WO2019017480A1 - Électrode et dispositif de stockage d'électricité - Google Patents

Électrode et dispositif de stockage d'électricité Download PDF

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WO2019017480A1
WO2019017480A1 PCT/JP2018/027304 JP2018027304W WO2019017480A1 WO 2019017480 A1 WO2019017480 A1 WO 2019017480A1 JP 2018027304 W JP2018027304 W JP 2018027304W WO 2019017480 A1 WO2019017480 A1 WO 2019017480A1
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meth
acrylate
mass
electrode
polymer
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PCT/JP2018/027304
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English (en)
Japanese (ja)
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一博 高橋
大明 進藤
義広 諸岡
松尾　孝
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株式会社大阪ソーダ
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Priority to JP2019530619A priority Critical patent/JP7180595B2/ja
Publication of WO2019017480A1 publication Critical patent/WO2019017480A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/26—Electrodes characterised by their structure, e.g. multi-layered, porosity or surface features
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/22—Electrodes
    • H01G11/30—Electrodes characterised by their material
    • H01G11/32—Carbon-based
    • H01G11/38—Carbon pastes or blends; Binders or additives therein
    • 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
    • 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
    • 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
    • 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 storage devices such as primary batteries, secondary batteries such as lithium ion secondary batteries and nickel hydrogen secondary batteries, electrochemical capacitors, etc.
  • non-aqueous electrolyte storage batteries using non-aqueous electrolytes such as organic solvents as electrolytes.
  • the present invention relates to an electrode used for a device and a storage device.
  • BACKGROUND Storage devices such as lithium ion secondary batteries and electrochemical capacitors are used in electronic devices such as mobile phones, notebook computers, camcorders and the like.
  • application to car applications such as electric vehicles and hybrid electric vehicles and storage batteries for household power storage has also been progressing due to rising awareness of environmental protection and maintenance of related laws.
  • An electrode used for such a storage device is usually obtained by applying and drying an electrode material composed of an active material, a conductive support agent, a binder, and a solvent on a current collector.
  • the binder is required to be excellent in binding property when used in an electrode and capable of imparting excellent electrical characteristics to an electricity storage device.
  • Patent Document 1 proposes a new binder.
  • the present invention has been made in view of the above circumstances, and it is a main object of the present invention to provide an electrode which is excellent in the binding property of a binder while maintaining low resistance in an electric storage device.
  • the present inventors have found that the electrode comprises a current collector and an electrode material layer formed on the surface of the current collector, and the electrode material layer is active.
  • the images obtained by observing the cross section of the electrode material layer with a scanning electron microscope containing material particles and binder particles, at least three 1 ⁇ m ⁇ 1 ⁇ m square fields of view in which no active material particles are present In the electrode, 3 to 20 binder particles are observed, and three or more binder particles are not continuously in contact with each other, the binding property of the binder is maintained while maintaining resistance reduction in the storage device. It was found to be excellent.
  • the present invention is an invention completed based on these findings and further studies. That is, the present invention relates to the following.
  • Item 1 An electrode comprising a current collector and an electrode material layer formed on the surface of the current collector, The electrode material layer contains active material particles and binder particles, Among the images obtained by observing the cross section of the electrode material layer with a scanning electron microscope, the binder particles are 3 to 6 within the field of view of at least three 1 ⁇ m ⁇ 1 ⁇ m squares where the active material particles are not present. 20. The electrode observed 20 and the said binder particle
  • a storage device comprising the electrode according to any one of Items 1 to 3.
  • the electrode which is excellent in the binding property of a binder can be provided, maintaining resistance reduction in an electrical storage device. Further, according to the present invention, it is also possible to provide an electricity storage device provided with the electrode.
  • the electrode of the present invention is provided with the excellent binding property of the binder, and can realize low resistance in a storage device such as a lithium ion secondary battery or an electrochemical capacitor.
  • a storage device such as a lithium ion secondary battery or an electrochemical capacitor.
  • the electrode of the present invention is used for a large battery (for example, a battery for in-vehicle use such as an electric car or a hybrid electric car or a storage battery for household power storage) having a low density compared to a small battery.
  • the binder can exhibit excellent binding power. Therefore, the electricity storage device provided with the electrode of the present invention is particularly useful for on-vehicle applications such as electric vehicles and hybrid electric vehicles, and storage batteries for household power storage.
  • the power storage device includes a primary battery, a secondary battery (such as a lithium ion secondary battery and a nickel hydrogen secondary battery), and an electrochemical capacitor.
  • a secondary battery such as a lithium ion secondary battery and a nickel hydrogen secondary battery
  • an electrochemical capacitor such as a lithium ion secondary battery and a nickel hydrogen secondary battery
  • (meth) acrylate means “acrylate or methacrylate”, and the same applies to expressions similar thereto.
  • the electrode of the present invention comprises a current collector and an electrode material layer.
  • a well-known thing can be used as a collector, Specifically, metals, such as aluminum, nickel, stainless steel, gold
  • the thickness of the current collector is not particularly limited, and may be, for example, about 5 to 50 ⁇ m, preferably about 10 to 20 ⁇ m.
  • the electrode material layer is formed on the surface of the current collector.
  • the electrode material layer contains active material particles and binder particles.
  • the electrode material layer can be formed by applying a binder composition containing active material particles constituting the electrode material layer, a binder and the like on the surface of the current collector.
  • the thickness of the electrode material layer is not particularly limited, and may be, for example, about 5 to 300 ⁇ m, preferably about 15 to 200 ⁇ m.
  • the present invention of the images obtained by observing the cross section of the electrode material layer with a scanning electron microscope (SEM), within the field of view of at least three 1 ⁇ m ⁇ 1 ⁇ m squares in which no active material particles are present, It is characterized in that 3 to 20 binder particles are observed, and three or more binder particles are not continuously in contact with each other. That is, an SEM image of the cross section of the electrode material layer is acquired, and 3 to 20 binder particles are observed in the field of at least three 1 ⁇ m ⁇ 1 ⁇ m squares in which no active material particles are observed among the SEM images. Ru. Furthermore, in the said visual field, what is in the state which 3 or more binder particles contact
  • SEM scanning electron microscope
  • the electrode of the present invention has a structure in which the binder particles of the electrode material layer are appropriately dispersed, so the binder particles exhibit excellent binding property and maintain low resistance in the electricity storage device. be able to.
  • the conventional electrode when acquiring the SEM image of the cross section of the electrode material layer, it has a structure in which three or more binder particles are aggregated, and the dispersibility is inferior as compared with the electrode of the present invention.
  • binder particles 3 to 20 binder particles are observed, and three or more binder particles are in contact continuously in the present invention from the viewpoint of exhibiting excellent binding property of binder particles and maintaining resistance reduction in the storage device.
  • the field of view of a square of 1 ⁇ m ⁇ 1 ⁇ m which does not exist may be present in at least three places in the SEM image, and it is more preferable that three to six places exist.
  • the visual field of three or more places may mutually overlap partially, about at least three places, it is preferable not to mutually overlap.
  • binder particles In the 1 ⁇ m ⁇ 1 ⁇ m square field of view, 3 to 20 binder particles may be observed, more preferably 3 to 15 and still more preferably 4 to 8.
  • the binder particles preferably have a particle diameter of about 30 to 200 nm, more preferably within a square of 1 ⁇ m ⁇ 1 ⁇ m, from the viewpoint of exhibiting excellent binding property of the binder particles and maintaining resistance reduction in the storage device. Preferably, about 50 to 180 nm can be mentioned.
  • the particle diameter of the binder particles is in such a range, it is possible to obtain an electrode having a structure in which the binder particles of the electrode material layer are more appropriately dispersed.
  • the content of the binder particles in the electrode material layer is preferably about 0.1 to 15% by mass, more preferably about 0.2 to 10% by mass, and still more preferably 0.3 to 7%. There are about%.
  • the content of the binder particles is in such a range, an electrode having a structure in which the binder particles of the electrode material layer are more appropriately dispersed can be obtained.
  • the density of the electrode material layer is preferably about 1.5 to 3.7 g / cc, more preferably about 1.8 to 3.5 g / cc.
  • the density of the electrode material layer is in such a range, an electrode having a structure in which the binder particles of the electrode material layer are more appropriately dispersed can be obtained.
  • the binder particle has a polymer (A) having a structural unit derived from a multifunctional (meth) acrylate at 0.1% by mass to 5% by mass, and more than 5% by mass a structural unit derived from a polyfunctional (meth) acrylate It is preferable to contain the polymer (B) which has 30 mass% or less.
  • a polymer (A) is a copolymer which has a structural unit derived from polyfunctional (meth) acrylate in the range of 0.1 mass% or more and 5 mass% or less.
  • the structural unit derived from the polyfunctional (meth) acrylate is preferably a structural unit derived from the following general formula (1).
  • R 11 is the same or different and is a hydrogen atom or a methyl group
  • R 12 is an organic group having 2 to 100 carbon atoms having a valence of 5 or less
  • m is an integer of 5 or less It is.
  • m is preferably 2 to 5 (that is, a structural unit derived from difunctional to pentafunctional (meth) acrylate), and 3 to 5 (that is, trifunctional to pentafunctional (meth)) It is more preferable that the structural unit is derived from an acrylate, and particularly preferably 3 to 4 (that is, a structural unit derived from a trifunctional to tetrafunctional (meth) acrylate).
  • Structural units derived from difunctional to pentafunctional (meth) acrylates are excellent in physical properties (flexibility, binding property) as binder particles.
  • the structural unit derived from the polyfunctional (meth) acrylate is particularly preferably a structural unit derived from a trifunctional or tetrafunctional (meth) acrylate.
  • the structural unit derived from the polyfunctional (meth) acrylate may be of one type or of two or more types.
  • specific examples of structural units derived from bifunctional (meth) acrylate include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, Tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, dioxane glycol di (meth) acrylate, bis (meth) acryloyloxy
  • the structural unit derived from bifunctional (meth) acrylates, such as ethyl phosphate, is mentioned.
  • specific examples of the structural unit derived from trifunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, trimethylolpropane PO-added tri (Meth) acrylate, pentaerythritol tri (meth) acrylate, 2,2,2-tris (meth) acryloyloxymethylethyl succinic acid, ethoxylated isocyanurate tri (meth) acrylate, ⁇ -caprolactone modified tris- (2-) Derived from trifunctional (meth) acrylates such as (meth) acryloxyethyl) isocyanurate, glycerin EO addition tri (meth) acrylate, glycerin PO addition tri (meth) acrylate and tris (meth) acryloyloxyethyl phosphate
  • They include structural units that.
  • structural units derived from a trifunctional (meth) acrylate selected from trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, and pentaerythritol tri (meth) acrylate are preferable.
  • specific examples of the structural unit derived from tetrafunctional (meth) acrylate include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate and pentaerythritol EO-added tetra (meth) acrylate And structural units derived from tetrafunctional (meth) acrylates such as
  • specific examples of structural units derived from pentafunctional (meth) acrylate include structural units derived from dipentaerythritol penta (meth) acrylate.
  • the minimum of the ratio of the structural unit derived from the polyfunctional (meth) acrylate in a polymer (A) is 0.1 mass% or more, and it is more preferable that it is 0.3 mass% or more 0.5 It is particularly preferable that the content is at least% by mass.
  • the upper limit of the ratio of the structural unit derived from the polyfunctional (meth) acrylate in the polymer (A) is preferably 5% by mass or less, more preferably 4% by mass or less, and 2.5% by mass It is particularly preferable that the content is less than%.
  • the polymer (A) is a structural unit derived from a (meth) acrylate having a hydroxyl group, a structural unit derived from a (meth) acrylic acid ester, and a (meth) acrylic acid, in addition to the structural unit derived from the polyfunctional (meth) acrylate It may further have at least one structural unit among structural units derived from an acid.
  • a structural unit derived from a (meth) acrylate having a hydroxyl group a structural unit derived from an alkylene glycol mono (meth) acrylate having a molecular weight of 100 to 1000 is preferable, and an alkylene glycol of the following general formula (2)
  • the structural unit derived from mono (meth) acrylate is more preferable, and the structural unit derived from alkylene glycol mono (meth) acrylate of the following general formula (3) is particularly preferable.
  • R 1 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms
  • x is an integer of 2 to 8
  • n is an integer of 2 to 30.
  • R 1 examples include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group and an isobutyl group.
  • R 1 is a hydrogen atom or a methyl group. That is, in the constituent unit, the monomer having a hydroxyl group is preferably a (meth) acrylate monomer (R 1 is a hydrogen atom or a methyl group).
  • (C x H 2 x O) is a linear or branched alkyl ether group
  • x is an integer of 2 to 8, preferably an integer of 2 to 7, and more preferably Is an integer of 2 to 6.
  • n is an integer of 2 to 30, preferably an integer of 3 to 25, and more preferably an integer of 4 to 20.
  • R 1 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms
  • o is an integer of 0 to 30
  • p is an integer of 0 to 30, and o + p Is 2-30.
  • o and p only represent the compositional ratio of the constituent unit, and it is possible to use a block of repeating units of (C 2 H 4 O) and a block of repeating units of (C 3 H 6 O). And the repeating unit of (C 2 H 4 O) and the repeating unit of (C 3 H 6 O) are alternately or randomly arranged, or the random part and the block part are mixed. It may be a compound.
  • R 1 examples include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group and an isobutyl group.
  • R 1 is a hydrogen atom or a methyl group. That is, in the constituent unit, the monomer having a hydroxyl group is preferably a (meth) acrylate monomer (R 1 is a hydrogen atom or a methyl group).
  • o is an integer of 0 to 30
  • p is an integer of 0 to 30
  • o + p is 2 to 30
  • o is an integer of 0 to 25 and p is 0 to 25
  • o is preferably an integer of 0 to 20
  • o is an integer of 0 to 20
  • p is an integer of 0 to 20
  • o + p is particularly preferably 4 to 20.
  • the (meth) acrylate-derived structural unit having a hydroxyl group include, as specific examples, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and polyethylene glycol mono (Meth) acrylate, dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol-propylene glycol-mono (meth) Acrylate, and (meth) acrylate having a hydroxyl group such as polyethylene glycol-tetramethylene glycol-mono (meth) acrylate It includes structural units of the come.
  • a (meth) acrylate-derived hydroxyl group having a hydroxyl group selected from tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate Constituent units are preferred.
  • the structural unit derived from the (meth) acrylate having a hydroxyl group, which the polymer (A) has, may be of one type or of two or more types.
  • the lower limit of the ratio of the structural unit derived from a (meth) acrylate having a hydroxyl group in the polymer (A) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and 1.5% by mass It is particularly preferable to be the above.
  • the upper limit of the ratio of the structural unit derived from a (meth) acrylate having a hydroxyl group in the polymer (A) is preferably 15% by mass or less, more preferably 12% by mass or less, and 10% by mass It is particularly preferred that
  • polymer (A) as a constitutional unit derived from (meth) acrylic acid ester, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid n-pentyl, (meth) acrylic acid n-amyl, (meth) acrylic acid isoamyl, (meth) acrylic acid n-hexyl ( Examples include structural units derived from (meth) acrylic acid alkyl esters such as n-heptyl acrylic acid, n-octyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, and lauryl (meth) acrylic acid.
  • the unit is preferably a unit, and is preferably a structural unit derived from a (meth) acrylic acid alkyl ester selected from methyl (meth) acrylate, ethyl (meth) acrylate and n-butyl (meth) acrylate.
  • the structural unit derived from the (meth) acrylic acid ester, which the polymer (A) has, may be of one type or of two or more types.
  • the lower limit of the ratio of the structural unit derived from (meth) acrylic acid ester in the polymer (A) is preferably 60% by mass or more, more preferably 70% by mass or more, and 75% by mass or more Is particularly preferred.
  • the upper limit of the ratio of the structural unit derived from the methacrylic acid ester in the polymer (A) is preferably 97 mass% or less, more preferably 95 mass% or less, and 93 mass% or less Is particularly preferred.
  • structural units derived from (meth) acrylic acid structural units derived from a compound selected from acrylic acid and methacrylic acid can be exemplified.
  • the structural unit derived from (meth) acrylic acid, which the polymer (A) has, may be of one type or of two or more types.
  • the lower limit of the ratio of the structural unit derived from (meth) acrylic acid in the polymer (A) is preferably 0% by mass or more, more preferably 1% by mass or more, and 3% by mass or more Is particularly preferred.
  • the upper limit of the ratio of the structural unit derived from (meth) acrylic acid in the polymer (A) is preferably 25% by mass or less, more preferably 15% by mass or less, and 10% by mass or less Is particularly preferred.
  • a polymer (B) is a copolymer which has a structural unit derived from polyfunctional (meth) acrylate in 5 mass% or more and 30 mass% or less range.
  • the structural unit derived from the polyfunctional (meth) acrylate is preferably a structural unit derived from the following general formula (1).
  • R 11 is the same or different and is a hydrogen atom or a methyl group
  • R 12 is an organic group having 2 to 100 carbon atoms having a valence of 5 or less
  • m is an integer of 5 or less It is.
  • m is preferably 2 to 5 (that is, a structural unit derived from difunctional to pentafunctional (meth) acrylate), and 3 to 5 (that is, trifunctional to pentafunctional (meth))
  • the structural unit is derived from an acrylate, and particularly preferably 3 to 4 (that is, a structural unit derived from a trifunctional to tetrafunctional (meth) acrylate).
  • Structural units derived from difunctional to pentafunctional (meth) acrylates are excellent in physical properties (flexibility, binding property) as binder particles.
  • the structural unit derived from the polyfunctional (meth) acrylate is particularly preferably a structural unit derived from a trifunctional or tetrafunctional (meth) acrylate.
  • the structural unit derived from the polyfunctional (meth) acrylate may be of one type or of two or more types.
  • specific examples of the structural unit derived from bifunctional (meth) acrylate are triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, Tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, dioxane glycol di (meth) acrylate, bis (meth) acryloyloxy
  • the structural unit derived from bifunctional (meth) acrylates, such as ethyl phosphate, is mentioned.
  • specific examples of the structural unit derived from trifunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, trimethylolpropane PO-added tri (Meth) acrylate, pentaerythritol tri (meth) acrylate, 2,2,2-tris (meth) acryloyloxymethylethyl succinic acid, ethoxylated isocyanurate tri (meth) acrylate, ⁇ -caprolactone modified tris- (2-) Derived from trifunctional (meth) acrylates such as (meth) acryloxyethyl) isocyanurate, glycerin EO addition tri (meth) acrylate, glycerin PO addition tri (meth) acrylate and tris (meth) acryloyloxyethyl phosphate
  • They include structural units that.
  • structural units derived from a trifunctional (meth) acrylate selected from trimethylolpropane tri (meth) acrylate, trimethylolpropane EO-added tri (meth) acrylate, and pentaerythritol tri (meth) acrylate are preferable.
  • structural units derived from tetrafunctional (meth) acrylate include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate and pentaerythritol EO-added tetra (meth) acrylate And structural units derived from tetrafunctional (meth) acrylates such as
  • polymer (B) specific examples of structural units derived from pentafunctional (meth) acrylate include structural units derived from dipentaerythritol penta (meth) acrylate.
  • the lower limit of the ratio of the structural unit derived from the polyfunctional (meth) acrylate in the polymer (B) is preferably more than 5% by mass, more preferably 8% by mass or more, particularly preferably 12% by mass or more preferable.
  • the upper limit of the ratio of the structural units derived from the polyfunctional (meth) acrylate in the polymer (B) is preferably 35% by mass or less, more preferably 30% by mass or less, and 25% by mass or less Is particularly preferred.
  • the polymer (B) is a structural unit derived from a (meth) acrylate having a hydroxyl group, a structural unit derived from a (meth) acrylic acid ester, and a (meth) acrylic acid, in addition to the structural unit derived from the polyfunctional (meth) acrylate It may further have at least one structural unit among structural units derived from an acid.
  • a structural unit derived from a (meth) acrylate having a hydroxyl group a structural unit derived from an alkylene glycol mono (meth) acrylate having a molecular weight of 100 to 1000 is preferable, and an alkylene glycol mono of the general formula (2)
  • the structural unit derived from (meth) acrylate is more preferable, and the structural unit derived from alkylene glycol mono (meth) acrylate of the general formula (3) is particularly preferable.
  • R 1 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms
  • x is an integer of 2 to 8
  • n is an integer of 2 to 30.
  • R 1 examples include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group and an isobutyl group.
  • R 1 is a hydrogen atom or a methyl group. That is, in the constituent unit, the monomer having a hydroxyl group is preferably a (meth) acrylate monomer (R 1 is a hydrogen atom or a methyl group).
  • (C x H 2 x O) is a linear or branched alkyl ether group
  • x is an integer of 2 to 8, preferably an integer of 2 to 7, and more preferably Is an integer of 2 to 6.
  • n is an integer of 2 to 30, preferably an integer of 3 to 25, and more preferably an integer of 4 to 20.
  • R 1 is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms
  • o is an integer of 0 to 30
  • p is an integer of 0 to 30, and o + p Is 2-30.
  • o and p only represent the compositional ratio of the constituent unit, and it is possible to use a block of repeating units of (C 2 H 4 O) and a block of repeating units of (C 3 H 6 O). And the repeating unit of (C 2 H 4 O) and the repeating unit of (C 3 H 6 O) are alternately or randomly arranged, or the random part and the block part are mixed. It may be a compound.
  • R 1 examples include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group and an isobutyl group.
  • R 1 is a hydrogen atom or a methyl group. That is, in the constituent unit, the monomer having a hydroxyl group is preferably a (meth) acrylate monomer (R 1 is a hydrogen atom or a methyl group).
  • o is an integer of 0 to 30
  • p is an integer of 0 to 30
  • o + p is 2 to 30
  • o is an integer of 0 to 25 and p is 0 to 25
  • o is preferably an integer of 0 to 20
  • o is an integer of 0 to 20
  • p is an integer of 0 to 20
  • o + p is particularly preferably 4 to 20.
  • the structural unit derived from (meth) acrylate having a hydroxyl group are diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and polyethylene glycol mono (meth) acrylate, Dipropylene glycol mono (meth) acrylate, tripropylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polyethylene glycol-propylene glycol-mono (meth) acrylate, and polyethylene glycol -A structural unit derived from a (meth) acrylate having a hydroxyl group such as tetramethylene glycol-mono (meth) acrylate It is below.
  • a (meth) acrylate-derived hydroxyl group having a hydroxyl group selected from tetraethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, tetrapropylene glycol mono (meth) acrylate and polypropylene glycol mono (meth) acrylate Constituent units are preferred.
  • the constituent unit derived from the (meth) acrylate having a hydroxyl group, which the polymer (B) has, may be of one type or of two or more types.
  • the lower limit of the ratio of the structural unit derived from a (meth) acrylate having a hydroxyl group in the polymer (B) is preferably 0.5% by mass or more, more preferably 1% by mass or more, and 1.5% by mass It is particularly preferable to be the above.
  • the upper limit of the ratio of the structural unit derived from a (meth) acrylate having a hydroxyl group in the polymer (B) is preferably 15% by mass or less, more preferably 12% by mass or less, and 10% by mass It is particularly preferred that
  • the polymer (B) as a constitutional unit derived from (meth) acrylic acid ester, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (Meth) acrylic acid n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid n-pentyl, (meth) acrylic acid n-amyl, (meth) acrylic acid isoamyl, (meth) acrylic acid n-hexyl ( Examples include structural units derived from (meth) acrylic acid alkyl esters such as n-heptyl acrylic acid, n-octyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, and lauryl (meth) acrylic acid.
  • the structural unit derived from the (meth) acrylic acid ester, which the polymer (B) has, may be of one type or of
  • the polymer (B) preferably has a constitutional unit derived from methyl methacrylate, and the lower limit of the ratio of the constitutional unit derived from methyl methacrylate in the polymer (B) is 45 mass% or more
  • the content is preferably 50% by mass or more, and particularly preferably 55% by mass or more.
  • the upper limit of the ratio of the structural unit derived from methyl methacrylate in the polymer (B) is preferably 90% by mass or less, more preferably 85% by mass or less, and 80% by mass or less Is particularly preferred.
  • the lower limit of the ratio of the constituent units derived from the (meth) acrylic acid ester other than methyl methacrylate in the polymer (B) is preferably 0% by mass or more, more preferably 5% by mass or more And 10% by mass or more is particularly preferable.
  • the upper limit of the ratio of the structural unit derived from methyl methacrylate in the polymer (B) is preferably 25% by mass or less, more preferably 20% by mass or less, and 15% by mass or less Is particularly preferred.
  • the structural unit derived from (meth) acrylic acid structural units derived from a compound selected from acrylic acid and methacrylic acid can be exemplified.
  • the structural unit derived from (meth) acrylic acid, which the polymer (B) has, may be of one type or of two or more types.
  • the lower limit of the ratio of the structural unit derived from (meth) acrylic acid in the polymer (B) is preferably 0% by mass or more, more preferably 1% by mass or more, particularly preferably 3% by mass or more preferable. Further, the upper limit of the ratio of the structural unit derived from (meth) acrylic acid in the polymer (B) is preferably 25% by mass or less, more preferably 15% by mass or less, and 10% by mass or less Being particularly preferred.
  • polymer (B) as a polymer having a structural unit derived from (meth) acrylic acid ester and a structural unit derived from polyfunctional (meth) acrylate, in addition to the above, as a structural unit derived from another monomer Selected from fumaric acid, maleic acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, acrylonitrile, methacrylonitrile, ⁇ -chloroacrylonitrile, crotononitrile, ⁇ -ethylacrylonitrile, ⁇ -cyanoacrylate, vinylidene cyanide, fumaronitrile Can have a structural unit derived from the
  • the mass ratio of the polymer (A) to the polymer (B) is not particularly limited, but is preferably 3:97 to 97: 3, and is 5:95 to 95: 5. It is more preferable that
  • a general emulsion polymerization method, a soap free emulsion polymerization method, etc. can be used, respectively.
  • a closed container equipped with a stirrer and a heating device is inert at room temperature and is inert to a composition containing a monomer, an emulsifier, a polymerization initiator, water, if necessary, a dispersant, a chain transfer agent, a pH adjuster, etc.
  • the monomers and the like are emulsified in water by stirring under a gas atmosphere.
  • a method of emulsification methods such as stirring, shearing, ultrasonic waves and the like can be applied, and a stirring blade, a homogenizer and the like can be used. Then, the temperature is raised while stirring to initiate polymerization, whereby a spherical polymer latex in which the polymer is dispersed in water can be obtained.
  • the monomer addition method during polymerization may be monomer dropping, pre-emulsion dropping, etc. in addition to batch feeding, and two or more of these methods may be used in combination.
  • pre-emulsion dropping refers to an addition method in which a monomer, an emulsifying agent, water and the like are previously emulsified in advance and the emulsion is dropped.
  • the emulsifier used in the present invention is not particularly limited.
  • the emulsifying agent is a surfactant, and the surfactant includes a reactive surfactant having a reactive group.
  • Nonionic surfactants and anionic surfactants which are generally used in the emulsion polymerization method can be used.
  • nonionic surfactant for example, polyoxyethylene alkyl ether, polyoxyethylene alcohol ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polycyclic phenyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene
  • examples thereof include fatty acid esters and polyoxyethylene sorbitan fatty acid esters
  • examples of the reactive nonionic surfactants include Latemul PD-420, 430, 450 (manufactured by Kao Corporation), Adekaria Soap ER (manufactured by Adeka), Aqualon. RN (made by Dai-ichi Kogyo Seiyaku Co., Ltd.), Antox LMA (made by Nippon Emulsifier), Antox EMH (made by Nippon Emulsifier), etc. are mentioned.
  • anionic surfactant examples include metal salts of sulfuric acid ester type, carboxylic acid type or sulfonic acid type, ammonium salts, triethanol ammonium salts, surfactants of phosphoric acid ester type and the like.
  • the sulfuric acid ester type, the sulfonic acid type and the phosphoric acid ester type are preferable, and the sulfuric acid ester type is particularly preferable.
  • anionic surfactants of sulfuric acid ester type include metal alkyl sulfates such as dodecyl sulfate, ammonium, or alkyl sulfate triethanolamine, polyoxyethylene dodecyl ether sulfate, polyoxyethylene isodecyl ether sulfate, polyoxyethylene Examples thereof include metal salts of polyoxyethylene alkyl ether sulfuric acid such as tridecyl ether sulfuric acid, ammonium salts, and triethanolamine etc.
  • Latemul PD-104, 105 manufactured by Kao Corporation
  • Adekaria Soap SR manufactured by Adeka
  • Aqualon HS manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
  • Aqualon KH manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.
  • sodium dodecyl sulfate, ammonium dodecyl sulfate, triethanolamine dodecyl sulfate, sodium dodecyl benzene sulfonate, Latem PD-104 and the like can be mentioned.
  • nonionic surfactants and / or anionic surfactants may be used.
  • the reactivity of the reactive surfactant means that it contains a reactive double bond and undergoes a polymerization reaction with the monomer during polymerization. That is, the reactive surfactant acts as an emulsifier for the monomer during polymerization for producing the polymer, and after polymerization, it is covalently bonded to a part of the polymer to be incorporated. Therefore, the emulsion polymerization and the dispersion of the produced polymer are good, and the physical properties (flexibility, binding property) as binder particles are excellent.
  • the amount of the constituent unit of the emulsifier may be an amount generally used in the emulsion polymerization method. Specifically, it is in the range of 0.01 to 25% by mass, preferably 0.05 to 20% by mass, and more preferably 0.1 to 20% by mass, based on the amount of monomers (100% by mass) of the charge. It is.
  • the polymerization initiator used in the present invention is not particularly limited, and polymerization initiators generally used in the emulsion polymerization method and suspension polymerization method can be used. Preferably, it is an emulsion polymerization method. In the emulsion polymerization method, a water-soluble polymerization initiator is used, and in the suspension polymerization method, an oil-soluble polymerization initiator is used.
  • water-soluble polymerization initiator examples include water-soluble polymerization initiators represented by persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, 2-2′-azobis [2- (2) -Imidazolin-2-yl) propane], or a hydrochloride or sulfate thereof, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2- Methylpropanamidine), or a hydrochloride or sulfate thereof, 3,3 ′-[azobis [(2,2-dimethyl-1-iminoethane-2,1-diyl) imino]] bis (propanoic acid), 2,2 Preferred are polymerization initiators of water-soluble azo compounds such as'-[azobis (dimethylmethylene)] bis (2-imidazoline).
  • persulfates such as potassium persulfate, sodium persulfate and ammoni
  • oil-soluble polymerization initiators examples include cumene hydroperoxide, benzoyl peroxide, organic peroxides such as acetyl peroxide and t-butyl hydroperoxide, azobisisobutyronitrile, 1,1'-azobis (cyclohexane Polymerization initiators of oil-soluble azo compounds such as carbonitriles) and redox initiators are preferred. These polymerization initiators may be used alone or in combination of two or more.
  • the amount of polymerization initiator used may be an amount generally used in emulsion polymerization or suspension polymerization. Specifically, it is in the range of 0.01 to 10% by mass, preferably 0.01 to 5% by mass, and more preferably 0.02 to 3% by mass, with respect to the amount of monomer (100% by mass) to be charged. It is.
  • Chain transfer agents can be used as needed.
  • specific examples of the chain transfer agent include alkyl mercaptan such as n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and n-stearyl mercaptan, and 2,4-diphenyl-4.
  • Xanthogen compounds such as -methyl-1-pentene, 2,4-diphenyl-4-methyl-2-pentene, dimethylxanthogen disulfide, diisopropyl xanthogen disulfide, terpinolene, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetramethylthiuram mono Thiuram compounds such as sulfide, phenol compounds such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol, allyl compounds such as allyl alcohol Halogenated hydrocarbon compounds such as ololmethane, dibromomethane and carbon tetrabromide, ⁇ -benzyloxystyrene, vinyl ethers such as ⁇ -benzyloxyacrylonitrile and ⁇ -benzyloxyacrylamide, triphenylethane, pentaphenylethane, acrolein and meth
  • the polymerization time and polymerization temperature of the polymer are not particularly limited.
  • the temperature can be appropriately selected depending on the type of polymerization initiator to be used, etc., but generally, the polymerization temperature is 20 to 100 ° C., and the polymerization time is 0.5 to 100 hours.
  • the polymer obtained by the above-mentioned method can be adjusted in pH by using a base as a pH adjuster as necessary.
  • a base include alkali metal (Li, Na, K, Rb, Cs) hydroxide, ammonia, an inorganic ammonium compound, an organic amine compound and the like.
  • the pH range is pH 2-11, preferably pH 3-10, more preferably pH 4-9.
  • the binder particles preferably include the polymer (A) and the polymer (B), and water or other substance such as an emulsifier may be contained in the inside of the polymer or attached to the outside.
  • the amount of the substance contained inside or attached to the outside is preferably 7 parts by mass or less, and 5 parts by mass with respect to 100 parts by mass of the total of the polymer (A) and the polymer (B). It is more preferably part or less, particularly preferably 3 parts by mass or less.
  • the binder composition may contain binder particles together with a solvent, and the binder particles may be dispersed in the solvent.
  • the solvent may be water or an organic solvent.
  • Organic solvents include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, alcohols such as amyl alcohol, acetone, methyl ethyl ketone, Ketones such as cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as diethyl ether, dioxane, and tetrahydrofuran, amide-based polar organic compounds such as N, N-dimethylformamide, N-methyl-2-pyrrolidone (NMP) Examples thereof include solvents
  • the binder composition is preferably an aqueous binder composition in which binder particles are dispersed in water.
  • the binder composition may be an emulsion obtained by mixing the emulsion produced in obtaining the polymer (A) and the emulsion produced in obtaining the polymer (B).
  • the content of the binder particles in the binder composition is not particularly limited, but it is preferable that the solid content concentration of the binder particles is 0.2 to 80% by mass, so that 0.5 to 70% by mass Is more preferable, and it is particularly preferable to contain 0.5 to 60% by mass.
  • the solid content of the binder composition is generally considered to be a polymer and an emulsifier (only when the polymer is used in emulsion polymerization).
  • the electrode material constituting the electrode material layer contains at least active material particles and binder particles, and may further contain a conductive aid.
  • a binder composition containing binder particles together with a solvent can also be used for producing the electrode material.
  • the positive electrode material used for the positive electrode contains a positive electrode active material and a binder particle, and may further contain a conductive aid.
  • the negative electrode material used for the negative electrode contains a negative electrode active material and binder particles, and further contains a conductive aid. It may contain an agent.
  • the positive electrode active material is an alkali metal-containing composite oxide having a composition of any of AMO 2 , AM 2 O 4 , A 2 MO 3 , and AMBO 4 .
  • A may be an alkali metal
  • M may be a single or two or more transition metals, and part of them may include non-transition metals.
  • B consists of P, Si or a mixture thereof.
  • the positive electrode active material is preferably a powder, and the particle diameter thereof is preferably 50 microns or less, more preferably 20 microns or less. These active materials have an electromotive force of 3 V (vs. Li / Li +) or more.
  • the cathode active material Li x CoO 2, Li x NiO 2, Li x MnO 2, Li x CrO 2, Li x FeO 2, Li x Co a Mn 1-a O 2, Li x Co a Ni 1-a O 2, Li x Co a Cr 1-a O 2, Li x Co a Fe 1-a O 2, Li x Co a Ti 1-a O 2, Li x Mn a Ni 1-a O 2 , Li x Mn a Cr 1 -a O 2 , Li x Mn a Fe 1 -a O 2 , Li x Mn a Ti 1 -a O 2 , Li x Ni a Cr 1 -a O 2 , Li x Ni a Fe 1-a O 2 , Li x Ni a Ti 1-a O 2 , Li x Cr a Fe 1-a O 2 , Li x Cr a Ti 1-a O 2 , Li x Fe a Ti 1-a O 2 , Li x Co b Mn c Ni 1-bc
  • the positive electrode active material include Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , Li x CrO 2 , Li x Co a Ni 1 -a O 2, Li x Mn a Ni 1-a O 2, Li x Co b Mn c Ni 1-bc O 2, Li x Ni a Co b Al c O 2, Li x Mn 2 O 4, Li y MnO 3 , Li y Mn e Fe 1-e O 3 , Li y Mn e Ti 1-e O 3 , Li x CoPO 4 , Li x MnPO 4 , Li x NiPO 4 , Li x FePO 4 , Li x Mn f Fe 1 -f PO 4 can be mentioned.
  • a negative electrode active material a carbon material (natural graphite, artificial graphite, amorphous carbon, etc.) having a structure (porous structure) capable of absorbing and desorbing lithium ions or lithium and aluminum-based materials capable of absorbing and desorbing lithium ions It is a powder made of a metal such as a compound, a tin-based compound, a silicon-based compound, and a titanium-based compound.
  • the particle diameter is preferably 10 nm or more and 100 ⁇ m or less, and more preferably 20 nm or more and 20 ⁇ m or less.
  • the negative electrode active material has a porosity of about 70%.
  • the content of the active material particles in the electrode material is not particularly limited, and is, for example, about 99.9 to 50% by mass, more preferably about 99.5 to 70% by mass, and still more preferably about 99 to 85% by mass It can be mentioned.
  • the active material particles may be used singly or in combination of two or more.
  • the conductive support agent may be a known conductive support agent, and examples thereof include conductive carbon blacks such as graphite, furnace black, acetylene black and ketjen black, carbon fibers such as carbon nanotubes, and metal powder, etc. It is preferable that the base material is a conductive base agent such as conductive carbon black such as furnace black, acetylene black and ketjen black, and carbon fiber such as carbon nanotube. These conductive aids may be used alone or in combination of two or more.
  • the content of the conductive auxiliary is not particularly limited, but is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, with respect to 100 parts by mass of the active material particles.
  • a conductive support agent is contained in positive electrode material, as a lower limit of content of a conductive support agent, 0.05 mass part or more, 0.1 mass part or more, 0.2 mass part or more, 0 normally .5 parts by mass or more, 2 parts by mass or more can be exemplified.
  • the electrode material may contain a thickener as needed.
  • the type of the thickener is not particularly limited, but preferred are sodium salts of cellulose compounds, ammonium salts, polyvinyl alcohol, polyacrylic acid and salts thereof and the like.
  • sodium salts or ammonium salts of the cellulose-based compounds include sodium salts or ammonium salts of alkylcelluloses in which a cellulose-based polymer is substituted by various derivative groups. Specific examples thereof include methylcellulose, methylethylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose (CMC), ammonium salt, triethanolammonium salt and the like. Particularly preferred is the sodium or ammonium salt of carboxymethylcellulose.
  • One of these thickeners may be used alone, or two or more thereof may be used in combination in any ratio.
  • the content of the thickener is not particularly limited, but preferably 5 parts by mass or less, more preferably 3 parts by mass or less, with respect to 100 parts by mass of the active material.
  • a thickener is contained, as a lower limit of content of a thickener, normally 0.05 mass part or more, 0.1 mass part or more, 0.2 mass part or more, 0.5 mass part Above, 1 mass part or more can be illustrated.
  • the electrode material may contain water to form a slurry.
  • Water is not particularly limited, and generally used water can be used. Specific examples thereof include tap water, distilled water, ion exchanged water, and ultrapure water. Among them, preferred are distilled water, ion exchange water, and ultrapure water.
  • the solid content concentration of the slurry is preferably 10 to 90% by mass, more preferably 20 to 85% by mass, and 30 to 80% by mass. Particularly preferred.
  • the proportion of the polymer in the solid content of the slurry is preferably 0.1 to 15% by mass, and more preferably 0.2 to 10% by mass. And 0.3 to 7% by mass is particularly preferable.
  • the method of preparing the electrode material is not particularly limited, and the positive electrode active material or the negative electrode active material, the binder particles, the conductive auxiliary agent, water and the like are dispersed using a common stirrer, a disperser, a kneader, a planetary ball mill, a homogenizer and the like. Just do it. In order to increase the efficiency of dispersion, heating may be performed in a range that does not affect the material.
  • the method for producing the electrode is not particularly limited, and a general method may be used. It is carried out by uniformly applying a battery material to a suitable thickness on the surface of a current collector (metal electrode substrate) by a doctor blade method, an applicator method, a silk screen method or the like.
  • the thickness is made uniform by a blade having a predetermined slit width.
  • the electrode is dried, for example, in a hot air at 100 ° C. or in a vacuum at 80 ° C. in order to remove excess organic solvent and water.
  • An electrode material is manufactured by press-molding the electrode after drying with a press apparatus. After pressing, heat treatment may be performed again to remove water, solvents, emulsifiers and the like.
  • the pressing of the electrode is preferably performed so that the density of the electrode material layer of the electrode of the present invention is preferably 3.7 g / cc or less, more preferably 3.5 g / cc or less.
  • the electrode of the present invention is used for a large battery (for example, a battery for in-vehicle use such as an electric car or a hybrid electric car or a storage battery for household power storage) having a low density compared to the small battery
  • a large battery for example, a battery for in-vehicle use such as an electric car or a hybrid electric car or a storage battery for household power storage
  • the preferred range of the density of the electrode material layer of the electrode of the present invention is as described above.
  • the electricity storage device of the present invention is characterized by comprising a positive electrode, a negative electrode, and an electrolytic solution.
  • the details of the electrode of the present invention are as described above.
  • the electrode of the present invention may be used for at least one of the positive electrode and the negative electrode.
  • the electrolyte is not particularly limited, and a known electrolyte can be used.
  • a specific example of the electrolytic solution includes a solution containing an electrolyte and a solvent.
  • the electrolyte and the solvent may be used alone or in combination of two or more.
  • a lithium salt compound can be exemplified. Specifically, LiBF 4 , LiPF 6 , LiClO 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2) ) 2, LiN etc. [CF 3 SC (C 2 F 5 SO 2) 3] 2 , and the like, but not limited thereto.
  • electrolytes other than lithium salt compounds examples include tetraethylammonium tetrafluoroborate, triethylmonomethylammonium tetrafluoroborate, tetraethylammonium hexafluorophosphate and the like.
  • the organic solvent or a normal temperature molten salt can be illustrated.
  • organic solvent examples include an aprotic organic solvent, and specifically, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane ⁇ -butyrolactone, tetrahydrofuran, 1,3-dioxolane, dipropyl carbonate, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propyl nitrile, anisole, acetate, propionate, diethyl ether and the like linear ethers And two or more types may be mixed and used.
  • propylene carbonate ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane ⁇ -butyrolactone, tetrahydrofuran, 1,3-dioxolane,
  • the room temperature molten salt is also called an ionic liquid, and is a "salt" composed only of ions (anion, cation), and in particular a liquid compound is called an ionic liquid.
  • the room temperature molten salt in the present invention refers to a salt in which at least a part is liquid at normal temperature
  • the normal temperature refers to a temperature range in which the battery is generally assumed to operate.
  • the upper limit of the temperature range in which the battery normally operates is about 120 ° C., sometimes about 80 ° C., and the lower limit is about ⁇ 40 ° C., sometimes about ⁇ 20 ° C.
  • quaternary ammonium organic cations As cationic species of the molten salt at room temperature, quaternary ammonium organic cations of pyridine type, aliphatic amine type and alicyclic amine type are known. Examples of quaternary ammonium organic cations include imidazolium ions such as dialkyl imidazolium and trialkyl imidazolium, tetraalkyl ammonium ions, alkyl pyridinium ions, pyrazolium ions, pyrrolidinium ions and piperidinium ions. In particular, imidazolium ion is preferred.
  • tetraalkyl ammonium ion examples include trimethylethyl ammonium ion, trimethylethyl ammonium ion, trimethylpropyl ammonium ion, trimethylhexyl ammonium ion, tetrapentyl ammonium ion, triethyl methyl ammonium ion and the like, but are limited thereto. is not.
  • alkyl pyridinium ion N-methyl pyridinium ion, N-ethyl pyridinium ion, N-propyl pyridinium ion, N-butyl pyridinium ion, 1-ethyl-2-methyl pyridinium ion, 1-butyl-4-methyl pyridinium
  • the ion include 1-butyl-2,4 dimethyl pyridinium ion and the like, but not limited thereto.
  • imidazolium ion 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, 1-methyl-3-ethylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1- Butyl-3-methylimidazolium ion, 1,2,3-trimethylimidazolium ion, 1,2-dimethyl-3-ethylimidazolium ion, 1,2-dimethyl-3-propylimidazolium ion, 1-butyl- Examples include 2,3-dimethylimidazolium ion and the like, but not limited thereto.
  • the anion species of the molten salt at room temperature include chloride ion, bromide ion, halide ion such as iodide ion, perchlorate ion, thiocyanate ion, tetrafluoroborate ion, nitrate ion, AsF 6 ⁇ , PF 6 ⁇
  • Inorganic acid ion such as stearyl sulfonate ion, octyl sulfonate ion, dodecylbenzene sulfonate ion, naphthalene sulfonate ion, dodecyl naphthalene sulfonate ion, 7,7,8,8-tetracyano-p-quinodimethane ion etc
  • a normal temperature molten salt may be used individually by 1 type, and may be used combining 2 or more types.
  • additives can be used in the electrolytic solution as required.
  • the additive include flame retardants, flame retardants, positive electrode surface treatment agents, negative electrode surface treatment agents, and overcharge inhibitors.
  • Flame retardants and flame retardants include brominated epoxy compounds, phosphazene compounds, halides such as tetrabromo bisphenol A, chlorinated paraffin, etc., antimony trioxide, antimony pentoxide, aluminum hydroxide, magnesium hydroxide, phosphoric acid ester, polyphosphate Examples include acid salts and zinc borate.
  • the positive electrode surface treatment agent include inorganic compounds such as carbon and metal oxides (MgO, ZrO 2 and the like) and organic compounds such as ortho-terphenyl and the like.
  • the negative electrode surface treatment agent include vinylene carbonate, fluoroethylene carbonate, polyethylene glycol dimethyl ether and the like.
  • the overcharge inhibitor include biphenyl and 1- (p-tolyl) adamantane.
  • the method for producing the electricity storage device of the present invention is not particularly limited, and is produced by a known method using a positive electrode, a negative electrode, an electrolytic solution, if necessary, a separator or the like.
  • a positive electrode a negative electrode
  • an electrolytic solution if necessary, a separator or the like.
  • the positive electrode, the separator if necessary, and the negative electrode are inserted into the outer can. Electrolyte is put into this and impregnated. Thereafter, the sealing body is joined to the sealing body by tab welding or the like, and the sealing body is sealed and crimped to obtain an electric storage device.
  • the shape of the storage device is not limited, examples thereof include coin, cylinder, and sheet.
  • the separator prevents the positive electrode and the negative electrode from being in direct contact with each other to short-circuit in the storage battery, and a known material can be used.
  • Specific examples of the separator include porous polymer films such as polyolefin and paper.
  • porous polymer film films of polyethylene, polypropylene and the like are preferable because they are less affected by the electrolytic solution.
  • an electrode and a coin battery were produced, and the electrode binding test was performed as the evaluation of the electrode, and the internal resistance measurement was performed as the evaluation of the coin battery in the following experiment.
  • the binding test was conducted by a 180 ° peel test. Specifically, cut the electrode into a width 2 cm ⁇ length 5 cm, affix a tape (adhesive tape: made by Nichiban, width 1.8 cm, length 5 cm), and make one end of the electrode in the longitudinal direction a strograph E3-L While fixed, the tape was peeled off at a test speed of 50 mm / min and a load range of 5 N in the direction of 180 °. The test was conducted three times and the weighted average value was determined.
  • the produced lithium ion battery was charged to 4.2 V by constant current-constant voltage charging.
  • the termination current was equivalent to 1 C.
  • the battery was rested for 10 minutes.
  • the average particle size of the polymer was measured under the following conditions.
  • Particle size distribution measuring device using dynamic light scattering Zetasizer Nano (Spectris Co., Ltd.) (measurement conditions) 1. 50 ⁇ L of the synthesized emulsion solution is sampled. 2. The sampled emulsion solution is diluted by adding 700 ⁇ L of ion-exchanged water three times. 3. Remove 2100 ⁇ L of solution from the dilution solution. 4. Add and dilute 700 ⁇ L ion-exchanged water to the remaining 50 ⁇ L sample and measure.
  • FIGS. 1 to 3 show images obtained by observing the cross section of the electrode material layer of the practical preparation example 1 of the electrode by the above-mentioned method with SEM.
  • FIGS. 2 and 3 respectively show the positions of binder particles when three 1 ⁇ m ⁇ 1 ⁇ m square fields of view are selected from the SEM image of FIG. 1.
  • binder particles about 100 to 150 nm in particle diameter
  • six binder particles (a particle diameter of about 100 to 150 nm) of a to f are observed in the field of view 5 at the lower left of FIG. 3, and e and f are in contact with each other, but the other binder particles are in contact with each other I did not.
  • four binder particles a to d (with a particle diameter of about 100 to 150 nm) are observed in the field 6 at the lower right of FIG. 3, and a and b are in contact with each other. Not in touch.
  • FIG. 4 shows numerically the positions of binder particles when two 1 ⁇ m ⁇ 1 ⁇ m square fields of view are selected. Of the two fields (squares) shown in FIG. 4, four binder particles a to d (particle diameter about 50 to 100 nm) are observed in the upper field 1 and b, c and d are continuous. It is in contact. In addition, two binder particles (a particle diameter of about 50 to 100 nm) of a and b are observed in the visual field 2 in the lower part of FIG. 4, and they are not in contact with each other.
  • FIG. 5 numerically shows the positions of binder particles when two 1 ⁇ m ⁇ 1 ⁇ m square fields of view are selected. Of the two fields (squares) shown in FIG. 5, six binder particles a to f (particle diameter about 100 to 150 nm) are observed in the upper field 1 and c to f are in contact continuously. ing. Further, six binder particles (about 100 to 150 nm in particle diameter) of a to f are observed in the visual field 2 in the lower part of FIG. 5, and a to f are in continuous contact.
  • Synthesis Example 1 In a beaker, 89.2 parts by mass of acrylic acid n-butyl, 1.55 parts by mass of acrylic acid, 4.40 parts by mass of methacrylic acid, 4.15 parts by mass of polyethylene glycol monomethacrylate (manufactured by NOF Corporation: Blenmer PE-90) Part, 0.70 parts by mass of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical: A-TMPT), 1 part by mass of sodium dodecyl sulfate as an emulsifier, 180.00 parts by mass of ion exchanged water, and ammonium persulfate 0.12 as a polymerization initiator The parts by mass were added, and the mixture was sufficiently stirred using an ultrasonic homogenizer to give an emulsion.
  • the reaction container equipped with a stirrer was heated to 55 ° C. in a nitrogen atmosphere, and the emulsion was added over 2 hours. After the addition of the emulsion, it was further polymerized for 1 hour and then cooled. After cooling, the pH of the polymerization solution is adjusted from 2.6 to 8.0 using a 28% aqueous ammonia solution, and an emulsion solution, binder composition A (polymerization conversion rate 97% or more, solid content concentration 39% by mass) I got The average particle size of the obtained polymer was 0.273 ⁇ m.
  • Synthesis Example 2 In a beaker, 69.57 parts by mass of methyl methacrylate, 1.68 parts by mass of acrylic acid, 4.79 parts by mass of methacrylic acid, and 4.52 parts by mass of polyethylene glycol monomethacrylate (manufactured by NOF Corporation: Blenmer PE-90) 19.44 parts by mass of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical: A-TMPT), 1 part by mass of sodium dodecyl sulfate as an emulsifier, 50.00 parts by mass of ion exchanged water, and 0.12 parts by mass of ammonium persulfate as a polymerization initiator The solution was put into an emulsion, and the mixture was sufficiently stirred using an ultrasonic homogenizer to obtain an emulsion.
  • the reaction container equipped with a stirrer was heated to 55 ° C. in a nitrogen atmosphere, and the emulsion was added over 2 hours. After the addition of the emulsion, it was further polymerized for 1 hour and then cooled. After cooling, the pH of the polymerization solution is adjusted from 2.9 to 8.0 using a 28% aqueous ammonia solution, and a binder composition B as an emulsion solution (polymerization conversion ratio 98% or more, solid content concentration 39% by mass) I got The average particle size of the obtained polymer was 0.242 ⁇ m.
  • Synthesis Example 3 In a beaker, 69.55 parts by mass of methyl methacrylate, 1.68 parts by mass of acrylic acid, 4.77 parts by mass of methacrylic acid, and 4.52 parts by mass of polyethylene glycol monomethacrylate (manufactured by NOF: Blenmer PE-90) 19.4 parts by mass of trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical: A-TMPT), 2 parts by mass of sodium dodecyl sulfate as an emulsifier, 40.00 parts by mass of ion exchange water, and 0.12 parts by mass of ammonium persulfate as a polymerization initiator The solution was put into an emulsion, and the mixture was sufficiently stirred using an ultrasonic homogenizer to obtain an emulsion.
  • the reaction container equipped with a stirrer was heated to 55 ° C. in a nitrogen atmosphere, and the emulsion was added over 1 hour and 30 minutes.
  • After adding 1.69 parts by mass of trimethylolpropane triacrylate manufactured by Shin-Nakamura Chemical Co., Ltd .: A-TMPT
  • the mixture was further polymerized for 1 hour, and then cooled.
  • the pH of the polymerization solution is adjusted from 2.6 to 8.0 using a 28% aqueous ammonia solution, and a binder composition C as an emulsion solution (polymerization conversion ratio 97% or more, solid content concentration 29% by mass) I got
  • the average particle size of the obtained polymer was 0.170 ⁇ m.
  • Example 1 of practical production of electrode Solid content of binder composition A obtained in Synthesis Example 1 of binder composition, to 3 parts by mass of acetylene black as a conductive support agent, 1 part by mass of carboxymethyl cellulose, as a positive electrode active material, 95 parts by mass of lithium cobalt cobalt lithium manganese oxide And 0.1 parts by mass, and 0.9 parts by mass as the solid content of the binder composition B obtained in Synthesis Example 2 of the binder composition, and further adding water so that the solid content concentration of the slurry becomes 72% by mass In addition, they were thoroughly mixed using a planetary mill to obtain a slurry for positive electrode.
  • the obtained positive electrode slurry is applied on a 20 ⁇ m thick aluminum current collector using a 100 ⁇ m gap baker applicator, dried at 110 ° C. for 12 hours or more in a vacuum state, and pressed using a roll press.
  • a positive electrode of 35 ⁇ m in diameter and 3.4 g / cc in density of the electrode material layer was produced.
  • the evaluation results of the binding test and the evaluation results of the SEM observation are shown in Example 1 of Table 1.
  • Table 1 shows the evaluation results of the physical properties of the electrodes of the example and the comparative example.
  • Examplementation example 1 of coin battery In the glove box replaced with argon gas, the positive electrode obtained in the practical preparation example 1 of the electrode, two 18 ⁇ m thick polypropylene / polyethylene / polypropylene porous membranes as separators, and 300 ⁇ m thick metal lithium foil as a counter electrode
  • the bonded laminate is sufficiently impregnated with 1 mol / L of lithium hexafluorophosphate ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (volume ratio 3: 5: 2) as an electrolytic solution and caulked, and used for test 2032 Type coin battery was manufactured.
  • the evaluation results of internal resistance measurement are shown in Example 1 of Table 2.
  • Comparative Production Example 1 of Coin Battery A coin battery was produced in the same manner as in Working Production Example 1 of a coin battery, except that the positive electrode obtained in Comparative Production Example 1 of the electrode was used. The evaluation result of internal resistance measurement is shown in Comparative Example 1 of Table 2.
  • Table 2 shows the evaluation results of the characteristics of the batteries of the example and the comparative example.
  • Example 1 which is a lithium ion battery using the positive electrode of the present invention has high binding property as compared with Comparative Examples 1 and 2, and charging as a coin battery is also possible as compared with Comparative Examples 1 and 2.
  • the performance was equivalent in the state 100% (SOC 100%).
  • the binder for electrodes of the present invention has excellent binding properties, and is usefully used in in-vehicle applications such as electric vehicles and hybrid electric vehicles, and storage devices such as storage batteries for household power storage.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Power Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Battery Electrode And Active Subsutance (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

L'invention concerne une électrode qui, tout en maintenant une plus faible résistance dans un dispositif de stockage d'électricité, possède d'excellentes propriétés de liaison du liant.　Plus spécifiquement, cette électrode comporte un collecteur de courant et une couche de matériau d'électrode formée sur la surface du collecteur de courant. La couche de matériau d'électrode contient des particules de substance active et des particules de liant, et dans une image d'une section transversale de cette couche de matériau d'électrode observée à l'aide d'un microscope électronique à balayage, dans au moins trois champs carrés de 1μmX1μm dans lesquels il n'y a pas de particules de substance active, entre 3 et 20 particules de liant sont observées, et il n'y a pas plus de deux particules de liant à la suite qui se touchent.
PCT/JP2018/027304 2017-07-20 2018-07-20 Électrode et dispositif de stockage d'électricité WO2019017480A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013039131A1 (fr) * 2011-09-14 2013-03-21 日本ゼオン株式会社 Électrode pour élément électrochimique
WO2017029902A1 (fr) * 2015-08-14 2017-02-23 旭化成株式会社 Électrode pour éléments électrochimiques
JP2017091789A (ja) * 2015-11-10 2017-05-25 株式会社大阪ソーダ 正極、二次電池およびその製造方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013039131A1 (fr) * 2011-09-14 2013-03-21 日本ゼオン株式会社 Électrode pour élément électrochimique
WO2017029902A1 (fr) * 2015-08-14 2017-02-23 旭化成株式会社 Électrode pour éléments électrochimiques
JP2017091789A (ja) * 2015-11-10 2017-05-25 株式会社大阪ソーダ 正極、二次電池およびその製造方法

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