JP2017142917A - Mixture for nonaqueous electrolyte secondary battery electrode, nonaqueous electrolyte secondary battery electrode including the same, nonaqueous electrolyte secondary battery including the same, and electric equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of bubbles in a simple and convenient manner when dispersing an electrode material, including an active material in water or solvent, and to provide a mixture for a nonaqueous electrolyte secondary battery electrode, which can suppress the biting of bubbles.SOLUTION: A mixture for nonaqueous electrolyte secondary battery electrode comprises: an active material for an electrode; a conductive assistant; a binding agent; and a defoaming agent. The binding agent includes a copolymer of vinyl alcohol and an ethylenic unsaturated carboxylic acid alkali metal neutralizer. The content of the defoaming agent is 0.001-1 mass% to a total mass of the active material for an electrode, the conductive assistant, the binding agent and the defoaming agent.SELECTED DRAWING: None

Description

  The present invention relates to a mixture for a non-aqueous electrolyte secondary battery electrode. Moreover, this invention relates also to the electrode for nonaqueous electrolyte secondary batteries (a positive electrode and a negative electrode) containing the said mixture, the nonaqueous electrolyte secondary battery provided with the said electrode, and an electric equipment.

  In recent years, with the spread of portable electronic devices such as notebook computers, smartphones, portable game devices, PDAs, etc., secondary batteries used as a power source in order to reduce the weight of these devices and enable long-term use. There is a demand for downsizing and higher energy density.

  Conventionally, nickel-cadmium batteries, nickel-hydrogen batteries, etc. have been mainstream as non-aqueous electrolyte secondary batteries, but the use of lithium ion secondary batteries has increased due to the above demands for miniaturization and high energy density. Tend to.

The electrode of the lithium ion secondary battery can be obtained by applying and drying an electrode mixture containing an active material, a binder and a conductive additive on a current collector. (For example, refer to Patent Documents 1 to 11 and Non-Patent Document 1) For example, the positive electrode includes LiCoO ₂ as an active material, polyvinylidene fluoride (PVdF) as a binder, and carbon black as a conductive aid, respectively. It is obtained by coating and drying the slurry of the positive electrode mixture dispersed on the aluminum foil (current collector).

  On the other hand, the negative electrode includes, for example, graphite (graphite) as an active material, carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), PVDF, or polyimide as a binder, and carbon black as a conductive auxiliary agent. It is obtained by coating and drying the slurry of the negative electrode mixture dispersed on the copper foil (current collector).

JP-A-8-264180 Japanese Patent Laid-Open No. 4-188559 Japanese Patent Laid-Open No. 10-284082 JP-A-7-240201 JP 10-294112 A International Publication No. 2004/049475 JP-A-10-302799 Japanese Patent Laid-Open No. 5-21068 Japanese Patent Laid-Open No. 5-74461 JP 2006-156228 A JP 2012-64574 A

Lithium secondary battery, p. 132 (Ohm Co., Ltd., issued on March 20, 2008)

  The electrode mixture is obtained, for example, by dispersing an electrode material such as an active material in a medium (for example, water or a solvent) (in this case, the electrode mixture is in a slurry form). If the electrode mixture contains air bubbles, a uniform electrode cannot be obtained at the time of electrode preparation. For this reason, air bubbles trapped at the time of dispersion are removed in the defoaming process, but vacuum defoaming and centrifugal defoaming increase the process time, and if there is no existing equipment, capital investment is required. Therefore, the defoaming step increases the production load.

  An object of the present invention is to easily suppress the generation of bubbles when an electrode material such as an active material is dispersed in water or a solvent, and further to provide a non-aqueous electrolyte secondary battery electrode mixture in which entrapment of bubbles is suppressed. To provide.

  As a result of intensive studies to solve the above problems, the present inventors have used a specific amount of an antifoaming agent, more preferably a specific antifoaming agent, to disperse an electrode material in a medium. It has been found that the generated bubbles can be suppressed, and as a result, a uniform electrode can be obtained, and further studies have been made to complete the present invention.

That is, the present invention includes, for example, the subject matters described in the following sections.
Item 1.
Contains an active material for electrodes, a conductive additive, a binder, and an antifoaming agent,
The binder includes a copolymer of vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid,
The content of the antifoaming agent is 0.001% by mass or more and 1% by mass or less based on the total mass of the electrode active material, the conductive additive, the binder, and the antifoaming agent.
Nonaqueous electrolyte secondary battery electrode mixture.
Item 2.
Item 2. The nonaqueous electrolyte secondary battery electrode mixture according to Item 1, wherein the antifoaming agent is at least one selected from the group consisting of a silicone-based antifoaming agent and a surfactant-based antifoaming agent.
Item 3.
Item 3. The nonaqueous electrolyte according to Item 1 or 2, wherein the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid has a molar copolymer composition ratio of 95: 5 to 5:95. Secondary battery electrode mixture.
Item 4.
Item 4. The nonaqueous electrolyte secondary according to any one of Items 1 to 3, wherein the ethylenically unsaturated carboxylic acid alkali metal neutralized product is an alkali metal acrylate neutralized product or an alkali metal methacrylic acid alkali metal neutralized product. Battery electrode mixture.
Item 5.
An electrode for a non-aqueous electrolyte secondary battery comprising the mixture for a non-aqueous electrolyte secondary battery electrode according to any one of Items 1 to 4 on a current collector.
Item 6.
Item 6. A nonaqueous electrolyte secondary battery comprising the nonaqueous electrolyte secondary battery electrode according to Item 5.
Item 7.
Item 7. An electric device including the nonaqueous electrolyte secondary battery according to item 6.

  According to the present invention, since a specific amount of the antifoaming agent is used during the production of the nonaqueous electrolyte secondary battery electrode mixture, air bubbles can be preferably suppressed and the defoaming step becomes unnecessary. In addition, the mixture is difficult to entrap bubbles. For this reason, it is possible to provide an electrode for nonaqueous electrolyte secondary battery and a nonaqueous electrolyte secondary battery that are low in production load and can be produced with excellent uniformity and excellent in battery characteristics. Therefore, the non-aqueous electrolyte secondary battery according to the present invention can be reduced in cost as compared with the conventional non-aqueous electrolyte secondary battery, and its usage can be expanded. The effect is more preferably achieved by using a specific amount of a specific antifoaming agent.

  Hereinafter, a mixture for a nonaqueous electrolyte secondary battery electrode according to an embodiment of the present invention, a nonaqueous electrolyte secondary battery electrode containing the mixture, and a nonaqueous electrolyte secondary battery will be described.

<Nonaqueous electrolyte secondary battery electrode mixture>
The nonaqueous electrolyte secondary battery electrode mixture of the present embodiment contains an electrode active material, a conductive additive, a binder and an antifoaming agent, and the binder includes vinyl alcohol and an ethylenically unsaturated carboxylic acid. Copolymers with neutralized alkali metals are included.

(Binder)
The copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid used as the binder in this embodiment is, for example, a monomer mainly composed of vinyl ester and ethylenically unsaturated carboxylic acid ester. Is polymerized in the presence of a polymerization catalyst to form a vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer, and the copolymer is mixed with an aqueous organic solvent and water in the presence of an alkali containing an alkali metal. It is obtained by saponification.

  Examples of the vinyl ester include vinyl acetate, vinyl propionate, and vinyl pivalate, and vinyl acetate is preferable from the viewpoint that the saponification reaction easily proceeds. These vinyl esters may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the ethylenically unsaturated carboxylic acid ester include acrylic acid, methacrylic acid methyl ester, ethyl ester, n-propyl ester, iso-propyl ester, n-butyl ester, and t-butyl ester. Methyl acrylate and methyl methacrylate are preferred from the viewpoint that the conversion reaction easily proceeds. One of these ethylenically unsaturated carboxylic acid esters may be used alone, or two or more thereof may be used in combination.

  Moreover, it is also possible to copolymerize the other ethylenically unsaturated monomer and crosslinking agent which can be copolymerized with vinyl ester and ethylenically unsaturated carboxylic acid ester as needed.

  As an example of the saponification reaction in this embodiment, the saponification reaction when the vinyl acetate / methyl acrylate copolymer is saponified 100% with potassium hydroxide (KOH) is shown below.

  As shown above, the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid used in this embodiment is obtained by random copolymerization of vinyl ester and ethylenically unsaturated carboxylic acid ester. , A substance obtained by saponifying an ester portion derived from a monomer, and a bond between the monomers is a C-C covalent bond (hereinafter referred to as a saponified product of vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer). Also, as is clear from the above explanation, “/” here indicates random copolymerization).

  Patent Document 11 discloses a cross-linking compound of polyacrylic acid substituted with an alkali cation and polyvinyl alcohol. This cross-linking compound is obtained by cross-linking polyacrylic acid and polyvinyl alcohol by an ester bond. It has a structure. Therefore, the bridged compound of polyacrylic acid substituted with an alkali cation and polyvinyl alcohol disclosed in Patent Document 11 includes vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid according to this embodiment. This is a completely different material from the copolymer of.

  In the vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer, the molar ratio of the vinyl ester and the ethylenically unsaturated carboxylic acid ester is preferably 95: 5 to 5:95, and 95: 5 to 50:50. Is more preferable, 90:10 to 55:45 is more preferable, and 85:15 to 60:40 is still more preferable. If the ratio is outside the range of 95: 5 to 5:95, the polymer obtained after saponification may be insufficient because the holding power as a binder may be insufficient.

  Therefore, in the copolymer of the obtained vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid, the copolymer composition ratio is preferably 95: 5 to 5:95, and 95: 5 to 50: 50 is more preferable, 90:10 to 55:45 is more preferable, and 85:15 to 60:40 is still more preferable.

  As the ethylenically unsaturated carboxylic acid alkali metal neutralized product, an alkali metal acrylate neutralized product or a methacrylic acid alkali metal neutralized product is preferable.

  From the viewpoint of obtaining a copolymer in the form of a powder, the vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer which is a precursor of a copolymer of vinyl alcohol and an alkali metal neutralized product of an ethylenically unsaturated carboxylic acid Suspension weight to be polymerized by polymerizing in a state in which a monomer mainly composed of vinyl ester and ethylenically unsaturated carboxylic acid ester is suspended in an aqueous solution containing a polymerization catalyst and in which a dispersant is dissolved. Those obtained by legal methods are preferred.

  Examples of the polymerization catalyst include organic peroxides such as benzoyl peroxide and lauryl peroxide, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile, and lauryl peroxide is particularly preferable.

  0.01-5 mass% is preferable with respect to the total mass of a monomer, and, as for the addition amount of a polymerization catalyst, 0.05-3 mass% is more preferable, and 0.1-3 mass% is further more preferable. If it is less than 0.01% by mass, the polymerization reaction may not be completed, and if it exceeds 5% by mass, the binding effect of the copolymer of vinyl alcohol and neutralized ethylenically unsaturated carboxylic acid is sufficient. It may not be.

  The dispersant used for the polymerization may be selected from appropriate substances depending on the type and amount of the monomer used. Specifically, polyvinyl alcohol (partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol) may be used. ), Poly (meth) acrylic acid and salts thereof, water-soluble polymers such as polyvinylpyrrolidone, methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and water-insoluble inorganic compounds such as calcium phosphate and magnesium silicate. These dispersants may be used alone or in combination of two or more.

  The amount of the dispersant used is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the total mass of the monomers, although it depends on the type of monomer used. .

  Furthermore, water-soluble salts such as alkali metals and alkaline earth metals can be added in order to adjust the surface active effect of the dispersant. For example, sodium chloride, potassium chloride, calcium chloride, lithium chloride, anhydrous sodium sulfate, potassium sulfate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, trisodium phosphate, and tripotassium phosphate. A water-soluble salt may be used individually by 1 type, and may be used in combination of 2 or more type.

  The amount of the water-soluble salt used is usually 0.01 to 10% by mass with respect to the mass of the aqueous dispersant solution, although it depends on the type and amount of the dispersant used.

  The temperature at which the monomer is polymerized is preferably -20 to + 20 ° C, more preferably -10 to + 10 ° C with respect to the 10-hour half-life temperature of the polymerization catalyst. If the temperature is less than −20 ° C. with respect to the 10-hour half-life temperature, the polymerization reaction may not be completed, and if it exceeds + 20 ° C., a copolymer of vinyl alcohol and alkali metal neutralized ethylenically unsaturated carboxylic acid obtained. The binding effect may not be sufficient. For example, the 10 hour half-life temperature of lauryl peroxide is about 62 ° C.

  The time for polymerizing the monomer is usually several hours to several tens of hours, although it depends on the type, amount, polymerization temperature and the like of the polymerization catalyst used.

  After completion of the polymerization reaction, the copolymer is separated by a method such as centrifugation or filtration, and obtained in the form of a water-containing cake. The obtained water-containing cake-like copolymer can be used as it is or after drying if necessary and used for the saponification reaction.

  The number average molecular weight of the polymer in the present specification is a value determined with a molecular weight measuring apparatus equipped with a GFC column (for example, OHpak manufactured by Shodex) using DMF as a solvent and polystyrene as a standard sample. Examples of such a molecular weight measuring device include 2695 manufactured by Waters Co., Ltd. and RI detector 2414.

  The number average molecular weight of the copolymer before saponification is preferably 10,000 to 1,000,000, and more preferably 50,000 to 800,000. By setting the number average molecular weight before saponification within the range of 10,000 to 1,000,000, the binding force as a binder is improved. Therefore, even if the negative electrode mixture is an aqueous slurry, thick coating of the slurry becomes easy.

  As the alkali containing an alkali metal used in the saponification reaction, conventionally known alkalis can be used, but alkali metal hydroxides are preferable, and sodium hydroxide and potassium hydroxide are preferred from the viewpoint of high reactivity. Is particularly preferred.

  60-140 mol% is preferable with respect to the number-of-moles of a monomer, and, as for the quantity of the said alkali, 80-120 mol% is more preferable. If the amount of alkali is less than 60 mol%, saponification may be insufficient, and even if it exceeds 140 mol%, no further effect is obtained and it is not economical.

  In the saponification reaction, it is preferable to use a mixed solvent of an aqueous organic solvent and water. Examples of the aqueous organic solvent include lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol and t-butanol, ketones such as acetone and methyl ethyl ketone, and mixtures thereof. Lower alcohols are preferred, and in particular, methanol is obtained because a copolymer of vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid having excellent binding effect and excellent resistance to mechanical shearing is obtained. Ethanol is preferred.

  The mass ratio of the aqueous organic solvent: water in the mixed solvent of the aqueous organic solvent and water is preferably 3: 7 to 8: 2, more preferably 3: 7 to 7: 3, and further preferably 4: 6 to 6: 4. preferable. When deviating from the range of 3: 7 to 8: 2, the solvent affinity of the copolymer before saponification or the solvent affinity of the copolymer after saponification is insufficient, and the saponification reaction proceeds sufficiently. You may not be able to. When the amount of the aqueous organic solvent is less than 3: 7, not only the binding power as a binder is decreased, but also the viscosity is remarkably increased during the saponification reaction, so that the vinyl ester / ethylenically unsaturated carboxylic acid is industrially used. When it is difficult to obtain a saponified ester copolymer, and the amount of the aqueous organic solvent is more than 8: 2, the water solubility of the saponified vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer is lowered, so that an electrode is obtained. When used for, the binding force after drying may be impaired. In addition, when using a water-containing cake-like copolymer as it is for a saponification reaction, the mass ratio of the said aqueous organic solvent: water shall contain the water in a water-containing cake-like copolymer.

  The temperature at which the vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer is saponified depends on the molar ratio of the monomers, but is preferably 20 to 60 ° C, more preferably 20 to 50 ° C. When saponification is carried out at a temperature lower than 20 ° C., the saponification reaction may not be completed. When the temperature exceeds 60 ° C., the inside of the reaction system may increase in viscosity and be unable to be stirred.

  The saponification reaction time varies depending on the type and amount of alkali used, but the reaction is usually completed in about several hours.

  When the saponification reaction is completed, a paste or slurry-like copolymer saponified dispersion is usually obtained. Solid liquid-liquid separation by a conventionally known method such as centrifugation or filtration, and drying the saponified liquid-containing copolymer obtained by washing well with a lower alcohol such as methanol, gives spherical single particles or spherical particles. A copolymer saponified product, that is, a copolymer of vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid can be obtained as agglomerated aggregated particles.

  The conditions for drying the saponified liquid-containing copolymer are not particularly limited, but usually it is preferably dried at a temperature of 30 to 120 ° C. under normal pressure or reduced pressure.

  The drying time is usually several hours to several tens of hours depending on the pressure and temperature during drying.

  The mass average particle diameter of the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid is preferably 1 to 200 μm, and more preferably 10 to 100 μm. If it is less than 1 μm, the binding effect is not sufficient, and if it exceeds 200 μm, the aqueous thickener becomes non-uniform and the binding effect may be reduced.

  When the liquid-containing copolymer saponified product is dried and the resulting copolymer saponified product has a mass-average particle diameter of more than 100 μm, it is pulverized by a conventionally known pulverization method such as mechanical milling. The diameter can be adjusted to 10 to 100 μm.

  In the present specification, the mass average particle diameter value of the polymer is the same as the volume average particle diameter value obtained by the laser diffraction / scattering method. That is, the volume average particle diameter value obtained by the method is used as the mass average particle diameter value.

  Mechanical milling is a method of applying external forces such as impact, tension, friction, compression, and shear to the saponified copolymer, and its equipment includes rolling mills, vibration mills, planetary mills, rocking Examples include a mill, a horizontal mill, an attritor mill, a jet mill, a grinder, a homogenizer, a fluidizer, a paint shaker, a mixer, and the like. For example, a planetary mill is one in which a copolymer saponified powder is pulverized or mixed by mechanical energy generated by putting a copolymer saponified product and a ball together in a container and causing rotation and revolution. According to this method, it is known that the material is pulverized to the nano order.

  A copolymer of vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid can function as a binder for a negative electrode of a non-aqueous electrolyte secondary battery having excellent binding power and binding durability. The reason is that the copolymer of the vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid strongly binds the current collector, the negative electrode active material, and the active material, and results from repeated charge and discharge. The capacity of the negative electrode active material is reduced by having a binding durability that prevents the negative electrode mixture from being peeled off from the current collector due to the volume change of the negative electrode active material or the negative electrode active material from dropping off. It is thought that this is because there is not.

  Another aqueous binder may be further added as a binder to the nonaqueous electrolyte secondary battery electrode mixture of the present embodiment. In this case, the amount of the other aqueous binder added is less than 80% by mass based on the total mass of the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid and the other aqueous binder. It is preferable that More preferably, it is less than 70% by mass. That is, in other words, the content ratio of the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid in the binder is preferably 20% by mass or more and 100% by mass or less. Preferably, it is 30 mass% or more and 100 mass% or less.

  Examples of other water-based binder materials include carboxymethylcellulose (CMC), polyacrylic acid, sodium polyacrylate, acrylic resin such as polyacrylate, sodium alginate, polyimide (PI), polytetrafluoroethylene ( Materials such as PTFE), polyamide, polyamideimide, styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), ethylene acetate copolymer (EVA) may be used alone or in combination of two or more. .

  Of the other aqueous binders, acrylic resins typified by sodium polyacrylate, sodium alginate, and polyimide are preferably used, and acrylic resins are particularly preferably used.

(Defoamer)
As the antifoaming agent, a silicone-based antifoaming agent and a surfactant-based antifoaming agent can be preferably used. These antifoaming agents can be used alone or in admixture of two or more. That is, at least one selected from the group consisting of silicone-based and surfactant-based antifoaming agents can be preferably used. Further, the shape of the antifoaming agent is not particularly limited, and any type such as an oil type, a compound type, an emulsion type, and a powder type can be used.

  Examples of the silicone surfactant include side chain modified polydimethylsiloxane, both end modified polydimethylsiloxane, one end modified polydimethylsiloxane, and side chain / both end modified polydimethylsiloxane.

  Examples of the surfactant-based antifoaming agent include polyoxyethylene alkyl ether, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, Polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester , Fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester Ter, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, polyoxyethylene alkylamide, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine, alkylamine oxide, acetylene glycol, ethoxylated acetylene glycol, acetylene alcohol, etc. Nonionic surfactant: Cationic surfactant such as aliphatic amine salt, aliphatic quaternary ammonium salt, benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt: polyoxyethylene alkyl ether acetic acid Salt, dodecylbenzenesulfonate, laurate, salt of polyoxyethylene alkyl ether sulfate, aliphatic acid soap, N-acyl-N-methylglycine salt, N-acyl- -Methyl-β-alanine salt, N-acyl glutamate, acylated peptide, alkyl sulfonate, alkyl bezene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acyl-methyl taurine, sulfonated oil, higher alcohol sulfate salt, secondary higher alcohol sulfate salt, alkyl ether sulfate, secondary higher alcohol ethoxy sulfate, polyoxyethylene alkylphenyl ether sulfate, mono Anionic surfactants such as glycolate, aliphatic acid alkylolamide sulfate salt, alkyl ether phosphate salt and alkyl phosphate salt: carboxybetaine type, sulfobetaine tie , And amphoteric surfactants such as amino acid salt and imidazolium betaine.

  The antifoaming agent may be synthesized or a commercially available product may be used. The commercially available products are: Big Chemie Japan Co., Ltd. (eg BYK093, BYK012 etc.), Shin-Etsu Chemical Co., Ltd. (eg KS506 etc.), Toray Dow Corning Co., Ltd., San Nopco Co., Ltd., Asahi Kasei Kogyo Co., Ltd. It may be obtained from Kyoeisha Chemical Co., Ltd.

(Positive electrode active material)
As the positive electrode active material, a positive electrode active material used in this technical field can be used. For example, lithium iron phosphate (LiFePO ₄ ), lithium manganese phosphate (LiMnPO ₄ ), lithium cobalt phosphate (LiCoPO ₄ ), iron pyrophosphate (Li ₂ FeP ₂ O ₇ ), lithium cobalt oxide composite oxide (LiCoO ₂₎ ), Spinel type lithium manganate composite oxide (LiMn ₂ O ₄ ), lithium manganate composite oxide (LiMnO ₂ ), lithium nickelate composite oxide (LiNiO ₂ ), lithium niobate composite oxide (LiNbO ₂ ), ferrate lithium composite oxide (LiFeO _2), magnesium lithium composite oxide (LiMgO _2), lithium composite oxide of calcium acid (LiCaO _2), cuprate lithium composite oxide (LiCuO _2), lithium zincate complex oxide (LiZnO ₂ ), lithium molybdate Complex oxide (LiMoO ₂ ), lithium tantalate complex oxide (LiTaO ₂ ), lithium tungstate complex oxide (LiWO ₂ ), lithium-nickel-cobalt-aluminum complex oxide (LiNi _0.8 Co _0.15 Al _0.05 O ₂ ), lithium-nickel-cobalt-manganese composite oxide (LiNi _0.33 Co _0.33 Mn _0.33 O ₂ ), Li-rich nickel-cobalt-manganese composite oxide (Li _x Ni _A Co _n Mn _c O ₂ solid solution), nickel manganese oxide (LiNi _0.5 Mn _1.5 O 4), manganese oxide (MnO ₂ ), vanadium oxide, sulfur oxide, silicate oxide, etc. used. These positive electrode active materials can be used singly or in combination of two or more.

(Negative electrode active material)
As a negative electrode active material, the material normally used with a lithium ion secondary battery can be used. For example, Li, Na, C (eg, graphite), Mg, Al, Si, P, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y , Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, W, Pb, Bi, alloys using these elements, oxides, chalcogenides, halides, and the like. These negative electrode active materials can be used individually by 1 type or in combination of 2 or more types.

Among these, Li, C, Mg, Al, Si, Ti, Zn, Ge, Ag, Cu, In, Sn, from the viewpoint that the region of the discharge plateau can be observed within the range of 0 to 1 V (vs. lithium potential). And at least one element selected from the group consisting of Pb and Pb, or an alloy or oxide using these elements is preferred. Further, from the viewpoint of energy density, the element is preferably Al, Si, Zn, Ge, Ag, Sn, or the like, and the alloy is Si—Al, Al—Zn, Si—Mg, Al—Ge, Si—Ge, Each combination of Si—Ag, Zn—Sn, Ge—Ag, Ge—Sn, Ge—Sb, Ag—Sn, Ag—Ge, Sn—Sb, etc. is preferable, and examples of the oxide include SiO, SnO, and SnO _2. CuO, Li ₄ Ti ₅ O _{12 and the} like are preferable.

  Among these, it is more preferable to use a Si-based material (a material containing Si) because not only energy density but also high rate discharge characteristics can be improved.

  In addition, even if it uses 2 or more types of materials which can occlude / release these lithium reversibly, there is no problem.

(Conductive aid)
A conductive support agent will not be specifically limited if it has electroconductivity. For example, powders such as metal, carbon, conductive polymer, and conductive glass can be exemplified. Of these, from the viewpoint of electronic conductivity and lithium stability, carbon powders such as spheres, fibers, needles, and blocks are used. Is preferred. Spherical carbon powders include acetylene black (AB), ketjen black (KB), graphite, thermal black, furnace black, lamp black, channel black, roller black, disk black, soft carbon, hard carbon, graphene, amorphous carbon Etc. Examples of the fibrous carbon powder include carbon nanotubes (CNT), carbon nanofibers (for example, vapor-grown carbon fiber named VGCF which is a registered trademark), and the like. These may be used individually by 1 type, or may use 2 or more types together.

  Among carbon powders, it is preferable to use carbon nanofibers or carbon nanotubes, and vapor grown carbon fibers that are carbon nanofibers are more preferable. Since carbon nanofibers or carbon nanotubes are in the form of fibers, structurally, one carbon powder can contact two or more active materials, forming a more efficient conductive network within the electrode. Therefore, the output characteristics of the electrode can be improved.

(Preparation of mixture)
By mixing at least an active material, a conductive additive, a binder, and an antifoaming agent, an electrode mixture can be obtained. In mixing these, it is preferable to further add a medium. As the medium, for example, water or a known solvent (organic solvent) can be used. For example, a conductive additive, a binder, an antifoaming agent, and water (medium) are added to the active material and mixed to obtain an electrode mixture that is a paste slurry. In this case, the binder may be dissolved in water in advance, or the active material and the binder powder may be mixed in advance, and then water may be added and mixed.

  The amount of the active material used is not particularly limited, but is preferably about 50 to 99.4% by mass, for example, 70 to 99% by mass with respect to the total mass of the active material, the conductive additive, and the binder. More preferably, the degree is more preferably about 85 to 98% by mass.

  About the usage-amount of a conductive support agent, although it is not specifically limited, For example, about 0.1-20 mass% is preferable with respect to the total mass of an active material, a conductive support agent, and a binder, 0.5- About 10 mass% is more preferable, and about 2-5 mass% is further more preferable. If the amount of the conductive aid used is less than 0.1% by mass, it is not preferable because the conductivity of the electrode cannot be sufficiently improved. If the amount of the conductive aid used exceeds 20% by mass, the active material ratio is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery, and the surface area increases because it is smaller than the active material. When the amount of the binder to be used is increased and mixing is performed by adding water, it is difficult to uniformly disperse the carbon because it repels water, which causes the aggregation of the active material.

  When carbon nanofibers or carbon nanotubes, which are fibrous carbon, are used as the conductive aid, the amount used is not particularly limited, but for example, 5 to 100% by mass of the total conductive aid is preferable, and 30 -100 mass% is more preferable. When the amount of carbon nanofibers or carbon nanotubes used is less than 5% by mass, a sufficient conductive path is not ensured between the electrode active material and the current collector, and a sufficient conductive path cannot be formed particularly in high-speed charge / discharge. Is not preferable.

  Further, the amount of the binder used is not particularly limited. For example, the amount used is 0.5% by mass or more and 30% by mass or less with respect to the total mass of the active material, the conductive additive, and the binder. It is preferable that it is 2 mass% or more and 20 mass% or less, More preferably, it is 3 mass% or more and 12 mass% or less. This is because when the amount of the binder is too large, the proportion of the active material is relatively reduced, so that it is difficult to obtain a high capacity during charging / discharging of the battery. On the other hand, when the amount is too small, the binding force is not sufficient. It will decline.

  About the usage-amount of an antifoamer, although based also on the kind of antifoamer to be used, etc., 0.001 mass% or more 1 with respect to the total mass of an active material for electrodes, a conductive support agent, a binder, and an antifoamer It is below mass%. If the use amount of the antifoaming agent is less than 0.001% by mass, the defoaming effect is small and the foam does not disappear, which is not preferable. If the use amount of the antifoaming agent exceeds 1% by mass, there is an antifoaming effect. This is not preferable because it is considered that the battery operation is affected by a decrease in the binding strength of the electrode.

  When the medium is added and mixed, the amount of the medium to be used is not particularly limited, but for example, about 40 to 900% by mass is preferable with respect to the total mass of the active material, the conductive additive and the binder. . In particular, when the medium is water, it is not preferable that the amount of water is less than 40% by mass because the viscosity of the prepared slurry becomes high, and the active material, conductive additive, and binder cannot be uniformly dispersed. Also, if the amount of water exceeds 900% by mass, the proportion of water is too high, and when carbon-based conductive assistants are used, carbon repels water, making it difficult to uniformly disperse and possibly causing active material aggregation. This is not preferable because the property is increased.

  In addition, when the active material is a powder that is coated with carbon, or when a carbon-based conductive additive is used, the carbon repels water when preparing a mixture of an aqueous slurry. It is difficult to uniformly disperse, and the possibility of causing aggregation of the active material tends to increase. In that case, it can be solved by adding a surfactant to the slurry.

  Surfactants at that time include saponins, phospholipids, peptides, octyl glucoside, sodium dodecyl sulfate, polyoxylen sorbitan monolaurate, polyoxylen sorbitan monooleate, alkylallyl polyoxyethylene ether, polysorbate, deoxycholate, triton, etc. What is necessary is just to add about 0.01-0.1 mass% with respect to the mixture whole quantity.

  In addition, any amount of thickener, preservative, etc. may be added.

<Electrode>
The electrode can be produced using a technique used in this technical field. For example, it can be produced by providing the above-mentioned mixture for non-aqueous electrolyte secondary battery electrodes on a current collector. More specifically, for example, the electrode mixture can be produced by coating (and drying if necessary) on the current collector. Furthermore, the coating film of the mixture may be tightly bonded to the current collector by a press machine (for example, a roll press machine). In this case, it can also be said that the electrode includes the mixture layer (a layer containing the mixture) on the current collector. Moreover, when the said mixture layer is a coating film, it can also be said that the said mixture coating film is provided.

In addition, although it does not specifically limit, About 5-20 mg / cm < ² > is preferable about the amount of active materials in the said mixture layer. Moreover, the density of the mixture layer is preferably about 1 to ³ g / cm ³ .

The current collector of the positive electrode is not particularly limited as long as it is a material that has electronic conductivity and can conduct electricity to the held positive electrode material. For example, conductive materials such as C, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, and Al, and alloys containing two or more of these conductive materials (for example, stainless steel ) Can be used. From the viewpoint of high electrical conductivity and good stability in the electrolyte and oxidation resistance, the current collector is preferably C, Al, stainless steel or the like, and more preferably Al from the viewpoint of material cost.

Although there is no restriction | limiting in particular in the shape of an electrical power collector, A foil-like base material, a three-dimensional base material, etc. can be used. In particular, when a three-dimensional base material (foamed metal, mesh, woven fabric, non-woven fabric, expanded, etc.) is used, an electrode with a high capacity density can be obtained even with a binder that lacks adhesion to the current collector. In addition, the high rate charge / discharge characteristics of the battery are also improved.

  The current collector of the negative electrode is not particularly limited as long as it is a material that has electronic conductivity and can conduct electricity to the held negative electrode material. For example, conductive materials such as C, Cu, Ni, Fe, V, Nb, Ti, Cr, Mo, Ru, Rh, Ta, W, Os, Ir, Pt, Au, AI, and two kinds of these conductive materials An alloy containing the above (for example, stainless steel) or the like can be used. Or what plated Cu to Fe etc. may be sufficient. As a current collector from the viewpoint of high electrical conductivity, good stability in the electrolyte and good oxidation resistance. Cu, Ni, stainless steel and the like are preferable, and Cu and Ni are more preferable from the viewpoint of material cost.

  Although there is no restriction | limiting in particular in the shape of an electrical power collector, A foil-like base material, a three-dimensional base material, etc. can be used. In particular, when a three-dimensional base material (foamed metal, mesh, woven fabric, non-woven fabric, expanded base material, etc.) is used, even a binder that lacks adhesion to the current collector has a high capacity density. An electrode is obtained. In addition, the high rate charge / discharge characteristics of the battery are also improved.

<Battery>
A nonaqueous electrolyte secondary battery can be produced using the nonaqueous electrolyte secondary battery electrode (positive electrode and / or negative electrode) of the present embodiment. A non-aqueous electrolyte secondary battery provided with this non-aqueous electrolyte secondary battery electrode (positive electrode and / or negative electrode) is also included in the present invention (that is, an embodiment of the present invention).

  Among the nonaqueous electrolyte secondary batteries of the present embodiment, the lithium ion secondary battery needs to contain lithium ions, and therefore, the electrolyte salt is preferably a lithium salt. The lithium salt is not particularly limited, and specific examples include lithium hexafluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium trifluoromethanesulfonate, and lithium trifluoromethanesulfonate. . These lithium salts can be used singly or in combination of two or more. Since the above lithium salt has high electronegativity and is easily ionized, it has excellent charge / discharge cycle characteristics and can improve the charge / discharge capacity of the secondary battery.

  Examples of the solvent for the electrolyte include propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and γ-butyrolactone, and these solvents can be used alone or in combination of two or more. In particular, propylene carbonate alone, a mixture of ethylene carbonate and diethyl carbonate, or γ-butyrolactone alone is suitable. In addition, the mixing ratio of the mixture of ethylene carbonate and diethyl carbonate can be arbitrarily adjusted in a range where one component is 10% by volume or more and 90% by volume or less.

  Moreover, the electrolyte of the lithium ion secondary battery of this embodiment may be a solid electrolyte or an ionic liquid.

  According to the lithium ion secondary battery having the above-described structure, it can function as a lithium ion secondary battery having excellent life characteristics.

  Although it does not specifically limit as a structure of a lithium ion secondary battery, It can apply to the existing battery forms and structures, such as a laminated type battery and a wound type battery.

<Electrical equipment>
The non-aqueous electrolyte secondary battery of this embodiment (particularly, the non-aqueous electrolyte secondary battery provided with the negative electrode of this embodiment) has excellent life characteristics, and various electrical devices (including vehicles that use electricity). Can be used as a power source.

  Examples of electrical equipment include portable TVs, notebook computers, tablets, smartphones, computer keyboards, computer displays, desktop computers, CRT monitors, computer racks, printers, integrated computers, wearable computers, word processors, mice, hard disks, computers Peripheral equipment, iron, cooling equipment, refrigerator, hot air heater, hot carpet, clothes dryer, futon dryer, humidifier, dehumidifier, window fan, blower, ventilation fan, toilet seat with cleaning function, car navigation system, flashlight, lighting equipment , Portable karaoke machine, microphone, air purifier, blood pressure monitor, coffee mill, coffee maker, kotatsu, mobile phone, game machine, music recorder, music player, disc changer, radio, shaver, juicer, shi Redder, water purifier, dish dryer, car component, stereo, speaker, headphones, walkie-talkie, trouser press, vacuum cleaner, body fat scale, weight scale, health meter, movie player, electric kettle, electric shaver, table lamp, electric kettle, Electronic game machines, portable game machines, electronic dictionaries, electronic notebooks, electromagnetic cookers, calculators, electric carts, electric wheelchairs, electric tools, electric toothbrushes, bean jam, haircut devices, telephones, clocks, intercoms, electric shock insecticides, hot plates , Toaster, dryer, electric drill, water heater, panel heater, pulverizer, soldering iron, video camera, facsimile, food processor, massage machine, miniature light bulb, mixer, sewing machine, mochi machine, remote control, water heater, air cooler, Bubbler, electronic musical instrument, motorcycle, toys, lawn mower , Float, bicycle, motor vehicles, hybrid vehicles, plug-in hybrid vehicles, electric vehicles, rail, ship, airplane, such as an emergency storage battery, and the like.

  Hereinafter, the present embodiment will be described more specifically by way of examples. However, the present invention is not limited to these examples.

<Preparation of binder>
(Production Example 1) Synthesis of vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer In a reaction tank having a capacity of 2 L equipped with a stirrer, thermometer, N ₂ gas introduction pipe, reflux condenser, and dropping funnel, 768 g of water Then, 12 g of anhydrous sodium sulfate was charged, and N2 gas was blown to deoxygenate the system. Subsequently, 1 g of partially saponified polyvinyl alcohol (saponification degree 88%) and 1 g of lauryl peroxide were charged and the temperature was raised to 60 ° C., followed by methyl acrylate 104 g (1.209 mol) and vinyl acetate 155 g (1.802 mol). The monomer was appropriately reduced with a dropping funnel over 4 hours, and was then held at an internal temperature of 65 ° C. for 2 hours to complete the reaction (the molar ratio of methyl acrylate and vinyl acetate used was about 6: 4). Then, 288 g (containing 10.4% water) of vinyl acetate / methyl acrylate copolymer was obtained by filtering the solid content. After the obtained polymer was dissolved in DMF, filtration was performed with a membrane filter (ADVANTEC: pore size 0.45 μm), and a molecular weight measurement apparatus (Waters 2695, manufactured by Shodex) was equipped with a GFC column (Shodex OHpak). The number average molecular weight determined by the RI detector 2414) was 188,000.

(Production Example 2) Synthesis of vinyl ester / ethylenically unsaturated carboxylic acid ester copolymer saponified product In the same reaction vessel as described above, 450 g of methanol, 420 g of water, 132 g (3.3 mol) of sodium hydroxide and obtained in Production Example 1 288 g (10.4% water content) of the obtained water-containing copolymer was charged, and a saponification reaction was performed with stirring at 30 ° C. for 3 hours. After completion of the saponification reaction, the obtained copolymer saponified product was washed with methanol, filtered, dried at 70 ° C. for 6 hours, and saponified vinyl acetate / methyl acrylate copolymer (a mixture of vinyl alcohol and sodium acrylate). 193 g of a copolymer was obtained. The saponified vinyl acetate / methyl acrylate copolymer (copolymer of vinyl alcohol and sodium acrylate) had a mass average particle diameter of 180 μm. In addition, the said average particle diameter is the value which measured with the laser diffraction type particle size distribution measuring apparatus (SALD-7100 by Shimadzu Corporation Corp.), and read the obtained volume average particle diameter into the mass average particle diameter.

(Production Example 3) Grinding of Copolymer of Vinyl Alcohol and Sodium Acrylate 193 g of the above copolymer of vinyl alcohol and sodium acrylate was crushed by a jet mill (LJ manufactured by Nippon Pneumatic Engineering Co., Ltd.) A 173 g copolymer of finely powdered vinyl alcohol and sodium acrylate was obtained. The particle size of the obtained copolymer was measured with a laser diffraction particle size distribution analyzer (SALD-7100, manufactured by Shimadzu Corporation), and the obtained volume average particle size was read as mass average particle size. The mass average particle diameter was 39 μm. The viscosity of a 1% by mass aqueous solution of the obtained copolymer was 1,630 mPa · s, and the copolymer composition ratio of vinyl alcohol and sodium acrylate was about 6: 4 in molar ratio.

<Defoaming effect test>
(Test Example 1)
1.0 part by mass of a copolymer of vinyl alcohol and sodium acrylate obtained in Production Example 3, 20 parts by mass of water, 0.03 part by mass of a silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) A binder solution was prepared by mixing.

(Test Example 2)
In Test Example 1, 0.225 parts by mass of a silicone-based antifoaming agent (KS506: manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 0.03 parts by mass of the silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.). A binder solution was prepared in the same manner as in Test Example 1 except that.

(Test Example 3)
Instead of 0.03 part by mass of the silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) in Test Example 1, 0.001 part by mass of the surfactant-based antifoaming agent (BYK012: manufactured by Big Chemy Japan Co., Ltd.) A binder solution was prepared in the same manner as in Test Example 1 except that was used.

(Test Example 4)
A binder solution was prepared in the same manner as in Test Example 1 except that no antifoaming agent was added in Test Example 1.

(1) Bubbling test of binder solution 20 ml of the binder solution prepared in Test Examples 1 to 4 is put into a 50 ml graduated cylinder, nitrogen gas (100 ml / min) is blown into the blow tube for 10 minutes, and foam after 5 minutes. The volume of was measured.

  The evaluation results are shown in Table 1.

From the said binder solution foaming test, the defoaming effect was able to be confirmed with the binder solution containing the antifoamer. Moreover, it turned out that a silicone type and surfactant type antifoamer has an antifoaming effect.

<Electrode production>
Example 1
Preparation of positive electrode mixture 94 parts by mass of LiFePO ₄ (manufactured by Sumitomo Osaka Cement Co., Ltd.) as a positive electrode active material, 4.0 mass of a copolymer of vinyl alcohol and sodium acrylate obtained in Production Example 3 as a binder Parts, carbon nanotubes (VGCF: Showa Denko Co., Ltd.) 1.0 parts by mass and Ketjen Black (ECP-300JD: Lion Specialty Chemicals Co., Ltd.) 1.0 parts by mass, water 120 parts by mass And 0.12 parts by mass of a silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) were mixed to prepare a slurry-like positive electrode mixture.

Preparation of test positive electrode After coating and drying the above mixture on an aluminum foil having a thickness of 20 μm, the aluminum foil and the coating film are closely bonded to each other by a roll press machine (manufactured by Ono Roll Co., Ltd.), followed by heat treatment. (Under reduced pressure, 140 ° C., 12 hours) to prepare a test positive electrode. The applied amount of the positive electrode active material in the produced electrode was 17.5 mg / cm ² , and the density of the coating film was 1.8 g / cm ³ . The coating amount of the active material was calculated from the active material content ratio in the coating weight per unit coating area, and the coating film density was calculated by {coating weight / (coating area × coating film thickness)}. The same applies to the following.

(Example 2)
In Example 1, 0.90 parts by mass of a silicone-based antifoaming agent (KS506: manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of 0.12 parts by mass of the silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.). Except for the above, a test positive electrode was produced and evaluated in the same manner as in Example 1.

(Example 3)
In Example 1, instead of 0.12 parts by mass of a silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.), 0.0050 parts by mass of a surfactant-based antifoaming agent (BYK012: manufactured by Big Chemy Japan Co., Ltd.) A test positive electrode was prepared and evaluated in the same manner as in Example 1 except that it was used.

(Comparative Example 1)
A test positive electrode was prepared and evaluated in the same manner as in Example 1 except that the amount of the silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) was changed to 2.0 parts by mass in Example 1.

(Comparative Example 2)
A test positive electrode was prepared and evaluated in the same manner as in Example 1 except that a positive electrode mixture was prepared without adding an antifoaming agent and centrifugal defoaming was performed.

Example 4
Preparation of a negative electrode mixture 97.5 parts by mass of artificial graphite (MAG-D: manufactured by Hitachi Chemical Co., Ltd.) as a negative electrode active material, and a combination of vinyl alcohol and sodium acrylate obtained in Production Example 3 as a binder 2 parts by mass of polymer, 0.50 parts by mass of acetylene black (AB: Denka Co., Ltd.) as a conductive assistant, 82 parts by mass of water, 0.12 mass of silicone antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) Parts were mixed to prepare a slurry-like negative electrode mixture.

Preparation of negative electrode for test After coating and drying the above mixture on a copper foil having a thickness of 10 μm, the copper foil and the coating film were closely bonded with a roll press machine (manufactured by Ono Roll Co., Ltd.), and then heat-treated. (Under reduced pressure at 140 ° C. for 12 hours) to prepare a test negative electrode. In addition, the application quantity of the negative electrode active material in the produced electrode was 8.0 mg / cm < ² >, and the density was 1.5 g / cm < ³ >.

(Comparative Example 3)
A negative electrode for testing was prepared and evaluated in the same manner as in Example 4 except that the amount of the silicone-based antifoaming agent (BYK093: manufactured by Big Chemie Japan Co., Ltd.) was changed to 2.0 parts by mass in Example 4.

(Comparative Example 4)
A negative electrode for testing was prepared and evaluated in the same manner as in Example 4 except that a negative electrode mixture was prepared without adding an antifoaming agent and centrifugal defoaming was performed.

  The positive electrodes and negative electrodes according to Examples 1 to 4 and Comparative Examples 1 to 4 are summarized in Table 2.

<Production of battery>
(Example 5)
Using the test positive electrode obtained in Example 1 and the test negative electrode obtained in Example 4, a glass filter (GA-100: manufactured by Advantech) as a separator, and ethylene carbonate (EC) and diethyl carbonate ( DEC) in a solvent mixed with a volume ratio of 1: 1, LiPF6 was dissolved at a concentration of 1 mol / L, and a coin cell (CR2032) including a solution in which 1% by mass of the additive vinylene carbonate (VC) for electrolyte was added. Produced.

(Example 6)
In Example 5, a coin cell was produced in the same manner as in Example 5 except that the test positive electrode was changed to the positive electrode obtained in Comparative Example 2.

(Example 7)
A coin cell was produced in the same manner as in Example 5 except that the test negative electrode was changed to the negative electrode obtained in Comparative Example 4 in Example 5.

(Example 8)
A coin cell was produced in the same manner as in Example 7 except that the test positive electrode was changed to the positive electrode obtained in Example 2 in Example 7.

Example 9
A coin cell was produced in the same manner as in Example 7 except that the test positive electrode was changed to the positive electrode obtained in Example 3 in Example 7.

(Comparative Example 5)
A coin cell was prepared in the same manner as in Example 5 except that the test positive electrode was changed to the positive electrode obtained in Comparative Example 1 and the test negative electrode was changed to the negative electrode obtained in Comparative Example 3.

(Comparative Example 6)
A coin cell was prepared in the same manner as in Example 5 except that the test positive electrode was changed to the positive electrode obtained in Comparative Example 2 and the test negative electrode was changed to the negative electrode obtained in Comparative Example 4.

  The produced electrode combinations are summarized in Table 3 below.

(2) Cycle test The coin cells produced in Examples 5 to 9 and Comparative Examples 5 and 6 were subjected to 10 cycles of aging treatment at 0.1 C in an environment of 30 ° C.

  Thereafter, a cycle test was performed in an environment of 30 ° C., respectively. The cycle test was performed under the condition of charging and discharging at 0.5 C to 0.5 C with a rest time of 1 minute between charging and discharging. The cut-off potential was set to 4.0-2.5V. The discharge capacity after one cycle was set to 100%, and the capacity retention rate at 100, 500, and 1000 cycles was calculated using the following formula.

Capacity retention rate (%) = (discharge capacity at each cycle × 100) / 1-cycle discharge capacity

The evaluation results are summarized in Table 4 below.

  From the results of the cycle test, the batteries of Examples 5 to 9 to which an appropriate amount of antifoaming agent was added had a capacity retention rate equal to or higher than that of the battery of Comparative Example 6 to which no antifoaming agent was added. When an appropriate amount of foaming agent is added, it is considered that there is no effect on battery operation. In addition, although not intended to be limited interpretation, it was possible to suppress the cycle deterioration slightly by the addition of the antifoaming agent, because the foam in the mixture slurry disappeared, the uniformity of the electrode increased, It is presumed that a good conductive path was formed and deterioration in a long-term cycle was suppressed. As for Comparative Example 5 having a large amount of antifoaming agent, the deterioration was severe and the device did not operate before 100 cycles. The reason for this is not intended to be a limited interpretation, but because the amount of antifoaming agent added is large, the binding between the active material and the current collector foil decreases, and the active material is collected during the cycle. It is presumed that it peeled off from the body and eventually stopped working.

  In addition, a battery including the electrode included in the present invention in both the positive electrode and the negative electrode (battery of Example 5) is a battery including an electrode prepared by defoaming by centrifugal defoaming (battery of Comparative Example 6). Compared with, the dose maintenance rate was significantly improved. In other words, an electrode produced by adding a defoaming agent and defoaming may be more suitable for battery production from the viewpoint of battery capacity retention than an electrode produced by defoaming without adding an antifoaming agent. all right.

Claims (7)

Contains an active material for electrodes, a conductive additive, a binder, and an antifoaming agent,
The binder includes a copolymer of vinyl alcohol and an alkali metal neutralized ethylenically unsaturated carboxylic acid,
The content of the antifoaming agent is 0.001% by mass or more and 1% by mass or less based on the total mass of the electrode active material, the conductive additive, the binder, and the antifoaming agent.
Nonaqueous electrolyte secondary battery electrode mixture.   2. The nonaqueous electrolyte secondary battery electrode mixture according to claim 1, wherein the antifoaming agent is at least one selected from the group consisting of a silicone antifoaming agent and a surfactant antifoaming agent.   3. The non-aqueous solution according to claim 1, wherein in the copolymer of vinyl alcohol and the alkali metal neutralized ethylenically unsaturated carboxylic acid, the copolymer composition ratio is 95: 5 to 5:95 in molar ratio. Electrolyte secondary battery electrode mixture.   The non-aqueous electrolyte 2 according to any one of claims 1 to 3, wherein the ethylenically unsaturated carboxylic acid alkali metal neutralized product is an alkali metal acrylate neutralized product or an alkali metal methacrylic acid alkali metal neutralized product. Secondary battery electrode mixture.   The electrode for nonaqueous electrolyte secondary batteries provided with the mixture for nonaqueous electrolyte secondary battery electrodes of any one of Claim 1 to 4 on the electrical power collector.   A nonaqueous electrolyte secondary battery comprising the electrode for a nonaqueous electrolyte secondary battery according to claim 5.   An electric device comprising the nonaqueous electrolyte secondary battery according to claim 6.