WO2013008564A1 - Composition de liant pour électrodes - Google Patents

Composition de liant pour électrodes Download PDF

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WO2013008564A1
WO2013008564A1 PCT/JP2012/064733 JP2012064733W WO2013008564A1 WO 2013008564 A1 WO2013008564 A1 WO 2013008564A1 JP 2012064733 W JP2012064733 W JP 2012064733W WO 2013008564 A1 WO2013008564 A1 WO 2013008564A1
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polymer
electrode
binder composition
mass
particle size
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PCT/JP2012/064733
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English (en)
Japanese (ja)
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巧治 大塚
博紀 北口
伸行 藤原
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Jsr株式会社
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Priority to JP2012544991A priority Critical patent/JP5163919B1/ja
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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
    • 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 an electrode binder composition.
  • the binder composition of the present invention contains polymer particles having a specific particle size distribution, is excellent in all of ionic conductivity, oxidation resistance and adhesion, and is used as a binder material for electrodes of power storage devices, particularly for positive electrodes. Is preferred.
  • a power storage device having a high voltage and a high energy density is required as a power source for driving electronic equipment.
  • Lithium ion batteries, lithium ion capacitors, and the like are expected as power storage devices that can meet this demand.
  • the electrode used for such an electricity storage device is usually produced by applying and drying a mixture of active material particles and polymer particles functioning as an electrode binder onto the surface of the current collector.
  • the properties required for the polymer particles used in the electrode include the ability to bind active material particles, the ability to bind the active material particles to the current collector, the abrasion resistance in the process of winding the electrode, and subsequent cutting.
  • powder-off resistance in which fine powder of the active material is not generated from the applied electrode composition layer (hereinafter also simply referred to as “active material layer”).
  • active material layer powder-off resistance in which fine powder of the active material is not generated from the applied electrode composition layer.
  • the degree of freedom in designing the structure of the electricity storage device such as the method of folding the obtained electrode and setting the winding radius, is increased, and the miniaturization of the device is achieved. Can do.
  • the quality of the active material particles is substantially proportional to the ability to bind the active material particles, the binding ability between the active material particles and the current collector, and the powder-off resistance. . Therefore, in the present specification, hereinafter, the term “adhesiveness” may be used in a comprehensive manner.
  • an electrode binder especially a binder used for manufacturing a positive electrode
  • an organic polymer containing a fluorine atom having excellent ionic conductivity and oxidation resistance such as polyvinylidene fluoride (PVDF).
  • PVDF polyvinylidene fluoride
  • organic polymers containing fluorine atoms generally have poor adhesion, and thus have a problem with the mechanical strength and durability of the resulting electrode. Therefore, various techniques for improving the adhesion while maintaining the ionic conductivity and oxidation resistance of the organic polymer have been studied and proposed.
  • Patent Document 1 For example, in JP 2011-3529 (Patent Document 1), by using PVDF and a rubbery polymer in combination, the lithium ion conductivity and oxidation resistance of the binder for the negative electrode are compatible with the adhesion. A technology has been proposed.
  • Patent Document 2 After applying a solution obtained by dissolving PVDF in a specific organic solvent on the surface of the current collector, a process of removing the solvent at a low temperature is performed. A technique for improving the adhesion is proposed.
  • JP-A-2002-42819 attempts to improve adhesion by applying an electrode binder having a side chain containing a fluorine atom in the main chain made of a vinylidene fluoride copolymer. Techniques to do this have been proposed.
  • Patent Document 1 in which an organic polymer containing a fluorine atom and a rubbery polymer are used in combination, although the adhesion is improved, the ionic conductivity of the organic polymer is reduced and the oxidation resistance is improved. It is greatly damaged. Therefore, the electrical storage device manufactured using this has the problem that charging / discharging characteristics will deteriorate irreversibly by repetition of charging / discharging. Further, according to the techniques of Patent Documents 2 and 3 that use only an organic polymer containing a fluorine atom as an electrode binder, the level of adhesion is still insufficient.
  • a binder composition for an electrode containing polymer particles and a liquid medium For the electrode, wherein at least a part of the polymer particles contain fluorine atoms, and the particle size frequency distribution measured by a dynamic light scattering method for the polymer particles is multimodal. This is achieved by the binder composition.
  • FIG. 1 is a particle size frequency distribution chart of the polymer particles obtained in Example 2.
  • FIG. 2 is a particle size frequency distribution chart of the polymer particles obtained in Comparative Example 3.
  • the binder composition for an electrode of the present invention contains polymer particles and a liquid medium.
  • the electrode binder composition may contain other components such as an emulsifier, a polymerization initiator or a residue thereof, a surfactant, and a neutralizing agent.
  • 1.1 Polymer particles Polymer particles contained in the electrode binder composition of the present invention, At least some of them contain fluorine atoms, and The particle size frequency distribution measured by the dynamic light scattering method is multimodal.
  • the content ratio of fluorine atoms to the whole polymer particles is preferably 2 to 30% by mass, more preferably 3 to 28% by mass, and particularly preferably 5 to 25% by mass.
  • the content rate of a fluorine atom can be set as the polymer particle excellent in the balance of oxidation resistance and adhesiveness, and is preferable.
  • the content ratio of the fluorine atom can be measured by, for example, combustion ion chromatography.
  • the polymer particles have a multimodal particle size frequency distribution measured by a dynamic light scattering method.
  • “the particle size distribution is multimodal” means that the peak of the appearance frequency in the particle size frequency distribution curve with the particle size (r) on the horizontal axis and the appearance frequency (f) on the vertical axis.
  • the particle size (r) when considering a graph in which the particle size (r) is plotted on the horizontal axis and the appearance frequency (f) is differentiated by the particle size (r) (df / dr) on the vertical axis, (df / dr) As the particle size (r) increases, the particle size frequency repeats a cycle starting from 0, increasing, then decreasing and going through 0 to become negative, then increasing again and returning to 0 multiple times. Distribution. At this time, the particle diameter (r) when the (df / dr) value starts from 0, increases, and then decreases to 0 is set as the maximum frequency diameter of the peak.
  • the particle size frequency distribution of the polymer particles in the present invention is preferably 2 to 6 peaks, more preferably 2 to 4 peaks, still more preferably 2 or 3 peaks, and particularly preferably. Is bimodal.
  • the first particle size range is more preferably 45 to 75 nm.
  • the second particle size range is more preferably 300 to 490 nm, and particularly preferably 400 to 480 nm.
  • An electrode manufactured using the binder composition for an electrode containing polymer particles having a particle size distribution having at least one peak in each of these two particle size ranges has adhesiveness (binding of active materials). And both the property and the adhesion between the active material layer and the current collector). The reason for this is not yet clear, but the smaller polymer particles belonging to the first particle size range fill the gaps in the structure generally bound by the large polymer particles belonging to the second particle size range, It is estimated that strong adhesion can be obtained. Furthermore, by setting the particle size of the polymer particles in the above range, the internal resistance of the active material layer can be kept low while obtaining strong adhesion. This is a truly surprising effect.
  • the polymer particles in the present invention exhibit a particle size frequency distribution that does not have a peak having the maximum frequency diameter other than the above two particle size ranges.
  • Area of peaks belonging to the first particle size range (S 1 ) And the area of the peak belonging to the second particle size range (S 2 ) And the area (S 1 ) (S) 1 / (S 1 + S 2 )) Is preferably 0.1 to 0.9, more preferably 0.2 to 0.8, and particularly preferably 0.4 to 0.6.
  • the particle size frequency distribution of the polymer particles particularly preferably, each of the first particle size range and the second particle size range has one peak, and the maximum frequency diameter is in the other range. This is a case of bimodality having no peaks.
  • the particle size frequency distribution of the polymer particles can be measured by a commercially available particle size frequency distribution measuring apparatus based on a dynamic light scattering method.
  • Examples of commercially available products of such a particle size frequency distribution measuring apparatus include model “MT3300” and “NPA150” manufactured by Nikkiso Co., Ltd.
  • the polymer particles having the particle size frequency distribution as described above can be, for example, a mixture of a plurality of types of polymer particles having a single particle size frequency distribution measured by a dynamic light scattering method.
  • This mixture can be easily obtained by preferably mixing a plurality of polymer latexes produced by emulsion polymerization under different conditions at a predetermined ratio.
  • the maximum frequency diameter of the peaks belonging to the first particle size range (D 1 ) (D) 2 / D 1 ) Is preferably a value exceeding 2, more preferably 2.5 or more, further preferably 3 or more, and particularly preferably 5 or more.
  • the polymer particles in the present invention the polymer particles belonging to at least one of multimodal in the particle size frequency distribution, Fluorine atom-containing polymer particles containing a polymer having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene are preferred.
  • the polymer particles belonging to peaks other than the peak to which the fluorine atom-containing polymer particles belong may be the same fluorine atom-containing polymer particles as described above, or The polymer particle which does not contain may be sufficient.
  • the particle size distribution of the polymer particles is bimodal, and each of the polymer particles belonging to both peaks is at least selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene.
  • fluorine atom-containing polymer particles containing a polymer having a repeating unit derived from one type or The particle size frequency distribution of the polymer particles is bimodal, and the polymer particles belonging to one of the peaks are at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene This is a case where the polymer particle is a fluorine atom-containing polymer particle containing a polymer having a repeating unit derived therefrom, and the polymer particle belonging to the other peak is a polymer particle containing no fluorine atom.
  • the fluorine atom-containing polymer particles may have only a repeating unit derived from one or more of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene, or in addition to these, vinylidene fluoride In addition, it may have a repeating unit derived from another unsaturated monomer copolymerizable with one or more of tetrafluoroethylene and hexafluoropropylene.
  • Examples of such other unsaturated monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, and (meth) acrylic.
  • N-butyl acid N-butyl acid, i-butyl (meth) acrylate, n-amyl (meth) acrylate, i-amyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acrylic 2-ethylhexyl acid, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, ethylene (meth) acrylate Glycol, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, tri (meth) Trimethylolpropane crylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate
  • (Meth) acrylic acid ester of Aromatic vinyl compounds such as styrene, ⁇ -methylstyrene, divinylbenzene; Vinyl esters of carboxylic acids such as vinyl acetate and vinyl propionate; Halogenated olefins such as vinyl fluoride, vinyl chloride, vinylidene chloride; Conjugated dienes such as butadiene, isoprene, chloroprene; ⁇ -olefins such as ethylene and propylene; ⁇ , ⁇ -unsaturated nitrile compounds; Unsaturated carboxylic acids; Alkyl amides of unsaturated carboxylic acids; Unsaturated dicarboxylic acid anhydrides; Monoalkyl esters of unsaturated dicarboxylic acids; Monoamides of unsaturated dicarboxylic acids; Examples thereof include aminoalkylamides of unsaturated carboxylic acids, and one or more selected from these can be used.
  • (meth) acrylic acid is a concept encompassing both “acrylic acid” and “methacrylic acid”.
  • the content of the repeating unit derived from at least one selected from vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene in the fluorine atom-containing polymer particles is preferably 1 with respect to the total mass of the polymer particles. It is at least mass%, more preferably from 3 to 70 mass%, more preferably from 5 to 60 mass%.
  • the content ratio of the repeating unit derived from vinylidene fluoride in the fluorine atom-containing polymer particles is preferably 1 to 70% by mass, and more preferably 3 to 50% by mass.
  • the content of repeating units derived from ethylene tetrafluoride in the fluorine atom-containing polymer particles is preferably 20% by mass or less, more preferably 1 to 10% by mass, and further preferably 2 to 5% by mass. is there.
  • the content ratio of repeating units derived from propylene hexafluoride in the fluorine atom-containing polymer particles is preferably 30% by mass or less, more preferably 1 to 20% by mass, and further preferably 2 to 10% by mass. is there.
  • Such fluorine atom-containing polymer particles include at least one unsaturated monomer selected from the above-mentioned vinylidene fluoride, ethylene tetrafluoride and propylene hexafluoride, and optionally other unsaturated monomers.
  • unsaturated monomer selected from the above-mentioned vinylidene fluoride, ethylene tetrafluoride and propylene hexafluoride, and optionally other unsaturated monomers.
  • fluorine atom-containing copolymer particles Polymer particles having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene may be used as they are, or A polymer A having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene; A polymer B having a repeating unit derived from an unsaturated carboxylic acid ester; The polymer alloy particle containing this may be sufficient.
  • Polymer alloy particles are a “generic name for multi-component polymers obtained by mixing or chemical bonding of two or more components” according to the definition in “Iwanami Physical and Chemical Dictionary 5th edition. Iwanami Shoten”. “Polymer blends physically mixed with different polymers, block and graft copolymers in which different polymer components are covalently bonded, polymer complexes in which different polymers are associated by intermolecular forces, and different polymers entangled with each other IPN (Interpenetrating Polymer Network) etc. ".
  • the polymer alloy particles contained in the binder composition for an electrode of the present invention mean “a polymer alloy in which different types of polymer components are not bonded by a covalent bond”, and a polymer blend, a polymer complex or This is called IPN (interpenetrating polymer network).
  • the polymer alloy particles in the present invention are preferably particles made of a polymer complex or particles made of IPN, and more preferably particles made of IPN.
  • the polymer A constituting the polymer alloy particle is excellent in ionic conductivity, and the hard segment of the crystalline resin is aggregated to give the main chain a pseudo-crosslinking point such as C—H—F—C. it is conceivable that.
  • the polymer A when used alone as the binder resin, its ionic conductivity and oxidation resistance are good, but the adhesion and flexibility are insufficient, and therefore the adhesion is low.
  • the polymer B constituting the polymer alloy particles is excellent in adhesion and flexibility, but has low oxidation resistance. Therefore, when the polymer B is used alone as an electrode (particularly positive electrode) as a binder resin, Good charge / discharge characteristics cannot be obtained because of repeated oxidative decomposition due to repeated discharge. However, by using polymer alloy particles containing the polymer A and the polymer B, an ionic conductivity, oxidation resistance, and adhesion can be expressed simultaneously, and an electrode having good charge / discharge characteristics is obtained.
  • the polymer alloy particles are composed only of the polymer A and the polymer B, the oxidation resistance can be further improved, which is preferable.
  • the polymer alloy particles are measured by differential scanning calorimetry (DSC) according to JIS K7121, it is preferable that the polymer alloy particles have only one endothermic peak in the temperature range of ⁇ 50 to 250 ° C. The temperature of this endothermic peak is more preferably in the range of ⁇ 30 to + 30 ° C.
  • the polymer A constituting the polymer alloy particles is present alone, it generally has an endothermic peak (melting temperature) at -50 to 250 ° C.
  • the polymer B constituting the polymer alloy particles generally has an endothermic peak (glass transition temperature) different from that of the polymer A.
  • endothermic peak glass transition temperature
  • the particles are polymer alloy particles.
  • the temperature of only one endothermic peak of the polymer alloy particles is in the range of ⁇ 30 to + 30 ° C., the particles can impart better flexibility and tackiness to the active material layer.
  • the polymer alloy particles preferably contained in the electrode binder composition of the present invention are polymers A having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene. contains.
  • the content ratio of the repeating unit derived from at least one selected from vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene in the polymer A is preferably 80% by mass with respect to the total mass of the polymer A. It is above, More preferably, it is 90 mass% or more.
  • the content ratio of the repeating unit derived from vinylidene fluoride in the polymer A is preferably 50 to 99% by mass and more preferably 80 to 98% by mass with respect to the total mass of the polymer A.
  • the content ratio of the repeating unit derived from ethylene tetrafluoride in the polymer A is preferably 50% by mass or less, more preferably 1 to 30% by mass, and further preferably 2 to 20% by mass.
  • the content of the repeating unit derived from propylene hexafluoride in the polymer particles is preferably 50% by mass or less, more preferably 1 to 30% by mass, and further preferably 2 to 25% by mass. is there.
  • the polymer A preferably has only a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene.
  • Polymer B The polymer alloy particles preferably contained in the electrode binder composition of the present invention contain a polymer B having a repeating unit derived from an unsaturated carboxylic acid ester. In general, a component such as polymer B has good adhesion, but is considered to have poor ionic conductivity and oxidation resistance, and has not been used for positive electrodes.
  • the unsaturated carboxylic acid ester that leads the repeating unit constituting the polymer B is preferably a (meth) acrylic acid ester.
  • (meth) acrylic acid ester 1.1.1.3.1 (Meth) acrylic acid ester
  • Specific examples of such (meth) acrylic acid esters include, for example, alkyl esters of (meth) acrylic acid, cycloalkyl esters of (meth) acrylic acid, alkenyl esters of (meth) acrylic acid, and (meth) acrylic acid.
  • Examples thereof include hydroxyalkyl esters and (poly) (meth) acrylic acid esters of polyhydric alcohols. Specific examples of these include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (meth) acrylate.
  • the cycloalkyl ester of (meth) acrylic acid include cyclohexyl (meth) acrylate and the like;
  • alkenyl ester of (meth) acrylic acid include allyl (meth) acrylate and ethylene di (meth) acrylate;
  • Examples of the hydroxyalkyl ester of (meth) acrylic acid include hydroxymethyl (meth) acrylate and hydroxyethyl (meth) acrylate;
  • alkyl esters of (meth) acrylic acid are preferable, and one or more selected from methyl (meth) acrylate, ethyl (meth) acrylate, and 2-ethylhexyl acrylate are more preferable. Particularly preferred is methyl (meth) acrylate.
  • the polymer B may be a polymer having only a repeating unit derived from an unsaturated carboxylic acid ester, and in addition to the repeating unit derived from an unsaturated carboxylic acid ester, another unsaturated monomer capable of copolymerization. You may have the structural unit derived from a body.
  • the content ratio of the repeating unit derived from the unsaturated carboxylic acid ester in the polymer B is preferably 65% by mass or more, more preferably 75% by mass or more with respect to the total mass of the polymer B.
  • the other unsaturated monomers include ⁇ , ⁇ -unsaturated nitrile compounds, unsaturated carboxylic acids, conjugated diene compounds, aromatic vinyl compounds, and other unsaturated monomers. 1.1.1.3.2 Structural units derived from ⁇ , ⁇ -unsaturated nitrile compounds When the polymer B has a repeating unit derived from an ⁇ , ⁇ -unsaturated nitrile compound, the swelling property of the polymer alloy particles with respect to the electrolytic solution can be further improved.
  • the presence of the nitrile group makes it easier for the solvent (medium) to enter the network structure composed of polymer chains and the network interval is widened, so that the solvated lithium ions can easily move through the network structure. Thereby, it is thought that the diffusibility of lithium ion improves, As a result, electrode resistance falls and it can implement
  • Specific examples of the ⁇ , ⁇ -unsaturated nitrile compound include acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, ⁇ -ethylacrylonitrile, vinylidene cyanide and the like. Can be.
  • At least one selected from acrylonitrile and methacrylonitrile is preferable, and acrylonitrile is particularly preferable.
  • the content ratio of the structural unit derived from the ⁇ , ⁇ -unsaturated nitrile compound is preferably 35% by mass or less, and more preferably 10 to 25% by mass in all the structural units. 1.1.1.3.3 Structural units derived from unsaturated carboxylic acids When the polymer B has a structural unit derived from an unsaturated carboxylic acid, the stability of the binder composition for an electrode of the present invention is improved.
  • the unsaturated carboxylic acid include mono- or dicarboxylic acids (anhydrides) such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. It can be more than a seed. In particular, at least one selected from acrylic acid, methacrylic acid and itaconic acid is preferable.
  • the content of the repeating unit derived from the unsaturated carboxylic acid is preferably 15% by mass or less, more preferably 0.3 to 10% by mass, based on all the structural units.
  • the conjugated diene compound examples include 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene and the like. , One or more selected from these.
  • 1,3-butadiene is particularly preferable.
  • the content ratio of the structural unit derived from the conjugated diene compound is preferably 35% by mass or less and more preferably 25% by mass or less in all the structural units. 1.1.1.3.5 Structural units derived from aromatic vinyl compounds
  • the electrode slurry prepared using the electrode binder composition of the present invention contains a conductivity-imparting agent.
  • the aromatic vinyl compound examples include styrene, ⁇ -methylstyrene, p-methylstyrene, vinyltoluene, chlorostyrene, divinylbenzene, and the like, and one or more selected from these can be used. be able to.
  • the aromatic vinyl compound is particularly preferably styrene.
  • the content ratio of the structural unit derived from the aromatic vinyl compound is preferably 35% by mass or less, and more preferably 25% by mass or less in all the structural units.
  • the polymer alloy particles preferably contained in the binder composition for an electrode of the present invention are not particularly limited as long as the polymer alloy particles have the above-described configuration.
  • a known emulsion polymerization step or this may be appropriately performed. By combining, it can be easily synthesized.
  • a polymer A having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene is synthesized by a known method, and then A monomer for constituting the polymer B is added to the polymer A, and the monomer is sufficiently absorbed in the stitch structure of the polymer particles made of the polymer A.
  • Polymer alloy particles can be easily produced by a method of synthesizing polymer B by polymerizing absorbed monomers in a stitch structure. When polymer alloy particles are produced by such a method, it is essential for the polymer A to sufficiently absorb the monomer of the polymer B.
  • the absorption temperature is preferably 30 to 100 ° C., more preferably 40 to 80 ° C .;
  • the absorption time is preferably 1 to 12 hours, more preferably 2 to 8 hours.
  • the absorption time when the absorption temperature is low it is preferable to lengthen the absorption time when the absorption temperature is low, and a short absorption time is sufficient when the absorption temperature is high.
  • Appropriate conditions are such that the value obtained by multiplying the absorption temperature (° C.) and the absorption time (h) is generally in the range of 120 to 300 (° C. ⁇ h), preferably 150 to 250 (° C. ⁇ h).
  • the operation of absorbing the monomer of the polymer B in the stitch structure of the polymer A is preferably performed in a known medium used for emulsion polymerization, for example, in water.
  • the content of the polymer A in the polymer alloy particles is preferably 3 to 60% by mass, more preferably 5 to 55% by mass, and more preferably 10 to 50% by mass in 100% by mass of the polymer alloy particles. More preferably, it is particularly preferably 20 to 40% by mass.
  • the polymer alloy particles contain the polymer A in the above range, the balance between the ionic conductivity and the oxidation resistance and the adhesion becomes better.
  • polymerization for producing preferable fluorine atom-containing polymer particles in the present invention that is, a polymer having a repeating unit derived from at least one selected from the group consisting of vinylidene fluoride, tetrafluoroethylene and hexafluoropropylene
  • polymerization of the polymer A, and polymerization of the polymer B in the presence of the polymer A are respectively known polymerization initiators, molecular weight regulators, emulsifiers (surfactants). ) And the like in the presence of a known method.
  • polymerization initiator examples include water-soluble polymerization initiators such as sodium persulfate, potassium persulfate, and ammonium persulfate; Oil-soluble polymerization initiators such as benzoyl peroxide, lauryl peroxide, 2,2′-azobisisobutyronitrile; A redox type polymerization initiator by a combination of any of the above polymerization initiators and a reducing agent such as sodium bisulfite can be mentioned. These polymerization initiators can be used singly or in combination of two or more.
  • the proportion of the polymerization initiator used is the sum of the monomers used (the total of the monomers used when the fluorine atom-containing polymer particles are synthesized by one-step polymerization, the polymer A in the production of the polymer A.
  • the molecular weight regulator examples include halogenated hydrocarbons such as chloroform and carbon tetrachloride; mercaptan compounds such as n-hexyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dotezyl mercaptan, thioglycolic acid; Xanthogen compounds such as dimethylxanthogen disulfide and diisopropylxanthogen disulfide; Other molecular weight regulators such as terpinolene and ⁇ -methylstyrene dimer can be mentioned. These molecular weight regulators can be used singly or in combination of two or more.
  • the use ratio of the molecular weight regulator is preferably 5 parts by mass or less with respect to 100 parts by mass in total of the monomers used.
  • the emulsifier include an anionic surfactant, a nonionic surfactant, an amphoteric surfactant, and a fluorine-based surfactant.
  • the anionic surfactant include higher alcohol sulfates, alkylbenzene sulfonates, aliphatic sulfonates, polyethylene glycol alkyl ether sulfates;
  • the nonionic surfactant include polyethylene glycol alkyl esters, polyethylene glycol alkyl ethers, polyethylene glycol alkyl phenyl ethers, and the like.
  • amphoteric surfactants include: The anionic moiety consists of carboxylate, sulfate, sulfonate or phosphate, and the like, and There may be mentioned those in which the cation moiety consists of an amine salt, a quaternary ammonium salt or the like.
  • amphoteric surfactants include betaine compounds such as lauryl betaine and stearyl betaine; Examples thereof include surfactants of amino acid type such as lauryl- ⁇ -alanine, lauryl di (aminoethyl) glycine, octyldi (aminoethyl) glycine.
  • fluorine-based surfactant examples include fluorobutyl sulfonate, phosphoric acid ester having a fluoroalkyl group, a salt of a carboxylic acid having a fluoroalkyl group, and a fluoroalkyl ethylene oxide adduct.
  • fluorosurfactants examples include F-top EF301, EF303, and EF352 (manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.); Megafuck F171, F172, F173 (manufactured by DIC Corporation); Fluorard FC430, FC431 (manufactured by Sumitomo 3M); Asahi Guard AG710, Surflon S-381, S-382, SC101, SC102, SC103, SC104, SC105, SC106, Surfinol E1004, KH-10, KH-20, KH-30, KH-40 (Asahi Glass Co., Ltd.) );
  • the solvent examples include 250, 251, 222F and FTX-218 (manufactured by Neos Co., Ltd.).
  • the 1 type (s) or 2 or more types selected from the above can be used as an emulsifier.
  • the use ratio of the emulsifier is preferably 0.01 to 10 parts by mass, and more preferably 0.02 to 5 parts by mass with respect to 100 parts by mass in total of the monomers used.
  • the emulsion polymerization is preferably carried out in a suitable aqueous medium, particularly preferably in water.
  • the total content of the monomers in the aqueous medium can be 10 to 50% by mass, and preferably 20 to 40% by mass.
  • the conditions for emulsion polymerization are preferably a polymerization time of 2 to 24 hours at a polymerization temperature of 40 to 85 ° C, and more preferably a polymerization time of 3 to 20 hours at a polymerization temperature of 50 to 80 ° C.
  • Polymer particles not containing fluorine atoms are preferably at least one selected from the group consisting of (meth) acrylic acid esters, aromatic vinyl compounds, vinyl esters of carboxylic acids, halogenated olefins, conjugated dienes and ⁇ -olefins.
  • Polymer particles having repeating units derived from a kind of unsaturated monomer more preferably at least one kind of unsaturated selected from the group consisting of (meth) acrylic acid esters, aromatic vinyl compounds and conjugated dienes It is a polymer particle having a repeating unit derived from a monomer. Specific examples of these unsaturated monomers are the same as those exemplified for the other unsaturated monomers that the fluorine atom-containing polymer particles can optionally have.
  • the polymer particles containing no fluorine atom can be easily produced by emulsion polymerization of the unsaturated monomer as described above or a mixture thereof according to a known method.
  • the emulsion polymerization can be performed in the same manner as described in 1.1.1.5 above. 1.1.3 Method for controlling the particle size range of polymer particles
  • the particle diameter ranges of the fluorine atom-containing polymer particles and the polymer particles not containing a fluorine atom can be made different by appropriately changing the conditions for emulsion polymerization.
  • the particle size range of the polymer particles obtained can be easily controlled by appropriately setting the use ratio of the emulsifier in the emulsion polymerization. If the use ratio of the emulsifier is decreased, the particle size of the obtained polymer tends to increase, and if the use ratio of the emulsifier is increased, the particle diameter of the obtained polymer tends to decrease.
  • the polymerization time does not significantly affect the particle size of the resulting polymer.
  • the polymer particles are polymer alloy particles, the number of polymer particles obtained is determined in advance depending on the number of polymer A serving as a seed. Therefore, when polymer B is polymerized in the presence of polymer A, The use ratio of the emulsifier hardly affects the particle diameter of the polymer alloy particles. In the case of polymer alloy particles, attention should be paid to the proportion of emulsifier used in the production of the polymer A.
  • the use ratio of the emulsifier for controlling the particle size range of the polymer particles used in the present invention is as follows for each specific embodiment of the polymer particles.
  • the use ratio of the emulsifier for obtaining polymer particles having the maximum frequency diameter in the first particle size range should be 0.5 to 5 parts by mass with respect to a total of 100 parts by mass of the monomers used.
  • the use ratio of the emulsifier for obtaining the polymer particles having the maximum frequency diameter in the second particle size range is 0.02 to 0.5 parts by mass with respect to 100 parts by mass in total of the monomers used. It is preferable.
  • the use ratio of the emulsifier in producing the polymer A greatly affects the particle size of the obtained polymer alloy particles as described above.
  • the use ratio of the emulsifier in producing the polymer A is as follows:
  • the proportion of the emulsifier used to obtain the polymer alloy particles having the maximum frequency diameter in the first particle size range is preferably 1 to 10 parts by mass with respect to a total of 100 parts by mass of the monomers used;
  • the use ratio of the emulsifier for obtaining the polymer alloy particles having the maximum frequency diameter in the second particle size range should be 0.05 to 1 part by mass with respect to 100 parts by mass in total of the monomers used. preferable.
  • a polymer A having a maximum frequency diameter of about 0.3 to 0.7, preferably about 0.4 to 0.6 is obtained with respect to the maximum frequency diameter of the desired polymer alloy particles.
  • the use ratio of the emulsifier for obtaining a polymer having the maximum frequency diameter in the first particle size range is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass in total of the monomers used. ;
  • the proportion of the emulsifier used to obtain the polymer having the maximum frequency diameter in the second particle size range should be 0.005 to 0.2 parts by mass with respect to 100 parts by mass in total of the monomers used. Is preferred.
  • the recommended usage ratio has an apparently overlapping portion.
  • the appropriate proportion of emulsifier can be easily set by a few preliminary experiments by those skilled in the art. As described above, a plurality of polymer particles having different particle size ranges or a plurality of latexes each containing polymer particles having different particle size ranges can be obtained.
  • the binder composition for electrodes of the present invention further contains a liquid medium.
  • the liquid medium is preferably an aqueous medium containing water.
  • This aqueous medium can contain a small amount of non-aqueous medium in addition to water.
  • Examples of such a non-aqueous medium include amide compounds, hydrocarbons, alcohols, ketones, esters, amine compounds, lactones, sulfoxides, sulfone compounds, and the like, and one or more selected from these are used. can do.
  • the content ratio of such a non-aqueous medium is preferably 10% by mass or less, more preferably 5% by mass or less, based on the entire aqueous medium.
  • the aqueous medium is composed only of water without containing a non-aqueous medium.
  • the binder composition for electrodes of the present invention uses an aqueous medium as a medium, and preferably does not contain a non-aqueous medium other than water. This is preferable because the degree of adverse effects on the environment is low and the safety for handling workers is high.
  • a composition containing an organic solvent as a medium has a problem of disposal and cost, requires fireproof storage equipment due to characteristics such as flammability, and has special skill and consideration in handling. There is a disadvantage that is necessary.
  • Electrode binder composition of the present invention is preferably present as a latex in which the polymer particles as described above are dispersed in a liquid medium as described above.
  • the binder composition for an electrode of the present invention polymer particles are synthesized (polymerized), preferably after mixing a plurality of polymerization reaction mixtures after stopping the reaction, and adjusting the liquidity of the mixture as necessary. This is preferably used as it is as the binder composition for an electrode of the present invention. Therefore, the electrode binder composition of the present invention may contain other components such as an emulsifier, a polymerization initiator or its residue, a surfactant, and a neutralizer in addition to the polymer particles as described above. .
  • the total mass of the other components is preferably 3% by mass or less, more preferably 2% by mass or less, as a ratio with respect to the mass of the solid content of the composition.
  • the solid content concentration of the binder composition for electrodes of the present invention (the ratio of the mass of components other than the aqueous medium in the composition to the total mass of the composition) is preferably 30 to 50% by mass. More preferably, it is 35 to 45% by mass.
  • the liquid property of the binder composition for electrodes is preferably near neutral, more preferably pH 6.0 to 8.5, and particularly preferably pH 7.0 to 8.0.
  • a known water-soluble acid or base can be used.
  • the binder composition for electrodes of the present invention as described above can be suitably used as an electrode material for power storage devices such as lithium ion secondary batteries, electric double layer capacitors, and lithium ion capacitors. Since the advantageous effect of this invention is exhibited to the maximum when the binder composition for electrodes is used as a material for the positive electrode of a lithium ion secondary battery, it is particularly preferable to apply to this application. 2 Slurries for electrodes As described above, an electrode slurry can be produced using the electrode binder composition of the present invention.
  • the electrode slurry is a dispersion used to form an active material layer on the current collector after being applied to the surface of the current collector and then dried.
  • This electrode slurry contains at least the polymer particles as described above, an active material, and water, and preferably further contains a conductivity-imparting material. In addition to these, a non-aqueous medium, a thickener and the like may be contained.
  • Active material The active material is appropriately selected according to the type of the target power storage device.
  • an active material for example, Li 1 + x M y N z O 2 (However, M represents at least one selected from Co, Ni and Mn, N represents at least one selected from Al and Sn, O represents an oxygen atom, and x, y and z represent 0.10, respectively.
  • a lithium atom-containing oxide having an olivine structure can be preferably used.
  • the lithium atom-containing oxide having the olivine structure has the following general formula (1): Li 1-x M x (XO 4 (1) (In the formula (1), M is a metal ion selected from the group consisting of Mg, Ti, V, Nb, Ta, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, Ge, and Sn.
  • X is at least one selected from the group consisting of Si, S, P and V; x is a number and satisfies the relationship 0 ⁇ x ⁇ 1.
  • a compound having an olivine type crystal structure is selected according to the valences of M and X so that the valence of the entire formula (1) becomes zero.
  • the lithium atom-containing oxide having the olivine structure has different electrode potentials depending on the type of the metal element M. Therefore, the battery voltage can be arbitrarily set by selecting the type of the metal element M.
  • LiFePO 4 As a typical lithium atom-containing oxide having an olivine structure, LiFePO 4 , LiCoPO 4 , Li 0.90 Ti 0.05 Nb 0.05 Fe 0.30 Co 0.30 Mn 0.30 PO 4 And so on. Of these, especially LiFePO 4 Is preferable because it is easy to obtain an iron compound as a raw material and is inexpensive.
  • a compound obtained by substituting Fe ions in the above compounds with Co ions, Ni ions, or Mn ions has the same crystal structure as each of the above compounds, and thus has the same effect as a positive electrode active material.
  • a carbon material, carbon, etc. can be used suitably, for example.
  • the carbon material include carbon materials obtained by firing organic polymer compounds, coke, pitch, and the like.
  • the organic polymer compounds that are precursors of the carbon materials include phenol resins and polyacrylonitrile. And cellulose.
  • the carbon include artificial graphite and natural graphite.
  • examples of the active material include graphite, non-graphitizable carbon, and hard carbon; Carbon material obtained by firing coke, pitch, etc .; A polyacene organic semiconductor (PAS) or the like can be used.
  • the active material is preferably particulate, and the average particle diameter (Db) is preferably in the range of 0.4 to 10 ⁇ m, and more preferably in the range of 0.5 to 7 ⁇ m.
  • the electrode slurry may further contain water. By containing water, the stability of the electrode slurry is improved, and the electrode can be produced with good reproducibility.
  • the electrode slurry may contain other components as necessary. Examples of such other components include a conductivity-imparting agent, a non-aqueous medium, and a thickener. be able to.
  • conductivity-imparting agent examples include carbon in a lithium ion secondary battery; In nickel-metal hydride secondary batteries, cobalt oxide is the positive electrode: For the negative electrode, nickel powder, cobalt oxide, titanium oxide, carbon and the like are used. In both the batteries, examples of carbon include graphite, activated carbon, acetylene black, furnace black, graphite, carbon fiber, and fullerene. Among these, acetylene black or furnace black can be preferably used.
  • the use ratio of the conductivity-imparting agent is preferably 20 parts by mass or less, more preferably 1 to 15 parts by mass, and particularly preferably 2 to 10 parts by mass with respect to 100 parts by mass of the active material particles.
  • the electrode slurry may contain a non-aqueous medium having a standard boiling point of 80 to 350 ° C. from the viewpoint of improving the coating property.
  • a non-aqueous medium include amide compounds such as N-methylpyrrolidone, dimethylformamide, N, N-dimethylacetamide; Hydrocarbons such as toluene, xylene, n-dodecane, tetralin; Alcohols such as 2-ethyl-1-hexanol, 1-nonanol, lauryl alcohol; Ketones such as methyl ethyl ketone, cyclohexanone, phorone, acetophenone, isophorone; Esters such as benzyl acetate, isopentyl butyrate, methyl lactate, ethyl lactate, butyl lactate; amine compounds such as o-toluidine, m-toluidine, p-toluid
  • the electrode slurry does not contain a non-aqueous medium from the viewpoints of reducing environmental load, ensuring worker safety, and reducing management costs.
  • the electrode slurry may contain a thickener from the viewpoint of improving the coatability or further improving the charge / discharge characteristics of the obtained electricity storage device.
  • thickeners examples include cellulose compounds such as carboxymethyl cellulose, methyl cellulose, and hydroxypropyl cellulose; An ammonium salt or an alkali metal salt of the cellulose compound; Polycarboxylic acids such as poly (meth) acrylic acid, modified poly (meth) acrylic acid; An alkali metal salt of the polycarboxylic acid; Vinyl alcohol (co) polymers such as polyvinyl alcohol, modified polyvinyl alcohol, ethylene-vinyl alcohol copolymer; Examples thereof include water-soluble polymers such as saponified products of copolymers of unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid and fumaric acid and vinyl esters.
  • particularly preferred thickeners include alkali metal salts of carboxymethyl cellulose and alkali metal salts of poly (meth) acrylic acid.
  • examples of commercially available products of these thickeners include CMC 1120, CMC 1150, CMC 2200, CMC 2280, CMC 2450 (manufactured by Daicel Corporation) as alkali metal salts of carboxymethyl cellulose.
  • the use ratio of the thickener is preferably 20% by mass or less, more preferably 0.1 to 15% by mass with respect to the total solid content of the electrode slurry. %, And more preferably 0.5 to 10% by mass.
  • the electrode binder composition of the present invention is preferably contained in an amount of 0.1 to 10 parts by mass in terms of solid content with respect to 100 parts by mass of the active material, and 0.3 to 4 parts by mass. More preferably it is contained.
  • the content ratio of the electrode binder composition is 0.1 to 10 parts by mass in terms of solid content, the polymer is difficult to dissolve in the electrolyte solution used in the electricity storage device, and as a result, even at high temperatures. An adverse effect on device characteristics due to an increase in overvoltage can be suppressed.
  • the electrode slurry is prepared by mixing the electrode binder composition of the present invention, the active material as described above, and other components used as necessary.
  • the electrode slurry is preferably prepared under reduced pressure.
  • the electrode binder composition of the present invention the electrode slurry as described above can form an active material layer having high adhesion between active materials and between an active material and a current collector, Moreover, the electrical storage device excellent in the electrochemical stability in a high temperature environment can be provided.
  • the electrode in the present invention is A current collector, An active material layer formed through a process of applying and drying the electrode slurry described above on the surface of the current collector; Is provided. After the coating film is dried, press working is preferably performed.
  • a current collector for example, a metal foil, an etching metal foil, an expanded metal, or the like can be used. Specific examples of these materials include metals such as aluminum, copper, nickel, tantalum, stainless steel, and titanium, and can be appropriately selected and used depending on the type of the target power storage device. For example, when forming the positive electrode of a lithium ion secondary battery, it is preferable to use aluminum among the above as a collector.
  • the thickness of the current collector is preferably 5 to 30 ⁇ m, and more preferably 8 to 25 ⁇ m.
  • the thickness of the current collector is preferably 5 to 30 ⁇ m, and more preferably 8 to 25 ⁇ m.
  • the thickness of the current collector is preferably 5 to 30 ⁇ m, and more preferably 8 to 25 ⁇ m.
  • the thickness of the current collector is preferably 5 to 100 ⁇ m, more preferably 10 to 70 ⁇ m, and particularly preferably 15 to 30 ⁇ m.
  • the active material layer in the electrode is formed by applying a slurry for the electrode and drying it on the surface of the current collector as described above.
  • a method for applying the electrode slurry onto the current collector for example, an appropriate method such as a doctor blade method, a reverse roll method, a comma bar method, a gravure method, or an air knife method can be applied.
  • the coating film is preferably dried in a temperature range of 20 to 250 ° C., more preferably 50 to 150 ° C., preferably for 1 to 120 minutes, more preferably 5 to 60 minutes.
  • the dried coating film is preferably subjected to press working.
  • Examples of means for performing the pressing include a roll press machine, a high-pressure super press machine, a soft calendar, and a 1-ton press machine.
  • the conditions for the press working are appropriately set according to the type of processing machine used and the desired thickness and density of the active material layer.
  • the preferable thickness and density of the active material layer vary depending on the application. In the case of a lithium ion secondary battery negative electrode, the thickness is 40 to 100 ⁇ m and the density is 1.3 to 1.9 g / cm. 3 Is preferably; In the case of a lithium ion secondary battery positive electrode, the thickness is 40 to 100 ⁇ m and the density is 2.0 to 5.0 g / cm.
  • the electricity storage device in the present invention includes the electrodes as described above.
  • the electricity storage device according to the present invention has a structure in which the electrode as described above is opposed to the counter electrode via the electrolytic solution, and is preferably isolated by the presence of the separator.
  • two electrodes two of a positive electrode and a negative electrode or two of a capacitor electrode
  • this is wound or folded in accordance with the battery shape. And injecting the electrolyte into the battery container and sealing it.
  • the shape of the battery can be an appropriate shape such as a coin shape, a button shape, a sheet shape, a cylindrical shape, a square shape, or a flat shape.
  • the electrolytic solution is appropriately selected and used depending on the type of the target electricity storage device.
  • As the electrolytic solution a solution in which an appropriate electrolyte is dissolved in a solvent is used.
  • a lithium compound is used as an electrolyte.
  • LiClO 4 , LiBF 4 , LiI, LiPF 6 , LiCF 3 SO 3 , LiAsF 6 , LiSbF 6 LiAlCl 4 , LiCl, LiBr, LiB (C 2 H 5 ) 4 , LiCH 3 SO 3 , LiC 4 F 9 SO 3 , Li (CF 3 SO 2 ) 2 N etc. can be mentioned.
  • the electrolyte concentration in this case is preferably 0.5 to 3.0 mol / L, more preferably 0.7 to 2.0 mol / L.
  • an electric double layer capacitor for example, tetraethylammonium tetrafluoroborate, triethylmethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate or the like is used as an electrolyte.
  • the electrolyte concentration in this case is preferably 0.5 to 3.0 mol / L, more preferably 0.7 to 2.0 mol / L.
  • the type and concentration of the electrolyte in manufacturing the lithium ion capacitor are the same as in the case of the lithium ion secondary battery.
  • examples of the solvent used in the electrolyte include carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate; lactones such as ⁇ -butyrolactone; Ethers such as trimethoxysilane, 1,2-dimethoxyethane, diethyl ether, 2-ethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran; Sulfoxides such as dimethyl sulfoxide; Oxolane derivatives such as 1,3-dioxolane, 4-methyl-1,3-dioxolane; Nitrogen-containing compounds such as acetonitrile and nitromethane; Esters such as methyl formate, methyl acetate, butyl acetate, methyl propionate, ethyl propionate, phosphate triester; Glyme compounds such as diglyme, triglyme and
  • Such an electricity storage device has high adhesion between the active materials and between the active material and the current collector in the active material layer, and is excellent in electrochemical stability in a high temperature environment. Therefore, this power storage device is suitable as a secondary battery or capacitor mounted on an automobile such as an electric vehicle, a hybrid car, a truck, etc., as well as a secondary battery and a capacitor used in AV equipment, OA equipment, communication equipment, etc. It is also suitable.
  • Synthesis example 1 (1) Synthesis of Polymer A The inside of an autoclave having an internal volume of about 6 L equipped with an electromagnetic stirrer was sufficiently purged with nitrogen. Thereafter, 2.5 L of deoxygenated pure water and 10 g of ammonium perfluorodecanoate as an emulsifier were charged into the autoclave, and the temperature was raised to 60 ° C. while stirring at 350 rpm.
  • a mixed gas consisting of 70% by mass of vinylidene fluoride (VDF) and 30% by mass of propylene hexafluoride (HFP) as monomers was charged until the internal pressure reached 20 kg / cm 2 . Furthermore, 25 g of Freon 113 solution containing 20% by mass of diisopropyl peroxydicarbonate as a polymerization initiator was injected using nitrogen gas to initiate polymerization. During the polymerization, a mixed gas composed of 60.2% by mass of VDF and 39.8% by mass of HFP was sequentially injected so that the internal pressure was maintained at 20 kg / cm 2 , and the pressure was maintained at 20 kg / cm 2 .
  • the polymerization rate decreased as the polymerization progressed, 3 hours after the start of polymerization, the same amount of the same polymerization initiator solution as that described above was injected using nitrogen gas, and the reaction was continued for another 3 hours. Thereafter, the reaction liquid was cooled and the stirring was stopped at the same time, and the reaction was stopped by releasing the unreacted monomer to obtain an aqueous dispersion containing 40% by mass of polymer A fine particles.
  • the particle size frequency distribution was measured using a particle size frequency distribution measuring apparatus (manufactured by Nikkiso Co., Ltd., model “NPA150”) based on the dynamic light scattering method. The determined maximum frequency diameter was 250 nm.
  • the particle size frequency distribution was measured using a particle size frequency distribution measuring device “NPA150”, and the maximum frequency size obtained from the distribution was 500 nm. Further, about 10 g of the obtained aqueous dispersion was taken into a Teflon (registered trademark) petri dish having a diameter of 8 cm and dried at 120 ° C. for 1 hour to form a film. 1 g of the obtained membrane (polymer) was accurately weighed and immersed in 400 mL of tetrahydrofuran (THF) and shaken at 50 ° C. for 3 hours.
  • NFA150 particle size frequency distribution measuring device
  • Synthesis Examples 2-4 In the synthesis example 1, “(1) Synthesis of polymer A”, the composition of the monomer gas and the amount of the emulsifier ammonium perfluorodecanoate were appropriately changed, and “(2) Synthesis of polymer particles” In Table 1, the amount of monomer charged (parts by mass) is as shown in Table 1, so that each of the polymer particles (P2) to (P4) having the particle diameters shown in Table 1 is dispersed in water. Got the body.
  • Synthesis example 5 In “(2) Synthesis of polymer particles” in Synthesis Example 1 above, the aqueous dispersion containing fine particles of polymer A was not used, and the monomer charge (parts by mass) was as shown in Table 1.
  • Example 1 Preparation of binder composition> A binder composition was obtained by stirring and mixing 50 parts by mass of the aqueous dispersion (P1) obtained in Synthesis Example 1 and 50 parts by mass of the aqueous dispersion (P2) obtained in Synthesis Example 2.
  • P1 aqueous dispersion
  • P2 aqueous dispersion
  • NPA150 particle size frequency distribution measuring device
  • LiFePO 4 lithium iron phosphate
  • ⁇ Preparation of slurry for positive electrode> In a biaxial planetary mixer (product name “TK Hibismix 2P-03” manufactured by PRIMIX Co., Ltd.), 1 part by weight of a thickener (product name “CMC1120”, manufactured by Daicel Corporation) (in terms of solid content) ), 100 parts by mass of the active material particles prepared in “Preparation of active material particles”, 5 parts by mass of acetylene black, and 68 parts by mass of water were added, and the mixture was stirred at 60 rpm for 1 hour. Next, the binder composition prepared in “Preparation of Binder Composition” is added so that the polymer particles contained in the composition are in the amount (parts by mass) described in Table 2, and further stirred for 1 hour.
  • a positive electrode slurry was prepared by stirring and mixing at 1,800 rpm for 5 minutes and further under vacuum (about 5.0 ⁇ 10 3 Pa) at 1,800 rpm for 1.5 minutes.
  • a negative electrode slurry was prepared by stirring and mixing at 1,800 rpm for 1.5 minutes under vacuum.
  • the negative electrode slurry prepared above was uniformly applied to the surface of a current collector made of copper foil having a thickness of 20 ⁇ m by a doctor blade method so that the film thickness after drying was 150 ⁇ m, and dried at 120 ° C. for 20 minutes. .
  • the negative electrode was obtained by pressing using a roll-press machine so that the density of a film
  • Lithium-ion battery cell assembly In a glove box substituted with Ar so that the dew point is ⁇ 80 ° C. or less, the negative electrode manufactured in “(2) Manufacturing of negative electrode” was punched and molded to a diameter of 16.16 mm. The product was placed on a bipolar coin cell (trade name “HS Flat Cell” manufactured by Hosen Co., Ltd.).
  • a separator made of a polypropylene porous membrane punched to a diameter of 24 mm (manufactured by Polypore Co., Ltd., trade name “Celguard # 2400”) is placed, and further, 500 ⁇ L of electrolyte is injected so that air does not enter,
  • a lithium ion battery is manufactured by placing the positive electrode manufactured in the above-mentioned “(1) Manufacturing of positive electrode” by punching and molding the positive electrode to a diameter of 15.95 mm, and sealing the outer body of the two-pole coin cell with a screw.
  • a cell (electric storage device) was assembled.
  • Evaluation of electricity storage device Evaluation of electricity storage device (Evaluation of charge / discharge rate characteristics) About the electrical storage device manufactured above, charging is started at a constant current (0.2 C), and when the voltage reaches 4.2 V, charging is continued at a constant voltage (4.2 V). The charging capacity at 0.2 C was measured with the time when 0.01 C was reached as the completion of charging (cut-off). Next, discharge was started at a constant current (0.2 C), and when the voltage reached 2.7 V, the discharge was completed (cut off), and the discharge capacity at 0.2 C was measured.
  • charging is started at a constant current (3C) for the same cell, and when the voltage reaches 4.2V, charging is continued at a constant voltage (4.2V).
  • the charging capacity at 3C was measured with the point of time when charging was completed (cut-off).
  • discharge was started at a constant current (3C), and when the voltage reached 2.7 V, the discharge was completed (cut-off), and the discharge capacity at 3C was measured.
  • the charge rate (%) is calculated by calculating the ratio (percent%) of the charge capacity at 3C to the charge capacity at 0.2C.
  • the discharge rate (%) was calculated by calculating the ratio (percentage) of the discharge capacity at 3C to the discharge capacity at 0.2C.
  • a binder composition was prepared in the same manner as in Example 1, and a positive electrode and an electricity storage device were produced and evaluated using the binder composition. The evaluation results are shown in Table 2.
  • Comparative Examples 2 to 6 one type of aqueous dispersion was used for each.
  • a particle size frequency distribution chart of the polymer particles in each binder composition obtained in Example 2 and Comparative Example 3 measured by a particle size frequency distribution measuring apparatus “NPA150” is shown in FIGS. 1 and 2, respectively.
  • the polymer particle having the larger maximum frequency diameter is “particle 1”
  • the polymer particle having the smaller maximum frequency diameter is “particle” 2 ”.
  • the notation "-" in Table 2 indicates that the corresponding component was not used or the measurement object did not exist.
  • An electricity storage device including an electrode manufactured using the binder composition for an electrode of the present invention has extremely good charge / discharge rate characteristics, which is one of electrical characteristics.

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

La présente invention concerne une composition de liant destinée à des électrodes. Ladite composition contient des particules polymères et un milieu liquide, et est caractérisée en ce qu'au moins certaines particules polymères contiennent un atome de fluor et en ce que la distribution de fréquence des diamètres des particules polymères, telle qu'elle est déterminée par un procédé de diffusion de lumière dynamique, est multimodale. La composition de liant destinée à des électrodes fournit une électrode qui présente une excellente conductivité des ions, une excellente résistance à l'oxydation (caractéristiques de charge et de décharge) et une excellente adhésion.
PCT/JP2012/064733 2011-07-14 2012-06-01 Composition de liant pour électrodes WO2013008564A1 (fr)

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WO2014201193A1 (fr) 2013-06-12 2014-12-18 E. I. Du Pont De Nemours And Company Liant pour batterie hybride à base d'un copolymère d'éthylène-fluoropolymère
WO2014201194A1 (fr) 2013-06-12 2014-12-18 E. I. Du Pont De Nemours And Company Liant de batterie hybride
JP2015103464A (ja) * 2013-11-27 2015-06-04 株式会社クレハ フッ化ビニリデン系重合体水系組成物およびその用途
JP2016015270A (ja) * 2014-07-03 2016-01-28 Jsr株式会社 蓄電デバイス用バインダー組成物およびその製造方法
WO2016039067A1 (fr) * 2014-09-08 2016-03-17 Jsr株式会社 Composition de liant pour électrode de dispositif de stockage, suspension épaisse pour électrode de dispositif de stockage, électrode de dispositif de stockage, et dispositif de stockage
CN111194502A (zh) * 2017-10-12 2020-05-22 富士胶片株式会社 全固态二次电池用粘合剂组合物、含固体电解质的片材及全固态二次电池、以及含固体电解质的片材及全固态二次电池的制造方法
CN113285078A (zh) * 2013-07-02 2021-08-20 旭化成株式会社 电解质溶液、电解质膜、电极催化剂层、膜电极接合体和燃料电池
JP2021128918A (ja) * 2020-02-17 2021-09-02 トヨタ自動車株式会社 リチウムイオン二次電池の負極およびその製造方法
CN113557089A (zh) * 2019-03-14 2021-10-26 巴斯夫公司 用于增强催化剂载体涂料粘附性的粘合剂组合物
WO2022045266A1 (fr) * 2020-08-31 2022-03-03 日本ゼオン株式会社 Composition d'agent de dispersion pour élément électrochimique, dispersion liquide de matériau conducteur pour élément électrochimique, composition de bouillie pour électrode d'élément électrochimique ainsi que procédé de fabrication de celle-ci, électrode pour élément électrochimique, et élément électrochimique
JP7639391B2 (ja) 2021-02-24 2025-03-05 トヨタ自動車株式会社 全固体電池

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CN113557089A (zh) * 2019-03-14 2021-10-26 巴斯夫公司 用于增强催化剂载体涂料粘附性的粘合剂组合物
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JP2021128918A (ja) * 2020-02-17 2021-09-02 トヨタ自動車株式会社 リチウムイオン二次電池の負極およびその製造方法
JP7240615B2 (ja) 2020-02-17 2023-03-16 トヨタ自動車株式会社 リチウムイオン二次電池の負極およびその製造方法
WO2022045266A1 (fr) * 2020-08-31 2022-03-03 日本ゼオン株式会社 Composition d'agent de dispersion pour élément électrochimique, dispersion liquide de matériau conducteur pour élément électrochimique, composition de bouillie pour électrode d'élément électrochimique ainsi que procédé de fabrication de celle-ci, électrode pour élément électrochimique, et élément électrochimique
JP2022041225A (ja) * 2020-08-31 2022-03-11 日本ゼオン株式会社 電気化学素子用分散剤組成物、電気化学素子用導電材分散液、電気化学素子電極用スラリー組成物及びその製造方法、電気化学素子用電極、並びに電気化学素子
JP7639391B2 (ja) 2021-02-24 2025-03-05 トヨタ自動車株式会社 全固体電池

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