WO2014021401A1 - Slurry composition for lithium ion secondary battery electrodes, electrode for lithium ion secondary batteries, and lithium ion secondary battery - Google Patents
Slurry composition for lithium ion secondary battery electrodes, electrode for lithium ion secondary batteries, and lithium ion secondary battery Download PDFInfo
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- WO2014021401A1 WO2014021401A1 PCT/JP2013/070811 JP2013070811W WO2014021401A1 WO 2014021401 A1 WO2014021401 A1 WO 2014021401A1 JP 2013070811 W JP2013070811 W JP 2013070811W WO 2014021401 A1 WO2014021401 A1 WO 2014021401A1
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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
- 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
- H01M4/137—Electrodes based on electro-active 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
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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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 slurry composition for a lithium ion secondary battery electrode, an electrode for a lithium ion secondary battery, and a lithium ion secondary battery.
- Lithium ion secondary batteries are frequently used as secondary batteries used as power sources for these portable terminals.
- Mobile terminals are required to have more comfortable portability, and are rapidly becoming smaller, thinner, lighter, and higher performance. As a result, mobile terminals are used in various places.
- secondary batteries are also required to be smaller, thinner, lighter, and have higher performance as with mobile terminals.
- the electrode is usually obtained by mixing an electrode active material and, if necessary, a conductive material such as conductive carbon in a solvent to obtain a slurry composition, applying the slurry composition to a current collector, and drying. Manufactured.
- high temperature cycle characteristics high temperature cycle characteristics
- low temperature output characteristics low temperature characteristics
- Improvement is required.
- the electrode since the electrode is manufactured using the slurry composition as described above, it is considered that the properties of the slurry composition affect the performance of the lithium ion secondary battery. Therefore, development of a technology capable of improving the performance of the lithium ion secondary battery by controlling the properties of the slurry composition is required.
- the present invention was devised in view of the above problems, and a slurry composition for a lithium ion secondary battery capable of realizing a lithium ion secondary battery excellent in high temperature cycle characteristics and low temperature characteristics, and lithium ion using the same It aims at providing the electrode for secondary batteries, and a lithium ion secondary battery.
- a slurry composition for a lithium ion secondary battery containing water has a predetermined amount of a hydroxyl group-containing monomer unit, a fluorine-containing (meth) acrylate ester monomer unit, and an acid. It has been found that by including a water-soluble polymer containing a group-containing monomer unit, the high-temperature cycle characteristics and low-temperature characteristics of a lithium ion secondary battery can be improved, and the present invention has been completed. That is, the present invention is as follows.
- the water-soluble polymer comprises a lithium ion secondary containing 0.5% to 10% by weight of a hydroxyl group-containing monomer unit, a fluorine-containing (meth) acrylate monomer unit and an acid group-containing monomer unit.
- a slurry composition for battery electrodes [2] The slurry composition according to [1], wherein the water-soluble polymer has a 1% by weight aqueous solution viscosity of 10 mPa ⁇ s to 1000 mPa ⁇ s.
- the slurry composition according to [8], wherein the particulate binder is an acrylic soft polymer or a diene soft polymer.
- the slurry composition for lithium ion secondary batteries which can implement
- (meth) acrylic acid means acrylic acid and methacrylic acid.
- (meth) acrylate means an acrylate and a methacrylate.
- (meth) acrylonitrile means acrylonitrile and methacrylonitrile.
- a certain substance is water-soluble means that an insoluble content is less than 0.5% by weight when 0.5 g of the substance is dissolved in 100 g of water at 25 ° C. Further, that a certain substance is water-insoluble means that an insoluble content is 90% by weight or more when 0.5 g of the substance is dissolved in 100 g of water at 25 ° C.
- the slurry composition of this invention is a slurry composition for lithium ion secondary battery electrodes, Comprising: An electrode active material, a water-soluble polymer, and water are included. Moreover, it is preferable that the slurry composition of this invention contains a particulate-form binder.
- Electrode active material As the electrode active material for the positive electrode (hereinafter sometimes referred to as “positive electrode active material” as appropriate), a material capable of inserting and desorbing lithium ions is usually used. Such positive electrode active materials are roughly classified into those made of inorganic compounds and those made of organic compounds.
- Examples of the positive electrode active material made of an inorganic compound include transition metal oxides, transition metal sulfides, lithium-containing composite metal oxides of lithium and transition metals, and the like.
- Examples of the transition metal include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Mo.
- transition metal oxide examples include MnO, MnO 2 , V 2 O 5 , V 6 O 13 , TiO 2 , Cu 2 V 2 O 3 , amorphous V 2 O—P 2 O 5 , MoO 3 , V 2 O 5 , V 6 O 13 and the like can be mentioned.
- MnO, V 2 O 5 , V 6 O 13 and TiO 2 are preferable from the viewpoint of cycle stability and capacity.
- transition metal sulfide examples include TiS 2 , TiS 3 , amorphous MoS 2 , FeS, and the like.
- lithium-containing composite metal oxide examples include a lithium-containing composite metal oxide having a layered structure, a lithium-containing composite metal oxide having a spinel structure, and a lithium-containing composite metal oxide having an olivine structure.
- lithium-containing composite metal oxide having a layered structure examples include lithium-containing cobalt oxide (LiCoO 2 ), lithium-containing nickel oxide (LiNiO 2 ), lithium composite oxide of Co—Ni—Mn, Ni—Mn— Examples thereof include lithium composite oxides of Al and lithium composite oxides of Ni—Co—Al.
- lithium-containing composite metal oxide having a spinel structure examples include lithium manganate (LiMn 2 O 4 ) or Li [Mn 3/2 M] in which a part of Mn of lithium manganate is substituted with another transition metal. 1/2 ] O 4 (where M is Cr, Fe, Co, Ni, Cu, etc.).
- lithium-containing composite metal oxide having an olivine type structure examples include Li X MPO 4 (wherein M is Mn, Fe, Co, Ni, Cu, Mg, Zn, V, Ca, Sr, Ba, Ti).
- Examples of the positive electrode active material made of an organic compound include conductive polymer compounds such as polyacetylene and poly-p-phenylene.
- the positive electrode active material which consists of a composite material which combined the inorganic compound and the organic compound.
- a composite material covered with a carbon material may be produced by reducing and firing an iron-based oxide in the presence of a carbon source material, and the composite material may be used as a positive electrode active material.
- Iron-based oxides tend to have poor electrical conductivity, but can be used as a high-performance positive electrode active material by using a composite material as described above.
- positive electrode active material what carried out the element substitution of the said compound partially.
- mixture of said inorganic compound and organic compound as a positive electrode active material.
- positive electrode active material one type may be used alone, or two or more types may be used in combination at any ratio.
- the volume average particle diameter of the positive electrode active material particles is preferably 1 ⁇ m or more, more preferably 2 ⁇ m or more, preferably 50 ⁇ m or less, more preferably 30 ⁇ m or less.
- the amount of the positive electrode active material is a ratio of the positive electrode active material in the electrode active material layer, and is preferably 90% by weight or more, more preferably 95% by weight or more, preferably 99.9% by weight or less, more preferably 99% by weight. % Or less.
- an electrode active material for a negative electrode is a substance that transfers electrons in the negative electrode.
- a material that can occlude and release lithium ions is usually used.
- An example of a suitable negative electrode active material is carbon. Examples of carbon include natural graphite, artificial graphite, and carbon black. Among these, natural graphite is preferably used.
- the negative electrode active material it is preferable to use a negative electrode active material containing at least one selected from the group consisting of tin, silicon, germanium and lead. This is because a negative electrode active material containing these elements has a small irreversible capacity. Among these, a negative electrode active material containing silicon is preferable. By using a negative electrode active material containing silicon, the electric capacity of the lithium ion secondary battery can be increased.
- the negative electrode active material one type may be used alone, or two or more types may be used in combination at any ratio. Therefore, two or more kinds of the negative electrode active materials may be used in combination. Among these, it is preferable to use a negative electrode active material containing a combination of carbon and one or both of metallic silicon and a silicon-based active material.
- a negative electrode active material containing a combination of carbon and one or both of metallic silicon and a silicon-based active material Li insertion and desorption from one or both of metallic silicon and a silicon-based active material occurs at a high potential, It is presumed that Li insertion and desorption from carbon occur at low potential. For this reason, since expansion and contraction are suppressed, the cycle characteristics of the lithium ion secondary battery can be improved.
- silicon-based active material examples include SiO, SiO 2 , SiO x (0.01 ⁇ x ⁇ 2), SiC, SiOC, and the like, and SiO x , SiC, and SiOC are preferable.
- SiO x is a compound formed from one or both of SiO and SiO 2 and metallic silicon. This SiO x can be produced, for example, by cooling and precipitating silicon monoxide gas generated by heating a mixture of SiO 2 and metal silicon.
- the compounding method include a method of compounding one or both of metallic silicon and silicon-based active material with carbon; conductive carbon and one or both of metallic silicon and silicon-based active material The method of compounding by granulating a mixture; etc. are mentioned.
- Examples of the method for coating one or both of metallic silicon and silicon-based active material with carbon include, for example, a method in which one or both of metallic silicon and silicon-based active material are subjected to heat treatment, and disproportionation; A method of performing chemical vapor deposition by subjecting one or both of the materials to a heat treatment; and the like.
- these methods include a method of subjecting SiO x to heat treatment in an atmosphere containing at least one or both of an organic gas and an organic vapor.
- This heat treatment is preferably 900 ° C. or more, more preferably 1000 ° C. or more, further preferably 1050 ° C. or more, particularly preferably 1100 ° C. or more, preferably 1400 ° C. or less, more preferably 1300 ° C. or less, particularly preferably 1200.
- SiO x can be disproportionated into a composite of silicon and silicon dioxide, and carbon can be chemically deposited on the surface.
- Another specific example is the following method. That is, one or both of metallic silicon and silicon-based active material is heat-treated in an inert gas atmosphere to disproportionate to obtain a silicon composite. This heat treatment is preferably performed at 900 ° C. or higher, more preferably 1000 ° C. or higher, particularly preferably 1100 ° C. or higher, and preferably 1400 ° C. or lower, more preferably 1300 ° C. or lower.
- the silicon composite thus obtained is preferably pulverized to a particle size of 0.1 ⁇ m to 50 ⁇ m.
- the pulverized silicon composite is heated at 800 ° C. to 1400 ° C. under an inert gas stream.
- the heated silicon composite is subjected to a heat treatment in an atmosphere containing at least one or both of an organic gas and an organic vapor to chemically vapor-deposit carbon on the surface.
- This heat treatment is preferably performed at 800 ° C. or higher, more preferably 900 ° C. or higher, particularly preferably 1000 ° C. or higher, preferably 1400 ° C. or lower, more preferably 1300 ° C. or lower, particularly preferably 1200 ° C. or lower.
- one or both of metal silicon and silicon-based active material is subjected to chemical vapor deposition with one or both of organic gas and organic vapor.
- This chemical vapor deposition treatment is preferably performed in a temperature range of 500 ° C. to 1200 ° C., more preferably 500 ° C. to 1000 ° C., and particularly preferably 500 ° C. to 900 ° C.
- This is heat-treated in an inert gas atmosphere to disproportionate.
- This heat treatment is preferably performed at 900 ° C. or higher, more preferably 1000 ° C. or higher, particularly preferably 1100 ° C. or higher, and preferably 1400 ° C. or lower, more preferably 1300 ° C. or lower.
- the amount of silicon atoms in the negative electrode active material is 0.1 parts by weight with respect to 100 parts by weight of the total carbon atoms. It is preferable that the amount be ⁇ 50 parts by weight. Thereby, a conductive path is formed satisfactorily and the conductivity of the negative electrode can be improved.
- a weight ratio of carbon to one or both of metallic silicon and a silicon-based active material (“carbon weight” / It is preferable that “weight of metal silicon and silicon-based active material”) be within a predetermined range. Specifically, the weight ratio is preferably 50/50 or more, more preferably 70/30 or more, preferably 97/3 or less, more preferably 90/10 or less. Thereby, the cycling characteristics of a lithium ion secondary battery can be improved.
- the negative electrode active material is preferably sized in the form of particles.
- a higher-density electrode can be formed when forming an electrode for a lithium ion secondary battery (hereinafter, also referred to as “electrode” as appropriate).
- the volume average particle diameter of the particles of the negative electrode active material is appropriately selected in consideration of other constituent requirements of the lithium ion secondary battery, and is preferably 0.1 ⁇ m or more, more preferably 1 ⁇ m or more, and particularly preferably 5 ⁇ m or more.
- the thickness is preferably 100 ⁇ m or less, more preferably 50 ⁇ m or less, and particularly preferably 20 ⁇ m or less.
- the specific surface area of the negative electrode active material is preferably 2 m 2 / g or more, more preferably 3 m 2 / g or more, particularly preferably 5 m 2 / g or more, preferably 20 m 2 / g or less, from the viewpoint of improving the output density. More preferably, it is 15 m 2 / g or less, particularly preferably 10 m 2 / g or less.
- the specific surface area of the negative electrode active material can be measured by, for example, the BET method.
- the amount of the negative electrode active material is a ratio of the negative electrode active material in the electrode active material layer, preferably 85% by weight or more, more preferably 88% by weight or more, preferably 99% by weight or less, more preferably 97% by weight or less. It is. By setting the amount of the negative electrode active material in the above range, it is possible to realize a negative electrode that exhibits flexibility and adhesion while exhibiting a high capacity.
- the water-soluble polymer usually has an action of uniformly dispersing the electrode active material in the slurry composition of the present invention. Further, the water-soluble polymer has an action of adjusting the viscosity of the slurry composition and can function as a thickener. Furthermore, the water-soluble polymer acts to bind the electrode active material and the current collector by interposing between the electrode active materials and between the electrode active material and the current collector in the electrode active material layer. Can play. In addition, the water-soluble polymer can form a stable layer that covers the electrode active material in the electrode active material layer, and can exert an action of suppressing decomposition of the electrolytic solution.
- the water-soluble polymer includes a hydroxyl group-containing monomer unit.
- a hydroxyl group-containing monomer unit is a structural unit having a structure formed by polymerizing a hydroxyl group-containing monomer.
- hydroxyl group-containing monomer examples include 2-hydroxyethyl acrylate, 2-hydroxy methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate.
- Hydroxyalkyl (meth) such as di- (ethylene glycol) maleate, di- (ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis (2-hydroxyethyl) maleate, and 2-hydroxyethyl methyl fumarate Acrylates; allyl alcohol, monoallyl ethers of polyhydric alcohols; vinyl alcohol, and the like.
- hydroxyalkyl (meth) acrylate is preferable, hydroxyalkyl acrylate is more preferable, and 2-hydroxyethyl acrylate is particularly preferable.
- a hydroxyl-containing monomer and a hydroxyl-containing monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the hydroxyl group-containing monomer does not include a monomer containing a carboxyl group.
- the proportion of the hydroxyl group-containing monomer unit in the water-soluble polymer is usually 0.5% by weight or more, preferably 1% by weight or more, more preferably 1.5% by weight or more, and usually 10% by weight or less, preferably It is 8% by weight or less, more preferably 5% by weight or less.
- the ratio of the hydroxyl group-containing monomer unit is at least the lower limit of the above range, the dispersibility of the particles such as the electrode active material and the particulate binder can be increased in the slurry composition of the present invention.
- the ratio of the hydroxyl group-containing monomer unit in the water-soluble polymer usually corresponds to the ratio (preparation ratio) of the hydroxyl group-containing monomer in all monomers of the water-soluble polymer.
- the water-soluble polymer contains a fluorine-containing (meth) acrylic acid ester monomer unit.
- the fluorine-containing (meth) acrylic acid ester monomer unit is a structural unit having a structure formed by polymerizing a fluorine-containing (meth) acrylic acid monomer.
- fluorine-containing (meth) acrylic acid ester monomer examples include monomers represented by the following formula (I).
- R 1 represents a hydrogen atom or a methyl group.
- R 2 represents a hydrocarbon group containing a fluorine atom.
- the carbon number of the hydrocarbon group is preferably 1 or more, and preferably 18 or less.
- the number of fluorine atoms contained in R 2 may be one or two or more.
- fluorine-containing (meth) acrylic acid ester monomers represented by formula (I) include (meth) acrylic acid alkyl fluoride, (meth) acrylic acid fluoride aryl, and (meth) acrylic acid fluoride.
- Aralkyl is mentioned. Of these, alkyl fluoride (meth) acrylate is preferable. Specific examples of such monomers include 2,2,2-trifluoroethyl (meth) acrylate, ⁇ - (perfluorooctyl) ethyl (meth) acrylate, 2,2, (meth) acrylic acid.
- a fluorine-containing (meth) acrylic acid ester monomer and a fluorine-containing (meth) acrylic acid ester monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. Also good.
- the proportion of the fluorine-containing (meth) acrylic acid ester monomer unit in the water-soluble polymer is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and particularly preferably 0.5% by weight or more. Yes, preferably 50% by weight or less, more preferably 45% by weight or less, and particularly preferably 40% by weight or less.
- the ratio of the fluorine-containing (meth) acrylic acid ester monomer unit is not less than the lower limit of the above range, the output characteristics such as the low-temperature characteristics of the lithium ion secondary battery can be improved.
- the cycle characteristic of a lithium ion secondary battery can be improved and battery life can be lengthened.
- the ratio of the fluorine-containing (meth) acrylate monomer units in the water-soluble polymer is usually the ratio of the fluorine-containing (meth) acrylate monomer units in all monomers of the water-soluble polymer ( It matches the charging ratio).
- the water-soluble polymer includes an acid group-containing monomer unit.
- the acid group-containing monomer unit is a structural unit having a structure formed by polymerizing an acid group-containing monomer.
- An acid group refers to a group that exhibits acidity.
- acid groups include carboxylic acid groups such as carboxyl groups and carboxylic anhydride groups, sulfonic acid groups, and phosphoric acid groups. Of these, carboxylic acid groups and sulfonic acid groups are preferred.
- Examples of the acid group-containing monomer include an ethylenically unsaturated carboxylic acid monomer, an ethylenically unsaturated sulfonic acid monomer, and an ethylenically unsaturated phosphoric acid monomer.
- Examples of the ethylenically unsaturated carboxylic acid monomer include an ethylenically unsaturated monocarboxylic acid monomer and derivatives thereof, an ethylenically unsaturated dicarboxylic acid monomer and acid anhydrides thereof, and derivatives thereof.
- Examples of ethylenically unsaturated monocarboxylic acid monomers include acrylic acid, methacrylic acid, and crotonic acid.
- Examples of derivatives of ethylenically unsaturated monocarboxylic acid monomers include 2-ethylacrylic acid, isocrotonic acid, ⁇ -acetoxyacrylic acid, ⁇ -trans-aryloxyacrylic acid, ⁇ -chloro- ⁇ -E-methoxy Examples include acrylic acid and ⁇ -diaminoacrylic acid.
- Examples of ethylenically unsaturated dicarboxylic acid monomers include maleic acid, fumaric acid, and itaconic acid.
- Examples of acid anhydrides of ethylenically unsaturated dicarboxylic acid monomers include maleic anhydride, acrylic anhydride, methyl maleic anhydride, and dimethyl maleic anhydride.
- Examples of derivatives of ethylenically unsaturated dicarboxylic acid monomers include maleic acid substituted with hydrocarbon groups such as methylmaleic acid, dimethylmaleic acid, phenylmaleic acid; chloromaleic acid, dichloromaleic acid, fluoromaleic acid And maleic esters such as methylallyl maleate, diphenyl maleate, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, fluoroalkyl maleate, and the like.
- ethylenically unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid are preferable. This is because the solubility of the obtained water-soluble polymer in water can be further increased.
- ethylenically unsaturated sulfonic acid monomers include monomers sulfonated one of conjugated double bonds of diene compounds such as isoprene and butadiene, vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, sulfone.
- diene compounds such as isoprene and butadiene
- vinyl sulfonic acid vinyl sulfonic acid
- styrene sulfonic acid styrene sulfonic acid
- allyl sulfonic acid sulfone.
- examples thereof include ethyl methacrylate, sulfopropyl methacrylate, sulfobutyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3-allyloxy-2-hydroxypropanesulfonic acid (HAPS), and salts thereof.
- the salt include lithium
- Examples of the ethylenically unsaturated phosphoric acid monomer include monomers having an ethylenically unsaturated group and a —OP ( ⁇ O) (— OR a ) —OR b group (R a and R b is independently a hydrogen atom or any organic group.) or a salt thereof.
- Specific examples of the organic group as R a and R b include an aliphatic group such as an octyl group and an aromatic group such as a phenyl group.
- Specific examples of the ethylenically unsaturated phosphoric acid monomer include a compound containing a phosphoric acid group and an allyloxy group, and a phosphoric acid group-containing (meth) acrylic acid ester.
- Examples of the compound containing a phosphoric acid group and an allyloxy group include 3-allyloxy-2-hydroxypropane phosphoric acid.
- Examples of phosphate group-containing (meth) acrylic acid esters include dioctyl-2-methacryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, monomethyl-2-methacryloyloxyethyl phosphate, dimethyl-2-methacrylate.
- ethylenically unsaturated carboxylic acid monomers and ethylenically unsaturated sulfonic acid monomers preferred are acrylic acid, methacrylic acid, itaconic acid and 2- Examples include acrylamido-2-methylpropanesulfonic acid, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is particularly preferable.
- the acid group-containing monomer and the acid group-containing monomer unit one type may be used alone, or two or more types may be used in combination at any ratio.
- the ratio of the acid group-containing monomer unit is preferably 20% by weight or more, more preferably 25% by weight or more, particularly preferably 30% by weight or more, and preferably 50% by weight or less.
- the amount is preferably 45% by weight or less, particularly preferably 40% by weight or less.
- the ratio of the acid group-containing monomer unit is at least the lower limit of the above range, the adhesion between the electrode active material layer and the current collector can be enhanced. Moreover, by being below the upper limit of the said range, the cycle characteristic of a lithium ion secondary battery can be improved and battery life can be lengthened.
- the ratio of the acid group-containing monomer unit in the water-soluble polymer usually corresponds to the ratio (preparation ratio) of the acid group-containing monomer in all the monomers of the water-soluble polymer.
- the water-soluble polymer preferably further contains a crosslinkable monomer unit.
- the crosslinkable monomer unit is a structural unit having a structure formed by polymerizing a crosslinkable monomer.
- the water-soluble polymer can be crosslinked, so that the strength and stability of the electrode active material layer can be increased.
- swelling of the electrode active material layer with respect to the electrolytic solution can be suppressed, and the low temperature characteristics of the lithium ion secondary battery can be improved.
- crosslinkable monomer a monomer capable of forming a crosslinked structure upon polymerization can be used.
- the crosslinkable monomer include monomers having two or more reactive groups per molecule. More specifically, a monofunctional monomer having a heat-crosslinkable crosslinkable group and one olefinic double bond per molecule, and a polyfunctional having two or more olefinic double bonds per molecule. Ionic monomers.
- thermally crosslinkable groups contained in the monofunctional monomer include epoxy groups, N-methylolamide groups, oxetanyl groups, oxazoline groups, and combinations thereof.
- an epoxy group is more preferable in terms of easy adjustment of crosslinking and crosslinking density.
- crosslinkable monomer having an epoxy group as a thermally crosslinkable group and having an olefinic double bond examples include vinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether, o-allylphenyl glycidyl.
- Unsaturated glycidyl ethers such as ether; butadiene monoepoxide, chloroprene monoepoxide, 4,5-epoxy-2-pentene, 3,4-epoxy-1-vinylcyclohexene, 1,2-epoxy-5,9-cyclododecadiene Monoepoxides of dienes or polyenes such as; alkenyl epoxides such as 3,4-epoxy-1-butene, 1,2-epoxy-5-hexene, 1,2-epoxy-9-decene; and glycidyl acrylate, glycidyl methacrylate, Glycidyl crotonate, glycy Unsaturated carboxylic acids such as ru-4-heptenoate, glycidyl sorbate, glycidyl linoleate, glycidyl-4-methyl-3-pentenoate, glycidy
- crosslinkable monomer having an N-methylolamide group as a thermally crosslinkable group and having an olefinic double bond have a methylol group such as N-methylol (meth) acrylamide (meta ) Acrylamides.
- crosslinkable monomer having an oxetanyl group as a thermally crosslinkable group and having an olefinic double bond examples include 3-((meth) acryloyloxymethyl) oxetane, 3-((meth) Acryloyloxymethyl) -2-trifluoromethyloxetane, 3-((meth) acryloyloxymethyl) -2-phenyloxetane, 2-((meth) acryloyloxymethyl) oxetane, and 2-((meth) acryloyloxymethyl) ) -4-trifluoromethyloxetane.
- crosslinkable monomer having an oxazoline group as a heat crosslinkable group and having an olefinic double bond examples include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2- Oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and And 2-isopropenyl-5-ethyl-2-oxazoline.
- multifunctional monomers having two or more olefinic double bonds include allyl (meth) acrylate, ethylene di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, Tetraethylene glycol di (meth) acrylate, trimethylolpropane-tri (meth) acrylate, dipropylene glycol diallyl ether, polyglycol diallyl ether, triethylene glycol divinyl ether, hydroquinone diallyl ether, tetraallyloxyethane, trimethylolpropane-diallyl
- Examples include ethers, allyl or vinyl ethers of polyfunctional alcohols other than those described above, triallylamine, methylenebisacrylamide, and divinylbenzene.
- crosslinkable monomer ethylene dimethacrylate, allyl glycidyl ether, glycidyl methacrylate and divinylbenzene are preferable, and ethylene dimethacrylate and glycidyl methacrylate are more preferable.
- crosslinked monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the crosslinkable monomer unit is preferably 0.05% by weight or more, more preferably 0.1% by weight or more, particularly preferably 0.2% by weight or more, preferably 2%. % By weight or less, more preferably 1.5% by weight or less, particularly preferably 1% by weight or less.
- the ratio of the crosslinkable monomer unit is not less than the lower limit of the above range, the cycle characteristics of the lithium ion secondary battery can be improved and the battery life can be extended.
- the adhesiveness of an electrode active material layer and a collector can be improved because it is below the upper limit of the said range.
- the ratio of the crosslinkable monomer unit in the water-soluble polymer coincides with the ratio (charge ratio) of the crosslinkable monomer in all the monomers of the water-soluble polymer.
- the water-soluble polymer has any structural unit other than the above-mentioned hydroxyl group-containing monomer unit, fluorine-containing (meth) acrylate monomer unit, acid group-containing monomer unit and crosslinkable monomer unit. May be included.
- the water-soluble polymer may contain (meth) acrylic acid ester monomer units other than the fluorine-containing (meth) acrylic acid ester monomer units.
- the (meth) acrylic acid ester monomer unit is a structural unit having a structure formed by polymerizing a (meth) acrylic acid ester monomer. However, among the (meth) acrylate monomers, those containing fluorine are distinguished from (meth) acrylate monomers as fluorine-containing (meth) acrylate monomers.
- Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, Acrylic acid alkyl esters such as 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, n-tetradecyl acrylate, stearyl acrylate; and methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, t -Butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl
- the proportion of the (meth) acrylic acid ester monomer unit is preferably 25% by weight or more, more preferably 30% by weight or more, particularly preferably 35% by weight or more, and preferably 75%. % By weight or less, more preferably 70% by weight or less, particularly preferably 65% by weight or less.
- the ratio of the (meth) acrylic acid ester monomer unit in the water-soluble polymer is usually the ratio of the (meth) acrylic acid ester monomer in all the monomers of the water-soluble polymer (preparation ratio). Match.
- the water-soluble polymer may contain a reactive surfactant unit.
- the reactive surfactant unit is a structural unit obtained by polymerizing a reactive surfactant monomer.
- the reactive surfactant unit forms part of the water-soluble polymer and can function as a surfactant.
- the reactive surfactant monomer is a monomer having a polymerizable group that can be copolymerized with other monomers and having a surfactant group (hydrophilic group and hydrophobic group).
- the reactive surfactant monomer has a polymerizable unsaturated group, and this group also acts as a hydrophobic group after polymerization.
- the polymerizable unsaturated group that the reactive surfactant monomer has include a vinyl group, an allyl group, a vinylidene group, a propenyl group, an isopropenyl group, and an isobutylidene group.
- One kind of the polymerizable unsaturated group may be used alone, or two or more kinds may be used in combination at any ratio.
- the reactive surfactant monomer usually has a hydrophilic group as a portion that exhibits hydrophilicity.
- Reactive surfactant monomers are classified into anionic, cationic and nonionic surfactants depending on the type of hydrophilic group.
- Examples of the anionic hydrophilic group include —SO 3 M, —COOM, and —PO (OM) 2 .
- M represents a hydrogen atom or a cation.
- Examples of cations include alkali metal ions such as lithium, sodium and potassium; alkaline earth metal ions such as calcium and magnesium; ammonium ions; ammonium ions of alkylamines such as monomethylamine, dimethylamine, monoethylamine and triethylamine; and And ammonium ions of alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine.
- Examples of the cationic hydrophilic group include —Cl, —Br, —I, and —SO 3 OR X.
- R X represents an alkyl group.
- Examples of R X is methyl group, an ethyl group, a propyl group, and isopropyl group.
- An example of a nonionic hydrophilic group is —OH.
- Suitable reactive surfactant monomers include compounds represented by the following formula (II).
- R represents a divalent linking group. Examples of R include —Si—O— group, methylene group and phenylene group.
- R 3 represents a hydrophilic group. An example of R 3 includes —SO 3 NH 4 .
- n represents an integer of 1 to 100.
- a suitable reactive surfactant monomer has a structural unit having a structure formed by polymerizing ethylene oxide and a structural unit having a structure formed by polymerizing butylene oxide, and Examples include compounds having an alkenyl group having a terminal double bond and —SO 3 NH 4 at the terminal (for example, trade names “Latemul PD-104” and “Latemul PD-105”, manufactured by Kao Corporation).
- a reactive surfactant monomer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the reactive surfactant unit is preferably 0.1% by weight or more, more preferably 0.2% by weight or more, particularly preferably 0.5% by weight or more, preferably 5%. % By weight or less, more preferably 4% by weight or less, particularly preferably 2% by weight or less.
- the dispersibility of the slurry composition can be improved by setting the ratio of the reactive surfactant unit to the lower limit value or more of the above range.
- durability of an electrode can be improved by setting it as below an upper limit.
- the ratio of the reactive surfactant unit in the water-soluble polymer usually coincides with the ratio (charge ratio) of the reactive surfactant monomer in all monomers of the water-soluble polymer.
- the water-soluble polymer may have include structural units having a structure formed by polymerizing the following monomers. That is, aromatic vinyl monomers such as styrene, chlorostyrene, vinyltoluene, t-butylstyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, hydroxymethylstyrene, ⁇ -methylstyrene, divinylbenzene, etc.
- aromatic vinyl monomers such as styrene, chlorostyrene, vinyltoluene, t-butylstyrene, vinylbenzoic acid, methyl vinylbenzoate, vinylnaphthalene, chloromethylstyrene, hydroxymethylstyrene, ⁇ -methylstyrene, divinylbenzene, etc.
- Unsaturated carboxylic acid amide monomers such as acrylamide; ⁇ , ⁇ -unsaturated nitrile compound monomers such as acrylonitrile and methacrylonitrile; olefin monomers such as ethylene and propylene; vinyl chloride, vinylidene chloride, etc.
- Halogen atom-containing monomers vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate; vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether; methyl vinyl ketone, ethyl Vinyl keto One or more of vinyl ketone monomers such as butyl vinyl ketone, hexyl vinyl ketone and isopropenyl vinyl ketone; and heterocyclic compound-containing vinyl compound monomers such as N-vinyl pyrrolidone, vinyl pyridine and vinyl imidazole; Examples include a structural unit having a structure to be formed.
- the viscosity of a 1% by weight aqueous solution of the water-soluble polymer is preferably 10 mPa ⁇ s or more, more preferably 20 mPa ⁇ s or more, particularly preferably 50 mPa ⁇ s or more, preferably 1000 mPa ⁇ s or less, more preferably 800 mPa ⁇ s. s or less, particularly preferably 500 mPa ⁇ s or less.
- the viscosity By setting the viscosity to be equal to or higher than the lower limit of the above range, the strength of the water-soluble polymer can be increased and the durability of the electrode can be improved.
- the coating strength of the slurry composition of this invention can be made favorable by setting it as an upper limit or less, and the adhesive strength of a collector and an electrode active material layer can be improved.
- the viscosity can be adjusted by, for example, the molecular weight of the water-soluble polymer.
- the weight average molecular weight of the water-soluble polymer is preferably 500 or more, more preferably 700 or more, particularly preferably 1000 or more, preferably 500,000 or less, more preferably 450,000 or less, and particularly preferably 400,000 or less.
- the weight average molecular weight of the water-soluble polymer is polystyrene using gel permeation chromatography (GPC) as a developing solvent, a solution obtained by dissolving 0.85 g / ml sodium nitrate in a 10% by volume aqueous solution of dimethylformamide. It can be obtained as a conversion value.
- GPC gel permeation chromatography
- the water-soluble polymer can be produced, for example, by polymerizing a monomer composition containing the above-described monomer in an aqueous solvent. At this time, the ratio of each monomer in the monomer composition is usually a structural unit in the water-soluble polymer (for example, an acidic group-containing monomer unit, a fluorine-containing (meth) acrylic acid monomer unit, The ratio of the acid group-containing monomer unit and the crosslinkable monomer unit).
- a structural unit in the water-soluble polymer for example, an acidic group-containing monomer unit, a fluorine-containing (meth) acrylic acid monomer unit, The ratio of the acid group-containing monomer unit and the crosslinkable monomer unit.
- the aqueous solvent is not particularly limited as long as the water-soluble polymer can be dispersed.
- the boiling point at normal pressure is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. Examples of the aqueous solvent will be given below. In the following examples, the number in parentheses after the solvent name is the boiling point (unit: ° C) at normal pressure, and the value after the decimal point is a value rounded off or rounded down.
- aqueous solvents examples include water (100); ketones such as diacetone alcohol (169) and ⁇ -butyrolactone (204); ethyl alcohol (78), isopropyl alcohol (82), and normal propyl alcohol (97).
- Alcohols propylene glycol monomethyl ether (120), methyl cellosolve (124), ethyl cellosolve (136), ethylene glycol tertiary butyl ether (152), butyl cellosolve (171), 3-methoxy-3-methyl-1-butanol (174), Ethylene glycol monopropyl ether (150), diethylene glycol monobutyl ether (230), triethylene glycol monobutyl ether (271), dipropylene glycol monomethyl ether (188), etc.
- Glycol ethers and 1,3-dioxolane (75), 1,4-dioxolane (101), ethers such as tetrahydrofuran (66) and the like.
- water is particularly preferable from the viewpoint that it is not flammable and a polymer dispersion can be easily obtained.
- water may be used as the main solvent, and an aqueous solvent other than the above-described water may be mixed and used within a range in which the dispersion state of the polymer can be ensured.
- the polymerization method is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, and an emulsion polymerization method can be used.
- the polymerization method any method such as ion polymerization, radical polymerization, and living radical polymerization can be used. It is easy to obtain a high molecular weight body, and since the polymer is obtained in a state of being dispersed in water as it is, no redispersion treatment is necessary, and it can be used for the production of the slurry composition of the present invention. From the viewpoint of efficiency, the emulsion polymerization method is particularly preferable.
- the emulsion polymerization method is usually performed by a conventional method. For example, it is carried out by the method described in “Experimental Chemistry Course” Vol. That is, water, an additive such as a dispersant, an emulsifier, a crosslinking agent, a polymerization initiator, and a monomer are added to a sealed container equipped with a stirrer and a heating device so as to have a predetermined composition, and the composition in the container
- a product is stirred to emulsify monomers and the like in water, and the temperature is increased while stirring to initiate polymerization.
- it is the method of putting into a sealed container and starting reaction similarly.
- polymerization initiators examples include organic compounds such as lauroyl peroxide, diisopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, t-butyl peroxypivalate, 3,3,5-trimethylhexanoyl peroxide, and the like. Peroxides; azo compounds such as ⁇ , ⁇ ′-azobisisobutyronitrile; ammonium persulfate; and potassium persulfate.
- a polymerization initiator may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- emulsifiers for example, emulsifiers, dispersants, polymerization initiators, and the like are generally used in these polymerization methods, and the amount used is generally the amount generally used.
- the polymerization temperature and polymerization time can be arbitrarily selected depending on the polymerization method and the type of polymerization initiator. Usually, the polymerization temperature is about 30 ° C. or more, and the polymerization time is about 0.5 to 30 hours. Further, additives such as amines may be used as a polymerization aid.
- a reaction solution containing a water-soluble polymer is usually obtained by polymerization.
- the obtained reaction solution is usually acidic, and the water-soluble polymer is often dispersed in an aqueous solvent.
- the water-soluble polymer dispersed in the aqueous solvent as described above can usually be made soluble in the aqueous solvent by adjusting the pH of the reaction solution to, for example, 7 to 13. You may take out a polymer from the reaction liquid obtained in this way.
- water is used as an aqueous solvent, and the slurry composition of the present invention is produced using a water-soluble polymer dissolved in water.
- Examples of the method for alkalinizing the pH to 7 to 13 include alkaline metal aqueous solutions such as lithium hydroxide aqueous solution, sodium hydroxide aqueous solution and potassium hydroxide aqueous solution; alkaline earth such as calcium hydroxide aqueous solution and magnesium hydroxide aqueous solution.
- Metal aqueous solution A method of mixing an alkaline aqueous solution such as an aqueous ammonia solution with the reaction solution.
- One kind of the alkaline aqueous solution may be used alone, or two or more kinds may be used in combination at any ratio.
- the amount of the water-soluble polymer is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, particularly preferably 0.5 parts by weight or more, preferably 100 parts by weight of the electrode active material. Is 10 parts by weight or less, more preferably 8 parts by weight or less, and particularly preferably 5 parts by weight or less. Adhesive strength can be ensured when the amount of the water-soluble polymer is not less than the lower limit of the above range. Moreover, a low temperature characteristic can be improved by being below an upper limit.
- the slurry composition of the present invention contains water.
- Water functions as a solvent or a dispersion medium, and can disperse the electrode active material or dissolve the water-soluble polymer.
- a solvent other than water may be used in combination with water.
- a liquid that can dissolve the particulate binder and the water-soluble polymer is combined with water, the dispersion of the electrode active material is stabilized by adsorbing the particulate binder and the water-soluble polymer on the surface of the electrode active material. Therefore, it is preferable.
- the type of liquid to be combined with water is preferably selected from the viewpoint of drying speed and environment.
- Preferred examples include cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; ketones such as ethyl methyl ketone and cyclohexanone; ethyl acetate, butyl acetate, ⁇ -butyrolactone, Esters such as ⁇ -caprolactone; Nitriles such as acetonitrile and propionitrile; Ethers such as tetrahydrofuran and ethylene glycol diethyl ether: Alcohols such as methanol, ethanol, isopropanol, ethylene glycol, and ethylene glycol monomethyl ether; N-methyl Examples include pyrrolidone and amides such as N, N-dimethylformamide, among which N-methylpyrrolidone (NMP) is preferable. One of these
- the amount of the solvent is preferably adjusted so that the viscosity of the slurry composition of the present invention is suitable for coating.
- the solid content concentration of the slurry composition of the present invention is preferably 30% by weight or more, more preferably 35% by weight or more, preferably 70% by weight or less, more preferably 65% by weight or less. The amount is adjusted to be used.
- the solid content of the slurry composition indicates a substance that remains as a constituent component of the electrode active material layer after the slurry composition is dried.
- the slurry composition of the present invention preferably contains a particulate binder.
- a particulate binder By including the particulate binder, the binding property of the electrode active material layer can be improved, and the strength against mechanical force applied to the electrode during handling such as winding and transportation can be improved.
- the risk of a short circuit or the like due to foreign matter is reduced.
- the electrode active material can be stably held in the electrode active material layer, durability such as cycle characteristics and high-temperature storage characteristics can be improved.
- the particulate binder can be bound to the electrode active material not by a surface but by a point by being particulate.
- the output resistance of the lithium ion secondary battery can be improved by reducing the internal resistance.
- the particulate binder various polymers can be used, but a water-insoluble polymer is usually used.
- the polymer that forms the particulate binder include polyethylene, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyacrylic acid derivatives, poly An acrylonitrile derivative or the like may be used.
- a soft polymer for example, (I) Polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer, etc.
- a soft polymer for example, (I) Polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer, etc.
- An acrylic soft polymer which is a homopolymer of acrylic acid or a methacrylic acid derivative or a copolymer thereof with a monomer copolymerizable therewith;
- isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
- the diene soft polymer is a polymer containing an aliphatic conjugated diene monomer unit.
- the aliphatic conjugated diene monomer unit is a structural unit having a structure formed by polymerizing an aliphatic conjugated diene monomer.
- Examples of the aliphatic conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3 butadiene, 2-chloro-1,3-butadiene; And pentadiene having a conjugated double bond in a chain and a substituted product thereof; and hexadiene having a conjugated double bond in a side chain and a substituted product thereof. Of these, 1,3-butadiene is preferred.
- an aliphatic conjugated diene monomer and an aliphatic conjugated diene monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the aliphatic conjugated diene monomer unit is preferably 20% by weight or more, more preferably 30% by weight or more, preferably 70% by weight or less, more preferably 60% by weight or less, Particularly preferred is 55% by weight or less.
- the ratio of the aliphatic conjugated diene monomer unit in the diene soft polymer is usually equal to the ratio (preparation ratio) of the aliphatic conjugated diene monomer in all the monomers of the diene soft polymer.
- the diene soft polymer preferably contains an aromatic vinyl monomer unit.
- the aromatic vinyl monomer unit is a structural unit having a structure formed by polymerizing an aromatic vinyl monomer.
- aromatic vinyl monomer examples include styrene, ⁇ -methylstyrene, vinyl toluene, and divinylbenzene. Of these, styrene is preferred.
- the diene soft polymer is preferably a polymer containing both an aliphatic conjugated diene monomer unit and an aromatic vinyl monomer unit. For example, a styrene-butadiene copolymer is preferable.
- an aromatic vinyl monomer and an aromatic vinyl monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the aromatic vinyl monomer unit in the diene soft polymer is preferably 30% by weight or more, more preferably 35% by weight or more, preferably 79.5% by weight or less, more preferably 69% by weight or less. is there.
- the ratio of the aromatic vinyl monomer unit in the diene soft polymer usually matches the ratio (charge ratio) of the aromatic vinyl monomer in all the monomers of the diene soft polymer.
- the diene soft polymer preferably contains an ethylenically unsaturated carboxylic acid monomer unit.
- the ethylenically unsaturated carboxylic acid monomer unit means a structural unit having a structure formed by polymerizing an ethylenically unsaturated carboxylic acid monomer. Since the ethylenically unsaturated carboxylic acid monomer unit is a structural unit containing a carboxyl group (—COOH group) and having high strength, the binding property of the electrode active material layer to the current collector can be increased, or the electrode active material The strength of the layer can be improved.
- the diene soft polymer contains an ethylenically unsaturated carboxylic acid monomer unit, peeling of the electrode active material layer from the current collector can be stably prevented, and the mechanical strength of the electrode active material layer can be prevented. Can be improved.
- Examples of the ethylenically unsaturated carboxylic acid monomer include the same examples as those exemplified in the section of the water-soluble polymer. Moreover, an ethylenically unsaturated carboxylic acid monomer and an ethylenically unsaturated carboxylic acid monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the ethylenically unsaturated carboxylic acid monomer unit in the diene soft polymer is preferably 0.5% by weight or more, more preferably 1% by weight or more, particularly preferably 2% by weight or more, preferably 10% by weight. % Or less, more preferably 8% by weight or less, and particularly preferably 7% by weight or less.
- the ratio of the ethylenically unsaturated carboxylic acid monomer unit in the diene soft polymer is usually the ratio of the ethylenically unsaturated carboxylic acid monomer in all the monomers of the diene soft polymer (preparation ratio). Match.
- the diene soft polymer may contain any structural unit other than those described above as long as the effects of the present invention are not significantly impaired.
- monomers corresponding to the above arbitrary structural units include vinyl cyanide monomers, unsaturated carboxylic acid alkyl ester monomers, unsaturated monomers containing hydroxyalkyl groups, and unsaturated carboxylic acids. Examples include acid amide monomers. One of these may be used alone, or two or more of these may be used in combination at any ratio.
- vinyl cyanide monomer examples include acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, and ⁇ -ethylacrylonitrile. Of these, acrylonitrile and methacrylonitrile are preferable.
- unsaturated carboxylic acid alkyl ester monomers include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, glycidyl methacrylate, dimethyl fumarate, diethyl fumarate, dimethyl maleate, diethyl maleate, and dimethyl itaco. Nates, monomethyl fumarate, monoethyl fumarate, and 2-ethylhexyl acrylate. Of these, methyl methacrylate is preferable.
- Examples of unsaturated monomers containing a hydroxyalkyl group include ⁇ -hydroxyethyl acrylate, ⁇ -hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2- Examples include hydroxypropyl methacrylate, di- (ethylene glycol) maleate, di- (ethylene glycol) itaconate, 2-hydroxyethyl maleate, bis (2-hydroxyethyl) maleate, and 2-hydroxyethyl methyl fumarate. Of these, ⁇ -hydroxyethyl acrylate is preferred.
- Examples of the unsaturated carboxylic acid amide monomer include acrylamide, methacrylamide, and N, N-dimethylacrylamide. Of these, acrylamide and methacrylamide are preferable.
- the diene soft polymer has a structure formed by polymerizing monomers used in usual emulsion polymerization such as ethylene, propylene, vinyl acetate, vinyl propionate, vinyl chloride, vinylidene chloride, etc. Units may be included.
- the acrylic soft polymer is a polymer containing a (meth) acrylic acid ester monomer unit.
- those containing fluorine are distinguished from (meth) acrylate monomers as fluorine-containing (meth) acrylate monomers. .
- Examples of (meth) acrylic acid ester monomers include the same examples as those exemplified in the section of the water-soluble polymer. Moreover, a (meth) acrylic acid ester monomer and a (meth) acrylic acid ester monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the (meth) acrylic acid ester monomer unit in the acrylic soft polymer is preferably 50% by weight or more, more preferably 70% by weight or more, particularly preferably 90% by weight or more, and preferably 99% by weight or less. More preferably, it is 98 weight% or less, Most preferably, it is 97 weight% or less.
- the ratio of the (meth) acrylic acid ester monomer unit in the acrylic soft polymer is usually the ratio (preparation ratio) of the (meth) acrylic acid ester monomer in all monomers of the acrylic soft polymer. Match.
- the acrylic soft polymer is preferably a copolymer containing a combination of a (meth) acrylonitrile monomer unit and a (meth) acrylic acid ester monomer unit.
- the (meth) acrylonitrile monomer unit means a structural unit having a structure formed by polymerizing (meth) acrylonitrile. Since an acrylic soft polymer containing a combination of a (meth) acrylonitrile monomer unit and a (meth) acrylic acid ester monomer unit is stable to oxidation and reduction, it is easy to obtain a battery having a long life.
- the acrylic soft polymer may contain only a structural unit having a structure formed by polymerizing acrylonitrile as a (meth) acrylonitrile monomer unit, and has a structure formed by polymerizing methacrylonitrile. It may contain only structural units, and includes both a structural unit having a structure formed by polymerizing acrylonitrile and a structural unit having a structure formed by polymerizing methacrylonitrile in an arbitrary ratio. May be.
- the weight ratio (weight ratio represented by “(meth) acrylonitrile monomer unit / (meth) acrylate monomer unit”) is preferably within a predetermined range. Specifically, the weight ratio is preferably 1/99 or more, more preferably 2/98 or more, 30/70 or less, and more preferably 25/75 or less.
- the weight ratio of (meth) acrylonitrile monomer unit to (meth) acrylic acid ester monomer unit in acrylic soft polymer is usually (meth) acrylic acid ester in all monomers of acrylic soft polymer. This corresponds to the ratio of (meth) acrylonitrile monomer to monomer.
- the acrylic soft polymer preferably contains an ethylenically unsaturated carboxylic acid monomer unit. Since the ethylenically unsaturated carboxylic acid monomer unit is a structural unit containing a carboxyl group (—COOH group) and having high strength, the binding property of the electrode active material layer to the current collector can be increased, or the electrode active material The strength of the layer can be improved. Therefore, when the acrylic soft polymer contains an ethylenically unsaturated carboxylic acid monomer unit, peeling of the electrode active material layer from the current collector can be stably prevented, and the mechanical strength of the electrode active material layer can be prevented. Can be improved.
- Examples of the ethylenically unsaturated carboxylic acid monomer include the same examples as those exemplified in the section of the water-soluble polymer. Moreover, an ethylenically unsaturated carboxylic acid monomer and an ethylenically unsaturated carboxylic acid monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the proportion of the ethylenically unsaturated carboxylic acid monomer unit in the acrylic soft polymer is preferably 0.5% by weight or more, more preferably 1% by weight or more, particularly preferably 2% by weight or more, preferably 10% by weight. % Or less, more preferably 8% by weight or less, and particularly preferably 7% by weight or less.
- the ratio of the ethylenically unsaturated carboxylic acid monomer unit in the acrylic soft polymer is usually the ratio (preparation ratio) of the ethylenically unsaturated carboxylic acid monomer in all the monomers of the acrylic soft polymer. Match.
- the acrylic soft polymer may contain a crosslinkable monomer unit.
- a crosslinkable monomer is a monomer that can form a crosslinked structure during or after polymerization by heating or irradiation with energy rays.
- the acrylic soft polymer contains a crosslinkable monomer unit, the particulate binders can be crosslinked, or the water-soluble polymer and the particulate binder can be crosslinked.
- crosslinkable monomer examples include the same examples as mentioned in the section of the water-soluble polymer.
- crosslinked monomer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the crosslinkable monomer unit may be introduced into the acrylic soft polymer by copolymerizing the crosslinkable monomer with the (meth) acrylic acid ester monomer unit.
- the crosslinkable monomer unit is introduced into the acrylic soft polymer by introducing a crosslinkable group into the acrylic soft polymer by a conventional modification means using a compound having a crosslinkable group (crosslinking agent). Also good.
- crosslinking agent for example, an organic peroxide, a crosslinking agent that exhibits an effect by heat or light, and the like are used. Moreover, a crosslinking agent may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios. Among the cross-linking agents, an organic peroxide and a cross-linking agent capable of causing a cross-linking reaction by heat are preferable because they contain a heat cross-linkable cross-linking group.
- the ratio of the crosslinkable monomer unit in the acrylic soft polymer is preferably 0.01 with respect to 100 parts by weight of the total amount of the (meth) acrylonitrile monomer unit and the (meth) acrylic acid ester monomer unit.
- Part by weight or more more preferably 0.05 part by weight or more, preferably 5 parts by weight or less, more preferably 4 parts by weight or less, and particularly preferably 3 parts by weight or less.
- the acrylic soft polymer can also include any structural unit.
- monomers corresponding to these arbitrary structural units include styrene, chlorostyrene, vinyl toluene, t-butyl styrene, vinyl benzoic acid, methyl vinyl benzoate, vinyl naphthalene, chloromethyl styrene, ⁇ -methyl.
- Aromatic vinyl monomers such as styrene and divinylbenzene; Olefin monomers such as ethylene and propylene; Diene monomers such as butadiene and isoprene; Monomers containing halogen atoms such as vinyl chloride and vinylidene chloride; Vinyl acetate Vinyl ester monomers such as vinyl propionate and vinyl butyrate; vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether and butyl vinyl ether; methyl vinyl ketone, ethyl vinyl ketone, butyl vinyl ketone, hexyl vinyl ketone and isopropenyl Such as vinyl ketone Nyl ketone monomers; N-vinyl pyrrolidone, vinyl pyridine, vinyl ring-containing vinyl compound monomers such as vinyl imidazole; Unsaturated carboxylic acid amide monomers such as acrylamide and acrylamide-2-methylpropane sulfonic acid; Can be mentioned.
- any structural unit is small from the viewpoint of remarkably exhibiting the advantages of including the (meth) acrylonitrile monomer unit and the (meth) acrylic acid ester monomer unit in combination as described above. It is particularly preferable that it does not contain any structural unit.
- particulate binder may be used alone, or two or more types may be used in combination at any ratio.
- the weight average molecular weight of the polymer forming the particulate binder is preferably 10,000 or more, more preferably 20,000 or more, preferably 1,000,000 or less, more preferably 500,000 or less.
- the weight average molecular weight of the polymer forming the particulate binder is in the above range, the strength of the electrode and the dispersibility of the electrode active material are easily improved.
- the glass transition temperature of the particulate binder is preferably ⁇ 75 ° C. or higher, more preferably ⁇ 55 ° C. or higher, particularly preferably ⁇ 35 ° C. or higher, preferably 40 ° C. or lower, more preferably 30 ° C. or lower, still more preferably. 20 ° C. or lower, particularly preferably 15 ° C. or lower.
- the glass transition temperature of the particulate binder can be adjusted by combining various monomers.
- the volume average particle diameter D50 of the particulate binder is preferably 50 nm or more, more preferably 70 nm or more, preferably 500 nm or less, more preferably 400 nm or less.
- the volume average particle diameter D50 of the particulate binder is in the above range, the strength and flexibility of the obtained electrode can be improved.
- the amount of the particulate binder is preferably 0.5 parts by weight or more, more preferably 0.7 parts by weight or more, particularly preferably 1 part by weight or more, preferably 10 parts by weight with respect to 100 parts by weight of the electrode active material. Parts or less, more preferably 7 parts by weight or less, and particularly preferably 5 parts by weight or less.
- the method for producing the particulate binder is not particularly limited, and any method such as a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method may be used.
- the emulsion polymerization method and the suspension polymerization method are preferable because they can be polymerized in water and used as they are as the material of the slurry composition of the present invention.
- the slurry composition of this invention can contain arbitrary components other than the electrode active material mentioned above, a water-soluble polymer, water, and a particulate binder.
- a water-soluble polymer examples include conductive materials, reinforcing materials, leveling agents, thickeners, nanoparticles, electrolyte additives, and the like.
- these components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the conductive material is a component that can improve electrical contact between the electrode active materials. By including a conductive material, the discharge rate characteristics of the lithium ion secondary battery can be improved. Examples of the conductive material include furnace black, acetylene black, ketjen black, carbon black, graphite, vapor grown carbon fiber, and conductive carbon such as carbon nanotube.
- a conductive material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the amount of the conductive material is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material.
- the reinforcing material for example, various inorganic and organic spherical, plate-like, rod-like or fibrous fillers can be used.
- a reinforcing material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
- the amount of the reinforcing material is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 20 parts by weight or less, more preferably 10 parts by weight with respect to 100 parts by weight of the electrode active material. It is as follows. By setting the amount of the reinforcing material in the above range, the lithium ion secondary battery can exhibit high capacity and high load characteristics.
- the leveling agent examples include surfactants such as alkyl surfactants, silicone surfactants, fluorine surfactants, and metal surfactants.
- a leveling agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. By using a leveling agent, it is possible to prevent the repelling that occurs during the application of the slurry composition of the present invention, and to improve the smoothness of the electrode.
- the amount of the leveling agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the leveling agent is within the above range, the productivity, smoothness, and battery characteristics during electrode production are excellent. Moreover, the dispersibility of an electrode active material can be improved in the slurry composition of this invention by containing surfactant, Furthermore, the smoothness of the electrode obtained by it can be improved.
- thickener examples include cellulose polymers such as carboxymethyl cellulose, methyl cellulose, hydroxypropyl cellulose and salts thereof; (modified) poly (meth) acrylic acid and salts thereof; (modified) polyvinyl alcohol, acrylic acid or acrylic Polyvinyl alcohols such as copolymers of acid salts and vinyl alcohol, maleic anhydride or maleic acid or copolymers of fumaric acid and vinyl alcohol; polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, modified polyacrylic acid, oxidized starch, phosphorus Acid starch, casein, various modified starches, acrylonitrile-butadiene copolymer hydride, and the like.
- cellulose polymers and salts thereof (modified) poly (meth) acrylic acid and salts thereof are preferable, and cellulose polymers and salts thereof are more preferable.
- the salt include ammonium salt and alkali metal salt. One of these may be used alone, or two or more of these may be used in combination at any ratio.
- “(modified) poly” means “unmodified poly” or “modified poly”.
- the amount of the thickener is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the thickener is in the above range, the dispersibility of the electrode active material in the slurry composition of the present invention can be further enhanced, so that a smooth electrode can be obtained. For this reason, it is possible to realize further excellent load characteristics and cycle characteristics.
- the nanoparticles include particles such as fumed silica and fumed alumina.
- One kind of nanoparticles may be used alone, or two or more kinds of nanoparticles may be used in combination at any ratio. Since the thixotropy of the slurry composition of this invention can be adjusted when it contains a nanoparticle, the leveling property of the electrode obtained by it can be improved.
- the amount of the nanoparticles is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the nanoparticles are in the above range, the stability and productivity of the slurry composition of the present invention can be improved, and high battery characteristics can be realized.
- the electrolytic solution additive examples include vinylene carbonate.
- One electrolyte solution additive may be used alone, or two or more electrolyte solution additives may be used in combination at any ratio.
- the amount of the electrolytic solution additive is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. By setting the amount of the electrolytic solution additive in the above range, a lithium ion secondary battery excellent in cycle characteristics and high temperature characteristics can be realized.
- the slurry composition of the present invention since it has the above-described configuration, the slurry composition of the present invention usually has the following advantages.
- the slurry composition of the present invention is excellent in dispersibility. That is, in the slurry composition of the present invention, components such as an electrode active material, a particulate binder, and a conductive material are uniformly dispersed. Therefore, also in the electrode active material layer manufactured using the slurry composition of this invention, since the said component can be disperse
- the slurry composition of the present invention is excellent in dispersion stability. That is, the slurry composition of the present invention can maintain high dispersibility over a long period of time. Moreover, the slurry composition of the present invention is less likely to cause a change in viscosity over time. Therefore, since the slurry composition of the present invention hardly changes its properties due to storage, it can be stored for a long period of time.
- the layer is stable and is not easily destroyed by the passage of time and temperature. Furthermore, since the water-soluble polymer has a high affinity for water, it is highly water-soluble and hardly causes precipitation. Therefore, it is considered that the slurry composition of the present invention is excellent in dispersibility and dispersion stability.
- the slurry composition of the present invention can increase viscosity and thixotropy.
- the reason why the viscosity and thixotropy can be improved in this way is not necessarily clear, but according to the study of the present inventor, it is presumed as follows. That is, the water-soluble polymer of the present invention acts as a thickener in the slurry composition.
- the thixotropy of the slurry composition containing the water-soluble polymer can be improved by the action of the hydroxyl group-containing monomer unit. Therefore, it is considered that the viscosity and thixotropy of the slurry composition can be improved to an extent suitable for application.
- the slurry composition of the present invention can be produced, for example, by mixing an electrode active material, a water-soluble polymer and water, and if necessary, a particulate binder and optional components.
- the specific procedure at this time is arbitrary.
- the electrode active material, the water-soluble polymer, the particulate binder and the conductive material are simultaneously added to water.
- Method of mixing after dissolving water-soluble polymer in water, mixing particulate binder dispersed in water, and then mixing electrode active material and conductive material; electrode in particulate binder dispersed in water And a method of mixing an active material and a conductive material, and mixing a water-soluble polymer dissolved in water into the mixture.
- mixing means include, for example, mixing equipment such as a ball mill, a sand mill, a bead mill, a roll mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a homomixer, and a planetary mixer.
- mixing equipment such as a ball mill, a sand mill, a bead mill, a roll mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a homomixer, and a planetary mixer.
- Electrode for lithium ion secondary battery The electrode of the present invention (electrode for a lithium ion secondary battery) can be obtained by a production method including forming a film of the slurry composition of the present invention on a current collector and drying the film.
- the current collector is not particularly limited as long as it has electrical conductivity and is electrochemically durable, but a metal material is preferable because it has heat resistance.
- the material for the current collector include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, and platinum.
- the current collector used for the positive electrode is preferably aluminum
- the current collector used for the negative electrode is preferably copper.
- One kind of the above materials may be used alone, or two or more kinds thereof may be used in combination at any ratio.
- the shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 mm to 0.5 mm is preferable.
- the current collector is preferably used after roughening the surface in advance.
- the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method.
- the mechanical polishing method for example, an abrasive cloth paper to which abrasive particles are fixed, a grindstone, an emery buff, a wire brush provided with a steel wire, or the like is used.
- an intermediate layer may be formed on the surface of the current collector.
- a film of the slurry composition of the present invention is formed on the current collector.
- membrane of a slurry composition is normally formed by apply
- a slurry composition may be apply
- the thickness of the slurry composition film can be appropriately set according to the thickness of the target electrode active material layer.
- the slurry composition of the present invention has excellent coating properties, a uniform film can be easily formed by the above coating. Moreover, since the slurry composition of this invention is excellent in a dispersibility and dispersion stability, the obtained film
- the liquid such as water is removed from the film by drying. Thereby, the electrode active material layer containing an electrode active material and a water-soluble polymer is formed in the surface of an electrical power collector, and an electrode is obtained.
- drying method examples include drying with warm air, hot air, low-humidity air, or the like; vacuum drying; drying with irradiation of energy rays such as infrared rays, far infrared rays, or electron beams. Among these, a drying method by irradiation with far infrared rays is preferable.
- the drying temperature and drying time are preferably a temperature and a time at which water can be removed from the slurry composition film. Specifically, the drying time is preferably 1 minute to 30 minutes, and the drying temperature is preferably 40 ° C. to 180 ° C.
- the porosity of the electrode active material layer can be lowered.
- the porosity is preferably 5% or more, more preferably 7% or more, preferably 30% or less, more preferably 20% or less.
- the electrode active material layer contains a polymer that can be cured by a curing reaction such as a crosslinking reaction
- the polymer may be cured after the electrode active material layer is formed.
- the thickness of the electrode active material layer formed as described above can be arbitrarily set according to the required battery performance.
- the thickness of the positive electrode active material layer is preferably 5 ⁇ m or more, more preferably 10 ⁇ m or more, preferably 300 ⁇ m or less, more preferably 250 ⁇ m or less.
- the thickness of the positive electrode active material layer is in the above range, high characteristics can be realized in both load characteristics and energy density.
- the thickness of the negative electrode active material layer is preferably 5 ⁇ m or more, more preferably 20 ⁇ m or more, particularly preferably 30 ⁇ m or more, preferably 1000 ⁇ m or less, more preferably 500 ⁇ m or less, still more preferably 300 ⁇ m or less, particularly preferably. Is 250 ⁇ m or less.
- load characteristics and cycle characteristics can be improved.
- the water content in the electrode active material layer is preferably 1000 ppm or less, and more preferably 500 ppm or less. By setting the moisture content of the electrode active material layer within the above range, an electrode having excellent durability can be realized.
- the amount of water can be measured by a known method such as the Karl Fischer method. Such a low water content can be achieved by appropriately adjusting the composition of the structural unit in the water-soluble polymer.
- the fluorine-containing (meth) acrylic acid ester monomer unit is preferably in the range of 0.5% by weight or more, more preferably 1% by weight or more, and preferably 20% by weight or less, more preferably 10% by weight or less. By doing so, the amount of water can be reduced.
- the adhesion strength between the current collector and the electrode active material layer is strong.
- the reason why such a strong adhesion strength is obtained is not necessarily clear, but according to the study of the present inventor, it is presumed as follows. That is, the hydroxyl group (—OH group) and acid group of the hydroxyl group-containing monomer unit have high polarity. Therefore, the water-soluble polymer can cause a strong interaction with the polar groups present on the surfaces of the electrode active material and the current collector, and thus can be firmly bound to the electrode active material and the current collector. In particular, it is considered that high binding properties can be expressed by the action of acid groups.
- the water-soluble polymer can act as a binder, and the water-soluble polymer increases the strength of the binding between the electrode active materials and the binding between the electrode active material and the current collector. It is presumed that the adhesion with the active material layer is improved. Moreover, since the slurry composition of this invention has high dispersibility, it is thought that the composition of a structural component is uniform also in the electrode active material layer regardless of the position. Therefore, in the electrode active material layer, a portion where the adhesion strength with the current collector is locally weak is unlikely to occur. Therefore, since the current collector and the electrode active material layer do not peel off starting from the portion, it is possible to improve the adhesion between the current collector and the electrode active material layer. Inferred.
- the electrode of the present invention has high flexibility and is not easily damaged even when it is bent.
- the reason for such a high flexibility is not necessarily clear, but according to the study of the present inventor, it is presumed as follows. That is, as described above, the electrode active material layer formed using the slurry composition of the present invention can improve the uniformity of the composition, so that a locally weak portion is generated in the electrode active material layer. Can be suppressed. For this reason, since the generation
- the lithium ion secondary battery of this invention is equipped with a positive electrode, a negative electrode, and electrolyte solution.
- the lithium ion secondary battery of the present invention may include a separator.
- one or both of the negative electrode and the positive electrode is an electrode of the present invention.
- the lithium ion secondary battery of the present invention is excellent in cycle characteristics and output characteristics, and in particular, the high temperature cycle characteristics and the low temperature characteristics can be remarkably improved.
- the reason why the lithium ion secondary battery of the present invention is excellent in cycle characteristics and output characteristics is not clear, but according to the study of the present inventors, it is presumed that the reason is as follows.
- the adhesion strength between the electrode active material layer and the current collector is high. Therefore, even if the electrode active material repeatedly expands and contracts due to charge and discharge, the electrode active material layer and the current collector are unlikely to peel off. Further, since the water-soluble polymer has high binding properties, the contact between the electrode active material layers and the contact between the electrode active material and the conductive material are hardly impaired. For this reason, since the electric conduction path is not easily cut by charging / discharging, the degree of increase in resistance accompanying charging / discharging is low. Moreover, in the electrode of this invention, a part of water-soluble polymer has adhered to the surface of the electrode active material.
- the coating can suppress decomposition of the electrolytic solution, it is possible to suppress an increase in resistance caused by a gas generated by the decomposition of the electrolytic solution. For these reasons, it is assumed that the lithium ion secondary battery of the present invention can exhibit excellent cycle characteristics.
- the fluorine-containing (meth) acrylic acid ester monomer unit has high ionic conductivity
- the water-soluble polymer also has high ionic conductivity. Therefore, even if the water-soluble polymer film covers the surface of the electrode active material, the degree of resistance increase due to the film can be reduced. Therefore, the resistance of the electrode can be suppressed.
- the swelling property of the water-soluble polymer with respect to electrolyte solution can be made small by including a fluorine-containing (meth) acrylic acid ester monomer unit. Therefore, swelling of the electrode can be suppressed in the lithium ion secondary battery. Therefore, swelling of the electrode active material layer can be suppressed, and the distance between the electrode active materials can be reduced.
- the internal resistance of the electrode can be suppressed.
- polymers containing fluorine-containing (meth) acrylic acid ester monomer units tend to become less compatible with the electrolyte solution, but in the water-soluble polymer according to the present invention, hydroxyl group-containing monomer units.
- the compatibility with the electrolytic solution is not deteriorated by the action of the acid group-containing monomer unit. Rather, since the water-soluble polymer has a hydroxyl group and an acid group, the affinity of the water-soluble polymer with respect to the polar solvent is increased, and the electrode active material layer has excellent wettability with respect to the electrolytic solution.
- the electrolytic solution can easily enter the electrode active material layer, the electric reaction field between the electrolytic solution and the electrode active material can be easily widened, and the internal resistance of the battery can be suppressed. .
- the lithium ion secondary battery of the present invention can exhibit excellent output characteristics.
- Electrolyte As the electrolytic solution, for example, a solution obtained by dissolving a lithium salt as a supporting electrolyte in a non-aqueous solvent may be used.
- the lithium salt include LiPF 6 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAlCl 4 , LiClO 4 , CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi , (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and other lithium salts.
- LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferably used.
- One of these may be used alone, or two or more of these may be used in combination at any ratio.
- the amount of the supporting electrolyte is preferably 1% by weight or more, more preferably 5% by weight or more, and preferably 30% by weight or less, more preferably 20% by weight or less with respect to the electrolytic solution. If the amount of the supporting electrolyte is too small or too large, the ionic conductivity is lowered, and the charging characteristics and discharging characteristics of the secondary battery may be lowered.
- the solvent used in the electrolytic solution is not particularly limited as long as it can dissolve the supporting electrolyte.
- the solvent include alkyl carbonates such as dimethyl carbonate (DMC), ethylene carbonate (EC), diethyl carbonate (DEC), propylene carbonate (PC), butylene carbonate (BC), methyl ethyl carbonate (MEC); Esters such as butyrolactone and methyl formate; ethers such as 1,2-dimethoxyethane and tetrahydrofuran; sulfur-containing compounds such as sulfolane and dimethyl sulfoxide; In particular, dimethyl carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, and methyl ethyl carbonate are preferred because high ion conductivity is easily obtained and the use temperature range is wide.
- a solvent may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- an additive may be included in the electrolytic solution as necessary.
- carbonate compounds such as vinylene carbonate (VC) are preferable.
- An additive may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
- Examples of the electrolytic solution other than the above include a gel polymer electrolyte obtained by impregnating a polymer electrolyte such as polyethylene oxide and polyacrylonitrile with an electrolytic solution; an inorganic solid electrolyte such as lithium sulfide, LiI, and Li 3 N; Can do.
- separator As the separator, a porous substrate having a pore portion is usually used.
- separators include (a) a porous separator having pores, (b) a porous separator having a polymer coating layer formed on one or both sides, and (c) a porous resin coat containing inorganic ceramic powder. And a porous separator having a layer formed thereon.
- Examples of these include polypropylene, polyethylene, polyolefin or aramid porous separators; for solid polymer electrolytes such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymers Or a polymer film for a gel polymer electrolyte; a separator coated with a gelled polymer coat layer; a separator coated with a porous film layer composed of an inorganic filler and an inorganic filler dispersant; and the like.
- solid polymer electrolytes such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymers
- a polymer film for a gel polymer electrolyte a separator coated with a gelled polymer coat layer
- a separator coated with a porous film layer composed of an inorganic filler and an
- the manufacturing method of the lithium ion secondary battery of the present invention is not particularly limited.
- the above-described negative electrode and positive electrode may be overlapped via a separator, and this may be wound or folded in accordance with the shape of the battery and placed in the battery container, and the electrolyte may be injected into the battery container and sealed.
- an expanded metal; an overcurrent prevention element such as a fuse or a PTC element; a lead plate or the like may be inserted to prevent an increase in pressure inside the battery or overcharge / discharge.
- the shape of the battery may be any of, for example, a laminate cell type, a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
- Adhesion strength The electrodes produced in the examples and comparative examples were cut into rectangles having a length of 100 mm and a width of 10 mm to obtain test pieces.
- Cellophane tape was affixed on the surface of the electrode active material layer of the test piece with the surface of the electrode active material layer facing down.
- a cellophane tape defined in JIS Z1522 was used.
- the cellophane tape was fixed on a horizontal test bench. Then, the stress when one end of the current collector was pulled vertically upward at a pulling speed of 50 mm / min and peeled was measured. This measurement was performed three times, the average value of the measured values was obtained, and the average value was taken as the peel strength.
- the higher the peel strength the higher the binding force of the electrode active material layer to the current collector, that is, the higher the adhesion strength.
- lithium ion secondary batteries of laminate type cells were produced and allowed to stand for 24 hours in an environment of 25 ° C. Thereafter, in a 25 ° C. environment, an operation of charging with a constant current method of 0.1 C over 5 hours was performed, and the voltage V0 at that time was measured. Thereafter, a discharge operation was performed at a discharge rate of 1 C in an environment of ⁇ 10 ° C., and the voltage V1 15 seconds after the start of discharge was measured.
- Example 1 (1-1. Production of water-soluble polymer) In a 5 MPa pressure vessel equipped with a stirrer, 4 parts 2-hydroxyethyl acrylate (hydroxyl group-containing monomer), 32.5 parts methacrylic acid (acid group-containing monomer), 0.8 ethylene dimethacrylate (crosslinkable monomer) Parts, 2,2,2-trifluoroethyl methacrylate (fluorine-containing (meth) acrylic acid ester monomer) 7.5 parts, ethyl acrylate (optional monomer) 55.2 parts, sodium dodecylbenzenesulfonate ( Surfactant (0.1 part), t-dodecyl mercaptan (molecular weight regulator) (0.1 part), ion-exchanged water (150 parts), and potassium persulfate (polymerization initiator) (0.5 part) were added and sufficiently stirred.
- 2-hydroxyethyl acrylate hydroxyl group-containing monomer
- methacrylic acid acid group-containing
- the mixture containing the particulate binder was adjusted to pH 8 by adding a 5% aqueous sodium hydroxide solution. Then, after removing the unreacted monomer from the mixture containing the particulate binder by heating under reduced pressure, the mixture was cooled to 30 ° C. or lower to obtain an aqueous dispersion containing the desired particulate binder.
- the slurry composition for positive electrode was applied on a 20 ⁇ m thick aluminum foil as a current collector with a comma coater so that the film thickness after drying was about 130 ⁇ m and dried. This drying was performed by conveying the aluminum foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Thereafter, heat treatment was performed at 120 ° C. for 2 minutes to obtain a positive electrode raw material.
- This positive electrode original fabric was rolled with a roll press to obtain a positive electrode having a positive electrode active material layer thickness of 80 ⁇ m. About this positive electrode, the adhesive strength and the softness
- the mixture containing the particulate binder was adjusted to pH 8 by adding a 5% aqueous sodium hydroxide solution. Then, after removing the unreacted monomer from the mixture containing the particulate binder by heating under reduced pressure, the mixture is cooled to 30 ° C. or lower, and an aqueous dispersion containing the desired particulate binder (a binder composition for negative electrode) Product).
- the negative electrode slurry composition obtained in the above step (1-5) was applied onto a 20 ⁇ m thick copper foil as a current collector with a comma coater so that the film thickness after drying was about 150 ⁇ m. And dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode original fabric was obtained by heat-processing at 120 degreeC for 2 minute (s). This negative electrode original fabric was rolled with a roll press to obtain a negative electrode having a negative electrode active material layer thickness of 80 ⁇ m.
- the positive electrode obtained in the above step (1-3) was cut into a 4 ⁇ 4 cm 2 square and placed so that the current collector-side surface was in contact with the aluminum packaging exterior.
- the square separator obtained in the above step (1-7) was disposed on the surface of the positive electrode active material layer of the positive electrode.
- the negative electrode obtained in the above step (1-6) was cut into a square of 4.2 ⁇ 4.2 cm 2 and arranged on the separator so that the surface on the negative electrode active material layer side faces the separator.
- Example 2 In the same manner as in Example 1, except that the amount of 2-hydroxyethyl acrylate was changed to 0.8 parts and the amount of ethyl acrylate was changed to 58.4 parts in the above step (1-1), lithium ion Secondary batteries were manufactured and evaluated.
- Example 3 In the same manner as in Example 1, except that the amount of 2-hydroxyethyl acrylate was changed to 9.5 parts and the amount of ethyl acrylate was changed to 49.7 parts in the above step (1-1), lithium ion Secondary batteries were manufactured and evaluated.
- Example 4 A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 4 parts of 2-hydroxyethyl methacrylate was used instead of 2-hydroxyethyl acrylate in the above step (1-1).
- Example 5 Copolymerization was carried out in the same manner as in the above step (1-1) except that vinyl acetate was used in place of 2-hydroxyethyl acrylate, and the resulting polymer was hydrolyzed with sodium hydroxide to produce a polymer acetic acid.
- the vinyl unit was converted to a vinyl alcohol unit to obtain an aqueous solution containing a water-soluble polymer.
- the vinyl acetate unit refers to a structural unit having a structure formed by polymerizing vinyl acetate.
- a vinyl alcohol unit shows the structural unit which has a structure formed by superposing
- a lithium ion secondary battery was produced and evaluated in the same manner as in Example 1 except that the aqueous solution containing the water-soluble polymer thus obtained was used as a thickener in the above step (1-3).
- Example 6 A lithium ion secondary battery was prepared in the same manner as in Example 1 except that 7.5 parts of perfluorooctyl acrylate was used instead of 2,2,2-trifluoroethyl methacrylate in the above step (1-1). Manufactured and evaluated.
- Example 7 A lithium ion secondary battery was prepared in the same manner as in Example 1 except that 7.5 parts of perfluorobutyl acrylate was used instead of 2,2,2-trifluoroethyl methacrylate in the above step (1-1). Manufactured and evaluated.
- Example 8 Same as Example 1 except that the amount of 2,2,2-trifluoroethyl methacrylate was changed to 0.2 parts and the amount of ethyl acrylate was changed to 62.5 parts in the above step (1-1). Thus, a lithium ion secondary battery was manufactured and evaluated.
- Example 9 In the same manner as in Example 1, except that the amount of 2,2,2-trifluoroethyl methacrylate was changed to 48 parts and the amount of ethyl acrylate was changed to 14.7 parts in the above step (1-1). A lithium ion secondary battery was manufactured and evaluated.
- Example 10 A lithium ion secondary battery was produced in the same manner as in Example 1 except that the amount of methacrylic acid was changed to 22 parts and the amount of ethyl acrylate was changed to 65.7 parts in the above step (1-1). And evaluated.
- Example 11 A lithium ion secondary battery was produced in the same manner as in Example 1, except that the amount of methacrylic acid was changed to 48 parts and the amount of ethyl acrylate was changed to 39.7 parts in the above step (1-1). And evaluated.
- Example 12 In the above step (1-1), the same procedure as in Example 1 was performed except that 25 parts of 2-acrylamido-2-methylpropanesulfonic acid was used instead of methacrylic acid and the amount of ethyl acrylate was changed to 62.7 parts. A lithium ion secondary battery was manufactured and evaluated.
- Example 13 In the above step (1-1), 30.0 parts of methacrylic acid and 5.0 parts of 2-acrylamido-2-methylpropanesulfonic acid were used in combination as the acid group-containing monomer, and the amount of ethyl acrylate was 52.7. A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that the part was changed to a part.
- Example 14 In the step (1-1), the lithium ion secondary was changed in the same manner as in Example 1 except that the amount of ethylene dimethacrylate was changed to 0.1 part and the amount of ethyl acrylate was changed to 55.9 parts. A battery was manufactured and evaluated.
- Example 15 In the same manner as in Example 1, except that the amount of ethylene dimethacrylate was changed to 1.8 parts and the amount of ethyl acrylate was changed to 54.2 parts in the above step (1-1), lithium ion secondary A battery was manufactured and evaluated.
- Example 16 A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 0.8 part of glycidyl methacrylate was used in place of ethylene dimethacrylate in the above step (1-1).
- Example 17 A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 0.8 part of allyl glycidyl ether was used in place of ethylene dimethacrylate in the above step (1-1).
- Example 18 In the step (1-3), a lithium ion secondary battery was produced and evaluated in the same manner as in Example 1 except that no binder was used.
- Example 19 (19-1. Production of slurry composition for negative electrode)
- 100 parts of artificial graphite (average particle size: 24.5 ⁇ m) having a specific surface area of 5.5 m 2 / g as a negative electrode active material, and the water-soluble heavy of the above step (1-1) as a thickener 2 parts of the aqueous solution containing the coalesced was added in an amount corresponding to the solid content, and ion-exchanged water was further added to adjust the solid content concentration to 65%, followed by mixing at 25 ° C. for 60 minutes. Next, ion-exchanged water was added to adjust the solid content concentration to 60%, and the mixture was further mixed at 25 ° C.
- the negative electrode slurry composition obtained in the above step (19-1) was applied onto a 20 ⁇ m thick copper foil as a current collector with a comma coater so that the film thickness after drying was about 150 ⁇ m. And dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode original fabric was obtained by heat-processing at 120 degreeC for 2 minute (s). This negative electrode original fabric was rolled with a roll press to obtain a negative electrode having a negative electrode active material layer thickness of 80 ⁇ m. About this negative electrode, the adhesive strength and the softness
- a positive electrode was produced in the same manner as in the step (1-3) of Example 1 except that 1 part of a 2% aqueous solution of carboxymethyl cellulose (“MAC350HC” manufactured by Nippon Paper Chemical Co., Ltd.) was used as a thickener. .
- MAC350HC carboxymethyl cellulose
- Example 20 Implemented except that 90 parts of artificial graphite (volume average particle diameter: 24.5 ⁇ m) and 10 parts of SiO x (volume average particle diameter: 5 ⁇ m) were used as the negative electrode active material in combination with a specific surface area of 5.5 m 2 / g. In the same manner as in Example 19, a lithium ion secondary battery was produced and evaluated.
- Example 21 Implemented except that 70 parts of artificial graphite (volume average particle diameter: 24.5 ⁇ m) and 30 parts of SiO x (volume average particle diameter: 8 ⁇ m) were used in combination as the negative electrode active material with a specific surface area of 5.5 m 2 / g. In the same manner as in Example 19, a lithium ion secondary battery was produced and evaluated.
- the obtained powder was a powder having a volume average particle size of 3.5 ⁇ m and a BET specific surface area of 11 m 2 / g.
- Analysis by the Scherrer method from the half-value width of this diffraction line revealed that the obtained powder was a silicon composite powder having a crystallite size of 40 nm of silicon dispersed in silicon dioxide. confirmed.
- a lithium ion secondary battery was produced and evaluated in the same manner as in Example 19 except that the silicon composite powder thus obtained was used as the negative electrode active material.
- a lithium ion secondary battery was produced and evaluated in the same manner as in Example 19 except that the polycrystalline silicon powder thus obtained was used as the negative electrode active material.
- a lithium ion secondary was prepared in the same manner as in Example 1 except that 1 part of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1000000) was used as a thickener. A battery was manufactured and evaluated.
- Example 5 In the above step (19-1), the same procedure as in Example 19 was performed except that 1 part of a 2% aqueous solution of carboxymethylcellulose (“MAC350HC” manufactured by Nippon Paper Chemical Co., Ltd.) was used as a thickener, corresponding to the solid content. An ion secondary battery was manufactured and evaluated.
- MAC350HC carboxymethylcellulose
- Examples 1 to 18 and Comparative Examples 1 to 4 are obtained by applying the slurry composition to the positive electrode, and Examples 19 to 23 and Comparative Example 5 are those using the slurry composition as the negative electrode. It is applied. From the above table, it can be seen that the present invention can realize a lithium ion secondary battery having excellent high-temperature cycle characteristics and low-temperature characteristics. Moreover, by comparing an Example and a comparative example, it turns out that the slurry composition of this invention is excellent in dispersion stability. Furthermore, it turns out that the electrode manufactured using the slurry composition of this invention is excellent in adhesive strength and a softness
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Abstract
Description
すなわち、本発明は以下の通りである。 The inventor has intensively studied to solve the above problems. As a result, the present inventors have found that a slurry composition for a lithium ion secondary battery containing water has a predetermined amount of a hydroxyl group-containing monomer unit, a fluorine-containing (meth) acrylate ester monomer unit, and an acid. It has been found that by including a water-soluble polymer containing a group-containing monomer unit, the high-temperature cycle characteristics and low-temperature characteristics of a lithium ion secondary battery can be improved, and the present invention has been completed.
That is, the present invention is as follows.
前記水溶性重合体が、水酸基含有単量体単位0.5重量%~10重量%、フッ素含有(メタ)アクリル酸エステル単量体単位及び酸基含有単量体単位を含む、リチウムイオン二次電池電極用のスラリー組成物。
〔2〕 前記水溶性重合体の1重量%水溶液粘度が、10mPa・s~1000mPa・sである、〔1〕記載のスラリー組成物。
〔3〕 前記水溶性重合体が、更に架橋性単量体単位を0.05重量%~2重量%含む、〔1〕又は〔2〕記載のスラリー組成物。
〔4〕 前記水溶性重合体の量が、電極活物質100重量部に対して、0.1重量部~10重量部である、〔1〕~〔3〕のいずれか一項に記載のスラリー組成物。
〔5〕 前記水溶性重合体における前記フッ素含有(メタ)アクリル酸エステル単量体単位の割合が、0.1重量%以上50重量%以下である、〔1〕~〔4〕のいずれか一項に記載のスラリー組成物。
〔6〕 前記水溶性重合体における前記酸基含有単量体単位の割合が、20重量%以上50重量%以下である、〔1〕~〔5〕のいずれか一項に記載のスラリー組成物。
〔7〕 前記水溶性重合体が、(メタ)アクリル酸エステル単量体単位を25重量%以上75重量%以下含む、〔1〕~〔6〕のいずれか一項に記載のスラリー組成物。
〔8〕 更に粒子状バインダーを含む、〔1〕~〔7〕のいずれか一項に記載のスラリー組成物。
〔9〕 前記粒子状バインダーが、アクリル軟質重合体又はジエン軟質重合体である、〔8〕に記載のスラリー組成物。
〔10〕 前記酸基含有単量体が、エチレン性不飽和カルボン酸単量体又はエチレン性不飽和スルホン酸単量体である、〔1〕~〔9〕のいずれか一項に記載のスラリー組成物。
〔11〕 〔1〕~〔10〕のいずれか一項に記載のスラリー組成物の膜を集電体上に形成し、前記の膜を乾燥して得られるリチウムイオン二次電池用電極。
〔12〕 正極、負極及び電解液を備えるリチウムイオン二次電池であって、
前記正極及び負極の一方又は両方が〔11〕記載のリチウムイオン二次電池用電極である、リチウムイオン二次電池。 [1] including an electrode active material, a water-soluble polymer and water,
The water-soluble polymer comprises a lithium ion secondary containing 0.5% to 10% by weight of a hydroxyl group-containing monomer unit, a fluorine-containing (meth) acrylate monomer unit and an acid group-containing monomer unit. A slurry composition for battery electrodes.
[2] The slurry composition according to [1], wherein the water-soluble polymer has a 1% by weight aqueous solution viscosity of 10 mPa · s to 1000 mPa · s.
[3] The slurry composition according to [1] or [2], wherein the water-soluble polymer further contains 0.05 to 2% by weight of a crosslinkable monomer unit.
[4] The slurry according to any one of [1] to [3], wherein the amount of the water-soluble polymer is 0.1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. Composition.
[5] Any one of [1] to [4], wherein a ratio of the fluorine-containing (meth) acrylic acid ester monomer unit in the water-soluble polymer is 0.1 wt% or more and 50 wt% or less. The slurry composition according to item.
[6] The slurry composition according to any one of [1] to [5], wherein a ratio of the acid group-containing monomer unit in the water-soluble polymer is 20% by weight or more and 50% by weight or less. .
[7] The slurry composition according to any one of [1] to [6], wherein the water-soluble polymer contains (meth) acrylic acid ester monomer units in an amount of 25 wt% to 75 wt%.
[8] The slurry composition according to any one of [1] to [7], further comprising a particulate binder.
[9] The slurry composition according to [8], wherein the particulate binder is an acrylic soft polymer or a diene soft polymer.
[10] The slurry according to any one of [1] to [9], wherein the acid group-containing monomer is an ethylenically unsaturated carboxylic acid monomer or an ethylenically unsaturated sulfonic acid monomer. Composition.
[11] An electrode for a lithium ion secondary battery obtained by forming a film of the slurry composition according to any one of [1] to [10] on a current collector and drying the film.
[12] A lithium ion secondary battery comprising a positive electrode, a negative electrode, and an electrolyte solution,
The lithium ion secondary battery whose one or both of the said positive electrode and a negative electrode are the electrodes for lithium ion secondary batteries as described in [11].
本発明のスラリー組成物は、リチウムイオン二次電池電極用のスラリー組成物であって、電極活物質、水溶性重合体及び水を含む。また、本発明のスラリー組成物は、粒子状バインダーを含むことが好ましい。 [1. Slurry composition for lithium ion secondary battery electrode]
The slurry composition of this invention is a slurry composition for lithium ion secondary battery electrodes, Comprising: An electrode active material, a water-soluble polymer, and water are included. Moreover, it is preferable that the slurry composition of this invention contains a particulate-form binder.
電極活物質のうち、正極用の電極活物質(以下、適宜「正極活物質」ということがある。)としては、通常、リチウムイオンの挿入及び脱離が可能な物質が用いられる。このような正極活物質は、無機化合物からなるものと有機化合物からなるものとに大別される。 [1.1. Electrode active material)
Among the electrode active materials, as the electrode active material for the positive electrode (hereinafter sometimes referred to as “positive electrode active material” as appropriate), a material capable of inserting and desorbing lithium ions is usually used. Such positive electrode active materials are roughly classified into those made of inorganic compounds and those made of organic compounds.
また、例えば、鉄系酸化物を炭素源物質の存在下において還元焼成することで、炭素材料で覆われた複合材料を作製し、この複合材料を正極活物質として用いてもよい。鉄系酸化物は電気伝導性に乏しい傾向があるが、前記のような複合材料にすることにより、高性能な正極活物質として使用できる。 Moreover, you may use the positive electrode active material which consists of a composite material which combined the inorganic compound and the organic compound.
Alternatively, for example, a composite material covered with a carbon material may be produced by reducing and firing an iron-based oxide in the presence of a carbon source material, and the composite material may be used as a positive electrode active material. Iron-based oxides tend to have poor electrical conductivity, but can be used as a high-performance positive electrode active material by using a composite material as described above.
また、上記の無機化合物と有機化合物の混合物を正極活物質として用いてもよい。
正極活物質は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 Furthermore, you may use as a positive electrode active material what carried out the element substitution of the said compound partially.
Moreover, you may use the mixture of said inorganic compound and organic compound as a positive electrode active material.
As the positive electrode active material, one type may be used alone, or two or more types may be used in combination at any ratio.
好適な負極活物質を挙げると、例えば、炭素が挙げられる。炭素としては、例えば、天然黒鉛、人造黒鉛、カーボンブラック等が挙げられ、中でも天然黒鉛を用いることが好ましい。 Among the electrode active materials, an electrode active material for a negative electrode (hereinafter also referred to as “negative electrode active material” as appropriate) is a substance that transfers electrons in the negative electrode. As the negative electrode active material, a material that can occlude and release lithium ions is usually used.
An example of a suitable negative electrode active material is carbon. Examples of carbon include natural graphite, artificial graphite, and carbon black. Among these, natural graphite is preferably used.
複合化の方法としては、例えば、金属ケイ素及びケイ素系活物質の一方又は両方をカーボンによりコーティングすることにより複合化する方法;導電性カーボンと金属ケイ素及びケイ素系活物質の一方又は両方とを含む混合物を造粒することにより複合化する方法;等が挙げられる。 When carbon is used in combination with one or both of metallic silicon and a silicon-based active material, it is preferable that one or both of metallic silicon and the silicon-based active material is combined with conductive carbon. By combining with conductive carbon, swelling of the negative electrode active material itself can be suppressed.
Examples of the compounding method include a method of compounding one or both of metallic silicon and silicon-based active material with carbon; conductive carbon and one or both of metallic silicon and silicon-based active material The method of compounding by granulating a mixture; etc. are mentioned.
負極活物質の粒子の体積平均粒子径は、リチウムイオン二次電池の他の構成要件との兼ね合いで適宜選択され、好ましくは0.1μm以上、より好ましくは1μm以上、特に好ましくは5μm以上であり、好ましくは100μm以下、より好ましくは50μm以下、特に好ましくは20μm以下である。 The negative electrode active material is preferably sized in the form of particles. When the shape of the particles is spherical, a higher-density electrode can be formed when forming an electrode for a lithium ion secondary battery (hereinafter, also referred to as “electrode” as appropriate).
The volume average particle diameter of the particles of the negative electrode active material is appropriately selected in consideration of other constituent requirements of the lithium ion secondary battery, and is preferably 0.1 μm or more, more preferably 1 μm or more, and particularly preferably 5 μm or more. The thickness is preferably 100 μm or less, more preferably 50 μm or less, and particularly preferably 20 μm or less.
水溶性重合体は、本発明のスラリー組成物において、通常、電極活物質を均一に分散させる作用を有する。また、水溶性重合体は、スラリー組成物の粘度を調整する作用を有し、増粘剤として機能しうる。さらに、水溶性重合体は、電極活物質層において、電極活物質同士の間並びに電極活物質と集電体との間に介在することにより、電極活物質及び集電体を結着する作用を奏しうる。また、水溶性重合体は、電極活物質層において、電極活物質を覆う安定した層を形成し、電解液の分解を抑制する作用を奏しうる。 [1.2. Water-soluble polymer)
The water-soluble polymer usually has an action of uniformly dispersing the electrode active material in the slurry composition of the present invention. Further, the water-soluble polymer has an action of adjusting the viscosity of the slurry composition and can function as a thickener. Furthermore, the water-soluble polymer acts to bind the electrode active material and the current collector by interposing between the electrode active materials and between the electrode active material and the current collector in the electrode active material layer. Can play. In addition, the water-soluble polymer can form a stable layer that covers the electrode active material in the electrode active material layer, and can exert an action of suppressing decomposition of the electrolytic solution.
水溶性重合体は、水酸基含有単量体単位を含む。水酸基含有単量体単位とは、水酸基含有単量体を重合して形成される構造を有する構造単位である。 [1.2.1. Hydroxyl-containing monomer unit]
The water-soluble polymer includes a hydroxyl group-containing monomer unit. A hydroxyl group-containing monomer unit is a structural unit having a structure formed by polymerizing a hydroxyl group-containing monomer.
水溶性重合体は、フッ素含有(メタ)アクリル酸エステル単量体単位を含む。フッ素含有(メタ)アクリル酸エステル単量体単位とは、フッ素含有(メタ)アクリル酸単量体を重合して形成される構造を有する構造単位である。 [1.2.2. Fluorine-containing (meth) acrylic acid ester monomer unit]
The water-soluble polymer contains a fluorine-containing (meth) acrylic acid ester monomer unit. The fluorine-containing (meth) acrylic acid ester monomer unit is a structural unit having a structure formed by polymerizing a fluorine-containing (meth) acrylic acid monomer.
前記の式(I)において、R2は、フッ素原子を含有する炭化水素基を表す。炭化水素基の炭素数は、好ましくは1以上であり、好ましくは18以下である。また、R2が含有するフッ素原子の数は、1個でもよく、2個以上でもよい。 In the above formula (I), R 1 represents a hydrogen atom or a methyl group.
In the above formula (I), R 2 represents a hydrocarbon group containing a fluorine atom. The carbon number of the hydrocarbon group is preferably 1 or more, and preferably 18 or less. Moreover, the number of fluorine atoms contained in R 2 may be one or two or more.
水溶性重合体は、酸基含有単量体単位を含む。酸基含有単量体単位とは、酸基含有単量体を重合して形成される構造を有する構造単位である。 [1.2.3. (Acid group-containing monomer unit)
The water-soluble polymer includes an acid group-containing monomer unit. The acid group-containing monomer unit is a structural unit having a structure formed by polymerizing an acid group-containing monomer.
酸基含有単量体及び酸基含有単量体単位は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 Among the above-mentioned examples, preferred are ethylenically unsaturated carboxylic acid monomers and ethylenically unsaturated sulfonic acid monomers, and more preferred are acrylic acid, methacrylic acid, itaconic acid and 2- Examples include acrylamido-2-methylpropanesulfonic acid, acrylic acid and methacrylic acid are more preferable, and methacrylic acid is particularly preferable.
As the acid group-containing monomer and the acid group-containing monomer unit, one type may be used alone, or two or more types may be used in combination at any ratio.
水溶性重合体は、更に架橋性単量体単位を含むことが好ましい。架橋性単量体単位は、架橋性単量体を重合して形成される構造を有する構造単位である。架橋性単量体単位を含むことにより、水溶性重合体を架橋させることができるので、電極活物質層の強度及び安定性を高めることができる。また、電解液に対する電極活物質層の膨潤を抑制して、リチウムイオン二次電池の低温特性を良好にできる。 [1.2.4. Crosslinkable monomer unit)
The water-soluble polymer preferably further contains a crosslinkable monomer unit. The crosslinkable monomer unit is a structural unit having a structure formed by polymerizing a crosslinkable monomer. By including a crosslinkable monomer unit, the water-soluble polymer can be crosslinked, so that the strength and stability of the electrode active material layer can be increased. In addition, swelling of the electrode active material layer with respect to the electrolytic solution can be suppressed, and the low temperature characteristics of the lithium ion secondary battery can be improved.
また、架橋性単量体及び架橋性単量体単位は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 Among these, as the crosslinkable monomer, ethylene dimethacrylate, allyl glycidyl ether, glycidyl methacrylate and divinylbenzene are preferable, and ethylene dimethacrylate and glycidyl methacrylate are more preferable.
Moreover, a crosslinking | crosslinked monomer and a crosslinking | crosslinked monomer unit may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
水溶性重合体は、上述した水酸基含有単量体単位、フッ素含有(メタ)アクリル酸エステル単量体単位、酸基含有単量体単位及び架橋性単量体単位以外に、任意の構造単位を含んでいてもよい。
例えば、水溶性重合体は、フッ素含有(メタ)アクリル酸エステル単量体単位以外の、(メタ)アクリル酸エステル単量体単位を含んでいてもよい。(メタ)アクリル酸エステル単量体単位は、(メタ)アクリル酸エステル単量体を重合して形成される構造を有する構造単位である。ただし、(メタ)アクリル酸エステル単量体の中でもフッ素を含有するものは、フッ素含有(メタ)アクリル酸エステル単量体として(メタ)アクリル酸エステル単量体とは区別する。 [1.2.5. Arbitrary structural unit)
The water-soluble polymer has any structural unit other than the above-mentioned hydroxyl group-containing monomer unit, fluorine-containing (meth) acrylate monomer unit, acid group-containing monomer unit and crosslinkable monomer unit. May be included.
For example, the water-soluble polymer may contain (meth) acrylic acid ester monomer units other than the fluorine-containing (meth) acrylic acid ester monomer units. The (meth) acrylic acid ester monomer unit is a structural unit having a structure formed by polymerizing a (meth) acrylic acid ester monomer. However, among the (meth) acrylate monomers, those containing fluorine are distinguished from (meth) acrylate monomers as fluorine-containing (meth) acrylate monomers.
カチオン系の親水基の例としては、-Cl、-Br、-I、及び-SO3ORXなどが挙げられる。ここでRXは、アルキル基を示す。RXの例としては、メチル基、エチル基、プロピル基、及びイソプロピル基が挙げられる。
ノニオン系の親水基の例としては、-OHが挙げられる。 Examples of the anionic hydrophilic group include —SO 3 M, —COOM, and —PO (OM) 2 . Here, M represents a hydrogen atom or a cation. Examples of cations include alkali metal ions such as lithium, sodium and potassium; alkaline earth metal ions such as calcium and magnesium; ammonium ions; ammonium ions of alkylamines such as monomethylamine, dimethylamine, monoethylamine and triethylamine; and And ammonium ions of alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine.
Examples of the cationic hydrophilic group include —Cl, —Br, —I, and —SO 3 OR X. Here, R X represents an alkyl group. Examples of R X is methyl group, an ethyl group, a propyl group, and isopropyl group.
An example of a nonionic hydrophilic group is —OH.
式(II)において、R3は親水性基を表す。R3の例としては、-SO3NH4が挙げられる。
式(II)において、nは1以上100以下の整数を表す。 In the formula (II), R represents a divalent linking group. Examples of R include —Si—O— group, methylene group and phenylene group.
In the formula (II), R 3 represents a hydrophilic group. An example of R 3 includes —SO 3 NH 4 .
In the formula (II), n represents an integer of 1 to 100.
反応性界面活性剤単量体は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 Another example of a suitable reactive surfactant monomer has a structural unit having a structure formed by polymerizing ethylene oxide and a structural unit having a structure formed by polymerizing butylene oxide, and Examples include compounds having an alkenyl group having a terminal double bond and —SO 3 NH 4 at the terminal (for example, trade names “Latemul PD-104” and “Latemul PD-105”, manufactured by Kao Corporation).
A reactive surfactant monomer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
水溶性重合体の1重量%水溶液の粘度は、好ましくは10mPa・s以上、より好ましくは20mPa・s以上、特に好ましくは50mPa・s以上であり、好ましくは1000mPa・s以下、より好ましくは800mPa・s以下、特に好ましくは500mPa・s以下である。前記の粘度を上記範囲の下限値以上とすることにより水溶性重合体の強度を高くして電極の耐久性を向上させることができる。また、上限値以下とすることにより本発明のスラリー組成物の塗工性を良好にして、集電体と電極活物質層との密着強度を向上させることができる。前記の粘度は、例えば、水溶性重合体の分子量によって調整できる。ここで、前記の粘度は、pH=8の条件下で、B型粘度計を用いて25℃、回転数60rpmで測定した時の値である。 [1.2.6. Properties of water-soluble polymer)
The viscosity of a 1% by weight aqueous solution of the water-soluble polymer is preferably 10 mPa · s or more, more preferably 20 mPa · s or more, particularly preferably 50 mPa · s or more, preferably 1000 mPa · s or less, more preferably 800 mPa · s. s or less, particularly preferably 500 mPa · s or less. By setting the viscosity to be equal to or higher than the lower limit of the above range, the strength of the water-soluble polymer can be increased and the durability of the electrode can be improved. Moreover, the coating strength of the slurry composition of this invention can be made favorable by setting it as an upper limit or less, and the adhesive strength of a collector and an electrode active material layer can be improved. The viscosity can be adjusted by, for example, the molecular weight of the water-soluble polymer. Here, the viscosity is a value when measured at 25 ° C. and a rotation speed of 60 rpm using a B-type viscometer under the condition of pH = 8.
ここで、水溶性重合体の重量平均分子量は、ゲルパーミエーションクロマトグラフィー(GPC)によって、ジメチルホルムアミドの10体積%水溶液に0.85g/mlの硝酸ナトリウムを溶解させた溶液を展開溶媒としたポリスチレン換算の値として求めうる。 The weight average molecular weight of the water-soluble polymer is preferably 500 or more, more preferably 700 or more, particularly preferably 1000 or more, preferably 500,000 or less, more preferably 450,000 or less, and particularly preferably 400,000 or less. By setting the weight average molecular weight of the water-soluble polymer to be equal to or higher than the lower limit of the above range, the strength of the water-soluble polymer can be increased and the durability of the electrode can be improved. Moreover, the adhesive strength of a collector and an electrode active material layer can be improved by setting it as an upper limit or less.
Here, the weight average molecular weight of the water-soluble polymer is polystyrene using gel permeation chromatography (GPC) as a developing solvent, a solution obtained by dissolving 0.85 g / ml sodium nitrate in a 10% by volume aqueous solution of dimethylformamide. It can be obtained as a conversion value.
水溶性重合体は、例えば、上述した単量体を含む単量体組成物を、水系溶媒中で重合して、製造しうる。この際、単量体組成物中の各単量体の比率は、通常、水溶性重合体における構造単位(例えば、酸性基含有単量体単位、フッ素含有(メタ)アクリル酸単量体単位、酸基含有単量体単位及び架橋性単量体単位)の比率と同様にする。 [1.2.7. Method for producing water-soluble polymer]
The water-soluble polymer can be produced, for example, by polymerizing a monomer composition containing the above-described monomer in an aqueous solvent. At this time, the ratio of each monomer in the monomer composition is usually a structural unit in the water-soluble polymer (for example, an acidic group-containing monomer unit, a fluorine-containing (meth) acrylic acid monomer unit, The ratio of the acid group-containing monomer unit and the crosslinkable monomer unit).
水系溶媒の例としては、水(100);ダイアセトンアルコール(169)、γ-ブチロラクトン(204)等のケトン類;エチルアルコール(78)、イソプロピルアルコール(82)、ノルマルプロピルアルコール(97)等のアルコール類;プロピレングリコールモノメチルエーテル(120)、メチルセロソルブ(124)、エチルセロソルブ(136)、エチレングリコールターシャリーブチルエーテル(152)、ブチルセロソルブ(171)、3-メトキシー3メチル-1-ブタノール(174)、エチレングリコールモノプロピルエーテル(150)、ジエチレングリコールモノブチルエーテル(230)、トリエチレングリコールモノブチルエーテル(271)、ジプロピレングリコールモノメチルエーテル(188)等のグリコールエーテル類;並びに1,3-ジオキソラン(75)、1,4-ジオキソラン(101)、テトラヒドロフラン(66)等のエーテル類が挙げられる。中でも水は可燃性がなく、重合体の分散体が容易に得られやすいという観点から特に好ましい。また、主溶媒として水を使用して、重合体の分散状態が確保可能な範囲において上記記載の水以外の水系溶媒を混合して用いてもよい。 The aqueous solvent is not particularly limited as long as the water-soluble polymer can be dispersed. Usually, the boiling point at normal pressure is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. Examples of the aqueous solvent will be given below. In the following examples, the number in parentheses after the solvent name is the boiling point (unit: ° C) at normal pressure, and the value after the decimal point is a value rounded off or rounded down.
Examples of aqueous solvents include water (100); ketones such as diacetone alcohol (169) and γ-butyrolactone (204); ethyl alcohol (78), isopropyl alcohol (82), and normal propyl alcohol (97). Alcohols: propylene glycol monomethyl ether (120), methyl cellosolve (124), ethyl cellosolve (136), ethylene glycol tertiary butyl ether (152), butyl cellosolve (171), 3-methoxy-3-methyl-1-butanol (174), Ethylene glycol monopropyl ether (150), diethylene glycol monobutyl ether (230), triethylene glycol monobutyl ether (271), dipropylene glycol monomethyl ether (188), etc. Glycol ethers; and 1,3-dioxolane (75), 1,4-dioxolane (101), ethers such as tetrahydrofuran (66) and the like. Among these, water is particularly preferable from the viewpoint that it is not flammable and a polymer dispersion can be easily obtained. Further, water may be used as the main solvent, and an aqueous solvent other than the above-described water may be mixed and used within a range in which the dispersion state of the polymer can be ensured.
また、アミン類などの添加剤を重合助剤として用いてもよい。 The polymerization temperature and polymerization time can be arbitrarily selected depending on the polymerization method and the type of polymerization initiator. Usually, the polymerization temperature is about 30 ° C. or more, and the polymerization time is about 0.5 to 30 hours.
Further, additives such as amines may be used as a polymerization aid.
水溶性重合体の量は、電極活物質100重量部に対して、好ましくは0.1重量部以上、より好ましくは0.2重量部以上、特に好ましくは0.5重量部以上であり、好ましくは10重量部以下、より好ましくは8重量部以下、特に好ましくは5重量部以下である。水溶性重合体の量が前記範囲の下限値以上であることにより密着強度を確保することができる。また、上限値以下であることにより低温特性を向上させることができる。 [1.2.8. Amount of water-soluble polymer]
The amount of the water-soluble polymer is preferably 0.1 parts by weight or more, more preferably 0.2 parts by weight or more, particularly preferably 0.5 parts by weight or more, preferably 100 parts by weight of the electrode active material. Is 10 parts by weight or less, more preferably 8 parts by weight or less, and particularly preferably 5 parts by weight or less. Adhesive strength can be ensured when the amount of the water-soluble polymer is not less than the lower limit of the above range. Moreover, a low temperature characteristic can be improved by being below an upper limit.
本発明のスラリー組成物は水を含む。水は溶媒又は分散媒として機能し、電極活物質を分散させたり、水溶性重合体を溶解させたりしうる。 [1.3. water〕
The slurry composition of the present invention contains water. Water functions as a solvent or a dispersion medium, and can disperse the electrode active material or dissolve the water-soluble polymer.
本発明のスラリー組成物は、粒子状バインダーを含むことが好ましい。粒子状バインダーを含むことにより、電極活物質層の結着性が向上し、捲回時、運搬時等の取扱い時に電極にかかる機械的な力に対する強度を向上させることができる。また、電極活物質が電極活物質層から脱落し難くなることから、異物による短絡等の危険性が小さくなる。さらに電極活物質層において電極活物質を安定して保持できるようになるので、サイクル特性及び高温保存特性等の耐久性を改善することができる。また、粒子状であることで、粒子状バインダーは電極活物質に対して面ではなく点で結着しうる。このため、電極活物質の表面の大部分はバインダーで覆われないので、電解液と電極活物質との間でイオンのやり取りをする場の広さを広くできる。したがって、内部抵抗を下げて、リチウムイオン二次電池の出力特性を改善できる。 [1.4. (Particulate binder)
The slurry composition of the present invention preferably contains a particulate binder. By including the particulate binder, the binding property of the electrode active material layer can be improved, and the strength against mechanical force applied to the electrode during handling such as winding and transportation can be improved. In addition, since it becomes difficult for the electrode active material to fall off the electrode active material layer, the risk of a short circuit or the like due to foreign matter is reduced. Furthermore, since the electrode active material can be stably held in the electrode active material layer, durability such as cycle characteristics and high-temperature storage characteristics can be improved. Moreover, the particulate binder can be bound to the electrode active material not by a surface but by a point by being particulate. For this reason, most of the surface of the electrode active material is not covered with the binder, so that the field of exchange of ions between the electrolytic solution and the electrode active material can be widened. Therefore, the output resistance of the lithium ion secondary battery can be improved by reducing the internal resistance.
(i)ポリブチルアクリレート、ポリブチルメタクリレート、ポリヒドロキシエチルメタクリレート、ポリアクリルアミド、ポリアクリロニトリル、ブチルアクリレート・スチレン共重合体、ブチルアクリレート・アクリロニトリル共重合体、ブチルアクリレート・アクリロニトリル・グリシジルメタクリレート共重合体などの、アクリル酸またはメタクリル酸誘導体の単独重合体またはそれと共重合可能な単量体との共重合体である、アクリル軟質重合体;
(ii)ポリイソブチレン、イソブチレン・イソプレンゴム、イソブチレン・スチレン共重合体などのイソブチレン系軟質重合体;
(iii)ポリブタジエン、ポリイソプレン、ブタジエン・スチレンランダム共重合体、イソプレン・スチレンランダム共重合体、アクリロニトリル・ブタジエン共重合体、アクリロニトリル・ブタジエン・スチレン共重合体、ブタジエン・スチレン・ブロック共重合体、スチレン・ブタジエン・スチレン・ブロック共重合体、イソプレン・スチレン・ブロック共重合体、スチレン・イソプレン・スチレン・ブロック共重合体などジエン軟質重合体;
(iv)ジメチルポリシロキサン、ジフェニルポリシロキサン、ジヒドロキシポリシロキサンなどのケイ素含有軟質重合体;
(v)液状ポリエチレン、ポリプロピレン、ポリ-1-ブテン、エチレン・α-オレフィン共重合体、プロピレン・α-オレフィン共重合体、エチレン・プロピレン・ジエン共重合体(EPDM)、エチレン・プロピレン・スチレン共重合体などのオレフィン系軟質重合体;
(vi)ポリビニルアルコール、ポリ酢酸ビニル、ポリステアリン酸ビニル、酢酸ビニル・スチレン共重合体などビニル系軟質重合体;
(vii)ポリエチレンオキシド、ポリプロピレンオキシド、エピクロルヒドリンゴムなどのエポキシ系軟質重合体;
(viii)フッ化ビニリデン系ゴム、四フッ化エチレン-プロピレンゴムなどのフッ素含有軟質重合体;
(ix)天然ゴム、ポリペプチド、蛋白質、ポリエステル系熱可塑性エラストマー、塩化ビニル系熱可塑性エラストマー、ポリアミド系熱可塑性エラストマーなどのその他の軟質重合体;などが挙げられる。これらの中でも、ジエン軟質重合体及びアクリル軟質重合体が好ましい。また、これらの軟質重合体は、架橋構造を有したものであってもよく、変性により官能基を導入したものであってもよい。 Furthermore, you may use the particle | grains of the soft polymer illustrated below as a particulate-form binder. That is, as a soft polymer, for example,
(I) Polybutyl acrylate, polybutyl methacrylate, polyhydroxyethyl methacrylate, polyacrylamide, polyacrylonitrile, butyl acrylate / styrene copolymer, butyl acrylate / acrylonitrile copolymer, butyl acrylate / acrylonitrile / glycidyl methacrylate copolymer, etc. An acrylic soft polymer which is a homopolymer of acrylic acid or a methacrylic acid derivative or a copolymer thereof with a monomer copolymerizable therewith;
(Ii) isobutylene-based soft polymers such as polyisobutylene, isobutylene-isoprene rubber, isobutylene-styrene copolymer;
(Iii) Polybutadiene, polyisoprene, butadiene / styrene random copolymer, isoprene / styrene random copolymer, acrylonitrile / butadiene copolymer, acrylonitrile / butadiene / styrene copolymer, butadiene / styrene / block copolymer, styrene -Diene soft polymers such as butadiene, styrene, block copolymers, isoprene, styrene, block copolymers, styrene, isoprene, styrene, block copolymers;
(Iv) silicon-containing soft polymers such as dimethylpolysiloxane, diphenylpolysiloxane, dihydroxypolysiloxane;
(V) Liquid polyethylene, polypropylene, poly-1-butene, ethylene / α-olefin copolymer, propylene / α-olefin copolymer, ethylene / propylene / diene copolymer (EPDM), ethylene / propylene / styrene copolymer Olefinic soft polymers such as polymers;
(Vi) Vinyl-based soft polymers such as polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, vinyl acetate / styrene copolymer;
(Vii) epoxy-based soft polymers such as polyethylene oxide, polypropylene oxide, epichlorohydrin rubber;
(Viii) Fluorine-containing soft polymers such as vinylidene fluoride rubber and tetrafluoroethylene-propylene rubber;
(Ix) Other soft polymers such as natural rubber, polypeptide, protein, polyester thermoplastic elastomer, vinyl chloride thermoplastic elastomer, polyamide thermoplastic elastomer, and the like. Among these, a diene soft polymer and an acrylic soft polymer are preferable. In addition, these soft polymers may have a cross-linked structure or may have a functional group introduced by modification.
架橋剤の中でも、熱架橋性の架橋性基を含有する点で、有機過酸化物、および熱により架橋反応を生じうる架橋剤が好ましい。 As the crosslinking agent, for example, an organic peroxide, a crosslinking agent that exhibits an effect by heat or light, and the like are used. Moreover, a crosslinking agent may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.
Among the cross-linking agents, an organic peroxide and a cross-linking agent capable of causing a cross-linking reaction by heat are preferable because they contain a heat cross-linkable cross-linking group.
本発明のスラリー組成物は、上述した電極活物質、水溶性重合体、水及び粒子状バインダー以外に任意の成分を含みうる。その例を挙げると、導電材、補強材、レベリング剤、増粘剤、ナノ粒子及び電解液添加剤等が挙げられる。また、これらの成分は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 [1.5. (Optional ingredients)
The slurry composition of this invention can contain arbitrary components other than the electrode active material mentioned above, a water-soluble polymer, water, and a particulate binder. Examples thereof include conductive materials, reinforcing materials, leveling agents, thickeners, nanoparticles, electrolyte additives, and the like. Moreover, these components may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
導電材としては、例えば、ファーネスブラック、アセチレンブラック、ケッチェンブラック、カーボンブラック、グラファイト、気相成長カーボン繊維、およびカーボンナノチューブ等の導電性カーボンなどが挙げられる。導電材は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。
導電材の量は、電極活物質の量100重量部に対して、好ましくは1重量部~20重量部、より好ましくは1重量部~10重量部である。 The conductive material is a component that can improve electrical contact between the electrode active materials. By including a conductive material, the discharge rate characteristics of the lithium ion secondary battery can be improved.
Examples of the conductive material include furnace black, acetylene black, ketjen black, carbon black, graphite, vapor grown carbon fiber, and conductive carbon such as carbon nanotube. A conductive material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.
The amount of the conductive material is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material.
補強材の量は、電極活物質の量100重量部に対して、好ましくは0.01重量部以上、より好ましくは1重量部以上であり、好ましくは20重量部以下、より好ましくは10重量部以下である。補強材の量を上記範囲とすることにより、リチウムイオン二次電池は高い容量と高い負荷特性を示すことができる。 As the reinforcing material, for example, various inorganic and organic spherical, plate-like, rod-like or fibrous fillers can be used. A reinforcing material may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. By using the reinforcing material, a tough and flexible electrode can be obtained, and a lithium ion secondary battery exhibiting excellent long-term cycle characteristics can be realized.
The amount of the reinforcing material is preferably 0.01 parts by weight or more, more preferably 1 part by weight or more, preferably 20 parts by weight or less, more preferably 10 parts by weight with respect to 100 parts by weight of the electrode active material. It is as follows. By setting the amount of the reinforcing material in the above range, the lithium ion secondary battery can exhibit high capacity and high load characteristics.
レベリング剤の量は、電極活物質の量100重量部に対して、好ましくは0.01重量部~10重量部である。レベリング剤が上記範囲であることにより電極作製時の生産性、平滑性及び電池特性に優れる。また、界面活性剤を含有させることにより本発明のスラリー組成物において電極活物質の分散性を向上することができ、さらにそれにより得られる電極の平滑性を向上させることができる。 Examples of the leveling agent include surfactants such as alkyl surfactants, silicone surfactants, fluorine surfactants, and metal surfactants. A leveling agent may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios. By using a leveling agent, it is possible to prevent the repelling that occurs during the application of the slurry composition of the present invention, and to improve the smoothness of the electrode.
The amount of the leveling agent is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the leveling agent is within the above range, the productivity, smoothness, and battery characteristics during electrode production are excellent. Moreover, the dispersibility of an electrode active material can be improved in the slurry composition of this invention by containing surfactant, Furthermore, the smoothness of the electrode obtained by it can be improved.
ナノ粒子の量は、電極活物質の量100重量部に対して、好ましくは0.01重量部~10重量部である。ナノ粒子が上記範囲であることにより、本発明のスラリー組成物の安定性及び生産性を改善し、高い電池特性を実現できる。 Examples of the nanoparticles include particles such as fumed silica and fumed alumina. One kind of nanoparticles may be used alone, or two or more kinds of nanoparticles may be used in combination at any ratio. Since the thixotropy of the slurry composition of this invention can be adjusted when it contains a nanoparticle, the leveling property of the electrode obtained by it can be improved.
The amount of the nanoparticles is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the nanoparticles are in the above range, the stability and productivity of the slurry composition of the present invention can be improved, and high battery characteristics can be realized.
電解液添加剤の量は、電極活物質の量100重量部に対して、好ましくは0.01重量部~10重量部である。電解液添加剤の量を上記範囲にすることにより、サイクル特性及び高温特性に優れたリチウムイオン二次電池を実現できる。 Examples of the electrolytic solution additive include vinylene carbonate. One electrolyte solution additive may be used alone, or two or more electrolyte solution additives may be used in combination at any ratio. By using the electrolytic solution additive, for example, decomposition of the electrolytic solution can be suppressed.
The amount of the electrolytic solution additive is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. By setting the amount of the electrolytic solution additive in the above range, a lithium ion secondary battery excellent in cycle characteristics and high temperature characteristics can be realized.
上述した構成を有するので、本発明のスラリー組成物は、通常、以下の利点を有する。
本発明のスラリー組成物は、分散性に優れる。すなわち、本発明のスラリー組成物においては、電極活物質、粒子状バインダー、導電材等の成分が均一に分散している。そのため、本発明のスラリー組成物を用いて製造される電極活物質層においても、前記の成分を均一に分散させることができるので、リチウムイオン二次電池の特性を改善することができる。 [1.6. Properties of slurry composition]
Since it has the above-described configuration, the slurry composition of the present invention usually has the following advantages.
The slurry composition of the present invention is excellent in dispersibility. That is, in the slurry composition of the present invention, components such as an electrode active material, a particulate binder, and a conductive material are uniformly dispersed. Therefore, also in the electrode active material layer manufactured using the slurry composition of this invention, since the said component can be disperse | distributed uniformly, the characteristic of a lithium ion secondary battery can be improved.
本発明のスラリー組成物は、例えば、電極活物質、水溶性重合体及び水、並びに必要に応じて粒子状バインダー及び任意の成分を混合して製造しうる。この際の具体的な手順は任意である。例えば、電極活物質、水溶性重合体、水、粒子状バインダー及び導電材を含むスラリー組成物を製造する場合には、水に電極活物質、水溶性重合体、粒子状バインダー及び導電材を同時に混合する方法;水に水溶性重合体を溶解した後、水に分散させた粒子状バインダーを混合し、その後で電極活物質及び導電材を混合する方法;水に分散させた粒子状バインダーに電極活物質及び導電材を混合し、この混合物に水に溶解させた水溶性重合体を混合する方法;などが挙げられる。 [1.7. Method for producing slurry composition]
The slurry composition of the present invention can be produced, for example, by mixing an electrode active material, a water-soluble polymer and water, and if necessary, a particulate binder and optional components. The specific procedure at this time is arbitrary. For example, when producing a slurry composition containing an electrode active material, a water-soluble polymer, water, a particulate binder and a conductive material, the electrode active material, the water-soluble polymer, the particulate binder and the conductive material are simultaneously added to water. Method of mixing; after dissolving water-soluble polymer in water, mixing particulate binder dispersed in water, and then mixing electrode active material and conductive material; electrode in particulate binder dispersed in water And a method of mixing an active material and a conductive material, and mixing a water-soluble polymer dissolved in water into the mixture.
本発明のスラリー組成物の膜を集電体上に形成し、前記の膜を乾燥することを含む製造方法により、本発明の電極(リチウムイオン二次電池用電極)を得ることができる。 [2. Electrode for lithium ion secondary battery]
The electrode of the present invention (electrode for a lithium ion secondary battery) can be obtained by a production method including forming a film of the slurry composition of the present invention on a current collector and drying the film.
集電体は、電気導電性を有し、且つ、電気化学的に耐久性のある材料であれば特に制限されないが、耐熱性を有するため金属材料が好ましい。集電体の材料としては、例えば、鉄、銅、アルミニウム、ニッケル、ステンレス鋼、チタン、タンタル、金、白金などが挙げられる。中でも、正極に用いる集電体としてはアルミニウムが好ましく、負極に用いる集電体としては銅が好ましい。前記の材料は、1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 [2.1. Current collector]
The current collector is not particularly limited as long as it has electrical conductivity and is electrochemically durable, but a metal material is preferable because it has heat resistance. Examples of the material for the current collector include iron, copper, aluminum, nickel, stainless steel, titanium, tantalum, gold, and platinum. Among them, the current collector used for the positive electrode is preferably aluminum, and the current collector used for the negative electrode is preferably copper. One kind of the above materials may be used alone, or two or more kinds thereof may be used in combination at any ratio.
集電体は、電極活物質層との密着強度を高めるため、表面に予め粗面化処理して使用することが好ましい。粗面化方法としては、例えば、機械的研磨法、電解研磨法、化学研磨法などが挙げられる。機械的研磨法においては、例えば、研磨剤粒子を固着した研磨布紙、砥石、エメリバフ、鋼線などを備えたワイヤーブラシ等が使用される。また、電極活物質層の密着強度や導電性を高めるために、集電体の表面に中間層を形成してもよい。 The shape of the current collector is not particularly limited, but a sheet shape having a thickness of about 0.001 mm to 0.5 mm is preferable.
In order to increase the adhesion strength with the electrode active material layer, the current collector is preferably used after roughening the surface in advance. Examples of the roughening method include a mechanical polishing method, an electrolytic polishing method, and a chemical polishing method. In the mechanical polishing method, for example, an abrasive cloth paper to which abrasive particles are fixed, a grindstone, an emery buff, a wire brush provided with a steel wire, or the like is used. In order to increase the adhesion strength and conductivity of the electrode active material layer, an intermediate layer may be formed on the surface of the current collector.
集電体を用意した後で、集電体上に、本発明のスラリー組成物の膜を形成する。この際、通常は、本発明のスラリー組成物を塗布することにより、スラリー組成物の膜を形成する。また、スラリー組成物は、集電体の片面に塗布してもよく、両面に塗布してもよい。 [2.2. Application of slurry composition)
After preparing the current collector, a film of the slurry composition of the present invention is formed on the current collector. Under the present circumstances, the film | membrane of a slurry composition is normally formed by apply | coating the slurry composition of this invention. Moreover, a slurry composition may be apply | coated to the single side | surface of a collector, and may be apply | coated to both surfaces.
また、スラリー組成物の膜の厚みは、目的とする電極活物質層の厚みに応じて適宜に設定しうる。 There is no restriction | limiting in the coating method, For example, methods, such as a doctor blade method, a dip method, a reverse roll method, a direct roll method, a gravure method, an extrusion method, a brush coating method, are mentioned.
Further, the thickness of the slurry composition film can be appropriately set according to the thickness of the target electrode active material layer.
スラリー組成物の膜を形成した後、乾燥により、この膜から水等の液体を除去する。これにより、電極活物質及び水溶性重合体を含む電極活物質層が集電体の表面に形成され、電極が得られる。 [2.3. (Drying the membrane)
After forming the slurry composition film, the liquid such as water is removed from the film by drying. Thereby, the electrode active material layer containing an electrode active material and a water-soluble polymer is formed in the surface of an electrical power collector, and an electrode is obtained.
乾燥温度及び乾燥時間は、スラリー組成物の膜から水を除去できる温度と時間が好ましい。具体的な範囲を挙げると、乾燥時間は好ましくは1分~30分であり、乾燥温度は好ましくは40℃~180℃である。 Examples of the drying method include drying with warm air, hot air, low-humidity air, or the like; vacuum drying; drying with irradiation of energy rays such as infrared rays, far infrared rays, or electron beams. Among these, a drying method by irradiation with far infrared rays is preferable.
The drying temperature and drying time are preferably a temperature and a time at which water can be removed from the slurry composition film. Specifically, the drying time is preferably 1 minute to 30 minutes, and the drying temperature is preferably 40 ° C. to 180 ° C.
スラリー組成物の膜を乾燥させた後で、必要に応じて、例えば金型プレス又はロールプレスなどを用い、電極活物質層に加圧処理を施すことが好ましい。加圧処理により、電極活物質層の空隙率を低くすることができる。空隙率は、好ましくは5%以上、より好ましくは7%以上であり、好ましくは30%以下、より好ましくは20%以下である。空隙率を前記範囲の下限値以上とすることにより、高い体積容量が得易くなり、電極活物質層を集電体から剥がれ難くすることができる。また、上限値以下とすることにより高い充電効率及び放電効率が得られる。 [2.4. Arbitrary process]
After drying the slurry composition film, it is preferable to apply pressure treatment to the electrode active material layer, for example, using a die press or a roll press, if necessary. By the pressure treatment, the porosity of the electrode active material layer can be lowered. The porosity is preferably 5% or more, more preferably 7% or more, preferably 30% or less, more preferably 20% or less. By setting the porosity to be equal to or higher than the lower limit of the above range, a high volume capacity can be easily obtained, and the electrode active material layer can be made difficult to peel from the current collector. Moreover, high charging efficiency and discharge efficiency are acquired by setting it as an upper limit or less.
上述した要領で形成される電極活物質層の厚みは、要求される電池性能に応じて任意に設定しうる。
例えば、正極活物質層の厚みは、好ましくは5μm以上、より好ましくは10μm以上であり、好ましくは300μm以下、より好ましくは250μm以下である。正極活物質層の厚みが上記範囲にあることにより、負荷特性及びエネルギー密度の両方で高い特性を実現できる。
また、例えば、負極活物質層の厚みは、好ましくは5μm以上、より好ましくは20μm以上、特に好ましくは30μm以上であり、好ましくは1000μm以下、より好ましくは500μm以下、更に好ましくは300μm以下、特に好ましくは250μm以下である。負極活物質層の厚みが上記範囲にあることにより、負荷特性及びサイクル特性を良好にすることができる。 [2.5. Other matters related to electrodes]
The thickness of the electrode active material layer formed as described above can be arbitrarily set according to the required battery performance.
For example, the thickness of the positive electrode active material layer is preferably 5 μm or more, more preferably 10 μm or more, preferably 300 μm or less, more preferably 250 μm or less. When the thickness of the positive electrode active material layer is in the above range, high characteristics can be realized in both load characteristics and energy density.
Further, for example, the thickness of the negative electrode active material layer is preferably 5 μm or more, more preferably 20 μm or more, particularly preferably 30 μm or more, preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 300 μm or less, particularly preferably. Is 250 μm or less. When the thickness of the negative electrode active material layer is in the above range, load characteristics and cycle characteristics can be improved.
本発明のリチウムイオン二次電池は、正極、負極及び電解液を備える。また、本発明のリチウムイオン二次電池は、セパレータを備えていてもよい。ただし、前記の負極及び正極の一方又は両方は、本発明の電極である。本発明の電極を備えることにより、本発明のリチウムイオン二次電池は、サイクル特性及び出力特性に優れ、中でも高温サイクル特性及び低温特性を顕著に改善することができる。本発明のリチウムイオン二次電池がサイクル特性及び出力特性に優れる理由は定かでは無いが、本発明者の検討によれば、以下の理由によるものと推察される。 [3. Lithium ion secondary battery]
The lithium ion secondary battery of this invention is equipped with a positive electrode, a negative electrode, and electrolyte solution. The lithium ion secondary battery of the present invention may include a separator. However, one or both of the negative electrode and the positive electrode is an electrode of the present invention. By providing the electrode of the present invention, the lithium ion secondary battery of the present invention is excellent in cycle characteristics and output characteristics, and in particular, the high temperature cycle characteristics and the low temperature characteristics can be remarkably improved. The reason why the lithium ion secondary battery of the present invention is excellent in cycle characteristics and output characteristics is not clear, but according to the study of the present inventors, it is presumed that the reason is as follows.
また、本発明の電極においては、水溶性重合体の一部は電極活物質の表面に付着している。すなわち、電極活物質の表面の少なくとも一部は、水溶性重合体の被膜により覆われていると考えられる。この被膜により、電解液の分解を抑制することができるので、電解液の分解により生じるガスを原因とした抵抗の上昇を抑制できる。
このような理由により、本発明のリチウムイオン二次電池は、優れたサイクル特性を発現しうるものと推察される。 In the electrode of the present invention, the adhesion strength between the electrode active material layer and the current collector is high. Therefore, even if the electrode active material repeatedly expands and contracts due to charge and discharge, the electrode active material layer and the current collector are unlikely to peel off. Further, since the water-soluble polymer has high binding properties, the contact between the electrode active material layers and the contact between the electrode active material and the conductive material are hardly impaired. For this reason, since the electric conduction path is not easily cut by charging / discharging, the degree of increase in resistance accompanying charging / discharging is low.
Moreover, in the electrode of this invention, a part of water-soluble polymer has adhered to the surface of the electrode active material. That is, it is considered that at least a part of the surface of the electrode active material is covered with a water-soluble polymer film. Since the coating can suppress decomposition of the electrolytic solution, it is possible to suppress an increase in resistance caused by a gas generated by the decomposition of the electrolytic solution.
For these reasons, it is assumed that the lithium ion secondary battery of the present invention can exhibit excellent cycle characteristics.
また、フッ素含有(メタ)アクリル酸エステル単量体単位を含むことにより、電解液に対する水溶性重合体の膨潤性を小さくできる。そのため、リチウムイオン二次電池において電極の膨潤を抑制できる。よって、電極活物質層の膨潤を抑制して、電極活物質間の距離を小さくできる。したがって、電極の内部抵抗を抑制できる。
さらに、一般にフッ素含有(メタ)アクリル酸エステル単量体単位を含む重合体は電解液とのなじみが悪くなる傾向があるが、本発明に係る水溶性重合体においては、水酸基含有単量体単位及び酸基含有単量体単位の作用により電解液とのなじみを悪くさせることはないと考えられる。むしろ、水溶性重合体が水酸基及び酸基を有するので、極性溶媒に対する水溶性重合体の親和性は高くなり、電極活物質層は電解液に対する濡れ性に優れる。したがって、電極活物質層に電解液が容易に進入できるようになるので、電解液と電極活物質との間での電気反応の場を容易に広くすることができ、電池の内部抵抗を抑制できる。
このような理由により、本発明のリチウムイオン二次電池は、優れた出力特性を発現しうるものと推察される。 Furthermore, since the fluorine-containing (meth) acrylic acid ester monomer unit has high ionic conductivity, the water-soluble polymer also has high ionic conductivity. Therefore, even if the water-soluble polymer film covers the surface of the electrode active material, the degree of resistance increase due to the film can be reduced. Therefore, the resistance of the electrode can be suppressed.
Moreover, the swelling property of the water-soluble polymer with respect to electrolyte solution can be made small by including a fluorine-containing (meth) acrylic acid ester monomer unit. Therefore, swelling of the electrode can be suppressed in the lithium ion secondary battery. Therefore, swelling of the electrode active material layer can be suppressed, and the distance between the electrode active materials can be reduced. Therefore, the internal resistance of the electrode can be suppressed.
Furthermore, in general, polymers containing fluorine-containing (meth) acrylic acid ester monomer units tend to become less compatible with the electrolyte solution, but in the water-soluble polymer according to the present invention, hydroxyl group-containing monomer units. In addition, it is considered that the compatibility with the electrolytic solution is not deteriorated by the action of the acid group-containing monomer unit. Rather, since the water-soluble polymer has a hydroxyl group and an acid group, the affinity of the water-soluble polymer with respect to the polar solvent is increased, and the electrode active material layer has excellent wettability with respect to the electrolytic solution. Accordingly, since the electrolytic solution can easily enter the electrode active material layer, the electric reaction field between the electrolytic solution and the electrode active material can be easily widened, and the internal resistance of the battery can be suppressed. .
For these reasons, it is assumed that the lithium ion secondary battery of the present invention can exhibit excellent output characteristics.
電解液としては、例えば、非水系の溶媒に支持電解質としてリチウム塩を溶解したものを使用してもよい。リチウム塩としては、例えば、LiPF6、LiAsF6、LiBF4、LiSbF6、LiAlCl4、LiClO4、CF3SO3Li、C4F9SO3Li、CF3COOLi、(CF3CO)2NLi、(CF3SO2)2NLi、(C2F5SO2)NLiなどのリチウム塩が挙げられる。特に溶媒に溶けやすく高い解離度を示すLiPF6、LiClO4、CF3SO3Liは好適に用いられる。これらは1種類を単独で用いてもよく、2種類以上を任意の比率で組み合わせて用いてもよい。 [3.1. Electrolyte)
As the electrolytic solution, for example, a solution obtained by dissolving a lithium salt as a supporting electrolyte in a non-aqueous solvent may be used. Examples of the lithium salt include LiPF 6 , LiAsF 6 , LiBF 4 , LiSbF 6 , LiAlCl 4 , LiClO 4 , CF 3 SO 3 Li, C 4 F 9 SO 3 Li, CF 3 COOLi, (CF 3 CO) 2 NLi , (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) NLi, and other lithium salts. In particular, LiPF 6 , LiClO 4 , and CF 3 SO 3 Li that are easily soluble in a solvent and exhibit a high degree of dissociation are preferably used. One of these may be used alone, or two or more of these may be used in combination at any ratio.
セパレーターとしては、通常、気孔部を有する多孔性基材を用いる。セパレーターの例を挙げると、(a)気孔部を有する多孔性セパレーター、(b)片面または両面に高分子コート層が形成された多孔性セパレーター、(c)無機セラミック粉末を含む多孔質の樹脂コート層が形成された多孔性セパレーター、などが挙げられる。これらの例としては、ポリプロピレン系、ポリエチレン系、ポリオレフィン系、またはアラミド系多孔性セパレーター;ポリビニリデンフルオリド、ポリエチレンオキシド、ポリアクリロニトリルまたはポリビニリデンフルオリドヘキサフルオロプロピレン共重合体などの固体高分子電解質用またはゲル状高分子電解質用の高分子フィルム;ゲル化高分子コート層がコートされたセパレーター;無機フィラーと無機フィラー用分散剤とからなる多孔膜層がコートされたセパレーター;などが挙げられる。 [3.2. separator〕
As the separator, a porous substrate having a pore portion is usually used. Examples of separators include (a) a porous separator having pores, (b) a porous separator having a polymer coating layer formed on one or both sides, and (c) a porous resin coat containing inorganic ceramic powder. And a porous separator having a layer formed thereon. Examples of these include polypropylene, polyethylene, polyolefin or aramid porous separators; for solid polymer electrolytes such as polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile or polyvinylidene fluoride hexafluoropropylene copolymers Or a polymer film for a gel polymer electrolyte; a separator coated with a gelled polymer coat layer; a separator coated with a porous film layer composed of an inorganic filler and an inorganic filler dispersant; and the like.
本発明のリチウムイオン二次電池の製造方法は、特に限定されない。例えば、上述した負極と正極とをセパレーターを介して重ね合わせ、これを電池形状に応じて巻く、折るなどして電池容器に入れ、電池容器に電解液を注入して封口してもよい。さらに、必要に応じてエキスパンドメタル;ヒューズ、PTC素子などの過電流防止素子;リード板などを入れ、電池内部の圧力上昇、過充放電の防止をしてもよい。電池の形状は、例えば、ラミネートセル型、コイン型、ボタン型、シート型、円筒型、角形、扁平型などいずれであってもよい。 [3.3. Method for producing lithium ion secondary battery]
The manufacturing method of the lithium ion secondary battery of the present invention is not particularly limited. For example, the above-described negative electrode and positive electrode may be overlapped via a separator, and this may be wound or folded in accordance with the shape of the battery and placed in the battery container, and the electrolyte may be injected into the battery container and sealed. Furthermore, if necessary, an expanded metal; an overcurrent prevention element such as a fuse or a PTC element; a lead plate or the like may be inserted to prevent an increase in pressure inside the battery or overcharge / discharge. The shape of the battery may be any of, for example, a laminate cell type, a coin type, a button type, a sheet type, a cylindrical type, a square type, and a flat type.
以下の説明において、量を表す「%」及び「部」は、別に断らない限り重量基準である。また、以下に説明する操作は、別に断らない限り、常温及び常圧の条件において行った。 Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the embodiments shown below, and may be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.
In the following description, “%” and “part” representing amounts are based on weight unless otherwise specified. In addition, the operations described below were performed under normal temperature and normal pressure conditions unless otherwise specified.
(1)密着強度
実施例及び比較例で製造した電極を、長さ100mm、幅10mmの長方形に切り出して試験片とした。この試験片を、電極活物質層の表面を下にして、電極活物質層の表面にセロハンテープを貼り付けた。この際、セロハンテープとしてはJIS Z1522に規定されるものを用いた。また、セロハンテープは水平な試験台に固定しておいた。その後、集電体の一端を鉛直上方に引張り速度50mm/分で引っ張って剥がしたときの応力を測定した。この測定を3回行い、測定値の平均値を求めて、当該平均値をピール強度とした。ピール強度が大きいほど、電極活物質層の集電体への結着力が大きいこと、すなわち、密着強度が大きいことを示す。 [Evaluation item]
(1) Adhesion strength The electrodes produced in the examples and comparative examples were cut into rectangles having a length of 100 mm and a width of 10 mm to obtain test pieces. Cellophane tape was affixed on the surface of the electrode active material layer of the test piece with the surface of the electrode active material layer facing down. At this time, a cellophane tape defined in JIS Z1522 was used. The cellophane tape was fixed on a horizontal test bench. Then, the stress when one end of the current collector was pulled vertically upward at a pulling speed of 50 mm / min and peeled was measured. This measurement was performed three times, the average value of the measured values was obtained, and the average value was taken as the peel strength. The higher the peel strength, the higher the binding force of the electrode active material layer to the current collector, that is, the higher the adhesion strength.
実施例及び比較例で製造した電極を、長さ100mm、幅10mmの長方形に切り出して試験片とした。この試験片の電極活物質層を外側にし、集電体側を内側にして、様々な曲げ径をもつSUS棒に試験片を巻き付け、電極活物質層にひびが入らない最小曲げ径を目視にて観察した。この曲げ径が小さいほど、柔軟性に優れていることを示す。 (2) Flexibility The electrodes manufactured in Examples and Comparative Examples were cut into rectangles having a length of 100 mm and a width of 10 mm to obtain test pieces. With the electrode active material layer of this test piece on the outside and the current collector side on the inside, the test piece is wrapped around a SUS rod having various bending diameters, and the minimum bending diameter that does not crack the electrode active material layer is visually observed. Observed. It shows that it is excellent in the softness, so that this bending diameter is small.
実施例及び比較例で製造したリチウムイオン二次電池電極用のスラリー組成物について、B型粘度計により、60rpmにおける粘度η0を測定した。また、そのスラリー組成物を室温で7日間保管し、保管後に60rpmにおける粘度η1を測定した。Δη(%)=η1/η0×100を算出した。Δηの値が小さいほど、分散安定性に優れることを示す。 (3) Dispersion stability About the slurry composition for lithium ion secondary battery electrodes manufactured by the Example and the comparative example, the viscosity (eta) 0 in 60 rpm was measured with the B-type viscosity meter. The slurry composition was stored at room temperature for 7 days, and after storage, the viscosity η1 at 60 rpm was measured. Δη (%) = η1 / η0 × 100 was calculated. The smaller the value of Δη, the better the dispersion stability.
実施例及び比較例においてラミネート型セルのリチウムイオン二次電池を作製し、25℃の環境下で24時間静置した。その後、この二次電池を25℃の環境下で、1Cの定電流法にて4.2Vに充電し3.0Vまで放電する充放電の操作を行い、初期容量C0を測定した。さらに、この二次電池を60℃環境下で、前記の充放電と同様に充放電を繰り返し、1000サイクル後の容量C2を測定した。高温サイクル特性は、ΔC=C2/C0×100(%)で示す容量維持率にて評価した。この容量維持率が高いほど、高温サイクル特性に優れることを示す。 (4) Cycle characteristics In the examples and comparative examples, a lithium ion secondary battery of a laminate type cell was produced and allowed to stand for 24 hours in an environment of 25 ° C. Thereafter, this secondary battery was charged and discharged to 4.2 V and discharged to 3.0 V by a 1 C constant current method in an environment of 25 ° C., and the initial capacity C0 was measured. Furthermore, this secondary battery was repeatedly charged and discharged in the same manner as the above-described charging and discharging in a 60 ° C. environment, and the capacity C2 after 1000 cycles was measured. The high-temperature cycle characteristics were evaluated by a capacity retention rate represented by ΔC = C2 / C0 × 100 (%). It shows that it is excellent in high temperature cycling characteristics, so that this capacity | capacitance maintenance factor is high.
実施例及び比較例においてラミネート型セルのリチウムイオン二次電池を作製し、25℃の環境下で24時間静置した。その後、25℃の環境下で、0.1Cの定電流法にて5時間かけて充電する操作を行い、その時の電圧V0を測定した。その後、-10℃環境下で、1Cの放電レートにて放電の操作を行い、放電開始15秒後の電圧V1を測定した。低温特性は、ΔV=V0-V1で示す電圧変化にて評価した。この電圧変化が小さいほど、低温特性に優れることを示す。 (5) Low temperature characteristics In the examples and comparative examples, lithium ion secondary batteries of laminate type cells were produced and allowed to stand for 24 hours in an environment of 25 ° C. Thereafter, in a 25 ° C. environment, an operation of charging with a constant current method of 0.1 C over 5 hours was performed, and the voltage V0 at that time was measured. Thereafter, a discharge operation was performed at a discharge rate of 1 C in an environment of −10 ° C., and the voltage V1 15 seconds after the start of discharge was measured. The low temperature characteristics were evaluated by a voltage change represented by ΔV = V0−V1. It shows that it is excellent in a low-temperature characteristic, so that this voltage change is small.
(1-1.水溶性重合体の製造)
攪拌機付き5MPa耐圧容器に、2-ヒドロキシエチルアクリレート(水酸基含有単量体)4部、メタクリル酸(酸基含有単量体)32.5部、エチレンジメタクリレート(架橋性単量体)0.8部、2,2,2-トリフルオロエチルメタクリレート(フッ素含有(メタ)アクリル酸エステル単量体)7.5部、エチルアクリレート(任意の単量体)55.2部、ドデシルベンゼンスルホン酸ナトリウム(界面活性剤)0.1部、t-ドデシルメルカプタン(分子量調節剤)0.1部、イオン交換水150部、及び過硫酸カリウム(重合開始剤)0.5部を入れ、十分に攪拌した。その後、60℃に加温して重合を開始した。重合転化率が96%になった時点で冷却し反応を停止して、水溶性重合体を含む混合物を得た。上記水溶性重合体を含む混合物に10%アンモニア水を添加してpH8に調整し、所望の水溶性重合体を含む水溶液を得た。この水溶液の一部を取り出し、濃度を1%に調整して、調整後の水溶液の粘度を測定した。 [Example 1]
(1-1. Production of water-soluble polymer)
In a 5 MPa pressure vessel equipped with a stirrer, 4 parts 2-hydroxyethyl acrylate (hydroxyl group-containing monomer), 32.5 parts methacrylic acid (acid group-containing monomer), 0.8 ethylene dimethacrylate (crosslinkable monomer) Parts, 2,2,2-trifluoroethyl methacrylate (fluorine-containing (meth) acrylic acid ester monomer) 7.5 parts, ethyl acrylate (optional monomer) 55.2 parts, sodium dodecylbenzenesulfonate ( Surfactant (0.1 part), t-dodecyl mercaptan (molecular weight regulator) (0.1 part), ion-exchanged water (150 parts), and potassium persulfate (polymerization initiator) (0.5 part) were added and sufficiently stirred. Then, it heated to 60 degreeC and superposition | polymerization was started. When the polymerization conversion reached 96%, the reaction was stopped by cooling to obtain a mixture containing a water-soluble polymer. 10% aqueous ammonia was added to the mixture containing the water-soluble polymer to adjust the pH to 8 to obtain an aqueous solution containing the desired water-soluble polymer. A part of this aqueous solution was taken out, the concentration was adjusted to 1%, and the viscosity of the adjusted aqueous solution was measured.
攪拌機付き5MPa耐圧容器に、アクリル酸2-エチルヘキシル76部、アクリロニトリル20部、イタコン酸4部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム1部、イオン交換水150部、及び重合開始剤として過硫酸カリウム0.8部を入れ、十分に攪拌した。その後、50℃に加温して重合を開始した。重合転化率が96%になった時点で冷却し反応を停止して、粒子状バインダーを含む混合物を得た。上記粒子状バインダーを含む混合物に5%水酸化ナトリウム水溶液を添加してpH8に調整した。その後、加熱減圧蒸留によって粒子状バインダーを含む混合物から未反応単量体の除去を行った後、その混合物を30℃以下まで冷却し、所望の粒子状バインダーを含む水分散液を得た。 (1-2. Production of particulate binder)
In a 5 MPa pressure vessel equipped with a stirrer, 76 parts of 2-ethylhexyl acrylate, 20 parts of acrylonitrile, 4 parts of itaconic acid, 1 part of sodium dodecylbenzenesulfonate as an emulsifier, 150 parts of ion-exchanged water, and potassium persulfate as a polymerization initiator were added in an amount of 0. 8 parts was added and stirred thoroughly. Then, it heated to 50 degreeC and superposition | polymerization was started. When the polymerization conversion reached 96%, the reaction was stopped by cooling to obtain a mixture containing a particulate binder. The mixture containing the particulate binder was adjusted to pH 8 by adding a 5% aqueous sodium hydroxide solution. Then, after removing the unreacted monomer from the mixture containing the particulate binder by heating under reduced pressure, the mixture was cooled to 30 ° C. or lower to obtain an aqueous dispersion containing the desired particulate binder.
正極活物質として体積平均粒子径12μmのLiCoO2を100部、導電材としてアセチレンブラック(電気化学工業社製「HS-100」)を2部、増粘剤として上記工程(1-1)の水溶性重合体を含む水溶液を固形分相当で2部、バインダーとして上記工程(1-2)の粒子状バインダーを含む水分散体の濃度を40%に調製したものを固形分相当で2部、及びイオン交換水を混合した。イオン交換水の量は、全固形分濃度が40%となる量とした。これらをプラネタリーミキサーにより混合し、正極用スラリー組成物を調製した。この正極用スラリー組成物について、上述した要領で、分散安定性を評価した。 (1-3. Production of positive electrode)
100 parts of LiCoO 2 having a volume average particle diameter of 12 μm as the positive electrode active material, 2 parts of acetylene black (“HS-100” manufactured by Denki Kagaku Kogyo Co., Ltd.) as the conductive material, and the aqueous solution of the above step (1-1) as the thickener 2 parts of an aqueous solution containing a conductive polymer corresponding to the solid content, 2 parts of the aqueous dispersion containing the particulate binder in the above step (1-2) as a binder prepared to a concentration of 40%, and Ion exchange water was mixed. The amount of ion-exchanged water was such that the total solid concentration was 40%. These were mixed by a planetary mixer to prepare a positive electrode slurry composition. This positive electrode slurry composition was evaluated for dispersion stability in the manner described above.
攪拌機付き5MPa耐圧容器に、1,3-ブタジエン33.5部、イタコン酸3.5部、スチレン62部、2-ヒドロキシエチルアクリレート1部、乳化剤としてドデシルベンゼンスルホン酸ナトリウム0.4部、イオン交換水150部、及び重合開始剤として過硫酸カリウム0.5部を入れ、十分に攪拌した。その後、50℃に加温して重合を開始した。重合転化率が96%になった時点で冷却し反応を停止して、粒子状バインダー(SBR)を含む混合物を得た。上記粒子状バインダーを含む混合物に5%水酸化ナトリウム水溶液を添加してpH8に調整した。その後、加熱減圧蒸留によって粒子状バインダーを含む混合物から未反応単量体の除去を行った後、その混合物を30℃以下まで冷却し、所望の粒子状バインダーを含む水分散液(負極用バインダー組成物)を得た。 (1-4. Production of binder composition for negative electrode)
In a 5 MPa pressure vessel with a stirrer, 33.5 parts of 1,3-butadiene, 3.5 parts of itaconic acid, 62 parts of styrene, 1 part of 2-hydroxyethyl acrylate, 0.4 part of sodium dodecylbenzenesulfonate as an emulsifier, ion exchange 150 parts of water and 0.5 part of potassium persulfate as a polymerization initiator were added and sufficiently stirred. Then, it heated to 50 degreeC and superposition | polymerization was started. When the polymerization conversion rate reached 96%, the reaction was stopped by cooling to obtain a mixture containing a particulate binder (SBR). The mixture containing the particulate binder was adjusted to pH 8 by adding a 5% aqueous sodium hydroxide solution. Then, after removing the unreacted monomer from the mixture containing the particulate binder by heating under reduced pressure, the mixture is cooled to 30 ° C. or lower, and an aqueous dispersion containing the desired particulate binder (a binder composition for negative electrode) Product).
ディスパー付きのプラネタリーミキサーに、負極活物質として比表面積5.5m2/gの人造黒鉛(体積平均粒子径:24.5μm)100部、及び増粘剤としてカルボキシメチルセルロース(日本製紙ケミカル社製「MAC-350HC」)の2%水溶液を固形分相当で1部入れ、さらにイオン交換水で固形分濃度65%に調整した後、25℃で60分間混合した。次に、イオン交換水で固形分濃度60%に調整した後、さらに25℃で15分間混合し、混合液を得た。上記混合液に、上記工程(1-4)の粒子状バインダーを含む水分散液を固形分相当量で1.0部、及びイオン交換水を入れ、最終固形分濃度52%となるように調整し、さらに10分間混合した。これを減圧下で脱泡処理して、流動性の良い負極用スラリー組成物を得た。 (1-5. Production of slurry composition for negative electrode)
In a planetary mixer with a disper, 100 parts of artificial graphite (volume average particle diameter: 24.5 μm) having a specific surface area of 5.5 m 2 / g as a negative electrode active material, and carboxymethyl cellulose (manufactured by Nippon Paper Chemical Co., Ltd. “ 1 part of a 2% aqueous solution of “MAC-350HC”) corresponding to the solid content was added, and the solid content concentration was adjusted to 65% with ion-exchanged water, followed by mixing at 25 ° C. for 60 minutes. Next, after adjusting to 60% of solid content concentration with ion-exchange water, it mixed for 15 minutes at 25 degreeC, and the liquid mixture was obtained. 1.0 part of the aqueous dispersion containing the particulate binder in the above step (1-4) and ion-exchanged water are added to the mixed liquid, and the final solid content concentration is adjusted to 52%. And mixed for another 10 minutes. This was defoamed under reduced pressure to obtain a negative electrode slurry composition having good fluidity.
上記工程(1-5)で得られた負極用スラリー組成物を、コンマコーターで、集電体である厚さ20μmの銅箔の上に、乾燥後の膜厚が150μm程度になるように塗布し、乾燥させた。この乾燥は、銅箔を0.5m/分の速度で60℃のオーブン内を2分間かけて搬送することにより行った。その後、120℃にて2分間加熱処理して負極原反を得た。この負極原反をロールプレスで圧延して、負極活物質層の厚みが80μmの負極を得た。 (1-6. Production of negative electrode)
The negative electrode slurry composition obtained in the above step (1-5) was applied onto a 20 μm thick copper foil as a current collector with a comma coater so that the film thickness after drying was about 150 μm. And dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode original fabric was obtained by heat-processing at 120 degreeC for 2 minute (s). This negative electrode original fabric was rolled with a roll press to obtain a negative electrode having a negative electrode active material layer thickness of 80 μm.
単層のポリプロピレン製セパレーター(セルガード社製「セルガード2500」)を、5×5cm2の正方形に切り抜いた。 (1-7. Preparation of separator)
A single-layer polypropylene separator (“Celguard 2500” manufactured by Celgard) was cut into a 5 × 5 cm 2 square.
電池の外装として、アルミニウム包材外装を用意した。上記工程(1-3)で得られた正極を、4×4cm2の正方形に切り出し、集電体側の表面がアルミニウム包材外装に接するように配置した。正極の正極活物質層の面上に、上記工程(1-7)で得られた正方形のセパレーターを配置した。さらに、上記工程(1-6)で得られた負極を、4.2×4.2cm2の正方形に切り出し、これをセパレーター上に、負極活物質層側の表面がセパレーターに向かい合うよう配置した。電解液(溶媒:エチレンカーボネート/ジエチルカーボネート/ビニレンカーボネート=68.5/30/1.5体積比、電解質:濃度1MのLiPF6)を空気が残らないように注入した。さらに、アルミニウム包材の開口を密封するために、150℃のヒートシールをしてアルミニウム外装を閉口し、リチウムイオン二次電池を製造した。このリチウムイオン二次電池について、上述した要領で、高温サイクル特性及び低温特性を評価した。 (1-8. Lithium ion secondary battery)
An aluminum packaging exterior was prepared as the battery exterior. The positive electrode obtained in the above step (1-3) was cut into a 4 × 4 cm 2 square and placed so that the current collector-side surface was in contact with the aluminum packaging exterior. On the surface of the positive electrode active material layer of the positive electrode, the square separator obtained in the above step (1-7) was disposed. Further, the negative electrode obtained in the above step (1-6) was cut into a square of 4.2 × 4.2 cm 2 and arranged on the separator so that the surface on the negative electrode active material layer side faces the separator. An electrolyte solution (solvent: ethylene carbonate / diethyl carbonate / vinylene carbonate = 68.5 / 30 / 1.5 volume ratio, electrolyte: LiPF 6 having a concentration of 1 M) was injected so that no air remained. Furthermore, in order to seal the opening of the aluminum packaging material, heat sealing at 150 ° C. was performed to close the aluminum exterior, and a lithium ion secondary battery was manufactured. About this lithium ion secondary battery, the high temperature cycling characteristic and the low temperature characteristic were evaluated in the way mentioned above.
上記工程(1-1)において、2-ヒドロキシエチルアクリレートの量を0.8部に変更し、エチルアクリレートの量を58.4部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 2]
In the same manner as in Example 1, except that the amount of 2-hydroxyethyl acrylate was changed to 0.8 parts and the amount of ethyl acrylate was changed to 58.4 parts in the above step (1-1), lithium ion Secondary batteries were manufactured and evaluated.
上記工程(1-1)において、2-ヒドロキシエチルアクリレートの量を9.5部に変更し、エチルアクリレートの量を49.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 3]
In the same manner as in Example 1, except that the amount of 2-hydroxyethyl acrylate was changed to 9.5 parts and the amount of ethyl acrylate was changed to 49.7 parts in the above step (1-1), lithium ion Secondary batteries were manufactured and evaluated.
上記工程(1-1)において、2-ヒドロキシエチルアクリレートの代わりに2-ヒドロキシエチルメタクリレートを4部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 4]
A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 4 parts of 2-hydroxyethyl methacrylate was used instead of 2-hydroxyethyl acrylate in the above step (1-1).
2-ヒドロキシエチルアクリレートの代わりに酢酸ビニルを用いたこと以外は上記工程(1-1)と同様に共重合を行い、得られた重合体を水酸化ナトリウムにより加水分解することによって重合体の酢酸ビニル単位をビニルアルコール単位に変換して、水溶性重合体を含む水溶液を得た。ここで酢酸ビニル単位とは、酢酸ビニルを重合して形成される構造を有する構造単位を示す。また、ビニルアルコール単位とは、ビニルアルコールを重合して形成される構造を有する構造単位を示す。こうして得た水溶性重合体を含む水溶液を上記工程(1-3)において増粘剤として用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 5]
Copolymerization was carried out in the same manner as in the above step (1-1) except that vinyl acetate was used in place of 2-hydroxyethyl acrylate, and the resulting polymer was hydrolyzed with sodium hydroxide to produce a polymer acetic acid. The vinyl unit was converted to a vinyl alcohol unit to obtain an aqueous solution containing a water-soluble polymer. Here, the vinyl acetate unit refers to a structural unit having a structure formed by polymerizing vinyl acetate. Moreover, a vinyl alcohol unit shows the structural unit which has a structure formed by superposing | polymerizing vinyl alcohol. A lithium ion secondary battery was produced and evaluated in the same manner as in Example 1 except that the aqueous solution containing the water-soluble polymer thus obtained was used as a thickener in the above step (1-3).
上記工程(1-1)において、2,2,2-トリフルオロエチルメタクリレートの代わりにパーフルオロオクチルアクリレートを7.5部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 6]
A lithium ion secondary battery was prepared in the same manner as in Example 1 except that 7.5 parts of perfluorooctyl acrylate was used instead of 2,2,2-trifluoroethyl methacrylate in the above step (1-1). Manufactured and evaluated.
上記工程(1-1)において、2,2,2-トリフルオロエチルメタクリレートの代わりにパーフルオロブチルアクリレートを7.5部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 7]
A lithium ion secondary battery was prepared in the same manner as in Example 1 except that 7.5 parts of perfluorobutyl acrylate was used instead of 2,2,2-trifluoroethyl methacrylate in the above step (1-1). Manufactured and evaluated.
上記工程(1-1)において、2,2,2-トリフルオロエチルメタクリレートの量を0.2部に変更し、エチルアクリレートの量を62.5部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 8]
Same as Example 1 except that the amount of 2,2,2-trifluoroethyl methacrylate was changed to 0.2 parts and the amount of ethyl acrylate was changed to 62.5 parts in the above step (1-1). Thus, a lithium ion secondary battery was manufactured and evaluated.
上記工程(1-1)において、2,2,2-トリフルオロエチルメタクリレートの量を48部に変更し、エチルアクリレートの量を14.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 9]
In the same manner as in Example 1, except that the amount of 2,2,2-trifluoroethyl methacrylate was changed to 48 parts and the amount of ethyl acrylate was changed to 14.7 parts in the above step (1-1). A lithium ion secondary battery was manufactured and evaluated.
上記工程(1-1)において、メタクリル酸の量を22部に変更し、エチルアクリレートの量を65.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 10]
A lithium ion secondary battery was produced in the same manner as in Example 1 except that the amount of methacrylic acid was changed to 22 parts and the amount of ethyl acrylate was changed to 65.7 parts in the above step (1-1). And evaluated.
上記工程(1-1)において、メタクリル酸の量を48部に変更し、エチルアクリレートの量を39.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 11]
A lithium ion secondary battery was produced in the same manner as in Example 1, except that the amount of methacrylic acid was changed to 48 parts and the amount of ethyl acrylate was changed to 39.7 parts in the above step (1-1). And evaluated.
上記工程(1-1)において、メタクリル酸の代わりに2-アクリルアミド-2-メチルプロパンスルホン酸を25部用い、エチルアクリレートの量を62.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 12]
In the above step (1-1), the same procedure as in Example 1 was performed except that 25 parts of 2-acrylamido-2-methylpropanesulfonic acid was used instead of methacrylic acid and the amount of ethyl acrylate was changed to 62.7 parts. A lithium ion secondary battery was manufactured and evaluated.
上記工程(1-1)において、酸基含有単量体としてメタクリル酸30.0部及び2-アクリルアミド-2-メチルプロパンスルホン酸5.0部を組み合わせて用い、エチルアクリレートの量を52.7部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 13]
In the above step (1-1), 30.0 parts of methacrylic acid and 5.0 parts of 2-acrylamido-2-methylpropanesulfonic acid were used in combination as the acid group-containing monomer, and the amount of ethyl acrylate was 52.7. A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that the part was changed to a part.
上記工程(1-1)において、エチレンジメタクリレートの量を0.1部に変更し、エチルアクリレートの量を55.9部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 14]
In the step (1-1), the lithium ion secondary was changed in the same manner as in Example 1 except that the amount of ethylene dimethacrylate was changed to 0.1 part and the amount of ethyl acrylate was changed to 55.9 parts. A battery was manufactured and evaluated.
上記工程(1-1)において、エチレンジメタクリレートの量を1.8部に変更し、エチルアクリレートの量を54.2部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 15]
In the same manner as in Example 1, except that the amount of ethylene dimethacrylate was changed to 1.8 parts and the amount of ethyl acrylate was changed to 54.2 parts in the above step (1-1), lithium ion secondary A battery was manufactured and evaluated.
上記工程(1-1)において、エチレンジメタクリレートの代わりにグリシジルメタクリレートを0.8部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 16]
A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 0.8 part of glycidyl methacrylate was used in place of ethylene dimethacrylate in the above step (1-1).
上記工程(1-1)において、エチレンジメタクリレートの代わりにアリルグリシジルエーテルを0.8部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 17]
A lithium ion secondary battery was manufactured and evaluated in the same manner as in Example 1 except that 0.8 part of allyl glycidyl ether was used in place of ethylene dimethacrylate in the above step (1-1).
上記工程(1-3)において、バインダーを使用しなかったこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 18]
In the step (1-3), a lithium ion secondary battery was produced and evaluated in the same manner as in Example 1 except that no binder was used.
(19-1.負極用スラリー組成物の製造)
ディスパー付きのプラネタリーミキサーに、負極活物質として比表面積5.5m2/gの人造黒鉛(平均粒子径:24.5μm)100部、増粘剤として上記工程(1-1)の水溶性重合体を含む水溶液を固形分相当で2部入れ、更にイオン交換水を加えて固形分濃度65%に調整した後、25℃で60分間混合した。次に、イオン交換水を加えて固形分濃度60%に調整した後、さらに25℃で15分間混合し混合液を得た。上記混合液に、上記工程(1-4)の粒子状バインダーを含む水分散液を固形分相当量で1.0部、及びイオン交換水を入れ、最終固形分濃度52%となるように調整し、さらに10分間混合した。これを減圧下で脱泡処理して流動性の良い負極用スラリー組成物を得た。この負極用スラリー組成物について、上述した要領で、分散安定性を評価した。 [Example 19]
(19-1. Production of slurry composition for negative electrode)
In a planetary mixer with a disper, 100 parts of artificial graphite (average particle size: 24.5 μm) having a specific surface area of 5.5 m 2 / g as a negative electrode active material, and the water-soluble heavy of the above step (1-1) as a thickener 2 parts of the aqueous solution containing the coalesced was added in an amount corresponding to the solid content, and ion-exchanged water was further added to adjust the solid content concentration to 65%, followed by mixing at 25 ° C. for 60 minutes. Next, ion-exchanged water was added to adjust the solid content concentration to 60%, and the mixture was further mixed at 25 ° C. for 15 minutes to obtain a mixed solution. 1.0 part of the aqueous dispersion containing the particulate binder in the above step (1-4) and ion-exchanged water are added to the mixed liquid, and the final solid content concentration is adjusted to 52%. And mixed for another 10 minutes. This was defoamed under reduced pressure to obtain a slurry composition for negative electrode having good fluidity. With respect to this negative electrode slurry composition, the dispersion stability was evaluated in the manner described above.
上記工程(19-1)で得られた負極用スラリー組成物を、コンマコーターで、集電体である厚さ20μmの銅箔の上に、乾燥後の膜厚が150μm程度になるように塗布し、乾燥させた。この乾燥は、銅箔を0.5m/分の速度で60℃のオーブン内を2分間かけて搬送することにより行った。その後、120℃にて2分間加熱処理して負極原反を得た。この負極原反をロールプレスで圧延して、負極活物質層の厚みが80μmの負極を得た。この負極について、上述した要領で、密着強度及び柔軟性を評価した。 (19-2. Production of negative electrode)
The negative electrode slurry composition obtained in the above step (19-1) was applied onto a 20 μm thick copper foil as a current collector with a comma coater so that the film thickness after drying was about 150 μm. And dried. This drying was performed by conveying the copper foil in an oven at 60 ° C. at a speed of 0.5 m / min for 2 minutes. Then, the negative electrode original fabric was obtained by heat-processing at 120 degreeC for 2 minute (s). This negative electrode original fabric was rolled with a roll press to obtain a negative electrode having a negative electrode active material layer thickness of 80 μm. About this negative electrode, the adhesive strength and the softness | flexibility were evaluated in the way mentioned above.
増粘剤としてカルボキシメチルセルロース(日本製紙ケミカル社製「MAC350HC」)の2%水溶液を固形分相当で1部用いたこと以外は実施例1の工程(1-3)と同様にして正極を製造した。 (19-3. Production of positive electrode)
A positive electrode was produced in the same manner as in the step (1-3) of Example 1 except that 1 part of a 2% aqueous solution of carboxymethyl cellulose (“MAC350HC” manufactured by Nippon Paper Chemical Co., Ltd.) was used as a thickener. .
負極として上記工程(19-2)で得たものを用い、正極として上記工程(19-3)で得たものを用いたこと以外は実施例1の工程(1-8)と同様にして、リチウムイオン二次電池を製造した。このリチウムイオン二次電池について、上述した要領で、高温サイクル特性及び低温特性を評価した。 (19-4. Lithium ion secondary battery)
Except that the negative electrode obtained in the step (19-2) was used and the positive electrode obtained in the step (19-3) was used, the same as in the step (1-8) of Example 1, A lithium ion secondary battery was manufactured. About this lithium ion secondary battery, the high temperature cycling characteristic and the low temperature characteristic were evaluated in the way mentioned above.
負極活物質として、比表面積5.5m2/gの人造黒鉛(体積平均粒子径:24.5μm)90部及びSiOx(体積平均粒子径:5μm)10部を組み合わせて用いたこと以外は実施例19と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 20]
Implemented except that 90 parts of artificial graphite (volume average particle diameter: 24.5 μm) and 10 parts of SiO x (volume average particle diameter: 5 μm) were used as the negative electrode active material in combination with a specific surface area of 5.5 m 2 / g. In the same manner as in Example 19, a lithium ion secondary battery was produced and evaluated.
負極活物質として、比表面積5.5m2/gの人造黒鉛(体積平均粒子径:24.5μm)70部及びSiOx(体積平均粒子径:8μm)30部を組み合わせて用いたこと以外は実施例19と同様にして、リチウムイオン二次電池を製造し、評価した。 [Example 21]
Implemented except that 70 parts of artificial graphite (volume average particle diameter: 24.5 μm) and 30 parts of SiO x (volume average particle diameter: 8 μm) were used in combination as the negative electrode active material with a specific surface area of 5.5 m 2 / g. In the same manner as in Example 19, a lithium ion secondary battery was produced and evaluated.
体積平均粒子径3μm、BET比表面積12m2/gの酸化珪素粉末(SiOx:x=1.02)を、窒化珪素製トレイに200g仕込んだ。その後、雰囲気を保持できる処理炉内に静置した。次に処理炉にアルゴンガスを流入させて処理炉内をアルゴン置換した。アルゴンガスを流速2NL/分で流入させつつ300℃/時間の昇温速度で1200℃まで昇温し、3時間保持した。保持終了後、降温を開始し、室温まで冷ました。室温到達後、粉末を回収した。得られた粉末は、体積平均粒子径3.5μm、BET比表面積11m2/gの粉末であった。この粉末についてCu-Kα線によるX線回折パターンを測定したところ、測定されたX線回折パターンには2θ=28.4°付近のSi(111)に帰属される回折線が存在していた。この回折線の半価幅からシェーラー法(Scherrer法)により分析したところ、得られた粉末が、二酸化珪素中に分散した珪素の結晶子の大きさが40nmである珪素複合体粉末であることが確認された。 [Example 22]
200 g of silicon oxide powder (SiO x : x = 1.02) having a volume average particle diameter of 3 μm and a BET specific surface area of 12 m 2 / g was placed in a silicon nitride tray. Then, it left still in the processing furnace which can hold | maintain an atmosphere. Next, argon gas was introduced into the processing furnace to replace the inside of the processing furnace with argon. While flowing argon gas at a flow rate of 2 NL / min, the temperature was raised to 1200 ° C. at a heating rate of 300 ° C./hour, and held for 3 hours. After holding, the temperature began to drop and cooled to room temperature. After reaching room temperature, the powder was collected. The obtained powder was a powder having a volume average particle size of 3.5 μm and a BET specific surface area of 11 m 2 / g. When an X-ray diffraction pattern by Cu—Kα ray was measured for this powder, a diffraction line attributed to Si (111) near 2θ = 28.4 ° was present in the measured X-ray diffraction pattern. Analysis by the Scherrer method from the half-value width of this diffraction line revealed that the obtained powder was a silicon composite powder having a crystallite size of 40 nm of silicon dispersed in silicon dioxide. confirmed.
内温800℃の流動層内に多結晶珪素微粒子を導入し、モノシランを送入することで製造した粒状多結晶珪素を、ジェットミルを用いて粉砕した。その後、粉砕により得られた粉末を分級機にて分級し、体積平均粒子径D50=10.2μmの多結晶珪素粉末を得た。X線回折線の半値全幅よりシェーラー法で分析したところ、結晶子の大きさが44nmであることを確認した。 [Example 23]
The granular polycrystalline silicon produced by introducing polycrystalline silicon fine particles into a fluidized bed with an internal temperature of 800 ° C. and feeding monosilane was pulverized using a jet mill. Thereafter, the powder obtained by pulverization was classified with a classifier to obtain a polycrystalline silicon powder having a volume average particle diameter D50 = 10.2 μm. Analysis by the Scherrer method from the full width at half maximum of the X-ray diffraction line confirmed that the crystallite size was 44 nm.
上記工程(1-3)において、増粘剤としてカルボキシメチルセルロース(日本製紙ケミカル社製「MAC350HC」)を固形分相当で1部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Comparative Example 1]
In the above step (1-3), a lithium ion secondary battery was obtained in the same manner as in Example 1, except that 1 part of carboxymethyl cellulose (“MAC350HC” manufactured by Nippon Paper Chemical Co., Ltd.) was used as the thickener. Were manufactured and evaluated.
上記工程(1-3)において、増粘剤としてポリビニルアルコール(クラレ社製「ポバール117」)を固形分相当で1部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Comparative Example 2]
In the above step (1-3), a lithium ion secondary battery was prepared in the same manner as in Example 1, except that 1 part of polyvinyl alcohol (“Poval 117” manufactured by Kuraray Co., Ltd.) was used as the thickener. Manufactured and evaluated.
上記工程(1-3)において、増粘剤としてポリアクリル酸(和光純薬社製、分子量1000000)を固形分相当で1部用いたこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Comparative Example 3]
In the above step (1-3), a lithium ion secondary was prepared in the same manner as in Example 1 except that 1 part of polyacrylic acid (manufactured by Wako Pure Chemical Industries, Ltd., molecular weight 1000000) was used as a thickener. A battery was manufactured and evaluated.
上記工程(1-1)において、2,2,2-トリフルオロエチルメタクリレート及びエチレンジメタクリレートを用いないで、エチルアクリレートの量を53.5部に変更したこと以外は実施例1と同様にして、リチウムイオン二次電池を製造し、評価した。 [Comparative Example 4]
In the above step (1-1), the same procedure as in Example 1 was conducted except that 2,2,2-trifluoroethyl methacrylate and ethylene dimethacrylate were not used and the amount of ethyl acrylate was changed to 53.5 parts. A lithium ion secondary battery was manufactured and evaluated.
上記工程(19-1)において、増粘剤としてカルボキシメチルセルロース(日本製紙ケミカル社製「MAC350HC」)の2%水溶液を固形分相当で1部用いたこと以外は実施例19と同様にして、リチウムイオン二次電池を製造し、評価した。 [Comparative Example 5]
In the above step (19-1), the same procedure as in Example 19 was performed except that 1 part of a 2% aqueous solution of carboxymethylcellulose (“MAC350HC” manufactured by Nippon Paper Chemical Co., Ltd.) was used as a thickener, corresponding to the solid content. An ion secondary battery was manufactured and evaluated.
各実施例及び比較例の結果を表1~表6に示す。ここで、下記の表における略称の意味は、以下の通りである。
LCO:LiCoO2
Si系活物質A:珪素複合体粉末
Si系活物質B:多結晶珪素粉末
OH単量体:水酸基含有単量体
β-HEA:2-ヒドロキシエチルアクリレート
HEMA:2-ヒドロキシエチルメタクリレート
F単量体:フッ素含有(メタ)アクリル酸エステル単量体
3FM:2,2,2-トリフルオロエチルメタクリレート
PFOA:パーフルオロオクチルアクリレート
PFBA:パーフルオロブチルアクリレート
酸単量体:酸基含有単量体
MAA:メタクリル酸
AMPS:2-アクリルアミド-2-メチルプロパンスルホン酸
EDMA:エチレンジメタクリレート
GMA:グリシジルメタクリレート
AGE:アリルグリシジルエーテル
EA:エチルアクリレート
ACL:アクリルゴム
SBR:スチレンブタジエンゴム
CMC:カルボキシメチルセルロース
PVOH:ポリビニルアルコール
PAA:ポリアクリル酸 [result]
Tables 1 to 6 show the results of the examples and comparative examples. Here, the meanings of the abbreviations in the following table are as follows.
LCO: LiCoO 2
Si-based active material A: silicon composite powder Si-based active material B: polycrystalline silicon powder OH monomer: hydroxyl group-containing monomer β-HEA: 2-hydroxyethyl acrylate HEMA: 2-hydroxyethyl methacrylate F monomer : Fluorine-containing (meth) acrylic acid ester monomer 3FM: 2,2,2-trifluoroethyl methacrylate PFOA: Perfluorooctyl acrylate PFBA: Perfluorobutyl acrylate Acid monomer: Acid group-containing monomer MAA: Methacryl Acid AMPS: 2-acrylamido-2-methylpropanesulfonic acid EDMA: Ethylene dimethacrylate GMA: Glycidyl methacrylate AGE: Allyl glycidyl ether EA: Ethyl acrylate ACL: Acrylic rubber SBR: Styrene butadiene rubber CMC: Carboxy Chill cellulose PVOH: polyvinyl alcohol PAA: Polyacrylic acid
前記の実施例及び比較例のうち、実施例1~18及び比較例1~4はスラリー組成物を正極に適用したものであり、実施例19~23及び比較例5はスラリー組成物を負極に適用したものである。前記の表から、本発明により高温サイクル特性及び低温特性に優れるリチウムイオン二次電池を実現できることが分かる。また、実施例及び比較例を対比することにより、本発明のスラリー組成物は分散安定性に優れることが分かる。さらに、本発明のスラリー組成物を用いて製造された電極は、密着強度及び柔軟性に優れることが分かる。 [Consideration]
Of the above Examples and Comparative Examples, Examples 1 to 18 and Comparative Examples 1 to 4 are obtained by applying the slurry composition to the positive electrode, and Examples 19 to 23 and Comparative Example 5 are those using the slurry composition as the negative electrode. It is applied. From the above table, it can be seen that the present invention can realize a lithium ion secondary battery having excellent high-temperature cycle characteristics and low-temperature characteristics. Moreover, by comparing an Example and a comparative example, it turns out that the slurry composition of this invention is excellent in dispersion stability. Furthermore, it turns out that the electrode manufactured using the slurry composition of this invention is excellent in adhesive strength and a softness | flexibility.
Claims (12)
- 電極活物質、水溶性重合体及び水を含み、
前記水溶性重合体が、水酸基含有単量体単位0.5重量%~10重量%、フッ素含有(メタ)アクリル酸エステル単量体単位及び酸基含有単量体単位を含む、リチウムイオン二次電池電極用のスラリー組成物。 Including an electrode active material, a water-soluble polymer and water,
The water-soluble polymer comprises a lithium ion secondary containing 0.5% to 10% by weight of a hydroxyl group-containing monomer unit, a fluorine-containing (meth) acrylate monomer unit and an acid group-containing monomer unit. A slurry composition for battery electrodes. - 前記水溶性重合体の1重量%水溶液粘度が、10mPa・s~1000mPa・sである、請求項1記載のスラリー組成物。 The slurry composition according to claim 1, wherein the water-soluble polymer has a 1% by weight aqueous solution viscosity of 10 mPa · s to 1000 mPa · s.
- 前記水溶性重合体が、更に架橋性単量体単位を0.05重量%~2重量%含む、請求項1又は2記載のスラリー組成物。 The slurry composition according to claim 1 or 2, wherein the water-soluble polymer further contains 0.05 to 2% by weight of a crosslinkable monomer unit.
- 前記水溶性重合体の量が、電極活物質100重量部に対して、0.1重量部~10重量部である、請求項1~3のいずれか一項に記載のスラリー組成物。 The slurry composition according to any one of claims 1 to 3, wherein the amount of the water-soluble polymer is 0.1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material.
- 前記水溶性重合体における前記フッ素含有(メタ)アクリル酸エステル単量体単位の割合が、0.1重量%以上50重量%以下である、請求項1~4のいずれか一項に記載のスラリー組成物。 The slurry according to any one of claims 1 to 4, wherein a ratio of the fluorine-containing (meth) acrylic acid ester monomer unit in the water-soluble polymer is 0.1 wt% or more and 50 wt% or less. Composition.
- 前記水溶性重合体における前記酸基含有単量体単位の割合が、20重量%以上50重量%以下である、請求項1~5のいずれか一項に記載のスラリー組成物。 The slurry composition according to any one of claims 1 to 5, wherein a ratio of the acid group-containing monomer unit in the water-soluble polymer is 20 wt% or more and 50 wt% or less.
- 前記水溶性重合体が、(メタ)アクリル酸エステル単量体単位を25重量%以上75重量%以下含む、請求項1~6のいずれか一項に記載のスラリー組成物。 The slurry composition according to any one of claims 1 to 6, wherein the water-soluble polymer contains (meth) acrylic acid ester monomer units in an amount of 25 wt% to 75 wt%.
- 更に粒子状バインダーを含む、請求項1~7のいずれか一項に記載のスラリー組成物。 The slurry composition according to any one of claims 1 to 7, further comprising a particulate binder.
- 前記粒子状バインダーが、アクリル軟質重合体又はジエン軟質重合体である、請求項8に記載のスラリー組成物。 The slurry composition according to claim 8, wherein the particulate binder is an acrylic soft polymer or a diene soft polymer.
- 前記酸基含有単量体が、エチレン性不飽和カルボン酸単量体又はエチレン性不飽和スルホン酸単量体である、請求項1~9のいずれか一項に記載のスラリー組成物。 The slurry composition according to any one of claims 1 to 9, wherein the acid group-containing monomer is an ethylenically unsaturated carboxylic acid monomer or an ethylenically unsaturated sulfonic acid monomer.
- 請求項1~10のいずれか一項に記載のスラリー組成物の膜を集電体上に形成し、前記の膜を乾燥して得られるリチウムイオン二次電池用電極。 An electrode for a lithium ion secondary battery obtained by forming a film of the slurry composition according to any one of claims 1 to 10 on a current collector and drying the film.
- 正極、負極及び電解液を備えるリチウムイオン二次電池であって、
前記正極及び負極の一方又は両方が請求項11記載のリチウムイオン二次電池用電極である、リチウムイオン二次電池。 A lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte solution,
The lithium ion secondary battery whose one or both of the said positive electrode and a negative electrode are the electrodes for lithium ion secondary batteries of Claim 11.
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014192238A1 (en) * | 2013-05-29 | 2014-12-04 | 日本ゼオン株式会社 | Slurry composition for lithium-ion secondary battery positive electrode, production method for lithium-ion secondary battery positive electrode, lithium-ion secondary battery positive electrode, and lithium-ion secondary battery |
WO2015098050A1 (en) * | 2013-12-26 | 2015-07-02 | 日本ゼオン株式会社 | Slurry composition for negative electrodes of lithium ion secondary batteries, negative electrode for lithium ion secondary batteries, and lithium ion secondary battery |
JP2015159069A (en) * | 2014-02-25 | 2015-09-03 | ダイソー株式会社 | Slurry composition for battery electrodes, electrode arranged by use thereof, and battery |
WO2015198530A1 (en) * | 2014-06-26 | 2015-12-30 | 日本ゼオン株式会社 | Laminate for nonaqueous secondary cell, method for producing same, and nonaqueous secondary cell |
WO2018173717A1 (en) | 2017-03-24 | 2018-09-27 | 日本ゼオン株式会社 | Binder composition for nonaqueous secondary batteries and slurry composition for nonaqueous secondary batteries |
WO2021065457A1 (en) * | 2019-09-30 | 2021-04-08 | 日本ゼオン株式会社 | Binder composition for secondary batteries, slurry composition for secondary battery electrodes, electrode for secondary batteries, and secondary battery |
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Publication number | Priority date | Publication date | Assignee | Title |
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PL3382777T3 (en) * | 2015-11-27 | 2022-06-20 | Zeon Corporation | Composition for non-aqueous secondary battery adhesive layer, adhesive layer for non-aqueous secondary battery, and non-aqueous secondary battery |
JP7010230B2 (en) * | 2016-09-27 | 2022-02-10 | 日本ゼオン株式会社 | Non-aqueous secondary battery positive electrode slurry composition, non-aqueous secondary battery positive electrode and non-aqueous secondary battery |
CN109216659B (en) * | 2017-07-06 | 2022-01-11 | 宁德时代新能源科技股份有限公司 | Binder, electrode plate using same and secondary battery |
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KR102288986B1 (en) * | 2018-12-17 | 2021-08-11 | 주식회사 엘지화학 | Slurry composition for electrode of secondary battery, electrode of secondary battery, and secondary battery |
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003217573A (en) * | 2002-01-22 | 2003-07-31 | Hitachi Powdered Metals Co Ltd | Slurry for forming negative electrode film of non- aqueous secondary battery and control method of slurry |
JP2003308841A (en) * | 2002-04-16 | 2003-10-31 | Hitachi Powdered Metals Co Ltd | Slurry for forming negative electrode coating film of nonaqueous secondary battery |
WO2012029805A1 (en) * | 2010-08-31 | 2012-03-08 | 日本ゼオン株式会社 | Slurry composition for porous film in battery, method for manufacturing porous film for secondary battery, porous film for secondary battery, electrode for secondary battery, separator for secondary battery, and secondary battery |
JP2013008667A (en) * | 2011-05-24 | 2013-01-10 | Nippon Zeon Co Ltd | Negative electrode for secondary battery, secondary battery, slurry composition for negative electrode, and method of manufacturing negative electrode for secondary battery |
JP2013012357A (en) * | 2011-06-28 | 2013-01-17 | Nippon Zeon Co Ltd | Negative electrode for secondary battery, secondary battery, slurry composition for negative electrode, and manufacturing method of negative electrode for secondary battery |
WO2013099990A1 (en) * | 2011-12-27 | 2013-07-04 | 日本ゼオン株式会社 | Positive electrode for secondary batteries, method for producing same, slurry composition, and secondary battery |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2002231251A (en) * | 2001-02-06 | 2002-08-16 | Nippon Zeon Co Ltd | Binder composition for lithium ion secondary battery electrode and lithium ion secondary battery |
CN101652884B (en) * | 2007-03-30 | 2013-05-15 | 日本瑞翁株式会社 | Binder for secondary battery electrode, secondary battery electrode, and secondary battery |
JP2010146870A (en) * | 2008-12-19 | 2010-07-01 | Nippon A&L Inc | Binder for secondary-battery electrode |
CN102439769B (en) * | 2009-04-03 | 2014-10-08 | 东洋油墨Sc控股株式会社 | Binder composition for non-aqueous secondary battery electrode |
CN102823029A (en) * | 2010-02-03 | 2012-12-12 | 日本瑞翁株式会社 | Lithium ion secondary battery negative electrode slurry composition, a lithium ion secondary battery negative electrode, and lithium ion secondary battery |
JP4988967B2 (en) * | 2010-07-16 | 2012-08-01 | 株式会社日本触媒 | Aqueous electrode binder for secondary battery |
WO2012026462A1 (en) * | 2010-08-24 | 2012-03-01 | 日本ゼオン株式会社 | Binder composition for secondary battery negative electrode, slurry composition for secondary battery negative electrode, secondary battery negative electrode, secondary battery, and method for producing binder composition for secondary battery negative electrode |
-
2013
- 2013-07-31 CN CN201380033823.8A patent/CN104396059B/en active Active
- 2013-07-31 JP JP2014528209A patent/JP6052290B2/en active Active
- 2013-07-31 WO PCT/JP2013/070811 patent/WO2014021401A1/en active Application Filing
- 2013-07-31 KR KR1020147032363A patent/KR102121446B1/en active IP Right Grant
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003217573A (en) * | 2002-01-22 | 2003-07-31 | Hitachi Powdered Metals Co Ltd | Slurry for forming negative electrode film of non- aqueous secondary battery and control method of slurry |
JP2003308841A (en) * | 2002-04-16 | 2003-10-31 | Hitachi Powdered Metals Co Ltd | Slurry for forming negative electrode coating film of nonaqueous secondary battery |
WO2012029805A1 (en) * | 2010-08-31 | 2012-03-08 | 日本ゼオン株式会社 | Slurry composition for porous film in battery, method for manufacturing porous film for secondary battery, porous film for secondary battery, electrode for secondary battery, separator for secondary battery, and secondary battery |
JP2013008667A (en) * | 2011-05-24 | 2013-01-10 | Nippon Zeon Co Ltd | Negative electrode for secondary battery, secondary battery, slurry composition for negative electrode, and method of manufacturing negative electrode for secondary battery |
JP2013012357A (en) * | 2011-06-28 | 2013-01-17 | Nippon Zeon Co Ltd | Negative electrode for secondary battery, secondary battery, slurry composition for negative electrode, and manufacturing method of negative electrode for secondary battery |
WO2013099990A1 (en) * | 2011-12-27 | 2013-07-04 | 日本ゼオン株式会社 | Positive electrode for secondary batteries, method for producing same, slurry composition, and secondary battery |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2014192238A1 (en) * | 2013-05-29 | 2014-12-04 | 日本ゼオン株式会社 | Slurry composition for lithium-ion secondary battery positive electrode, production method for lithium-ion secondary battery positive electrode, lithium-ion secondary battery positive electrode, and lithium-ion secondary battery |
WO2015098050A1 (en) * | 2013-12-26 | 2015-07-02 | 日本ゼオン株式会社 | Slurry composition for negative electrodes of lithium ion secondary batteries, negative electrode for lithium ion secondary batteries, and lithium ion secondary battery |
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JP2015159069A (en) * | 2014-02-25 | 2015-09-03 | ダイソー株式会社 | Slurry composition for battery electrodes, electrode arranged by use thereof, and battery |
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KR20190125986A (en) | 2017-03-24 | 2019-11-07 | 니폰 제온 가부시키가이샤 | Binder Composition for Non-aqueous Secondary Battery and Slurry Composition for Non-aqueous Secondary Battery |
JPWO2018173717A1 (en) * | 2017-03-24 | 2020-02-06 | 日本ゼオン株式会社 | Binder composition for non-aqueous secondary battery and slurry composition for non-aqueous secondary battery |
JP7003987B2 (en) | 2017-03-24 | 2022-01-21 | 日本ゼオン株式会社 | Binder composition for non-aqueous secondary battery and slurry composition for non-aqueous secondary battery |
US11532817B2 (en) | 2017-03-24 | 2022-12-20 | Zeon Corporation | Binder composition for nonaqueous secondary batteries and slurry composition for nonaqueous secondary batteries |
WO2021065457A1 (en) * | 2019-09-30 | 2021-04-08 | 日本ゼオン株式会社 | Binder composition for secondary batteries, slurry composition for secondary battery electrodes, electrode for secondary batteries, and secondary battery |
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CN104396059A (en) | 2015-03-04 |
CN104396059B (en) | 2017-08-18 |
KR102121446B1 (en) | 2020-06-10 |
KR20150040250A (en) | 2015-04-14 |
JPWO2014021401A1 (en) | 2016-07-21 |
JP6052290B2 (en) | 2016-12-27 |
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