JP2020187866A - Conductive material dispersion and utilization thereof - Google Patents

Abstract

To provide a conductive material dispersion having high dispersibility, a conductive material-containing resin composition and a slurry of a mixture material which are arranged for obtaining an electrode film high in adhesion and conductivity and more specifically, a nonaqueous electrolyte secondary battery having superior rate and cycle characteristics.SOLUTION: A conductive material dispersion for a nonaqueous electrolyte secondary battery comprises a conductive material (A), a dispersion medium (B) and a dispersant (C). The dispersant (C) is a copolymer containing a (meth)acrylonitrile-originating unit, and a conjugated diene monomer-originating unit. The copolymer contains 15-50 mass% of the (meth)acrylonitrile-originating unit. The conductive material dispersion has a weight-average molecular weight of 5000-400000.SELECTED DRAWING: None

Description

The present invention relates to a conductive material dispersion. More specifically, a conductive material dispersion, a conductive material-containing resin composition containing a conductive material dispersion and a binder resin, a mixed material slurry containing a conductive material dispersion, a binder resin and an active material, and a film-like form thereof are formed. The present invention relates to a non-aqueous electrolyte secondary battery comprising an electrode film, an electrode film, and an electrolyte.

With the widespread use of electric vehicles, the reduction in size and weight of mobile devices, and the increase in performance, secondary batteries having a high energy density and the capacity of the secondary batteries are required to be increased. Against this background, non-aqueous electrolyte secondary batteries that use non-aqueous electrolytes have come to be used in many devices due to their characteristics of high energy density and high voltage, and lithium-ion secondary batteries are particularly attracting attention. ing.

As the negative electrode material used for the lithium ion secondary battery, a carbon material typified by graphite having a low potential close to that of lithium (Li) and a large charge / discharge capacity per unit mass is used. However, these electrode materials are used to the point where the charge / discharge capacity per mass is close to the theoretical value, and the energy density of the battery is approaching the limit. Therefore, attempts have been made to reduce conductive materials and binders that do not contribute to the discharge capacity inside the battery.

As the conductive material, carbon-based fillers such as carbon black, Ketjen black, fullerene, graphene, and fine carbon materials are used. In particular, carbon nanotubes, which are a type of fine carbon fibers, are often used. For example, by adding carbon nanotubes to graphite or silicon negative electrodes, electrode resistance can be reduced, battery load resistance can be improved, electrode strength can be increased, and electrode expansion / contraction properties can be increased to increase lithium ions. The cycle life of the secondary battery is improved (see, for example, Patent Documents 1, 2 and 3). Further, studies have been conducted to reduce the electrode resistance by adding carbon nanotubes to the positive electrode (see, for example, Patent Documents 4 and 5). Among them, multi-walled carbon nanotubes having an outer diameter of 10 nm to several tens of nm are relatively inexpensive and are expected to be put into practical use.

When a conductive material having a large specific surface area is used, a conductive network can be efficiently formed with a small amount, and the amount of the conductive material contained in the positive electrode and the negative electrode for a lithium ion secondary battery can be reduced. However, since a conductive material having a large specific surface area has a strong cohesive force and is difficult to disperse, it has not been possible to obtain a conductive material dispersion having sufficient dispersibility.

Therefore, a method of dispersing and stabilizing the conductive material by using various dispersants has been proposed. For example, dispersion in water and NMP (N-methyl-2-pyrrolidone) using a polymer-based dispersant such as the water-soluble polymer polyvinylpyrrolidone has been proposed (see Patent Documents 4 and 5).

Further, in Cited Document 6, an aqueous conductive material dispersion using a particulate polymer containing a nitrile group-containing monomer unit and a (meth) acrylic acid ester monomer unit as a dispersant has been proposed. It was necessary to use a large amount of dispersant in order to disperse the conductive material having a large specific surface area.

On the other hand, in Patent Document 7, by coexisting a salt or a strong base of a weak acid together with carbon nanotubes in an organic solvent, the salt or the strong base of the weak acid functions as a dispersant, and the amount of the dispersant used is significantly reduced. A carbon nanotube composite that can be used has been proposed. However, it has been difficult to put it into practical use because it only mentions the improvement of dispersibility at a low concentration of carbon nanotubes in the liquid of 1 w% or less.

Therefore, obtaining a conductive material dispersion in which a conductive material having a large specific surface area is uniformly dispersed in a dispersion medium at a high concentration has been an important issue for expanding applications.

Japanese Unexamined Patent Publication No. 4-155776 Japanese Unexamined Patent Publication No. 4-237971 Japanese Unexamined Patent Publication No. 2004-178922 Japanese Unexamined Patent Publication No. 2011-070908 Japanese Unexamined Patent Publication No. 2005-162877 JP-A-2017-10821 JP 2015-168610

Michael J. O’Connel et al. Chemical Physics Letters, 13 July 2001, 265-271 Coloring of polyacrylonitrile and its copolymer https://www.jstage.jst.go.jp/article/koron1944/19/210/19_210_653/_pdf/-char/ja

An object to be solved by the present invention is to provide a conductive material dispersion, a conductive material-containing resin composition, and a mixed material slurry having high dispersibility in order to obtain an electrode film having high adhesion and conductivity. .. More specifically, it is to provide a non-aqueous electrolyte secondary battery having excellent rate characteristics and cycle characteristics.

As a result of diligent studies in order to solve the above problems, the present inventors have found a conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C). , Dispersant (C) is a copolymer containing a unit derived from (meth) acrylonitrile and a unit derived from a conjugated diene monomer, and is derived from the (meth) acrylonitrile in the copolymer. By using a conductive material dispersion for a non-aqueous electrolyte secondary battery, which contains 15 to 50% by mass of units and has a weight average molecular weight of 5,000 to 400,000, an electrode film having high adhesion and conductivity and excellent properties are used. We have found that a non-aqueous electrolyte secondary battery having high rate characteristics and cycle characteristics can be obtained, and have arrived at the present invention.

That is, the present invention is a conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C), and the dispersant (C) is derived from (meth) acrylonitrile. It is a copolymer containing a unit and a unit derived from a conjugated diene monomer, and contains 15 to 50% by mass of the unit derived from the (meth) acrylonitrile in the copolymer, and has a weight average molecular weight of 5000 to 5000. The present invention relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery, which is characterized by being 400,000.

The present invention further relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery, which further comprises at least one (D) selected from the group consisting of an inorganic metal salt, an inorganic base and an organic base.

The present invention also relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery, wherein the dispersant (C) has a cyclic structure in a unit derived from acrylonitrile.

The present invention also relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery, wherein the conductive material (A) is a carbon-based filler.

The present invention also relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery, characterized in that a part of units derived from a conjugated diene monomer is hydrogenated.

The present invention also relates to a conductive material-containing resin composition containing a conductive material dispersion and a binder resin (E).

The present invention also relates to a mixed material slurry characterized by containing a conductive material-containing resin composition and an active material (F).

The present invention also relates to an electrode film (G) formed by forming a mixture slurry in the form of a film.

Further, the present invention is a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode, and an electrolyte in which ions can move, and at least one of the positive electrode and the negative electrode includes an electrode film (G). It relates to a characteristic non-aqueous electrolyte secondary battery.

By using the conductive material dispersion of the present invention, a conductive material-containing resin composition, a mixture slurry, and an electrode film having excellent conductivity and adhesion can be obtained. In addition, a non-aqueous electrolyte secondary battery having excellent rate characteristics and cycle characteristics can be obtained. Therefore, the non-aqueous electrolyte secondary battery of the present invention can be used in various application fields where high conductivity, adhesion, and durability are required.

Hereinafter, the conductive material dispersion for the non-aqueous electrolyte secondary battery of the present invention, the conductive material-containing resin composition, the mixture slurry, the electrode film formed by forming the mixture in the form of a film, and the non-aqueous electrolyte secondary battery will be described in detail. ..

<Conducting material dispersion for non-aqueous electrolyte secondary batteries>
The conductive material dispersion for a non-aqueous electrolyte secondary battery of the present embodiment is characterized by containing at least a conductive material (A), a dispersion medium (B), and a dispersant (C).

<Conductive material (A)>
The conductive material (A) of the present embodiment is, for example, gold, silver, copper, silver-plated copper powder, silver-copper composite powder, silver-copper alloy, amorphous copper, nickel, chromium, palladium, rhodium, ruthenium, indium, silicon. , Metal powders such as aluminum, tungsten, molybdenum, platinum, inorganic powders coated with these metals, powders of metal oxides such as silver oxide, indium oxide, tin oxide, zinc oxide, ruthenium oxide, these metal oxides. Inorganic powder coated with, and carbon-based fillers such as carbon black and graphite can be used. These conductive materials may be used alone or in combination of two or more. Among these conductive materials, a carbon-based filler is preferable.

As the carbon-based filler of the present embodiment, various commercially available acetylene black, furnace black, hollow carbon black, channel black, thermal black, Ketjen black and the like can be used. Further, the usual oxidation-treated carbon black, graphitized carbon black, carbon nanotubes, carbon nanofibers, and the like can also be used.

The carbon nanotube of this embodiment has a shape in which flat graphite is wound into a cylindrical shape. The carbon nanotubes may be a mixture of single-walled carbon nanotubes. Single-walled carbon nanotubes have a structure in which one layer of graphite is wound. Multi-walled carbon nanotubes have a structure in which two or three or more layers of graphite are wound. Further, the side wall of the carbon nanotube does not have to have a graphite structure. For example, a carbon nanotube having a side wall having an amorphous structure can be used as the carbon nanotube.

The shape of the carbon nanotubes of this embodiment is not limited. Such shapes include various shapes including needle shape, cylindrical tube shape, fish bone shape (fishbone or cup laminated type), playing card shape (platelet) and coil shape. In the present embodiment, the shape of the carbon nanotubes is preferably needle-shaped or cylindrical tube-shaped. The carbon nanotubes may have a single shape or a combination of two or more shapes.

The form of the carbon nanotubes of the present embodiment includes, but is not limited to, graphite whisker, carbonentas carbon, graphite fiber, ultrafine carbon tube, carbon tube, carbon fibril, carbon microtube and carbon nanofiber. .. The carbon nanotubes may have a single form thereof or a combination of two or more kinds thereof.

BET specific surface area of the conductive material of the present embodiment (A) is preferably from 20~1000m ² / g, more preferably 150~800m ² / g.

When carbon nanotubes are used as the conductive material (A) of the present embodiment, the outer diameter of the carbon nanotubes is preferably 1 to 30 nm, more preferably 1 to 20 nm.

The average particle size and the average outer diameter of the conductive material (A) of the present embodiment are obtained as follows. First, the conductive material is observed and imaged with a transmission electron microscope. Next, in the observation photograph, any 300 conductive materials are selected, and the particle size and outer diameter of each are measured. Next, the average particle size (nm) and the average outer diameter (nm) of the conductive material are calculated as the number average of the outer diameters.

The carbon purity of the conductive material (A) of the present embodiment is represented by the content of carbon atoms (mass%) in the conductive material. The carbon purity is preferably 90% by mass, more preferably 95% by mass or more, still more preferably 98% by mass or more, based on 100% by mass of the conductive material.

The volume resistivity of the conductive material (A) of the present embodiment is preferably 1.0 × 10 ^{-3 to} 1.0 × 10 ^-1 Ω · cm, and 1.0 × 10 ^{-3 to} 1.0 ×. It is more preferably ^10-2 Ω · cm. The volume resistivity of the conductive material can be measured using a powder resistivity measuring device (manufactured by Mitsubishi Chemical Analytech Co., Ltd .: Lorester GP powder resistivity measuring system MCP-PD-51)).

<Dispersion medium (B)>
The dispersion medium (B) of the present embodiment is not particularly limited as long as the conductive material (A) can be dispersed, but is a mixture of water and / or a water-soluble organic solvent of any one or two or more. It is preferably a solvent.

Water-soluble organic solvents include alcohols (methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, benzyl alcohol, etc.) and polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, polyethylene). Glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc., polyhydric alcohol ethers (ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene) Glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl Ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amine-based (ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholin, N-ethylmorpholin , Ethylene diamine, diethylene diamine, triethylene tetramine, tetraethylene pentamine, polyethylene imine, pentamethyldiethylene triamine, tetramethyl propylene diamine, etc.), amides (N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone) (NEP), N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methylcaprolactam, etc.), heterocyclic system (cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2 -Imidazolidinone, γ-butyrolactone, etc.), sulfoxide type (dimethylsulfoxide, etc.), sulfone type (hexamethylphosphorotriamide, sulfolane, etc.), lower ketone type (acetone, methylethylketone, etc.), etc. Nitrile and the like can be used. Of these, water or an amide-based organic solvent is more preferable, and N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone are particularly preferable among the amide-based organic solvents.

<Dispersant (C)>
The conjugated diene monomer of the present embodiment will be described. Examples of the conjugated diene monomer include 1,3-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, and 2-ethyl-1,3-butadiene. , 1,3-Pentaniene and the like. These conjugated diene monomers may be used alone or in combination of two or more.

The dispersant (C) may contain another copolymerizable ethylenically unsaturated monomer as a copolymerization component. Examples of the copolymerizable ethylenically unsaturated monomer include ethylenically unsaturated carboxylic acids such as (meth) acrylic acid, (anhydrous) maleic acid, fumaric acid, and itaconic acid; methyl (meth) acrylate and ethyl ( Meta) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, mono or dimethyl maleate, mono or diethyl fumarate, mono or di-n-butyl fumarate, mono or itaconic acid. Mono or dialkyl ester of the ethylenically unsaturated carboxylic acid such as di-n-butyl; alkoxyalkyl ester of the ethylenically unsaturated carboxylic acid such as methoxyacrylate, ethoxyacrylate, methoxyethoxyethyl acrylate, methoxyethoxybutyl acrylate; 2 (Meta) acrylate having a hydroxyalkyl group such as −hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate; glycidyl (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, N-butoxymethyl ( (Meta) Acrylic acid amide such as acrylamide and its derivatives; Acrylate having an amino group such as dimethylaminomethyl acrylate and diethylaminomethyl acrylate; Aromatic vinyl such as styrene, α-methylstyrene, vinyltoluene and chlorostyrene. Body: α-olefin such as ethylene and propylene; non-conjugated diene monomer such as dicyclopentadiene and vinylnorbornene can be mentioned.

The dispersant (C) of the present embodiment having such characteristics can be obtained by a usual emulsion polymerization method. The polymerization agents such as emulsifiers (surfactants), polymerization initiators, chelating agents, oxygen scavengers, and molecular weight modifiers used for emulsion polymerization can be any conventionally known agents and are not particularly limited. For example, as the emulsifier, an anionic or anionic and nonionic (nonionic) emulsifier is usually used.

Examples of anionic emulsifiers include fatty acid salts such as potassium beef fatty acid, partially hydrogenated beef fatty acid potassium, potassium oleate, and sodium oleate; potassium loginate, sodium logate, potassium hydrogenated loginate, and sodium hydrogenated loginate. And the like; alkylbenzene sulfonates such as sodium dodecylbenzene sulfonate and the like can be mentioned. Examples of the nonionic emulsifier include polyethylene glycol ester type, polyethylene glycol ester type, and pluronic type emulsifiers such as block copolymers of ethylene oxide and propylene oxide.

Examples of the polymerization initiator include thermal decomposition initiators such as persulfates such as potassium persulfate and ammonium persulfate; t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, octanoyl peroxide, and the like. Organic peroxides such as 3,5,5-trimethylhexanoyl peroxide; azo compounds such as azobisisobutyronitrile; redox-based initiators composed of these and a reducing agent such as divalent iron ions. Be done. Of these, a redox-based initiator is preferable. The amount of these initiators used is typically in the range 0.01-10 wt% relative to the monomeric mixture.

The emulsion polymerization reaction may be a continuous type or a batch type, and the polymerization temperature may be any of low temperature to high temperature polymerization, but is preferably 0 to 50 ° C., more preferably 0 to 35 ° C. Further, the method of adding the monomer (collective addition, partial addition, etc.), polymerization time, polymerization conversion rate, etc. are not particularly limited.

Further, a part of the unit derived from the conjugated diene monomer of the present embodiment may be hydrogenated, and the unit derived from (meth) acrylonitrile, the conjugated diene monomer, and the ethylenic property copolymerizable with these. It can be produced by copolymerizing an unsaturated monomer and then hydrogenating the C = C double bond in the copolymer. At this time, the polymerization reaction step and the hydrogenation step can be carried out by a usual method.

The dispersant (C) of the present embodiment contains 15 to 50% by mass of a unit derived from (meth) acrylonitrile, preferably 20 to 50% by mass, and particularly preferably 30 to 50% by mass. By containing a unit derived from (meth) acrylonitrile in the above range, the adsorptivity to the dispersion and the affinity to the dispersion medium can be controlled, and the dispersion can be stably present in the dispersion medium. Can be done.

The molecular weight of the dispersant (C) of the present embodiment is usually 5,000 or more and 400,000 or less on a polystyrene-equivalent weight average, preferably in the range of 10,000 or more and 350,000 or less, and particularly preferably in the range of 50,000 or more and 300,000 or less. When the molecular weight of the dispersant is less than 5,000 or more than 400,000, the adsorptivity to the object to be dispersed and the affinity for the dispersion medium tend to decrease, and the stability of the dispersion tends to decrease.

A resin containing a high concentration of (meth) acrylonitrile changes to a ring structure such as hydrogenated diazanaphthalene by alkaline treatment (Non-Patent Document 2). This ring structure can also enhance the adsorptivity to the object to be dispersed and the affinity to the dispersion medium. As the alkali treatment of the dispersant of the present invention, an alkali treatment may be performed in advance, or a structural change to the ring structure may be promoted by using an alkali or the like in combination at the time of use.

The conductive material dispersion of the present invention is at least one selected from the group consisting of an inorganic metal salt, an inorganic base and an organic base in addition to the conductive material (A), the dispersion medium (B) and the dispersant (C). D) may be contained. As a result, the dispersion stability of the conductive material dispersion is improved. The inorganic base and the inorganic metal salt are preferably compounds having at least one of an alkali metal and an alkaline earth metal. Specifically, the alkali metal and the alkaline earth metal are chloride, hydroxide, and carbonic acid. Examples thereof include salts, nitrates, sulfates, phosphates, tungstates, vanadium salts, molybdates, niobates, borates and the like. Further, among these, alkali metals, chlorides of alkaline earth metals, hydroxides and carbonates are preferable in terms of easily supplying cations. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Examples of the hydroxide of the alkaline earth metal include calcium hydroxide and magnesium hydroxide. Examples of the alkali metal carbonate include lithium carbonate, lithium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate and the like. Examples of carbonates of alkaline earth metals include calcium carbonate and magnesium carbonate. Among these, lithium hydroxide, sodium hydroxide, lithium carbonate and sodium carbonate are more preferable. The metal contained in the inorganic base and the inorganic metal salt of the present invention may be a transition metal.

Examples of the organic base include primary, secondary and tertiary alkylamines having 1 to 40 carbon atoms.

Primary alkylamines having 1 to 40 carbon atoms include propylamine, butylamine, isobutylamine, octylamine, 2-ethylhexylamine, laurylamine, stearylamine, oleylamine, 2-aminoethanol, 3-aminopropanol, and 3-ethoxy. Examples thereof include propylamine and 3-lauryloxypropylamine.

Examples of the secondary alkylamine having 1 to 40 carbon atoms include dibutylamine, diisobutylamine, N-methylhexylamine, dioctylamine, distearylamine, 2-methylaminoethanol and the like.

Examples of tertiary alkylamines having 1 to 40 carbon atoms include triethylamine, tributylamine, N, N-dimethylbutylamine, N, N-diisopropylethylamine, dimethyloctylamine, trioctylamine, dimethyldecylamine, dimethyllaurylamine, and dimethylmyristyl. Examples thereof include amines, dimethyl palmitylamines, dimethylstearylamines, dilaurylmonomethylamines, triethanolamines, 2- (dimethylamino) ethanols and the like.

Of these, primary, secondary or tertiary alkylamines having 1 to 30 carbon atoms are preferable, and primary, secondary or tertiary alkylamines having 1 to 20 carbon atoms are even more preferable.

As organic bases, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU), 1,5-diazabicyclo [4.3.0] nonen-5 (DBN), 1,4-diazabicyclo [2] .2.2] Compounds containing a basic nitrogen atom such as octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, imidazole, and 1-methylimidazole may be used.

The blending amount of the inorganic base, the inorganic metal salt, and the organic base is preferably 1 to 60 parts by mass, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the dispersant (C). Dispersibility is further improved when an appropriate amount is blended.

In the conductive material dispersion of the present embodiment, the conductive material is placed in a dispersant carrier such as a dispersant and a binder resin and / or a dispersion medium in a kneader, two roll mills, three roll mills, a ball mill, a horizontal sand mill, and a vertical type. It can be finely dispersed and manufactured by using various dispersion means such as a sand mill, an annual bead mill, or an attritor. At this time, two or more kinds of objects to be dispersed or the like may be simultaneously dispersed in the carrier and / or dispersion medium to be dispersed, or separately dispersed substances may be mixed.

The solid content of the conductive material dispersion of the present embodiment is preferably 0.05 to 30% by mass, more preferably 0.1 to 20% by mass, based on 100% by mass of the conductive material dispersion.

The amount of the dispersant (C) in the conductive material dispersion of the present embodiment is preferably 3 to 200% by mass, preferably 5 to 50% by mass, based on 100% by mass of the conductive material dispersion. More preferred.

<Conducting material-containing resin composition>
The conductive material-containing resin composition of the present embodiment further contains at least a binder in the conductive material dispersion.

<Binder resin (E)>
The binder resin (E) of the present embodiment is a resin for bonding substances.

Examples of the binder resin (E) of the present embodiment include ethylene, propylene, vinyl chloride, vinyl acetate, vinyl alcohol, maleic acid, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylonitrile, styrene, and vinyl butyral. , Vinyl acetal, vinyl pyrrolidone, etc. as constituent units; polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, acrylic resin, formaldehyde resin, silicon Resins, fluororesins; cellulose resins such as carboxymethyl cellulose; rubbers such as styrene butadiene rubbers and fluororubbers; conductive resins such as polyaniline and polyacetylene. Further, modified products and mixtures of these resins and copolymers may be used. Among them, when used as a binder resin for a positive electrode, it is preferable to use a polymer compound having a fluorine atom in the molecule from the viewpoint of resistance, for example, polyvinylidene fluoride (PVDF), polyvinyl fluoride, tetrafluoroethylene and the like. When used as a binder resin for the negative electrode, carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), and polyacrylic acid having good adhesion are preferable.

The weight average molecular weight of these resins as the binder resin (E) of the present embodiment is preferably 10,000 to 2,000,000, more preferably 100,000 to 1,000,000, and 200,000 to 200,000. 1,000,000 is particularly preferred.

<Mixed material slurry>
The mixture slurry of the present embodiment further contains at least the active material (F) in the conductive material-containing resin composition.

<Active material (F)>
The active material (F) of the present embodiment is a material that is the basis of a battery reaction. The active material is divided into a positive electrode active material and a negative electrode active material according to the electromotive force.

The positive electrode active material is not particularly limited, but a metal oxide capable of doping or intercalating lithium ions, a metal compound such as a metal sulfide, a conductive polymer, or the like can be used. Examples thereof include oxides of transition metals such as Fe, Co, Ni and Mn, composite oxides with lithium, and inorganic compounds such as transition metal sulfides. Specifically, transition metal oxide powders such as MnO, V ₂ O ₅ , V ₆ O ₁₃ , TiO ₂ , layered lithium nickel oxide, lithium cobalt oxide, lithium manganate, lithium nickel manganese cobalt oxide, spinel structure. Examples thereof include a composite oxide powder of lithium and a transition metal such as lithium manganate, a lithium iron oxide-based material which is a phosphoric acid compound having an olivine structure, and a transition metal sulfide powder such as TiS ₂ and FeS. Further, a conductive polymer such as polyaniline, polyacetylene, polypyrrole, or polythiophene can also be used. Further, the above-mentioned inorganic compounds and organic compounds may be mixed and used.

The negative electrode active material is not particularly limited as long as it can be doped with or intercalated with lithium ions. For example, metal Li, alloys such as tin alloy, silicon alloy, lead alloy, etc., Li _X Fe ₂ O ₃ , Li _X Fe ₃ O ₄ , Li _X WO ₂ (x is a number of 0 <x <1). ), Metal oxides such as lithium titanate, lithium vanadium, lithium siliconate, conductive polymers such as polyacetylene and poly-p-phenylene, and amorphous carbonaceous materials such as soft carbon and hard carbon. Examples thereof include artificial graphite such as highly graphitized carbon material, carbonaceous powder such as natural graphite, carbon black, mesophase carbon black, resin-fired carbon material, vapor-grown carbon fiber, and carbon-based material such as carbon fiber. These negative electrode active materials may be used alone or in combination of two or more.

The amount of the conductive material (A) in the mixture slurry of the present embodiment is preferably 0.01 to 10% by mass, preferably 0.02 to 5% by mass, based on 100% by mass of the active material. It is preferably 0.03 to 3% by mass.

The amount of the binder resin (E) in the mixture slurry of the present embodiment is preferably 0.5 to 30% by mass, more preferably 1 to 25% by mass, based on 100% by mass of the active material. , 2 to 20% by mass is particularly preferable.

The solid content of the mixture slurry of the present embodiment is preferably 30 to 90% by mass, more preferably 30 to 80% by mass, and 40 to 75% by mass with respect to 100% by mass of the mixture slurry. It is preferably mass%.

The mixture slurry of the present embodiment can be produced by various conventionally known methods. For example, a method of adding the active material (F) to the conductive material (A) or a method of adding the active material (F) to the conductive material dispersion and then adding the binder resin (E) to prepare the material. Can be mentioned.

In order to obtain the mixture slurry of the present embodiment, it is preferable to add the active material to the conductive material (A) and then disperse it. The disperser used to perform such processing is not particularly limited. As the mixture slurry, the mixture slurry can be obtained by using the dispersion means described in the conductive material dispersion.

<Electrode film (G)>
The electrode film (G) of the present embodiment is formed by forming a mixture slurry in the form of a film. For example, it is a coating film in which an electrode mixture layer is formed by applying and drying a mixture slurry on a current collector.

The material and shape of the current collector used for the electrode film of the present embodiment are not particularly limited, and those suitable for various secondary batteries can be appropriately selected. For example, examples of the material of the current collector include metals and alloys such as aluminum, copper, nickel, titanium, and stainless steel. As the shape, a foil on a flat plate is generally used, but a foil with a roughened surface, a foil with holes, and a mesh-shaped current collector can also be used.

The method of applying the mixture slurry on the current collector is not particularly limited, and a known method can be used. Specific examples include a die coating method, a dip coating method, a roll coating method, a doctor coating method, a knife coating method, a spray coating method, a gravure coating method, a screen printing method or an electrostatic coating method, and drying. As the method, a neglected drying, a blower dryer, a warm air dryer, an infrared heater, a far infrared heater and the like can be used, but the method is not particularly limited thereto.

Further, after coating, a rolling process such as a lithographic press or a calendar roll may be performed. The thickness of the electrode mixture layer is generally 1 μm or more and 500 μm or less, preferably 10 μm or more and 300 μm or less.

<Non-aqueous electrolyte secondary battery>
The non-aqueous electrolyte secondary battery of the present embodiment includes a positive electrode, a negative electrode, and an electrolyte.

As the positive electrode, a current collector obtained by applying and drying a mixture slurry containing a positive electrode active material to prepare an electrode film can be used.

As the negative electrode, a mixture slurry containing the negative electrode active material on the current collector is coated and dried to prepare an electrode film.

As the electrolyte, various conventionally known electrolytes in which ions can move can be used. For example, LiBF ₄ , LiClO ₄ , LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₃ C, LiI , LiBr, LiCl, LiAlCl, LiHF ₂ , LiSCN, or LiBPh ₄ (where Ph is a phenyl group) and the like containing lithium salts, but are not limited thereto. The electrolyte is preferably dissolved in a non-aqueous solvent and used as an electrolytic solution.

The non-aqueous solvent is not particularly limited, and is, for example, carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate; γ-butylolactone, γ-valerolactone, and γ. -Lactones such as octanoic lactones; tetrahydrofuran, 2-methyl tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1, Glymes such as 2-dibutoxyethane; esters such as methylformate, methylacetate, and methylpropionate; sulfoxides such as dimethyl sulfoxide and sulfolane; and nitriles such as acetonitrile. Each of these solvents may be used alone, or two or more kinds may be mixed and used.

The non-aqueous electrolyte secondary battery of the present embodiment preferably contains a separator. Examples of the separator include polyethylene non-woven fabric, polypropylene non-woven fabric, polyamide non-woven fabric, and those obtained by subjecting them to a hydrophilic treatment, but the separator is not particularly limited thereto.

The structure of the non-aqueous electrolyte secondary battery of the present embodiment is not particularly limited, but is usually composed of a positive electrode and a negative electrode, and a separator provided as needed, such as a paper type, a cylindrical type, a button type, and a laminated type. It can have various shapes according to the purpose of use.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. In the examples, "carbon black" may be abbreviated as "CB" and "carbon nanotube" may be abbreviated as "CNT". Unless otherwise specified, "parts" represents "parts by mass" and "%" represents "% by mass".

<Measurement method of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) was measured by gel permeation chromatography (GPC) equipped with an RI detector. Using HLC-8320GPC (manufactured by Tosoh Corporation) as an apparatus, three separation columns are connected in series, and the fillers are "TSK-GELSUPER AW-4000", "AW-3000", and "AW" manufactured by Tosoh Corporation in order. -2500 ”was used, an oven temperature of 40 ° C., a solution of 30 mM triethylamine and 10 mM LiBr in N, N-dimethylformamide as an eluent, and the measurement was performed at a flow rate of 0.6 ml / min. The sample was prepared in a solvent consisting of the above eluent at a concentration of 1 wt%, and 20 microliters were injected. The molecular weight is a polystyrene-equivalent value.

<Measurement of viscosity of conductive material dispersion>
To measure the viscosity value, use a B-type viscometer (“BL” manufactured by Toki Sangyo Co., Ltd.), stir the dispersion with a spatula at a dispersion temperature of 25 ° C, and then rotate the rotor of the B-type viscometer. Immediately at 60 rpm. When the viscosity value of the rotor used for the measurement was less than 100 mPa · s, No. If 1 is 100 or more and less than 500 mPa · s, No. If 2 is 500 or more and less than 2000 mPa · s, No. If 3 is 2000 or more and less than 10000 mPa · s, No. Each of 4 was used. The lower the viscosity, the better the dispersibility, and the higher the viscosity, the poorer the dispersibility. If the obtained dispersion was clearly separated or settled, it was regarded as poor dispersibility.
Judgment criteria ◎: Less than 500 mPa · s (excellent)
◯: 500 or more and less than 2000 mPa · s (good)
Δ: 2000 or more and less than 10000 mPa · s (possible)
X: 10000 mPa · s or more, settling or separation (defective)

<Dispersion stability evaluation method>
The storage stability was evaluated from the change in liquid properties after the dispersion was allowed to stand at 50 ° C. for 7 days and stored. The change in liquid properties was judged from the ease of stirring with a spatula.
Judgment criteria ○: No problem (good)
Δ: Viscosity has increased but not gelled (possible)
×: Gelled (extremely defective)

<Method for evaluating conductivity of electrode film using mixture slurry for negative electrode>
The mixture slurry for the negative electrode is applied onto a copper foil using an applicator so that the amount of the electrode per unit is 10 mg / cm ^2, and then in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes. The coating was dried. Then, the surface resistivity (Ω / □) of the coating film after drying was measured using Lorester GP and MCP-T610 manufactured by Mitsubishi Chemical Analytech Co., Ltd. After the measurement, the thickness of the electrode mixture layer formed on the copper foil was multiplied to obtain the volume resistivity (Ω · cm) of the electrode film for the negative electrode. The thickness of the electrode mixture layer is determined by subtracting the thickness of the copper foil from the average value measured at three points in the electrode film using a film thickness meter (DIKIMICRO MH-15M manufactured by NIKON). The volume resistivity (Ω · cm) was used. For the conductivity evaluation of the electrode film, the volume resistivity (Ω · cm) of the electrode film is ◎ (excellent) when it is less than 0.3, 〇 (good) when it is 0.3 or more and less than 0.5, and × when it is 0.5 or more. (Defective).

<Method for evaluating adhesion of electrode film using mixture slurry for negative electrode>
The mixture slurry for the negative electrode is applied onto a copper foil using an applicator so that the amount of the electrode per unit is 10 mg / cm ^2, and then in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes. The coating was dried. Then, two pieces were cut into a rectangle of 90 mm × 20 mm with the coating direction as the long axis. A desktop tensile tester (Strograph E3, manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to measure the peel strength, and the peel strength was evaluated by a 180-degree peel test method. Specifically, a 100 mm × 30 mm size double-sided tape (No. 5000NS, manufactured by Nitoms Co., Ltd.) was attached onto a stainless steel plate, and the produced battery electrode mixture layer was brought into close contact with the other surface of the double-sided tape. Peeling was performed while pulling from the bottom to the top at a constant speed (50 mm / min), and the average value of stress at this time was taken as the peel strength. The evaluation of the adhesion (N / cm) of the electrode film was evaluated as ⊚ (excellent) for 0.5 or more, 〇 (good) for 0.1 or more and less than 0.5, and × (poor) for less than 0.1.

<Method for evaluating conductivity of electrode film using mixture slurry for positive electrode>
The positive electrode mixture slurry is applied onto an aluminum foil using an applicator so that the amount of the electrodes per unit is 20 mg / cm ^2, and then in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes. The coating film was dried. Then, the surface resistivity (Ω / □) of the coating film after drying was measured using Lorester GP and MCP-T610 manufactured by Mitsubishi Chemical Analytech Co., Ltd. After the measurement, the thickness of the electrode mixture layer formed on the aluminum foil was multiplied to obtain the volume resistivity (Ω · cm) of the electrode film for the positive electrode. The thickness of the electrode mixture layer is determined by subtracting the thickness of the aluminum foil from the average value measured at three points in the electrode film using a film thickness meter (DIKIMICRO MH-15M manufactured by NIKON). The volume resistivity (Ω · cm) was used. In the evaluation of the conductivity of the electrode film, a volume resistivity (Ω · cm) of the electrode film of less than 10 was evaluated as ⊚ (excellent), 10 or more and less than 20 was evaluated as 〇 (good), and 20 or more was evaluated as × (poor).

<Method of evaluating adhesion of electrode film using mixture slurry for positive electrode>
The positive electrode mixture slurry is applied onto a copper foil using an applicator so that the amount of the electrodes per unit is 20 mg / cm ^2, and then in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes. The coating was dried. Then, two pieces were cut into a rectangle of 90 mm × 20 mm with the coating direction as the long axis. A desktop tensile tester (Strograph E3, manufactured by Toyo Seiki Seisakusho Co., Ltd.) was used to measure the peel strength, and the peel strength was evaluated by a 180-degree peel test method. Specifically, a 100 mm × 30 mm size double-sided tape (No. 5000NS, manufactured by Nitoms Co., Ltd.) was attached onto a stainless steel plate, and the produced battery electrode mixture layer was brought into close contact with the other surface of the double-sided tape. Peeling was performed while pulling from the bottom to the top at a constant speed (50 mm / min), and the average value of stress at this time was taken as the peel strength. The evaluation of the adhesion (N / cm) of the electrode film was 1 or more as ⊚ (excellent), 0.5 or more and less than 1 as 〇 (good), and less than 0.5 as x (poor).

<Method for evaluating rate characteristics of non-aqueous electrolyte secondary batteries>
A non-aqueous electrolyte secondary battery was installed in a constant temperature room at 25 ° C., and charge / discharge measurement was performed using a charge / discharge device (SM-8 manufactured by Hokuto Denko Co., Ltd.). After performing constant current constant voltage charging (cutoff current 1mA (0.02C)) at a charging end voltage of 4.3V at a charging current of 10mA (0.2C), discharge at a discharge current of 10mA (0.2C). A constant current discharge was performed at a final voltage of 3 V. After repeating this operation three times, constant current constant voltage charging (cutoff current (1mA 0.02C)) is performed at a charging end voltage of 4.3V at a charging current of 10mA (0.2C), and a discharge current of 0.2C and Constant current discharge was performed at 3C until the discharge end voltage reached 3.0 V, and the discharge capacity was determined for each. The rate characteristic can be expressed by the following equation 1 which is the ratio of the 0.2C discharge capacity to the 3C discharge capacity.
(Equation 1) Rate characteristics = 3C discharge capacity / 3rd 0.2C discharge capacity x 100 (%)
As for the rate characteristics, those having a rate characteristic of 80% or more were evaluated as ⊚ (excellent), those having a rate characteristic of 60% or more and less than 80% were evaluated as 〇 (good), and those having a rate characteristic of less than 60% were evaluated as × (poor).

<Method for evaluating cycle characteristics of non-aqueous electrolyte secondary batteries>
A non-aqueous electrolyte secondary battery was installed in a constant temperature room at 25 ° C., and charge / discharge measurement was performed using a charge / discharge device (SM-8 manufactured by Hokuto Denko Co., Ltd.). After performing constant current constant voltage charging (cutoff current 2.5mA (0.05C)) at a charging end voltage of 4.3V at a charging current of 25mA (0.5C), the discharge current is 25mA (0.5C). , Constant current discharge was performed with a discharge end voltage of 3 V. This operation was repeated 200 times. The cycle characteristics can be expressed by the following equation 2 which is the ratio of the third 0.5C discharge capacity to the 200th 0.5C discharge capacity at 25 ° C.
(Equation 2) Cycle characteristics = 3rd 0.5C discharge capacity / 200th 0.5C discharge capacity x 100 (%)
The cycle characteristics were defined as ⊚ (excellent) when the cycle characteristics were 85% or more, 〇 (good) when 80% or more and less than 85%, and − (poor) when the cycle characteristics were less than 80%.

<Production Example 1-1 Production of Dispersant (C-1)>
40 parts of acrylonitrile, 60 parts of 1,3-butadiene, 3 parts of potassium oleate, 0.3 part of azobisisobutyronitrile, 0.6 part of t-dodecyl mercaptan, ion-exchanged water in a stainless polymerization reactor. 200 parts were charged, and polymerization was carried out at 45 ° C. for 20 hours under stirring in a nitrogen atmosphere, and the polymerization was completed at a conversion rate of 90%. The unreacted monomer was removed by vacuum stripping to obtain a (meth) acrylonitrile-conjugated diene rubber latex having a solid content concentration of about 30%. Subsequently, the solid content was recovered from the latex to obtain a dispersant (C-1). After drying, the content of 1,3-butadiene and acrylonitrile units of the dispersant (C-1) was determined by elemental analysis. As a result, 1,3-butadiene units were 59% by weight and acrylonitrile units were 41% by weight. .. The weight average molecular weight (Mw) of the dispersant (C-1) was 15,000.

<Manufacturing Examples 1-2-1-6 Dispersants (C-2) to (C-6)>
Dispersants (C-2) to (C-6) were prepared in the same manner as in Production Example 1-1, except that the monomers used were changed according to Table 1. The weight average molecular weight (Mw) of each dispersant was as shown in Table 1.

<Production Example 2-1 Production of Dispersant (C-7)>
In a glass bottle (M-225, manufactured by Kashiwayo Glass Co., Ltd.), 0 is a commercially available H-NBR Therban (R) 4637 (hydrogenated nitrile-butadiene rubber, acrylonitrile content 43%, weight average molecular weight 200,000) manufactured by LANXESS. .5 parts, 0.15 parts of NaOH, 99.35 parts of N-methyl-2-pyrrolidone were charged, mixed and dissolved with a paint conditioner using zirconia beads (bead diameter 0.5 mmφ) as media, and a reddish brown solution was prepared. Obtained. The obtained solution was dried at 140 ° C. to volatilize N-methyl-2-pyrrolidone to obtain a dispersant (C-7).

<Production Example 2-2 Production of Dispersant (C-8)>
In a glass bottle (M-225, manufactured by Kashiwayo Glass Co., Ltd.), a commercially available H-NBR Zetpole (R) 3300 (hydrogenated nitrile-butadiene rubber, acrylonitrile content 23.6%, weight average molecular weight 150,000) manufactured by Nippon Zeon Co., Ltd. ), 0.15 parts of LiOH, 99.35 parts of N-methyl-2-pyrrolidone, and zirconia beads (bead diameter 0.5 mmφ) as media, mixed and dissolved with a paint conditioner to make it thin. A yellow solution was obtained. The obtained solution was dried at 140 ° C. to volatilize N-methyl-2-pyrrolidone to obtain a dispersant (C-8).

<Manufacturing Example 3 Preparation of Standard Positive Electrode Mixture Slurry>
Positive positive active material (BASF Toda Battery Materials GK, HED (registered trademark) NCM-111 1100) 93 parts by mass, acetylene black (Denka Corporation, Denka Black (registered trademark) HS100) 4 parts by mass, PVDF (stock) company Inc. Kureha battery Mateiraruzu Japan Ltd., were added to a plastic container of Kureha KF polymer W # 1300) 3 parts by weight of the volume 150 cm ^3, and mixed until the powder is homogeneous with a spatula. Then, 20.5 parts by mass of NMP was added, and the mixture was stirred at 2000 rpm for 30 seconds using a rotation / revolution mixer (Awatori Rentaro manufactured by Shinky Co., Ltd., ARE-310). Then, the mixture in the plastic container was mixed using a spatula until uniform, and the mixture was stirred at 2000 rpm for 30 seconds using the rotation / revolution mixer. After that, 14.6 parts by mass of NMP was added, and the mixture was stirred at 2000 rpm for 30 seconds using the rotation / revolution mixer. Finally, using a high-speed stirrer, the mixture was stirred at 3000 rpm for 10 minutes to obtain a mixture slurry for a positive electrode.

<Manufacturing Example 4 Preparation of standard positive electrode>
The above-mentioned mixture slurry for positive electrode is applied on an aluminum foil having a thickness of 20 μm as a current collector using an applicator, and then dried in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes per unit area of the electrode. The basis weight of the mixture was adjusted to 20 mg / cm ² . Further, a rolling process was performed by a roll press (3t hydraulic roll press manufactured by Thunk Metal Co., Ltd.) to prepare a positive electrode having a density of the mixture layer of 3.1 g / cm ³ .

<Preparation of conductive material dispersion>
<Examples 1-1 to 1-14, Comparative Examples 1-1 to 1-5>
According to the composition and dispersion time shown in Table 2, a dispersant, an additive, and a dispersion medium are charged in a glass bottle (M-225, manufactured by Kashiwayo Glass Co., Ltd.), and the conductive material is sufficiently mixed and dissolved or mixed. Was added and dispersed with a paint conditioner using zirconia beads (bead diameter 0.5 mmφ) as a medium to obtain each conductive material dispersion (dispersions 1 to 14, comparative dispersions 1 to 5). As shown in Table 2, all of the conductive material dispersions (dispersions 1 to 14) of the present invention had low viscosity and good storage stability.

HS-100: Denka Black HS-100 (manufactured by Denka, acetylene black, average primary particle diameter 48 nm, specific surface area 39 m ² / g)
-EC-300J: Ketjen Black EC-300J (Made by Lion Specialty Chemicals, Ketjen Black, average primary particle size 40 nm, specific surface area 800 m ² / g)
・ 8S: JENOTUBE8S (manufactured by JEIO, multi-walled CNT, outer diameter 6-9 nm)
100T: K-Nanos 100T (manufactured by Kumho Petrochemical, multi-walled CNT, outer diameter 10 to 15 nm)
H-NBR: Therban (R) 4637 (LANXESS hydrogenated nitrile-butadiene rubber, solid content 100%, acrylonitrile content 43%, weight average molecular weight 200,000)
-PVP: Polyvinylpyrrolidone K-30 (manufactured by Nippon Shokubai Co., Ltd., 100% solid content)
-PVA: Kuraray POVAL PVA403 (manufactured by Kuraray, 100% solid content)
-PVB: Eslek BL-10 (manufactured by Sekisui Chemical Co., Ltd., 100% solid content)
・ NMP: N-methyl-2-pyrrolidone

<Preparation of mixture slurry for negative electrode>
<Example 2-1>
After adding the conductive material dispersion (dispersion 3), CMC, and water to a plastic container with a capacity of 150 cm ³ , a rotation / revolution mixer (Awatori Rentaro manufactured by Shinky Co., Ltd., ARE-310) is used at 2000 rpm. The mixture was stirred for 30 seconds to obtain a conductive-containing resin composition 3. Then, the active material was added, and the mixture was stirred at 2000 rpm for 150 seconds using the rotation / revolution mixer. After that, SBR was added, and the mixture was stirred at 2000 rpm for 30 seconds using the rotation / revolution mixer to obtain a negative electrode mixture slurry 3. The solid content of the negative electrode mixture slurry 3 was 48% by mass. The solid content ratio of active material: conductive material: CMC: SBR in the negative electrode mixture slurry was 97: 0.5: 1: 1.5.

<Examples 2-2, 2-3, Comparative Example 2-1)
Conductive material-containing resin compositions 4 and 13, comparative conductive material-containing resin compositions 2 and negative electrode mixture slurries 4 and 13 were carried out in the same manner as in Example 2-1 except that the type of the conductive material dispersion was changed. , A mixed material slurry 2 for a comparative negative electrode was obtained. As shown in Table 3, the electrode films using the conductive material dispersion of the present invention all had good conductivity and adhesion.

-Artificial graphite: CGB-20 (manufactured by Nippon Graphite Industry Co., Ltd.), 100% solid content
-CMC: # 1190 (manufactured by Daicel Fine Chem Ltd.), 100% solid content
-SBR: TRD2001 (manufactured by JSR), solid content 48%

<Preparation of mixture slurry for positive electrode>
<Example 3-1>
After adding the conductive material dispersion (dispersion 1) and NMP in which 8% by mass PVDF is dissolved to a plastic container having a capacity of 150 cm, a rotation / revolution mixer (Awatori Rentaro manufactured by Shinky Co., Ltd., ARE-310) is used. Then, the mixture was stirred at 2000 rpm for 30 seconds to obtain a conductive material-containing resin composition 1. Then, the active material was added, and the mixture was stirred at 2000 rpm for 150 seconds using the rotation / revolution mixer. After that, NMP was added, and the mixture was stirred at 2000 rpm for 30 seconds using the rotation / revolution mixer to obtain a positive electrode mixture slurry 1. The solid content of the positive electrode mixture slurry 1 was 75% by mass. The solid content ratio of active material: conductive material: PVDF in the mixture slurry for the positive electrode was 98.5: 0.5: 1.

<Examples 3-2, 3-5-3-12, 3-14, Comparative Examples 3-1-3-4>
Conductive material-containing resin compositions 2, 5 to 12, 14 and comparative conductive material-containing resin compositions 1, 3 to 5 were prepared by the same method as in Example 3-1 except that the type of the conductive material dispersion was changed. Positive electrode mixture slurries 2, 5 to 12, 14 and comparative positive electrode mixture slurries 1, 3 to 5 were obtained. As shown in Table 4, all of the electrode films using the conductive material dispersion of the present invention had good conductivity and adhesion.

-NMC (lithium nickel manganese cobalt oxide): HED (registered trademark) NCM-111 1100 (manufactured by BASF Toda Battery Materials LLC), 100% solid content
-PVDF: Solef # 5130 (manufactured by Solvay), 100% solid content

<Preparation of electrode film>
<Examples 4-1 to 4-14, Comparative Examples 4-1 to 4-5)
The mixture slurry shown in Table 5 was applied onto a metal foil using an applicator, and then the coating film was dried in an electric oven at 120 ° C. ± 5 ° C. for 25 minutes to prepare an electrode film. Then, the electrode film was rolled by a roll press (3t hydraulic roll press manufactured by Thunk Metal Co., Ltd.). When coating the mixture slurry for the positive electrode, aluminum foil is used as the metal foil, and the coating is applied so that the grain size per unit of the electrode is 20 mg / cm ^2, and the density of the electrode film after drying is 3. Rolled to .1 g / cc. When coating the mixture slurry for the negative electrode, a copper foil is used as the metal foil, and the coating is applied so that the grain size per unit of the electrode is 10 mg / cm ^2, and the density of the electrode film after drying is 1. It was rolled to a concentration of .6 g / cc.

<Manufacturing of non-aqueous electrolyte secondary battery>
The negative electrode and the positive electrode shown in Table 6 are punched into 50 mm × 45 mm and 45 mm × 40 mm, respectively, and the separator (porous polypropylene film) inserted between them is inserted into an aluminum laminate bag and placed in an electric oven at 70 ° C. It was dried for 1 hour. Then, in a glove box filled with argon gas, an electrolytic solution (a mixed solvent in which ethylene carbonate, dimethyl carbonate, and diethyl carbonate were mixed at a ratio of 1: 1: 1 (volume ratio) was prepared, and further, as an additive, After adding 1 part by mass of VC (vinylene carbonate) to 100 parts by mass, 2 mL of a non-aqueous electrolyte solution in which LiPF ₆ is dissolved at a concentration of 1 M) is injected, and then the aluminum laminate is sealed and the non-aqueous electrolyte is sealed. Secondary batteries 1 to 14 and comparative non-aqueous electrolyte secondary batteries 1 to 5 were prepared.

In the above embodiment, the dispersant is a copolymer containing a unit derived from (meth) acrylonitrile and a unit derived from a conjugated diene monomer, and is derived from the (meth) acrylonitrile in the copolymer. A conductive material dispersion containing 15 to 50% by mass of units and having a weight average molecular weight of 5,000 to 400,000 was used. In the examples, a non-aqueous electrolyte secondary battery having excellent cycle characteristics as compared with the comparative example was obtained. In particular, in a conductive material dispersion containing 10 to 50 parts by mass of at least one selected from the group consisting of an inorganic metal salt, an inorganic base and an organic base with respect to 100 parts by mass of the dispersant, the unit derived from acrylonitrile has a cyclic structure. Therefore, a non-aqueous electrolyte secondary battery having excellent cycle characteristics as compared with the comparative example was obtained. Therefore, it has been clarified that the present invention can provide a non-aqueous electrolyte secondary battery having cycle characteristics that cannot be realized by a conventional conductive material dispersion.

Although the invention of the present application has been described above with reference to the embodiments, the invention of the present application is not limited to the above. Various changes that can be understood by those skilled in the art can be made within the scope of the invention in the configuration and details of the invention of the present application.

Claims (9)

A conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C), wherein the dispersant (C) is a unit derived from (meth) acrylonitrile and a conjugated diene simple substance. It is a copolymer containing a unit derived from a metric body, and is characterized in that the copolymer contains 15 to 50% by mass of a unit derived from the (meth) acrylonitrile and has a weight average molecular weight of 5,000 to 400,000. Conductive material dispersion for non-aqueous electrolyte secondary batteries. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to claim 1, further comprising at least one (D) selected from the group consisting of an inorganic metal salt, an inorganic base and an organic base. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the dispersant (C) has a cyclic structure in a unit derived from acrylonitrile. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the conductive material (A) is a carbon-based filler. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein a part of the unit derived from the conjugated diene monomer is hydrogenated. A conductive material-containing resin composition containing the conductive material dispersion according to any one of claims 1 to 5 and a binder resin (E). A mixture slurry comprising the conductive material-containing resin composition according to claim 6 and the active material (F). The electrode film (G) formed by forming the mixture slurry according to claim 7 in the form of a film. A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and an electrolyte in which ions can move, wherein at least one of the positive electrode and the negative electrode includes the electrode film (G) according to claim 8. Characterized non-aqueous electrolyte secondary battery.