べて、比較例1-4で得られた負極を備えた電池は実施例1-7に比べて、それぞれ容量維持率が低く、電池特性に劣っていた。
<重合体(A)の製造>
試験1の製造例1と同様にして、N-ビニルホルムアミド重合体(A1)を製造した。
(粘度の測定)
100mLねじ口ガラス瓶に、樹脂組成物の水溶液を入れ、B型粘度計(東機産業株式会社製、「TVB-10M型粘度計」)を用いて粘度を測定した。ローターはM4またはM2を使用し、回転速度3rpm、6rpm、20rpmのいずれかでの粘度を読み取った。
まず、重合体(A)の濃度が1質量%となるように、イオン交換水に重合体(A)を溶解して、重合体(A)の1質量%水溶液を得た。得られた重合体(A)の1質量%水溶液について、B型粘度計を用いて、25℃での粘度を測定し、その値を粘度(α)とした。
別途、重合体(A)の濃度が1質量%となるように、イオン交換水に重合体(A)を溶解して、重合体(A)の1質量%水溶液を得た。この水溶液に、重合体(B-2)を重合体(A)100質量部に対して10質量部となるように添加して溶液を得た。得られた溶液について、重合体(A)の1質量%水溶液と同様にして粘度を測定し、その値を粘度(β)とした。
上記方法により測定した粘度(α)と粘度(β)との比(β/α)を算出した。
得られた負極用スラリーについて、以下の方法でスラリーの安定性を評価した。
各例の負極用スラリーを24時間放置した後、スラリーの分離や活物質の沈降などがないかを目視で確認し、以下の評価基準にてスラリーの安定性を評価した。
○:分離、沈降がない。
×:分離または沈降していた。
得られた電極について、試験1の剥離強度の測定方法と同様にして、剥離強度を測定した。
得られた電極について、試験1の電池特性の評価方法と同様にして、電池特性を評価した。
(樹脂組成物の調製)
重合体(A)としてN-ビニルホルムアミド重合体(A1)2質量部と、重合体(B-2)としてポリ(2-スルホ-5-メトキシ-1,4-イミノフェニレン)水溶液(固形分5質量%)4質量部(固形分換算で0.2質量部)と、脱イオン水94質量部とを計量し、十分に溶解して樹脂組成物の水溶液を得た。
得られた樹脂組成物の水溶液について、粘度を測定した。なお、ローターはM4を使用し、回転速度3rpmでの粘度を読み取った。また、粘度比を算出した。測定結果を表3に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)2質量部と、重合体(B-2)としてポリスチレンスルホン酸ナトリウム水溶液(東ソー有機化学株式会社製、「ポリナス PS-5」、固形分20質量%)1質量部(固形分換算で0.2質量部)と、脱イオン水97質量部とを計量し、十分に溶解して樹脂組成物の水溶液を得た。
得られた樹脂組成物の水溶液について、粘度を測定した。なお、ローターはM4を使用し、回転速度6rpmでの粘度を読み取った。また、粘度比を算出した。測定結果を表3に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)2質量部と、重合体(B-2)としてポリアクリル酸ナトリウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)5質量部(固形分換算で0.2質量部)と、脱イオン水93質量部とを計量し、十分に溶解して樹脂組成物の水溶液を得た。
得られた樹脂組成物の水溶液について、粘度を測定した。なお、ローターはM4を使用し、回転速度6rpmでの粘度を読み取った。また、粘度比を算出した。測定結果を表3に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)2質量部と、重合体(B-2)としてポリアクリル酸リチウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)5質量部(固形分換算で0.2質量部)と、脱イオン水93質量部とを計量し、十分に溶解して樹脂組成物の水溶液を得た。
得られた樹脂組成物の水溶液について、粘度を測定した。なお、ローターはM4を使用し、回転速度6rpmでの粘度を読み取った。また、粘度比を算出した。測定結果を表3に示す。
重合体(A)としてN-ビニルホルムアミド重合体(A1)2質量部と、脱イオン水98質量部とを計量し、十分に溶解して樹脂組成物の水溶液を得た。
得られた樹脂組成物の水溶液について、粘度を測定した。なお、ローターはM2を使用し、回転速度20rpmでの粘度を読み取った。測定結果を表3に示す。
(負極用スラリーの調製)
軟膏容器に、重合体(A)としてN-ビニルホルムアミド重合体(A1)の4質量%水溶液を50質量部(固形分換算で2質量部)と、重合体(B-2)としてポリ(2-スルホ-5-メトキシ-1,4-イミノフェニレン)水溶液(固形分5質量%)4質量部(固形分換算で0.2質量部)と、脱イオン水40質量部とを計量し、これに天然の黒鉛系負極活物質(三菱化学株式会社製、「MPGC16」)100質量部を加え、自公転攪拌機(Thinky社製、「あわとり練太郎」)を用い、自転1000rpm、公転2000rpmの条件にて混練した。十分に混練した後、塗工可能な粘度になるまで脱イオン水を用いて粘度調節し、負極用スラリーを得た。
負極用スラリーの配合組成を表4に示す。また、得られた負極用スラリーの安定性を評価した。評価結果を表5に示す。
得られた負極用スラリーを集電体(銅箔、19cm×25cm、厚み18μm)上にドクターブレードを用いて塗布し、循環式熱風乾燥機中60℃で30分間乾燥させ、さらに真空乾燥機にて80℃で12時間減圧乾燥させて、膜厚80μmの電極層が集電体(銅箔)上に形成された負極を得た。
得られた負極について、剥離強度を測定し、電池特性を評価した。結果を表5に示す。
重合体(B-2)としてポリスチレンスルホン酸ナトリウム水溶液(東ソー有機化学株式会社製、「ポリナス PS-5」、固形分20質量%)1質量部(固形分換算で0.2質量部)を用いた以外は、実施例2-5と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表4に示す。また、測定・評価結果を表5に示す。
重合体(B-2)としてポリアクリル酸ナトリウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)5質量部(固形分換算で0.2質量部)を用い、導電助剤としてアセチレンブラック1質量部を用いた以外は、実施例2-5と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表4に示す。また、測定・評価結果を表5に示す。
重合体(B-2)としてポリアクリル酸リチウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)5質量部(固形分換算で0.2質量部)を用い、導電助剤としてアセチレンブラック1質量部を用いた以外は、実施例2-5と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表4に示す。また、測定・評価結果を表5に示す。
重合体(B-2)としてポリアニリンスルホン酸水溶液を用いなかった以外は、実施例2-5と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表4に示す。また、測定・評価結果を表5に示す。
・MPGC16:天然の黒鉛系負極活物質(三菱化学株式会社製、「MPGC16」)。
・AB:アセチレンブラック(電気化学工業株式会社製)
このことは表5のスラリー安定性の評価結果からも明らかである。重合体(A)と重合体(B-2)を用いた実施例2-5~2-8は、重合体(B-2)を用いなかった比較例2-2と比較して、負極用スラリーの安定性が向上している。すなわち重合体(A)と重合体(B-2)を含む本発明の樹脂組成物を用いた電極用スラリーは安定性に優れる。
なお、比較例2-1である重合体(A)の水溶液は、2質量%程度の濃度の場合、粘度が剪断速度に依存しないニュートン流体に近いことが分かっており、B型粘度計による測定において回転速度を3rpm乃至6rpmに変えた場合においても、20rpmと同等の粘度が測定値として示されるものと思われる。
一方、重合体(B-2)を用いずに形成された比較例2-2の負極は剥離強度が低く、この負極を備えた電池は実施例2-5~2-8に比べて容量維持率が低く、電池特性に劣っていた。
<重合体(A)の製造>
試験1の製造例1と同様にして、N-ビニルホルムアミド重合体(A1)を製造した。
(スラリー安定性の評価)
得られた負極用スラリーについて、試験2のスラリー安定性の評価方法と同様にして、スラリーの安定性を評価した。
得られた電極について、試験1の剥離強度の測定方法と同様にして、剥離強度を測定した。
得られた電極について、試験1の柔軟性の評価方法と同様にして、柔軟性を評価した。
得られた電極について、試験1の電池特性の評価方法と同様にして、電池特性を評価した。
(正極用スラリーの調製)
軟膏容器に、重合体(A)としてN-ビニルホルムアミド重合体(A1)の4質量%水溶液を50質量部(固形分換算で2質量部)と、重合体(B-2)としてポリアクリル酸ナトリウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)を5質量部(固形分換算で0.2質量部)と、脱イオン水40質量部とを計量し、これにコバルト酸リチウム(日本化学工業株式会社製、「セルシードC-5H」)100質量部と、アセチレンブラック(電気化学工業株式会社製)5質量部を加え、自公転攪拌機(Thinky社製、「泡とり練太郎」)を用い、自転1000rpm、公転2000rpmの条件にて混練した。十分に混錬した後、重合体(B-1)としてポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)を4質量部(固形分換算で2質量部)添加し、自公転攪拌機で攪拌しながら、塗工可能な粘度になるまで脱イオン水を用いて粘度調節し、正極用スラリーを得た。
正極用スラリーの配合組成を表6に示す。
得られた正極用スラリーを集電体(アルミニウム箔、19cm×25cm、厚み20μm)上にドクターブレードを用いて塗布し、循環式熱風乾燥機中60℃で30分間乾燥させ、さらに真空乾燥機にて80℃で12時間減圧乾燥させて、膜厚80μmの電極層が集電体(アルミニウム箔)上に形成された正極を得た。
得られた正極について、剥離強度を測定し、柔軟性および電池特性を評価した。結果を表7に示す。
(負極用スラリーの調製)
軟膏容器に、重合体(A)としてN-ビニルホルムアミド重合体(A1)の4質量%水溶液を50質量部(固形分換算で2質量部)と、重合体(B-2)としてポリアクリル酸ナトリウム水溶液(和光純薬工業株式会社製、分子量100万、固形分4質量%)を5質量部(固形分換算で0.2質量部)と、脱イオン水40質量部とを計量し、これに天然の黒鉛系負極活物質(三菱化学(株)製、「MPGC16」)100質量部とアセチレンブラック(電気化学工業株式会社製)1質量部を加え、自公転攪拌機(Thinky社製、「あわとり練太郎」)を用い、自転1000rpm、公転2000rpmの条件にて混練した。十分に混練した後、重合体(B-1)としてポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)を4質量部(固形分換算で2質量部)添加し、自公転攪拌機で攪拌しながら、塗工可能な粘度になるまで脱イオン水を用いて粘度調節し、負極用スラリーを得た。
負極用スラリーの配合組成を表6に示す。また、得られた負極用スラリーの安定性を評価した。評価結果を表7に示す。
得られた負極用スラリーを集電体(銅箔、19cm×25cm、厚み18μm)上にドクターブレードを用いて塗布し、循環式熱風乾燥機中60℃で30分間乾燥させ、さらに真空乾燥機にて80℃で12時間減圧乾燥させて、膜厚80μmの電極層が集電体(銅箔)上に形成された負極を得た。
得られた負極について、剥離強度を測定し、柔軟性および電池特性を評価した。結果を表7に示す。
ポリアクリル酸ナトリウム水溶液およびポリフッ化ビニリデンラテックスを用いなかった以外は、実施例3-1と同様にして正極用スラリーを調製し、正極を作製し、各種測定・評価を行った。
正極用スラリーの配合組成を表6に示す。また、測定・評価結果を表7に示す。
ポリアクリル酸ナトリウム水溶液およびポリフッ化ビニリデンラテックスを用いなかった以外は、実施例3-2と同様にして負極用スラリーを調製し、負極を作製し、各種測定・評価を行った。
負極用スラリーの配合組成を表6に示す。また、測定・評価結果を表7に示す。
・PVDF-Em:ポリフッ化ビニリデンラテックス(アルケマ社製、平均粒子径127nm、固形分49.6質量%)。
・LCO:コバルト酸リチウム(日本化学工業株式会社製、「セルシードC-5H」)。
・MPGC16:天然の黒鉛系負極活物質(三菱化学株式会社製、「MPGC16」)。
・AB:アセチレンブラック(電気化学工業株式会社製)
さらに、重合体(A)と、重合体(B-1)および重合体(B-2)を用いた実施例3-1、3-2の電極を備えた電池は、50サイクル目の電池容量が1サイクル目の電池容量の92%以上を維持しており、電池特性にも優れていた。
一方、重合体(B-1)および重合体(B-2)を用いずに形成された比較例3-2の負極を備えた電池は実施例3-2に比べて容量維持率が低く、電池特性に劣っていた。
本発明の第一の態様の二次電池電極用スラリーは、第一の態様の二次電池電極用バインダ樹脂組成物を用いて得られるものであり、柔軟性に優れた電極を形成でき、電池特性、特に長期のサイクル特性に優れた電池が得られる。
本発明の第一の態様の二次電池用電極は、柔軟性に優れる。そのため該電極を備えたリチウムイオン二次電池によれば、電池特性、特に長期のサイクル特性に優れる。
本発明の第二の態様の二次電池電極用スラリーは、第二の態様の二次電池電極用バインダ樹脂組成物を用いて得られるものであり、負極に用いる場合でも安定性に優れ、活物質やバインダの偏在を抑制した電極を形成でき、電池特性、特に長期のサイクル特性に優れた電池が得られる。
本発明の第二の態様の二次電池用電極は、活物質やバインダが偏在しにくい。そのため該電極を備えたリチウムイオン二次電池によれば、電池特性、特に長期のサイクル特性に優れる。
Claims (12)
- 前記重合体(B-1)の平均粒子径が10~1000nmである、請求項1に記載の二次電池電極用バインダ樹脂組成物。
- 前記重合体(A)と重合体(B-1)との質量比(重合体(A)/重合体(B-1))が5/95~95/5である、請求項1に記載の二次電池電極用バインダ樹脂組成物。
- 下記柔軟性試験により電極の柔軟性の評価を行ったときに、電極層に変化がない、請求項1に記載の二次電池電極用バインダ樹脂組成物。
(柔軟性試験)
当該二次電池電極用バインダ樹脂組成物と水とを混練する。これに活物質を加えて混練し、さらに電極が正極の場合には導電助剤を加えて混練した後、塗工可能な粘度まで水で調整して電極用スラリーを得る。配合量は、活物質100質量部に対して、二次電池電極用バインダ樹脂組成物を2質量部とし、導電助剤を5質量部とする。
得られた電極用スラリーを集電体に塗布し、乾燥して、膜厚20~200μmの電極層が集電体上に形成された電極を得る。
得られた電極を横3cm、縦5cmに切り出し、試験片とする。
得られた試験片の集電体面に直径5mmのマンドレルをあて、試験片の片側をテープで固定し、湿度10%以下の環境にて、集電体面が内側になるよう試験片を折り曲げたときの電極層の状態を観察し、電極の柔軟性を評価する。 - 前記酸性基または/およびその塩が、カルボキシル基、カルボキシル基の塩、スルホン酸基、スルホン酸基の塩、リン酸基およびリン酸基の塩からなる群より選ばれる少なくとも1つである、請求項1に記載の二次電池電極用バインダ樹脂組成物。
- 前記重合体(A)と重合体(B-2)との質量比(重合体(A)/重合体(B-2))が5/95~99.5/0.5である、請求項1に記載の二次電池電極用バインダ樹脂組成物。
- 前記重合体(A)の1質量%水溶液の粘度(α)と、該水溶液に前記重合体(B-2)を重合体(A)100質量部に対して10質量部となるように添加した溶液の粘度(β)との比(β/α)が5以上である、請求項1に記載の二次電池電極用バインダ樹脂組成物。
- 請求項1に記載の二次電池電極用バインダ樹脂組成物と、活物質と、溶媒とを含有する、二次電池電極用スラリー。
- 集電体と、該集電体上に設けられた電極層とを備え、
前記電極層は、活物質と、請求項1に記載の二次電池電極用バインダ樹脂組成物とを含有する、二次電池用電極。 - 請求項9に記載の二次電池用電極を備える、リチウムイオン二次電池。
- 集電体と、該集電体上に設けられた電極層とを備え、
前記電極層は、請求項8に記載の二次電池電極用スラリーを集電体に塗布し、乾燥させて得られるものである、二次電池用電極。 - 請求項11に記載の二次電池用電極を備える、リチウムイオン二次電池。
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US14/371,115 US10446850B2 (en) | 2012-01-11 | 2013-01-11 | Binder resin composition for secondary battery electrodes, slurry for secondary battery electrodes, electrode for secondary batteries, and lithium ion secondary battery |
EP13736240.6A EP2804243B1 (en) | 2012-01-11 | 2013-01-11 | Binder resin composition for secondary battery electrodes, slurry for secondary battery electrodes, electrode for secondary batteries, and lithium ion secondary battery |
CN201380005127.6A CN104081567B (zh) | 2012-01-11 | 2013-01-11 | 二次电池电极用粘合剂树脂组合物、二次电池电极用浆料、二次电池用电极、锂离子二次电池 |
JP2013506021A JP6015649B2 (ja) | 2012-01-11 | 2013-01-11 | 二次電池電極用バインダ樹脂組成物、二次電池電極用スラリー、二次電池用電極、リチウムイオン二次電池 |
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1167213A (ja) | 1997-08-21 | 1999-03-09 | Jsr Corp | 電池電極用組成物および電池電極 |
JP2002117860A (ja) | 2000-10-11 | 2002-04-19 | Matsushita Electric Ind Co Ltd | 電極およびリチウム二次電池 |
JP2002251999A (ja) | 2001-02-22 | 2002-09-06 | Showa Denko Kk | 非水電池並びに該電池に用いる電極用ペースト及び電極 |
JP2002279980A (ja) * | 2001-01-10 | 2002-09-27 | Hitachi Maxell Ltd | 電極およびそれを用いた電池 |
JP2010061997A (ja) * | 2008-09-03 | 2010-03-18 | Toyo Ink Mfg Co Ltd | リチウム二次電池用正極合剤ペースト |
JP2010061996A (ja) * | 2008-09-03 | 2010-03-18 | Toyo Ink Mfg Co Ltd | 電池用組成物 |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09245836A (ja) * | 1996-03-08 | 1997-09-19 | Fuji Photo Film Co Ltd | 非水電解質二次電池 |
JP3702353B2 (ja) * | 1996-05-24 | 2005-10-05 | 日本電池株式会社 | リチウム電池用正極活物質の製造方法およびリチウム電池 |
JP3174030B2 (ja) | 1998-08-04 | 2001-06-11 | 日立マクセル株式会社 | 正極用ペ―スト、ペ―スト式水酸化ニツケル正極およびアルカリ蓄電池 |
JP2001093518A (ja) | 1999-09-21 | 2001-04-06 | Sanyo Electric Co Ltd | 水素吸蔵合金電極及びこれを用いたニッケル・水素蓄電池 |
US6500319B2 (en) * | 2001-04-05 | 2002-12-31 | Giner Electrochemical Systems, Llc | Proton exchange membrane (PEM) electrochemical cell having an integral, electrically-conductive, compression pad |
JP3960193B2 (ja) * | 2001-12-20 | 2007-08-15 | 株式会社デンソー | リチウム二次電池用電極及びリチウム二次電池並びにその製造方法 |
KR100477987B1 (ko) * | 2002-09-11 | 2005-03-23 | 삼성에스디아이 주식회사 | 리튬-황 전지용 양극 및 이를 포함하는 리튬-황 전지 |
KR100831143B1 (ko) * | 2004-06-10 | 2008-05-20 | 스미토모덴키고교가부시키가이샤 | 금속촉매와 그 제조방법 |
JP4693372B2 (ja) * | 2004-07-16 | 2011-06-01 | 三洋電機株式会社 | 非水電解質二次電池 |
US7875388B2 (en) * | 2007-02-06 | 2011-01-25 | 3M Innovative Properties Company | Electrodes including polyacrylate binders and methods of making and using the same |
JP2011071100A (ja) * | 2009-08-31 | 2011-04-07 | Sanyo Electric Co Ltd | 非水電解質二次電池用正極及びそれを用いた非水電解質二次電池 |
-
2013
- 2013-01-11 EP EP13736240.6A patent/EP2804243B1/en not_active Not-in-force
- 2013-01-11 US US14/371,115 patent/US10446850B2/en not_active Expired - Fee Related
- 2013-01-11 JP JP2013506021A patent/JP6015649B2/ja not_active Expired - Fee Related
- 2013-01-11 WO PCT/JP2013/050358 patent/WO2013105623A1/ja active Application Filing
- 2013-01-11 KR KR1020147022026A patent/KR101654448B1/ko active IP Right Grant
- 2013-01-11 CN CN201380005127.6A patent/CN104081567B/zh not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH1167213A (ja) | 1997-08-21 | 1999-03-09 | Jsr Corp | 電池電極用組成物および電池電極 |
JP2002117860A (ja) | 2000-10-11 | 2002-04-19 | Matsushita Electric Ind Co Ltd | 電極およびリチウム二次電池 |
JP2002279980A (ja) * | 2001-01-10 | 2002-09-27 | Hitachi Maxell Ltd | 電極およびそれを用いた電池 |
JP2002251999A (ja) | 2001-02-22 | 2002-09-06 | Showa Denko Kk | 非水電池並びに該電池に用いる電極用ペースト及び電極 |
JP2010061997A (ja) * | 2008-09-03 | 2010-03-18 | Toyo Ink Mfg Co Ltd | リチウム二次電池用正極合剤ペースト |
JP2010061996A (ja) * | 2008-09-03 | 2010-03-18 | Toyo Ink Mfg Co Ltd | 電池用組成物 |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2014139912A (ja) * | 2012-02-14 | 2014-07-31 | Mitsubishi Chemicals Corp | 非水系二次電池負極用活物質並びにそれを用いた負極及び非水系二次電池 |
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US10418632B2 (en) | 2013-08-19 | 2019-09-17 | Lg Chem, Ltd. | Binder composition for secondary batteries, electrode using the same, and lithium secondary battery |
JP2015076225A (ja) * | 2013-10-08 | 2015-04-20 | 三菱レイヨン株式会社 | 二次電池電極用バインダ樹脂組成物、二次電池電極用スラリー、二次電池用電極、リチウムイオン二次電池 |
WO2015115845A1 (ko) * | 2014-01-29 | 2015-08-06 | 삼성전자 주식회사 | 전기 흡착 탈이온 장치용 전극 조성물, 및 이를 포함하는 전기 흡착 탈이온 장치용 전극 |
US10376874B2 (en) | 2014-01-29 | 2019-08-13 | Samsung Electronics Co., Ltd. | Electrode composition for capacitive deionization device, and electrode for capacitive deionization device containing the same |
US10593992B2 (en) * | 2014-10-15 | 2020-03-17 | Tokyo University Of Science Foundation | Negative electrode for potassium ion secondary batteries, negative electrode for potassium ion capacitors, potassium ion secondary battery, potassium ion capacitor, and binder for negative electrodes of potassium ion secondary batteries or negative electrodes of potassium ion capacitors |
CN110088951A (zh) * | 2016-12-20 | 2019-08-02 | 三星Sdi株式会社 | 用于二次电池的粘合剂、用于二次电池的粘合剂树脂组合物、二次电池用电极及二次电池 |
CN110088951B (zh) * | 2016-12-20 | 2022-08-16 | 三星Sdi株式会社 | 用于二次电池的粘合剂、用于二次电池的粘合剂树脂组合物、二次电池用电极及二次电池 |
WO2020241384A1 (ja) * | 2019-05-31 | 2020-12-03 | 日本ゼオン株式会社 | 二次電池正極用スラリー組成物の製造方法、二次電池用正極の製造方法、及び、二次電池の製造方法 |
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KR20140116190A (ko) | 2014-10-01 |
CN104081567B (zh) | 2017-09-15 |
KR101654448B1 (ko) | 2016-09-05 |
EP2804243A4 (en) | 2015-06-17 |
US20140349185A1 (en) | 2014-11-27 |
US10446850B2 (en) | 2019-10-15 |
EP2804243A1 (en) | 2014-11-19 |
JP6015649B2 (ja) | 2016-10-26 |
JPWO2013105623A1 (ja) | 2015-05-11 |
CN104081567A (zh) | 2014-10-01 |
EP2804243B1 (en) | 2017-10-25 |
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