JP6743954B1 - Conductive material dispersion and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive material dispersion having a high dispersibility, a conductive material-containing resin composition, and a mixture slurry in order to obtain an electrode film having high adhesiveness and conductivity. More specifically, to provide a non-aqueous electrolyte secondary battery having excellent rate characteristics and cycle characteristics. A conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C), in which the dispersant (C) is derived from (meth)acrylonitrile, and A copolymer containing an active hydrogen group-containing monomer, a basic monomer, and one or more monomer units selected from the group consisting of (meth)acrylic acid alkyl esters, wherein the (meth)acrylonitrile is contained in the copolymer. The problem is solved by using a conductive material dispersion for a non-aqueous electrolyte secondary battery, which contains 40 to 99% by mass of a unit derived from, and has a weight average molecular weight of 5,000 to 50,000. [Selection diagram] 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 mixture slurry containing a conductive material dispersion, a binder resin and an active material, and forming it in a film form. The present invention relates to a non-aqueous electrolyte secondary battery including the electrode film, the electrode film, and the electrolyte.

Along with the spread of electric vehicles, the reduction in size and weight of mobile devices, and the increase in performance thereof, secondary batteries having a high energy density and further higher capacity of the secondary batteries are required. Against this background, non-aqueous electrolyte secondary batteries that use non-aqueous electrolytes have come to be used in many devices because of their high energy density and high voltage, and lithium-ion secondary batteries have received particular attention. ing.

As a negative electrode material used in a lithium ion secondary battery, a carbon material typified by graphite, which has a base potential close to lithium (Li) and has a large charge/discharge capacity per unit mass, is used. However, these electrode materials are used up 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 the amount of conductive materials and binders that do not contribute to the discharge capacity inside the battery.

As the conductive material, carbon black, Ketjen black, fullerene, graphene, a fine carbon material or the like is used. In particular, carbon nanotubes, which are a type of fine carbon fiber, are often used. For example, by adding carbon nanotubes to graphite or a silicon negative electrode, the lithium ion can be reduced by reducing the electrode resistance, improving the load resistance of the battery, increasing the strength of the electrode, or increasing the expansion and contraction of the electrode. It improves the cycle life of the secondary battery. (See, for example, Patent Documents 1, 2 and 3) Also, studies are being made to reduce the electrode resistance by adding carbon nanotubes to the positive electrode. Among them (see, for example, Patent Documents 4 and 5), 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, a conductive material dispersion having sufficient dispersibility cannot be obtained.

Therefore, a method of stabilizing dispersion of 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 a water-soluble polymer polyvinylpyrrolidone has been proposed (see Patent Documents 4 and 5).

Further, in Patent 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 is proposed. It was necessary to use a large amount of a dispersant in order to disperse the conductive material having a large specific surface area.

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 the applications.

JP-A-4-155776 Japanese Unexamined Patent Publication No. 4-237971 JP, 2004-178922, A JP, 2011-70908, A JP, 2005-162877, A JP, 2017-10821, A

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

As a result of intensive studies to solve the above problems, the present inventors have found that a conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C) is obtained. The dispersant (C) contains a unit derived from (meth)acrylonitrile, and one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer, a basic monomer, and a (meth)acrylic acid alkyl ester. A non-aqueous electrolyte secondary battery, which is a copolymer, comprising 40 to 99 mass% of the unit derived from the (meth)acrylonitrile in the copolymer, and has a weight average molecular weight of 5,000 to 50,000. The inventors have found that the use of a conductive material dispersion makes it possible to obtain an electrode film having high adhesion and conductivity, and a non-aqueous electrolyte secondary battery having excellent rate characteristics and cycle characteristics, and 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), wherein the conductive material (A) is carbon nanotubes and/or Ketjenblack. Wherein the dispersant (C) is a unit derived from (meth)acrylonitrile, and one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer, a basic monomer, and a (meth)acrylic acid alkyl ester. And a unit derived from the (meth)acrylonitrile in an amount of more than 80% by mass and 99% by mass or less, and having a weight average molecular weight of 5,000 to 50,000. The present invention relates to a conductive material dispersion for a non-aqueous electrolyte secondary battery.

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

The present invention also relates to a conductive material dispersion for a secondary battery, which further comprises at least one 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-containing resin composition containing a conductive material dispersion and a binder resin (D).

The present invention also relates to a mixture slurry containing a conductive material-containing resin composition and an active material (E).

The present invention also relates to an electrode film (F) formed by forming a mixture slurry into a film shape.

Further, the present invention is a non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and an electrolyte capable of moving ions, wherein at least one of the positive electrode and the negative electrode comprises an electrode film (F). The present invention 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 adhesiveness can be obtained. Moreover, 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 fields of application where high conductivity, adhesion and durability are required.

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

<Conductive material dispersion for non-aqueous electrolyte secondary battery>
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, molbutene and platinum, inorganic powders coated with these metals, powders of metal oxides such as silver oxide, indium oxide, tin oxide, zinc oxide and ruthenium oxide, and metal oxides thereof Inorganic powder coated with, carbon black, graphite and the like can be used. As the carbon black, any carbon black such as neutral, acidic or basic can be used. These conductive materials may be used alone or in combination of two or more. Among these conductive materials, carbon black is preferable.

As the carbon black of the present embodiment, various kinds of commercially available acetylene black, furnace black, hollow carbon black, channel black, thermal black, Ketjen black and the like can be used. In addition, commonly used oxidation-treated carbon black, graphitized carbon black, carbon nanotubes, carbon nanofibers and the like can also be used.

The carbon nanotube of the present embodiment has a shape in which planar graphite is rolled 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 more layers of graphite are wound. Further, the side wall of the carbon nanotube does not have to have the graphite structure. For example, carbon nanotubes having sidewalls having an amorphous structure can also be used as carbon nanotubes.

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

Examples of the form of the carbon nanotube of the present embodiment include, but are not limited to, graphite whiskers, filamentous carbon, graphite fibers, ultrafine carbon tubes, carbon tubes, carbon fibrils, carbon microtubes, and carbon nanofibers. .. The carbon nanotubes may have a single form or a combination of two or more types.

The conductive material (A) of the present embodiment preferably has a BET specific surface area of 20 to 1000 m ² /g, and more preferably 150 to 800 m ² /g.

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

The average particle diameter and the average outer diameter of the conductive material (A) of this embodiment are obtained as follows. First, the conductive material is observed and imaged by a transmission electron microscope. Next, in the observation photograph, 300 arbitrary conductive materials are selected, and the particle diameter and outer diameter of each are measured. Next, the average particle diameter (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 rate (% by mass) of carbon atoms 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, with respect to 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×. More preferably, it is 10 ⁻² Ω·cm. The volume resistivity of the conductive material can be measured using a powder resistivity measuring device (Made 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 therein, but any one or a mixture of water and a water-soluble organic solvent can be used. It is preferably a solvent.

Water-soluble organic solvents include alcohols (methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, benzyl alcohol, etc.), 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 ether type (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 Ether, triethylene glycol monobutyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amine-based (ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine) , Ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, 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.), sulfoxides (dimethyl sulfoxide, etc.), sulfones (hexamethylphosphorotriamide, sulfolane, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), others, tetrahydrofuran, urea, aceto Nitriles and the like can be used. Among these, water or an amide-based organic solvent is more preferable, and among the amide-based organic solvents, N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone are particularly preferable.

(Dispersant (C))
The dispersant (C) contains a unit derived from (meth)acrylonitrile, and one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer, a basic monomer, and a (meth)acrylic acid alkyl ester. It is a copolymer, and contains 40 to 99 mass% of the unit derived from the (meth)acrylonitrile in the copolymer, and has a weight average molecular weight of 5,000 to 50,000.

The active hydrogen group-containing monomer of this embodiment will be described.
The active hydrogen group-containing monomer is not particularly limited as long as it has one or more active hydrogen groups in one molecule, and the active hydrogen group is a hydroxyl group, a carboxyl group, a primary amino group, a secondary amino group, or a mercapto group. Groups and the like.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono (meth)acrylate, 4-hydroxyvinylbenzene, 2- Examples thereof include hydroxy-3-phenoxypropyl acrylate and caprolactone adducts of these monomers (addition mole number is 1 to 5).

The carboxyl group-containing monomer is, for example, (meth)acrylic acid, (meth)acrylic acid dimer, itaconic acid, maleic acid, fumaric acid, crotonic acid, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryl acid. Royloxypropyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxypropyl hexahydrophthalate, ethylene oxide modified succinic acid (meth)acrylate, β-carboxyethyl (meth)acrylate, And monofunctional alcohol adducts of acid anhydride group-containing monomers such as maleic anhydride, itaconic anhydride, and citraconic acid.

Examples of the primary amino group-containing monomer include aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, allylamine hydrochloride, allylamine dihydrogen phosphate, 2-isopropenylaniline, 3-vinylaniline, 4-vinylaniline. Etc.

Examples of the secondary amino group-containing monomer include t-butylaminoethyl (meth)acrylate.

Examples of the mercapto group-containing monomer include 2-(mercaptoacetoxy)ethyl acrylate and allyl mercaptan.

From the viewpoint of easy availability of raw materials, easy handling, and affinity with a dispersion medium described later, hydroxyl group-containing monomer and carboxyl group-containing monomer, hydroxyethyl (meth)acrylate and (meth)acrylic acid are preferable, and more preferable. Is hydroxyethyl acrylate, acrylic acid.

Next, the basic monomer will be described. The basic monomer in the present invention is a basic monomer containing no primary amino group or secondary amino group.

For example, dialkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate and dimethylaminopropyl (meth)acrylate;
N-substituted (meth)acrylamides such as (meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, and acryloylmorpholine;
Heterocyclic aromatic amine-containing vinyl monomers such as 1-vinylpyridine, 4-vinylpyridine and 1-vinylimidazole;
N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide; N-(alkylaminoalkyl) (meth) such as N-(dimethylaminoethyl)(meth)acrylamide and N-(dimethylaminopropyl)acrylamide Acrylamides;
Examples include N,N-alkyl(meth)acrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide.

Dimethylaminoethyl (meth)acrylate and dimethylaminopropyl (meth)acrylate are preferable, and dimethylaminoethyl acrylate is most preferable, from the viewpoints of availability of raw materials, easy handling, and affinity with a dispersion medium described later.

Next, the (meth)acrylic acid alkyl ester will be described. The (meth)acrylic acid alkyl ester of the present invention has a C=C-CO-O- skeleton, has an alkyl group having 1 or more carbon atoms, and does not contain active hydrogen or a basic group. Without limitation, for example, a chain aliphatic alkyl group-containing (meth)acrylic acid ester such as methyl (meth)acrylate and ethyl (meth)acrylate;
(Meth)acrylic acid ester containing a branched aliphatic alkyl group such as 2-ethylhexyl (meth)acrylate and isostearyl (meth)acrylate;
Cycloaliphatic alkyl group-containing (meth)acrylic acid esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate;
Aromatic group-substituted (meth)acrylic acid alkyl esters such as benzyl (meth)acrylate and phenoxyethyl (meth)acrylate;
A fluoro group-substituted (meth)acrylic acid alkyl ester such as (meth)acrylic acid trifluoroethyl or (meth)acrylic acid tetrafluoropropyl;
Glycidyl (meth)acrylate, (meth)acrylic acid (3-ethyloxetan-3-yl)methyl and other alicyclic epoxy group-substituted (meth)acrylic acid alkyl esters;
(Meth)acrylic acid alkyl esters substituted with a silyl ether group such as 3-methacryloxypropylmethyldimethoxysilane;
(Meth)acrylic acid alkyl esters substituted with an alkylene glycol monoalkyl ether group such as (meth)acrylic acid 2-methoxyethyl and (meth)acrylic acid polyethylene glycol monomethyl ether;
Etc.

Ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid from the viewpoints of availability of raw materials, easy handling, and affinity with the dispersion medium described later. Lauryl is preferable, and 2-ethylhexyl acrylate and lauryl acrylate are more preferable.

The dispersant (C) of the present embodiment may further be copolymerized with the above-mentioned other monomer components. Other monomers include, for example, styrene and styrenes such as α-methylstyrene;
Vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, and isobutyl vinyl ether;
Fatty acid vinyls such as vinyl acetate and vinyl propionate;
Heterocyclic (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate or 3-methyloxetanyl (meth)acrylate;
Etc.

The method for producing the dispersant (C) of the present embodiment is not particularly limited, and for example, any method such as a solution polymerization method, a suspension polymerization method, a bulk polymerization method, an emulsion polymerization method, or a precipitation polymerization method may be used. In the present invention, the solution polymerization or precipitation polymerization method is preferred. As the polymerization reaction system, addition polymerization such as ionic polymerization, free radical polymerization and living radical polymerization can be used, and free radical polymerization or living radical polymerization is preferred in the present invention. As the radical polymerization initiator, compounds selected from peroxides, azo initiators and the like or a mixture thereof can be used, and a molecular weight modifier such as a chain transfer agent may be used as necessary.

The dispersant (C) of the present embodiment contains 40 to 99% by mass of a unit derived from (meth)acrylonitrile, preferably 50 to 99% by mass, and particularly preferably 75 to 99% by mass. .. By containing the unit derived from (meth) acrylonitrile in the above range, it is possible to control the adsorptivity to the substance to be dispersed and the affinity to the dispersion medium, and to make the substance to be dispersed stably exist in the dispersion medium. You can

The molecular weight of the dispersant (C) of the present embodiment is a polystyrene-equivalent mass average, and is usually in the range of 5,000 or more and 50,000 or less, more preferably in the range of 6000 or more and 40,000 or less, and particularly preferably in the range of 7,000 or more and 30,000 or less. preferable. When the molecular weight of the dispersant is less than 5,000 or more than 50,000, the adsorptivity to the substance to be dispersed and the affinity to the dispersion medium are lowered, and the stability of the dispersion tends to be lowered.

A resin containing 75% by mass or more and 99% by mass or less of (meth)acrylonitrile is preferable because it is converted into a ring structure such as hydrogenated naphthyridine by the alkali treatment. This ring structure can also improve the adsorptivity to the substance to be dispersed and the affinity to the dispersion medium. As the alkali treatment of the dispersant of the present invention, alkali treatment may be carried out in advance, or a structural change to a ring structure may be promoted by using an alkali or the like together during use.

Further, when the copolymer has a (meth)acrylic acid unit, it forms a glutarimide ring as a cyclic structure together with a unit derived from acrylonitrile by alkali treatment, so that a ring structure such as a hydrogenated naphthyridine ring and a glutarimide ring are formed. Coexist. The (meth)acrylic acid unit is preferably 1 to 25% by mass, more preferably 10 to 25% by mass, based on all the monomer units of the copolymer. The unit derived from acrylonitrile is preferably 40 to 99% by mass, and more preferably 75 to 99% by mass, based on the total monomer units of the copolymer.

The conductive material dispersion of the present invention may contain an inorganic base, an inorganic metal salt and an organic base in addition to the conductive material (A), the dispersion medium (B) and the dispersant (C). This improves the dispersion stability of the conductive material dispersion. The inorganic base and the inorganic metal salt are preferably compounds having at least one of an alkali metal and an alkaline earth metal, and specifically, a chloride, a hydroxide, a carbonate of an alkali metal and an alkaline earth metal. Examples thereof include salts, nitrates, sulfates, phosphates, tungstates, vanadates, molybdates, niobates, and borates. Of these, alkali metal, alkaline earth metal chlorides, hydroxides, and carbonates are preferable from the viewpoint of easily supplying cations. Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like. Examples of the alkaline earth metal hydroxides include calcium hydroxide and magnesium hydroxide. Examples of alkali metal carbonates 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.

Examples of the primary alkylamine having 1 to 40 carbon atoms include propylamine, butylamine, isobutylamine, octylamine, 2-ethylhexylamine, laurylamine, stearylamine, oleylamine, 2-aminoethanol, 3-aminopropanol, 3-ethoxy. Examples include propylamine and 3-lauryloxypropylamine.

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

Examples of the tertiary alkylamine having 1 to 40 carbon atoms include triethylamine, tributylamine, N,N-dimethylbutylamine, N,N-diisopropylethylamine, dimethyloctylamine, trioctylamine, dimethyldecylamine, dimethyllaurylamine and dimethylmyristyl. Examples thereof include amine, dimethylpalmitylamine, dimethylstearylamine, dilaurylmonomethylamine, triethanolamine and 2-(dimethylamino)ethanol.

Among 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 more preferable.

As the organic base, 1,8-diazabicyclo[5.4.0]undecene-7(DBU), 1,5-diazabicyclo[4.3.0]nonene-5(DBN), 1,4-diazabicyclo[2] are used. 2.2.2] Octane (DABCO), tri-n-butylamine, dimethylbenzylamine, monoethanolamine, imidazole, 1-methylimidazole and the like compounds containing a basic nitrogen atom may be used.

The content of the inorganic base, the inorganic metal salt, and the organic base is more preferably 1 to 50 parts by mass with respect to 100 parts by mass of the dispersant (C). The dispersibility is further improved by adding an appropriate amount.

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

The amount of solids of the conductive material dispersion of the present embodiment is preferably 0.05 to 30 mass% and more preferably 0.1 to 20 mass% with respect to 100 mass% of the conductive material dispersion.

The amount of the dispersant (C) in the conductive material dispersion according to the present embodiment is preferably 3 to 200 mass %, and more preferably 5 to 50 mass% with respect to 100 mass% of the conductive material dispersion. More preferable.

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

(Binder resin (D))
The binder resin (D) of this embodiment is a resin for binding substances.

Examples of the binder resin (D) 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, vinyl butyral. , Copolymers containing 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, silicone Resins, fluororesins; cellulose resins such as carboxymethyl cellulose; rubbers such as styrene-butadiene rubber and fluororubber; conductive resins such as polyaniline and polyacetylene. Further, modified products and mixtures of these resins, and copolymers may also be used. Among them, when used as a binder resin for the positive electrode, it is preferable to use a polymer compound having a fluorine atom in the molecule, such as polyvinylidene fluoride (PVDF), polyvinyl fluoride, or tetrafluoroethylene, from the viewpoint of resistance. When used as a binder resin for the negative electrode, carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR) and polyacrylic acid, which have good adhesion, are preferable.

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

<Compound material slurry>
The mixture slurry of the present embodiment is one in which the conductive material-containing resin composition further contains at least the active material (E).

(Active material (E))
The active material (E) of the present embodiment is a material that becomes a base of battery reaction. Active materials are classified into positive electrode active materials and negative electrode active materials based on electromotive force.

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

The negative electrode active material is not particularly limited as long as it can dope or intercalate lithium ions. For example, metal Li, alloys such as tin alloy, silicon alloy, lead alloy, 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 vanadate, and lithium silicate, conductive polymer materials such as polyacetylene and poly-p-phenylene, and amorphous carbonaceous materials such as soft carbon and hard carbon. Also, 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, carbon fiber and other carbon-based materials. 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, and preferably 0.02 to 5% by mass with respect to 100% by mass of the active material. It is preferably 0.03 to 3% by mass.

The amount of the binder resin (D) 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 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% with respect to 100% by mass of the mixture slurry. It is preferably mass%.

The mixture slurry of this embodiment can be produced by various conventionally known methods. For example, a method of producing by adding the active material (E) to the conductive material (A) or a method of adding the active material (E) to the conductive material dispersion and then adding the binder resin (D) 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 perform a treatment of dispersing the active material. The dispersion device used for performing such processing is not particularly limited. The mixture slurry can be obtained by using the dispersion means described in the conductive material dispersion.

(Electrode film (F))
The electrode film (F) of the present embodiment is formed by forming a mixture slurry in a film shape. For example, it is a coating film in which an electrode mixture layer is formed by coating 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. In addition, as the shape, a flat foil is generally used, but a roughened surface, a perforated foil, and a mesh current collector can also be used.

The method for applying the mixture slurry onto the current collector is not particularly limited and a known method can be used. Specific examples thereof 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 a method, standing drying, blow dryer, warm air dryer, infrared heater, far infrared heater and the like can be used, but the method is not particularly limited thereto.

In addition, a rolling treatment using a lithographic press, a calendar roll or the like may be performed after coating. 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 this embodiment includes a positive electrode, a negative electrode, and an electrolyte.

As the positive electrode, it is possible to use one in which an electrode film is prepared by applying and drying a mixture slurry containing a positive electrode active material on a current collector.

As the negative electrode, it is possible to use one in which a mixture slurry containing a negative electrode active material is applied and dried on a current collector to form an electrode film.

As the electrolyte, various conventionally known ones capable of moving ions 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), but 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, but examples thereof include carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate; γ-butyrolactone, γ-valerolactone, and γ. -Lactones such as octanoic lactone; tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1, Examples thereof include glymes such as 2-dibutoxyethane; esters such as methyl formate, methyl acetate, and methyl propionate; sulfoxides such as dimethyl sulfoxide and sulfolane; and nitriles such as acetonitrile. These solvents may be used alone, or two or more kinds may be mixed and used.

The non-aqueous electrolyte secondary battery of this embodiment preferably includes a separator. Examples of the separator include polyethylene non-woven fabric, polypropylene non-woven fabric, polyamide non-woven fabric, and those obtained by subjecting these to hydrophilic treatment, but are 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 that is provided as necessary, a paper type, a cylindrical type, a button type, a laminated type, etc. It can have various shapes according to the purpose of use.

Hereinafter, the present invention will be described more specifically with reference to Examples. The present invention is not limited to the following examples unless it exceeds the gist. In the examples, “carbon black” may be abbreviated as “CB” and “carbon nanotube” may be abbreviated as “CNT”. Unless otherwise specified, "part" means "part by mass" and "%" means "% 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 a RI detector.
HLC-8320GPC (manufactured by Tosoh Corporation) was used as an apparatus, three separation columns were connected in series, and the packing material was “TSK-GELSUPER AW-4000” manufactured by Tosoh Corporation in order.
, "AW-3000", and "AW-2500" were used at an oven temperature of 40° C., using 30 mM triethylamine and 10 mM LiBr N,N-dimethylformamide solution as an eluent at a flow rate of 0.6 ml/min. .. A sample was prepared at a concentration of 1 wt% in a solvent composed of the above-mentioned eluent, and 20 microliters thereof was injected. The molecular weight is a polystyrene equivalent value.

(Viscosity measurement of conductive material dispersion)
The viscosity value was measured using a B-type viscometer (“BL” manufactured by Toki Sangyo Co., Ltd.), the dispersion liquid temperature was 25° C., the dispersion liquid was sufficiently stirred with a spatula, and then the B-type viscometer rotor rotation speed. Immediately at 60 rpm. The rotor used for the measurement was No. 1 when the viscosity value was less than 100 mPa·s. No. 1 is 100 or more and less than 500 mPa·s, No. No. 2 is 500 or more and less than 2000 mPa·s, No. No. 3 is 2000 or more and less than 10000 mPa·s, No. 4 were used respectively. 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, the dispersibility was determined to be poor.
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)
×: 10000 mPa·s or more, sedimentation or separation (defective)

(Dispersion stability evaluation method)
The storage stability was evaluated based on the change in liquid properties after the dispersion was stored at 50° C. for 7 days. The change in liquid properties was judged from the ease of stirring when stirring with a spatula. ◎: No problem (good), ◯: Viscosity increased but gelation did not occur (possible), ×: Gel (It is extremely defective).

(Evaluation method of conductivity of electrode film using negative electrode mixture slurry)
The mixture slurry for negative electrode was coated on a copper foil using an applicator so that the basis weight per unit of electrode would be 10 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 Mitsubishi Chemical Analytech Co., Ltd.: Lorester GP, MCP-T610. 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 negative electrode film. The thickness of the electrode mixture layer was calculated by subtracting the thickness of the copper foil from the average value obtained by measuring 3 points in the electrode film using a film thickness meter (manufactured by NIKON, DIGIMICRO MH-15M). The volume resistivity (Ω·cm) was used. Regarding the conductivity evaluation of the electrode film, the volume resistivity (Ω·cm) of the electrode film is less than 0.3 ◎ (excellent), 0.3 or more and less than 0.5 ◯ (good), 0.5 or more ×. (Poor)

<Method for evaluating adhesion of electrode film using negative electrode mixture slurry>
The mixture slurry for negative electrode was coated on a copper foil using an applicator so that the basis weight per unit of electrode would be 10 mg/cm ^2, and then in an electric oven at 120° C.±5° C. for 25 minutes, The coating film was dried. Then, two pieces were cut into a rectangle of 90 mm×20 mm with the coating direction as the major axis. For the measurement of the peel strength, a desktop tensile tester (Strograph E3, manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used and evaluated by the 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 plate, and the produced battery electrode mixture layer was adhered to the other surface of the double-sided tape, Peeling was performed while pulling upward from below at a constant speed (50 mm/min), and the average value of the stress at this time was taken as the peel strength. In the evaluation of the adhesion (N/cm) of the electrode film, 0.5 or more was evaluated as ⊚ (excellent), 0.1 or more and less than 0.5 was evaluated as ◯ (good), and less than 0.1 was evaluated as x (defective).

(Method for evaluating conductivity of electrode film using positive electrode mixture slurry)
The positive electrode mixture slurry was applied on an aluminum foil using an applicator so that the weight per unit area of the electrode would be 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 Mitsubishi Chemical Analytech Co., Ltd.: Lorester GP, MCP-T610. 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 was calculated by subtracting the film thickness of the aluminum foil from the average value obtained by measuring 3 points in the electrode film using a film thickness meter (manufactured by NIKON, DIGIMICRO MH-15M). The volume resistivity (Ω·cm) was used. In the evaluation of the conductivity of the electrode film, the volume resistivity (Ω·cm) of the electrode film was less than 10 (excellent), 10 or more and less than 20 was ◯ (good), and 20 or more was x (bad).

(Method for evaluating adhesion of electrode film using positive electrode mixture slurry)
The positive electrode mixture slurry was applied on an aluminum foil using an applicator so that the weight per unit area of the electrode would be 20 mg/cm ^2, and then in an electric oven at 120°C ± 5°C for 25 minutes, The coating film was dried. Then, two pieces were cut into a rectangle of 90 mm×20 mm with the coating direction as the major axis. For the measurement of the peel strength, a desktop tensile tester (Strograph E3, manufactured by Toyo Seiki Seisaku-sho, Ltd.) was used and evaluated by the 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 plate, and the produced battery electrode mixture layer was adhered to the other surface of the double-sided tape, Peeling was performed while pulling upward from below at a constant speed (50 mm/min), and the average value of the stress at this time was taken as the peel strength. The evaluation of the adhesiveness (N/cm) of the electrode film was 1 or more as ⊚ (excellent), 0.5 or more and less than 1 as ◯ (good), and less than 0.5 as x (defective).

(Method for evaluating rate characteristics of non-aqueous electrolyte secondary battery)
The non-aqueous electrolyte secondary battery was installed in a thermostatic chamber at 25° C., and charge/discharge measurement was performed using a charge/discharge device (manufactured by Hokuto Denko, SM-8). After performing constant-current constant-voltage charging (cut-off current 1 mA (0.02 C)) at a charging end voltage of 4.3 V at a charging current 10 mA (0.2 C), discharge at a discharge current 10 mA (0.2 C). Constant current discharge was performed at a final voltage of 3V. After repeating this operation three times, constant-current constant-voltage charging (cut-off current (1 mA 0.02 C)) was performed at a charging end voltage of 4.3 V with a charging current of 10 mA (0.2 C), and a discharging current of 0.2 C and Constant current discharge was performed at 3 C until the discharge end voltage reached 3.0 V, and the discharge capacity was obtained for each. The rate characteristic can be expressed by the ratio of 0.2C discharge capacity to 3C discharge capacity, and the following expression 1.
(Equation 1) Rate characteristics=3C discharge capacity/3rd 0.2C discharge capacity×100 (%)
The rate characteristics were rated as ⊚ (excellent) when the rate characteristics were 80% or more, as ◯ (good) when the rate characteristics were 60% or more and less than 80%, and as x (bad) when the rate characteristics were less than 60%.

(Method for evaluating cycle characteristics of non-aqueous electrolyte secondary battery)
The non-aqueous electrolyte secondary battery was installed in a thermostatic chamber at 25° C., and charge/discharge measurement was performed using a charge/discharge device (manufactured by Hokuto Denko, SM-8). After performing constant-current constant-voltage charging (cut-off current 2.5 mA (0.05 C)) with a charging end voltage of 4.3 V at a charging current 25 mA (0.5 C), discharge current 25 mA (0.5 C). A constant current discharge was performed at a discharge end voltage of 3V. This operation was repeated 200 times. The cycle characteristics can be expressed by the following equation 2 which is the ratio of the 0.5C discharge capacity at the third time and the 0.5C discharge capacity at the 200th time at 25°C.
(Formula 2) Cycle characteristics = 0.5C discharge capacity at the third time/0.5C discharge capacity at the 200th time x 100 (%)
Regarding the cycle characteristics, when the cycle characteristics were 85% or more, ⊚ (excellent), 80% or more and less than 85% were evaluated as ◯ (good), and less than 80% was determined as − (bad).

(Production Example 1) Production of Dispersant (A-1) A reactor equipped with a gas inlet tube, a thermometer, a condenser and a stirrer was charged with 100 parts of acetonitrile and replaced with nitrogen gas. The inside of the reaction vessel was heated to 70° C. to obtain 50.0 parts of acrylonitrile, 25.0 parts of acrylic acid, 25.0 parts of styrene, and 2,2′-azobis(2,4-dimethylvaleronitrile) (NOF Corporation). V-65) (5.0 parts) was added dropwise over 3 hours to carry out a polymerization reaction. After completion of dropping, the reaction was further performed at 70° C. for 1 hour, 0.5 part of V-65 was added, and the reaction was further continued at 70° C. for 1 hour. After that, it was confirmed by non-volatile content measurement that the conversion rate exceeded 98%, and the dispersion medium was completely removed by concentration under reduced pressure to obtain a dispersant (A-1). The weight average molecular weight (Mw) of the dispersant (A-1) was 15,000.

(Production Examples 2 to 10) Production of Dispersants (A-2) to (A-10) Dispersants (A-2) were produced in the same manner as in Production Example 1 except that the monomers used were changed according to Table 1. (A-10) were produced. The weight average molecular weight (Mw) of each dispersant was as shown in Table 1.

AA: acrylic acid HEA: hydroxyethyl acrylate DMAEA: dimethylaminoethyl acrylate BA: butyl acrylate 2EHMA: 2 ethylhexyl acrylate

(Production Example 11) Production of Dispersant (A-11) 50 parts of the dispersant (A-3) obtained in Production Example 3 was added to 198 parts of purified water and stirred with a disper to form a slurry. Next, 2.0 parts of 1N sodium hydroxide aqueous solution was added dropwise at 25° C., and the mixture was stirred with a disper for 2 hours. It was confirmed by IR measurement (apparatus: FT/IR-410, manufactured by JASCO Corporation) that the peak intensity derived from the cyano group was reduced to 80% or less, and formation of a cyclic structure was confirmed. Then, it was washed with purified water, filtered and dried to obtain a dispersant (A-11) having a hydrogenated naphthyridine ring and a glutarimide ring. The weight average molecular weight (Mw) was 14,000.

(Production Example 12) Production of Dispersant (A-12) A dispersant having a hydrogenated naphthyridine ring was produced in the same manner as in Production Example 13 except that the dispersant used was changed from (A-3) to (A-6). A-12) was obtained. The weight average molecular weight (Mw) was 14,000.

(Production Example 13) Preparation of standard positive electrode mixture slurry 93 parts by mass of positive electrode active material (BASF Toda Battery Materials LLC, HED (registered trademark) NCM-111 1100), acetylene black (Denka Corporation, Denka Black) (Registered trademark) HS100) 4 parts by mass, PVDF (Kureha Battery Materials Japan Co., Ltd., Kureha KF Polymer W#1300) 3 parts by mass were added to a plastic container having a capacity of 150 cm ³ , and then a spatula was added. Used to mix until powder is uniform. 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 (Awatoritaro, ARE-310 manufactured by Shinky Co., Ltd.). Then, the mixture in the plastic container was mixed with a spatula until the mixture became uniform, and the mixture was stirred at 2000 rpm for 30 seconds using the above-described 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 above-described rotation/revolution mixer. Finally, using a high-speed stirrer, the mixture was stirred at 3000 rpm for 10 minutes to obtain a standard positive electrode mixture slurry.

(Production Example 14) Preparation of standard positive electrode The above-mentioned standard positive electrode mixture slurry was applied onto an aluminum foil having a thickness of 20 μm serving as a current collector using an applicator, and then at 120° C.±5° C. in an electric oven. It was dried for 25 minutes and adjusted so that the basis weight per unit area of the electrode was 20 mg/cm ² . Further, rolling treatment was carried out by a roll press (3t hydraulic roll press manufactured by Sank Metal Co., Ltd.) to produce a positive electrode having a composite material layer density of 3.1 g/cm ³ .

<Preparation of conductive material dispersion>
(Examples 1 to 23, Comparative examples 1 to 5)
According to the composition and dispersion time shown in Table 2, a dispersant, an additive, and a dispersion medium were charged in a glass bottle (M-225, manufactured by Kashiwa Glass Co., Ltd.), and the mixture was sufficiently mixed and dissolved or mixed, and then the conductive material. Was added and dispersed with a paint conditioner using zirconia beads (bead diameter 0.5 mmφ) as a medium to obtain respective conductive material dispersions (dispersion 1 to dispersion 23, comparative dispersions 1 to 5). As shown in Table 2, all of the conductive material dispersions of the present invention (Dispersion 1 to Dispersion 23) had low viscosity and good storage stability.
However, in this specification, the conductive material dispersions of Examples 1, 2 , 9 , 10, 12, and 19 and the mixture slurry, electrode film, and battery using the dispersions are reference examples.

· HS-100: Denka Black HS-100 (Denka Co., acetylene black, average primary particle diameter 48 nm, specific surface area 39m ² / g)
EC-300J: Ketjenblack EC-300J (Ketjenblack manufactured by Lion Specialty Chemicals, average primary particle diameter 40 nm, specific surface area 800 m ² /g)
8S: JENOTUBE8S (manufactured by JEIO, multi-layer CNT, outer diameter 6 to 9 nm)
100T: K-Nanos 100T (manufactured by Kumho Petrochemical, multi-layer CNT, outer diameter 10 to 15 nm)
-NTP3121: NTP3121 (manufactured by NTP, multi-layer CNT, outer diameter 20 to 35 nm)
-PVP: Polyvinylpyrrolidone K-30 (manufactured by Nippon Shokubai, solid content 100%)
PVA: Kuraray POVAL PVA403 (Kuraray Co., Ltd., solid content 100%)
-PVB: S-REC BL-10 (manufactured by Sekisui Chemical Co., Ltd., solid content 100%)
・DMAE: Tokyo Chemical Industry Co., Ltd., 2-(dimethylamino)ethanol ・NMP: N-methylpyrrolidone

<Preparation of negative electrode mixture slurry>
(Example 24)
After adding the conductive material dispersion (dispersion 1), CMC, and water to a plastic container having a capacity of 150 cm ³ , 2000 rpm using a rotation/revolution mixer (Awatori Kentaro, ARE-310 manufactured by Shinky Co.). And stirred for 30 seconds to obtain a conductive-containing resin composition 1. Then, the active material was added, and the mixture was stirred at 2000 rpm for 150 seconds using the above-described rotation/revolution mixer. After that, SBR was added, and the mixture was stirred at 2000 rpm for 30 seconds using the above-described rotation/revolution mixer to obtain a negative electrode mixture slurry 1. The solid content of the negative electrode mixture slurry 1 was set to 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 25 to 43, Comparative Examples 6 to 9)
Conductive material-containing resin compositions 2-18, 21, 22 and comparative conductive material-containing resin compositions 1, 3-5, and negative electrode were prepared in the same manner as in Example 24 except that the type of conductive material dispersion was changed. The composite material slurries 2-18, 21, 22 and the negative electrode comparative composite material slurries 1, 3-5 were obtained. As shown in Table 3, all the electrode films using the conductive material dispersion of the present invention had good conductivity and adhesion.

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

<Preparation of positive electrode mixture slurry>
(Example 44)
A conductive material dispersion (dispersion 19) and NMP in which 8% by mass PVDF was dissolved were added to a plastic container having a capacity of 150 cm, and then a rotation/revolution mixer (Awatori Kentaro, ARE-310 manufactured by Shinky Co., Ltd.) was used. Then, the mixture was stirred at 2000 rpm for 30 seconds to obtain a conductive material-containing resin composition 19. Then, the active material was added, and the mixture was stirred at 2000 rpm for 150 seconds using the above-described rotation/revolution mixer. After that, NMP was added, and the mixture was stirred at 2000 rpm for 30 seconds using the above-described rotation/revolution mixer to obtain a positive electrode material mixture slurry 19. The solid content of the positive electrode mixture slurry 19 was 75% by mass. The solid content ratio of active material:conductive material:PVDF in the positive electrode mixture slurry was 98.5:0.5:1.

(Examples 45 to 46, Comparative Example 10)
The conductive material-containing resin compositions 20, 23 and the comparative conductive material-containing resin composition 2, the positive electrode mixture slurry 20, 23, and the positive electrode were prepared in the same manner as in Example 44 except that the kind of the conductive material dispersion was changed. A comparative mixture slurry 2 was 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), solid content 100%
PVDF: Solef #5130 (manufactured by Solvey), solid content 100%

<Production of electrode film>
(Examples 47 to 69, Comparative Examples 11 to 15)
The mixture slurry shown in Table 5 was applied on 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 Sank Metal Co., Ltd.). When the positive electrode mixture slurry is applied, aluminum foil is used as the metal foil so that the weight per unit area of the electrode is 20 mg/cm ^2, and the density of the electrode film after drying is 3 It rolled so that it might become 0.1 g/cc. When the negative electrode mixture slurry is applied, copper foil is used as the metal foil so that the weight per unit area of the electrode is 10 mg/cm ^2, and the density of the electrode film after drying is 1 It rolled so that it might be set to 0.6 g/cc.

<Preparation of non-aqueous electrolyte secondary battery>
The negative electrode and the positive electrode listed in Table 6 were punched out into 50 mm×45 mm and 45 mm×40 mm, respectively, and the separator (porous polypropylene film) inserted between them was inserted into an aluminum laminate bag, and the mixture was placed in an electric oven at 70° C. And 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 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 was dissolved at a concentration of 1 M) was injected, and an aluminum laminate was sealed to seal the non-aqueous electrolyte. Secondary batteries 1 to 23 and comparative non-aqueous electrolyte secondary batteries 1 to 4 were produced.

In the above examples, the dispersant comprises a unit derived from (meth)acrylonitrile, and one or more monomer units selected from the group consisting of an active hydrogen group-containing monomer, a basic monomer, and a (meth)acrylic acid alkyl ester. A conductive material dispersion containing 40 to 99 mass% of the unit derived from the (meth)acrylonitrile in the copolymer and having a weight average molecular weight of 5,000 to 50,000 was used. In the example, a non-aqueous electrolyte secondary battery having excellent cycle characteristics as compared with the comparative example was obtained. In particular, in the conductive material dispersion containing 75% by mass of the unit derived from the (meth)acrylonitrile and having a weight average molecular weight of 5,000 to 50,000, the unit derived from the acrylonitrile has a cyclic structure, and therefore, as compared with Comparative Examples. A non-aqueous electrolyte secondary battery having excellent cycle characteristics 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 the conventional conductive material dispersion.

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

Claims (8)

A conductive material dispersion containing a conductive material (A), a dispersion medium (B), and a dispersant (C), wherein the conductive material (A) is carbon nanotubes and/or Ketjen black, and the dispersant ( C) is a copolymer containing units derived from (meth)acrylonitrile, and one or more monomer units selected from the group consisting of active hydrogen group-containing monomers, basic monomers, and (meth)acrylic acid alkyl esters. A non-aqueous electrolyte secondary battery characterized in that the copolymer contains units derived from the (meth)acrylonitrile in an amount of more than 80% by mass and 99% by mass or less, and having a weight average molecular weight of 5,000 to 50,000. Conductive material dispersion. The unit derived from acrylonitrile of the dispersant (C) has a cyclic structure, and the conductive material dispersion for a non-aqueous electrolyte secondary battery according to claim 1. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein the conductive material (A) has a BET specific surface area of 150 to 1000 m ² /g. The conductive material dispersion for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, further comprising at least one selected from the group consisting of an inorganic metal salt, an inorganic base and an organic base. A conductive material-containing resin composition comprising the conductive material dispersion according to claim 1 and a binder resin (D). A mixture slurry, comprising the conductive material-containing resin composition according to claim 5 and an active material (E). An electrode film (F) formed by forming the mixture slurry according to claim 6 into a film shape. A non-aqueous electrolyte secondary battery comprising a positive electrode, a negative electrode, and an electrolyte capable of moving ions, wherein at least one of the positive electrode and the negative electrode comprises the electrode film (F) according to claim 7. Characteristic non-aqueous electrolyte secondary battery.