JP2014107073A - Conductive primer composition for forming nonaqueous secondary battery electrode, nonaqueous secondary battery electrode using the same, and nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive primer composition for forming a nonaqueous secondary battery that is excellent in charge/discharge cycle characteristics, which is excellent in reduced resistance at a contact interface with a mixture layer.SOLUTION: A conductive primer composition for forming a nonaqueous secondary battery electrode contains: graphite particles (A) comprising lamellate natural graphite having an average particle size of 1-50 μm; carbon black (B) having an average particle size of 0.01-0.3 μm; an amphoteric resin type dispersion agent (C) obtained by neutralizing at least a part of a carboxyl group in a copolymer formed by the copolymerization of the following monomer, with a basic compound; a binder (D); and an aqueous liquid medium (E).

Description

  The present invention relates to a conductive primer composition for forming a non-aqueous secondary battery electrode, an electrode obtained using the composition, and a secondary battery obtained using the electrode.

  In recent years, small portable electronic devices such as digital cameras and mobile phones have been widely used. These electronic devices have always been required to minimize the volume and reduce the weight, and the batteries to be mounted are also required to be small, light, and have a large capacity. In addition, in large-sized secondary batteries for use in automobiles or the like, it is desired to realize a large-sized battery that is lightweight and has high output performance instead of the conventional lead-acid battery.

  In order to meet such demands, development of secondary batteries such as lithium ion secondary batteries, for example, development of composite inks used for forming electrodes has been actively conducted. Attempts have been made to introduce a conductive primer composition used for forming an underlayer for further improving the performance of the electrode. The purpose of introducing the conductive primer composition is to form a battery by reducing the contact interface resistance of the composite layer by laminating a base layer between the composite layer and the foil-like current collector. It is possible to reduce internal resistance.

Patent Document 1 discloses an electrode in which a base layer is used between an electrode active material layer and a current collector to improve adhesion. However, since the base layer does not contain a conductive material, there is a problem that the conductivity of the obtained electrode is remarkably lowered.
Patent Document 2 discloses an electrode underlayer containing a water-soluble polymer. However, like the patent document 1, the said base layer has the problem that the electroconductivity of the electrode obtained since it does not contain a conductive material falls remarkably.
Patent Document 3 discloses an electrode base layer containing a conductive material and a compound containing a sulfur atom. However, only the carbon black is described as the conductive material of the example, and the effect of reducing the contact interface resistance with the composite layer is low only with the carbon black.
Patent Document 4 discloses an electrode underlayer containing a fluorine-based polymer and carbon black. However, as in Patent Document 3, only carbon black is used as the conductive material, and the effect of reducing the contact interface resistance with the composite layer is low only with carbon black.
Patent Document 5 discloses an electrode underlayer containing graphite or carbon black as a carbonaceous component. However, the literature does not specify the type of graphite, and the graphite KS-6 (manufactured by TIMCAL Co., Ltd.) used in the examples is artificial graphite, so the surface of the resulting underlayer is not sufficiently smooth. .
Patent Document 6 discloses an electrode underlayer containing a conductive filler having an average particle diameter of 0.5 μm or less. However, only the conductive filler having an average particle diameter of 0.5 μm or less does not provide sufficient smoothness of the surface of the resulting underlayer.
Patent Document 7 discloses a conductive underlayer containing foliar graphite and carbon black in an electric double layer capacitor electrode. However, just mixing these conductive fillers results in insufficient conductivity because the contact between the fillers is insufficient in the obtained underlayer, and the surface smoothness of the underlayer is also poor. It is necessary to improve the adhesion to the layer.
As described above, in the conventional underlayer, the effect of reducing the contact interface resistance, which has a great influence on the battery performance, is insufficient. For this purpose, further improvement in conductivity is desired. Moreover, although improvement of the adhesion between the composite material layer and the current collector has been studied, it is still insufficient and improvement is desired.

JP-A-10-149810 JP 11-339771 A JP 2000-123823 A Japanese Patent No. 3229740 JP 2001-52710 A Japanese Patent No. 3478077 JP 2005-136401 A

  An object of the present invention is a non-aqueous secondary battery electrode-forming conductive primer composition for forming a non-aqueous secondary battery having excellent charge / discharge cycle characteristics, and an interface contact between a composite material layer and a current collector It is an object to provide a conductive primer composition that can reduce resistance and that can form an underlayer with good adhesion and high conductivity.

  The present invention has been studied to obtain a non-aqueous secondary battery having a high potential, a high energy density and excellent cycle characteristics. As a result, an amphoteric dispersant is used between the current collector and the composite material layer (active material layer). It has been found that by using a conductive primer composition using uniformly dispersed leaf-like natural graphite particles and carbon black, an undercoat layer having good adhesion and conductivity can be obtained.

That is, the present invention is obtained by copolymerizing graphite particles (A) made of leaf-like natural graphite having an average particle size of 1 to 50 μm, carbon black (B) having an average particle size of 0.01 to 0.3 μm, and the following monomers. Non-aqueous secondary containing an amphoteric resin type dispersant (C) obtained by neutralizing at least a part of carboxyl groups in a copolymer with a basic compound, a binder (D), and an aqueous liquid medium (E) The present invention relates to a conductive primer composition for battery electrode formation.
Ethylenically unsaturated monomer having an aromatic ring (c1): 5 to 70% by weight
Ethylenically unsaturated monomer having a carboxyl group (c2): 15 to 60% by weight
Ethylenically unsaturated monomer having an amino group (c3): 1 to 80% by weight
Ethylenically unsaturated monomers (c4) other than (c1) to (c3): 0 to 79% by weight
(However, the total of (c1) to (c4) is 100% by weight)

In the present invention, the total amount of the foliar graphite particles (A) and the carbon black (B) is 100% by weight. The conductive primer composition for forming a non-aqueous secondary battery electrode is 40% by weight.

  Furthermore, this invention relates to the secondary battery electrode base layer formed from the said conductive primer composition for non-aqueous secondary battery electrode formation.

Furthermore, the present invention relates to a non-aqueous secondary battery electrode, wherein the non-aqueous secondary battery electrode base layer and the composite material layer are laminated on a current collector.

  Furthermore, the present invention relates to the nonaqueous secondary battery electrode, wherein the composite layer is formed from a composite ink containing an amphoteric resin type dispersant (C).

  Furthermore, the present invention relates to a non-aqueous secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode or the negative electrode is the non-aqueous secondary battery electrode.

  By using the leaf-like natural graphite particles, carbon black, and the amphoteric resin type dispersant, the conductive primer composition for forming a non-aqueous secondary battery electrode of the present invention could be obtained. The conductive primer composition for electrode formation of the present invention is uniformly dispersed by the amphoteric dispersant to improve the adhesion between the current collector and the composite material layer, and the interface contact between the current collector and the composite material layer Not only can a base layer that can reduce resistance be formed, but also the conductive network of the base layer can be improved and the conductivity can be improved, so that a non-aqueous secondary battery having excellent charge / discharge cycle characteristics can be provided.

  First, the graphite particles (A) made of leaf-like natural graphite forming the conductive primer composition for forming a non-aqueous secondary battery electrode will be described. Graphite particles generally have a particle size as large as 1 μm or more compared to carbon black (B). Examples of the graphite particles include natural graphite particles and artificial graphite particles, and it is known that natural graphite has a smoother and softer surface. Therefore, natural graphite is preferable from the viewpoint of reducing interfacial contact. Examples of natural graphite particles include leaf-like, spherical, earth-like, etc. Among natural graphite, leaf-like graphite having a high aspect ratio is preferable from the viewpoint of surface smoothness.

The foliar graphite particles (A) preferably have an average particle size of 1 to 50 μm, more preferably an average particle size of 3 to 40 μm. In addition, the average particle diameter here is a diameter of 10 to 50 particles (maximum diameter and minimum diameter in the surface direction) from an image appropriately enlarged 500 to 1000 times using a reflection electron microscope (SEM). (Average value) is obtained by averaging. The thickness of the foliar graphite particles (A) is not limited, but is preferably 0.01 to 2 μm from the viewpoint of surface smoothness and conductivity of the underlayer.

The foliar graphite particles (A) can be obtained, for example, by pulverizing massive natural graphite or by performing delamination along the cleavage plane of the intercalation compound of natural graphite. In the case of pulverization, for example, foliar graphite can be obtained by a dry pulverization method using a ball mill or the like.

  The foliar graphite particles (A) can also be obtained by a method utilizing the cleavage plane of the intercalation compound. Specifically, for example, an intercalation compound of graphite and sulfuric acid obtained by treating natural graphite with a mixed acid of sulfuric acid and nitric acid, or graphite and sulfuric acid obtained by electrically oxidizing natural graphite in sulfuric acid. The expanded graphite obtained by heating and expanding the intercalation compound or the like can be obtained by a method of peeling the cleavage plane of the crystal structure. In the expanded graphite, since the interlayer of the cleavage plane is spread, delamination is easily performed along the cleavage plane, and a smooth particle surface, that is, foliar graphite particles can be obtained.

  Although the foliar graphite particles (A) are not particularly limited, for example, commercially available products such as CX-3000, FBF, BF, CBR, SSC-3000, SSC-600, SSC-3, SSC, CX manufactured by Chuetsu Graphite Co., Ltd. -600, CPF-8, CPF-3, CPB-6S, CPB-3, 96E, 96L, 96L-3, 90L-3, CPC, S-87, K-3, CF-80, CF-48, CF -32, CP-150, CP-100, CP, HF-80, HF-48, HF-32, SC-120, SC-80, SC-60, SC-32, manufactured by Fuji Graphite Industry Co., Ltd. UF-2, CBF-1, CBF-3, CPF-3, 96L, COP, FAC-1, FAC-2, FGB, CSP-2, CF-2, SNO-20, SNO manufactured by SEC Carbon Co., Ltd. -10, SNO-5, S E-20, SNE-10, SNE-5, Nippon Graphite Industries Co., Ltd. CSSP, CSPE, CSP, CP, CB-150, CB-100, ACP, ACB-150, SP-10, SP-20, J-SP, SP-270, HOP, CMX, UP-5, UP-10, UP-20, Z-5F, CNP-7, CNP-15, CNP-35, Z-100 from Ito Graphite Industries Co., Ltd. , Z + 80, Z-25, Z-50, X-10, X-20.

  Next, carbon black (B) will be described. Carbon black (B) serves as a conductive network that connects the graphite particles (A). Carbon black (B) is a furnace black produced by continuously pyrolyzing a gas or liquid raw material in a reaction furnace, in particular ketjen black using ethylene heavy oil as a raw material, burning a raw material gas, Channel black deposited on the bottom of the channel steel and rapidly deposited, thermal black obtained by periodically repeating combustion and thermal decomposition using gas, especially acetylene black using acetylene gas as a raw material alone Alternatively, two or more types can be used in combination. Ordinarily oxidized carbon black, hollow carbon and the like can also be used.

  The average primary particle size of carbon black (B) is preferably 0.01 to 0.3 μm. More preferably, the average primary particle diameter is 0.03 to 0.2 μm, and the average primary particle diameter is 10 to 50 from an image appropriately magnified 10,000 to 100,000 times using a transmission electron microscope (TEM). It is obtained by averaging the diameter of the particles.

As the specific surface area of carbon black increases, the number of contact points between the carbon black particles increases, which is advantageous in reducing the internal resistance of the electrode. Specifically, the specific surface area (BET) determined from the adsorption amount of nitrogen is 20 m ² / g or more and 1500 m ² / g or less, preferably 50 m ² / g or more and 1500 m ² / g or less, more preferably 100 m ^2. / G or more and 1500 m ² / g or less are desirable. When carbon black having a specific surface area of less than 20 m ² / g is used, it may be difficult to obtain sufficient conductivity, and carbon black of more than 1500 m ² / g may be difficult to obtain from commercially available materials. is there.

  Examples of commercially available carbon blacks include Toka Black # 4300, # 4400, # 4500, # 5500 (Tokai Carbon Co., Ltd., Furnace Black), Printex L, etc. (Degussa Co., Ltd., Furnace Black), Raven 7000, 5750, 5250, 5000 ULTRA III, 5000 ULTRA, etc., Conductex SC ULTRA, Conductex 975 ULTRA, etc., PUER BLACK100, 115, 205, etc. (Columbian Co., Ltd., Furnace Black), # 2350, # 2400B, # 2600B, # 2600B, # 50 3030B, # 3230B, # 3350B, # 3400B, # 5400B, etc. (Mitsubishi Chemical Corporation, Furnace Black), MONARCH1400, 1300, 900, Vu lcanXC-72R, BlackPearls2000, etc. (Cabot Corporation, Furnace Black), Ensaco250G, Ensaco260G, Ensaco350G, SuperP-Li (manufactured by TIMCAL Corporation), Ketjen Black EC-300J, EC-600JD (Akzo Corporation) ), Denka Black, Denka Black HS-100, FX-35 (manufactured by Denki Kagaku Kogyo Co., Ltd., acetylene black) and the like, but are not limited to these, and two or more types may be used in combination. good.

Next, the amphoteric resin type dispersant (C) in the present invention will be described.
The amphoteric resin type dispersant (C) in the present invention includes an ethylenically unsaturated monomer (c1) having an aromatic ring, an ethylenically unsaturated monomer (c2) having a carboxyl group, and an ethylene having an amino group. Is obtained by neutralizing at least a part of the carboxyl group in the copolymer containing the basic unsaturated monomer (c3) as an essential component with a basic compound.

  The ethylenically unsaturated monomer constituting the amphoteric resin type dispersant (C) in the present invention means a monomer having one ethylenically unsaturated group in one molecule unless otherwise specified.

First, the ethylenically unsaturated monomer (c1) having an aromatic ring will be described.
Examples of the ethylenically unsaturated monomer (c1) having an aromatic ring used in the present invention include styrene, α-methylstyrene, and benzyl (meth) acrylate.

Next, the ethylenically unsaturated compound (c2) having a carboxyl group will be described.
The monomer (c2) used in the present invention is, as a carboxyl group-containing unsaturated compound, maleic acid, fumaric acid, itaconic acid, citraconic acid, or an alkyl or alkenyl monoester thereof, phthalic acid β- (meth) Acryloxyethyl monoester, isophthalic acid β- (meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid And crotonic acid, cinnamic acid, and the like. In particular, methacrylic acid and acrylic acid are preferable.

Next, the ethylenically unsaturated monomer (c3) having an amino group will be described.
The ethylenically unsaturated monomer (c3) having an amino group used in the present invention includes dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methylethylaminoethyl (meth) acrylate, dimethylaminostyrene, diethylamino Examples include styrene.

Next, the monomer (c4) other than the above (c1) to (c3) will be described.
Examples of (meth) acrylate compounds include alkyl (meth) acrylates and alkylene glycol (meth) acrylates.

  More specifically, examples of the alkyl-based (meth) acrylate include alkyl (meth) acrylate having 1 to 22 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. ) When there is an acrylate and the purpose is to adjust the polarity, an alkyl group-containing acrylate having an alkyl group having 2 to 10 carbon atoms, more preferably 2 to 8 carbon atoms, or a corresponding methacrylate is preferable.

Examples of the alkylene glycol (meth) acrylate include diethylene glycol mono (meth) acrylate and polyethylene glycol mono (meth) acrylate, which are monoacrylates having a hydroxyl group at the terminal and having a polyoxyalkylene chain, or corresponding monometas. Acrylate, etc.
Methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, etc., monoacrylate having an alkoxy group at the terminal and having a polyoxyalkylene chain or the corresponding monomethacrylate,
There are polyoxyalkylene-based acrylates having a phenoxy or aryloxy group at the terminal, such as phenoxyethylene glycol (meth) acrylate, or corresponding methacrylates.

  Examples of hydroxyl-containing unsaturated compounds other than the above include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, 4-hydroxyvinylbenzene And so on.

Nitrogen-containing unsaturated compounds other than the above include monoalkylol (meth) acrylamides such as (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl- (meth) acrylamide,
Examples thereof include acrylamide-type unsaturated compounds such as N, N-di (methylol) acrylamide, N-methylol-N-methoxymethyl (meth) acrylamide, and dialalkylol (meth) acrylamide such as N, N-di (methoxymethyl) acrylamide. .

Furthermore, as other unsaturated compounds, perfluoromethylmethyl (meth) acrylate, perfluoroethylmethyl (meth) acrylate, 2-perfluorobutylethyl (meth) acrylate, 2-perfluorohexylethyl (meth) acrylate, etc. Perfluoroalkyl alkyl (meth) acrylates having a C 1-20 perfluoroalkyl group;
Perfluoroalkyl such as perfluorobutylethylene, perfluorohexylethylene, perfluorooctylethylene, perfluorodecylethylene, and perfluoroalkyl group-containing vinyl monomers such as alkylene, vinyltrichlorosilane, vinyltris (βmethoxyethoxy) silane, vinyl Examples thereof include silanol group-containing vinyl compounds such as triethoxysilane and γ- (meth) acryloxypropyltrimethoxysilane and derivatives thereof, and a plurality of them can be used from these groups.

  Examples of the fatty acid vinyl compound include vinyl acetate, vinyl butyrate, vinyl propionate, vinyl hexanoate, vinyl caprylate, vinyl laurate, vinyl palmitate, and vinyl stearate.

  Examples of the alkyl vinyl ether compound include butyl vinyl ether and ethyl vinyl ether.

  Examples of the α-olefin compound include 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and the like.

Examples of vinyl compounds include allyl compounds such as allyl acetate, allyl alcohol, allylbenzene, and allyl cyanide, vinyl cyanide, vinylcyclohexane, vinyl methyl ketone, styrene, α-methylstyrene, 2-methylstyrene, and chlorostyrene. Can be mentioned.

  Examples of the ethynyl compound include acetylene, ethynylbenzene, ethynyltoluene, 1-ethynyl-1-cyclohexanol and the like. These can be used alone or in combination of two or more.

The ratio of the monomers constituting the copolymer in the amphoteric resin type dispersant (C) used in the present invention is such that the total of the monomers (c1) to (c4) is 100% by weight,
5 to 70% by weight of the ethylenically unsaturated monomer (c1) having an aromatic ring,
15 to 60% by weight of an ethylenically unsaturated monomer (c2) having a carboxyl group,
1 to 80% by weight of an ethylenically unsaturated monomer having an amino group (c3),
The other monomer (d4) other than (c1) to (c3) is 0 to 79% by weight.
Preferably, (c1): 20 to 70% by weight, (c2): 15 to 45% by weight, (c3): 1 to 70% by weight, and (c4): 0 to 50% by weight.
More preferably, they are (d1): 30-70 weight%, (d2): 15-35 weight%, (d3): 1-40 weight%, (d4): 0-40 weight%.

  An aromatic ring derived from an ethylenically unsaturated monomer (c1) having an aromatic ring and an amino group derived from an ethylenically unsaturated monomer (c3) having an amino group are an active material (A) or a carbon material described later. Presumed to be the main adsorption site to (B).

The ethylenically unsaturated monomer (c2) having a carboxyl group has a function of dissolving or dispersing a neutralized copolymer in an aqueous liquid medium.
Then, the foliar graphite particles (A), the carbon material (B), and the active material (F) are adsorbed with the copolymer via the aromatic ring or amino group, neutralized, and by charge repulsion of the ionized carboxyl group, It is considered that the dispersed state of the foliar graphite particles (A), the carbon material (B), and the active material (F) in the aqueous liquid medium can be stably maintained.

The molecular weight of the copolymer obtained by copolymerizing the monomers (c1) to (c4) is not particularly limited, but the viscosity of the amphoteric resin dispersant (C) in a 20% solid content aqueous solution is preferably 5 to 100. 000 mPa · s, more preferably 10 to 50,000 mPa · s. When the molecular weight of the amphoteric resin type dispersant (C) is lower than the predetermined range and the molecular weight of the amphoteric resin type dispersant (C) is higher than the predetermined range, the foliar graphite particles There is a possibility of causing poor dispersion of (A), the carbon material (B), and the active material (F).
In addition, the viscosity in this invention is the value measured on 25 degreeC conditions using the B-type viscosity meter.

The copolymer is obtained by copolymerizing the carboxyl group-containing unsaturated compound (c2), and it is preferable that the constituent ratio of the monomer having an anionic functional group in the copolymer is represented by the acid value as follows. That is, the acid value of the copolymer used is preferably in the range of 50 mgKOH / g to 400 mgKOH / g, and the acid value is preferably in the range of 80 mgKOH / g to 300 mgKOH / g.
When the acid value of the copolymer used in the present invention is lower than the above range, the dispersion stability of the dispersion tends to decrease and the viscosity tends to increase. Moreover, when the acid value of the copolymer used in the present invention is higher than the above range, the adhesion of the copolymer to the pigment surface tends to decrease, and the storage stability of the dispersion tends to decrease.
In addition, the acid value of the copolymer in the present invention is a value obtained by converting the measured acid value (mgKOH / g) into a solid content according to the potentiometric titration method of JIS K0070.

The amphoteric resin dispersant (C) can be obtained by various production methods.
For example, the monomers (c1) to (c4) are polymerized in an organic solvent that can be azeotroped with water. Thereafter, an aqueous liquid medium typified by water and a neutralizing agent are added to neutralize at least a part of the carboxyl groups, the azeotropic solvent is distilled off, and an aqueous solution of the amphoteric resin dispersant (C) or An aqueous dispersion can be obtained.
The organic solvent at the time of polymerization is not particularly limited as long as it is azeotropic with water, but is preferably highly soluble in the copolymer, preferably ethanol, 1-propanol, 2-propanol, 1-butanol, 1-butanol is preferred.

Alternatively, it is copolymerized in a hydrophilic organic solvent, neutralized by adding water and an amine to make it aqueous, and as described above, the hydrophilic organic solvent is not distilled off, and an aqueous liquid medium containing the hydrophilic organic solvent and water In addition, a solution in which the amphoteric resin dispersant (C) is dissolved or dispersed can be obtained.
In this case, the hydrophilic organic solvent used is preferably one having high solubility in the copolymer, preferably glycol ethers, diols, more preferably (poly) alkylene glycol monoalkyl ethers having 3 to 6 carbon atoms. Alkanediols are good.

The following are mentioned as a basic compound which is a neutralizing agent used for neutralization of a copolymer.
For example, inorganic alkaline agents such as ammonia water, various organic amines such as dimethylaminoethanol, diethanolamine, and triethanolamine, and alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide can be used. . The copolymer as described above is dispersed or dissolved in an aqueous liquid medium.

    Next, the binder (D) will be described. When the binder (D) binds the graphite particles (A) and carbon black (B) and further forms an underlayer, the binder layer and the foil-like current collector, and the composite material layer and the underlayer are in close contact with each other. Therefore, the effect of dispersing the particles in the solvent is small.

As the binder (D), for example, acrylic resin, polyurethane resin, polyester resin, phenol resin, epoxy resin, phenoxy resin, urea resin, melamine resin, alkyd resin, formaldehyde resin, silicon resin, fluororesin, carboxymethylcellulose and other cellulose Examples include resins, synthetic rubbers such as styrene-butadiene rubber and fluororubber, conductive resins such as polyaniline and polyacetylene, and polymer compounds containing fluorine atoms such as polyvinylidene fluoride, polyvinyl fluoride, and tetrafluoroethylene. Further, a modified product, a mixture, or a copolymer of these resins may be used. These binders can be used alone or in combination.
The binder is preferably an aqueous medium from the viewpoint of the environment, and examples of the aqueous medium binder include a water-soluble type, an emulsion type, and a hydrosol type, and can be appropriately selected.

The ratio of using the foliar graphite particles (A) and the carbon black (B) is such that the ratio of the graphite particles (A) is 60 to 99 wt% in the total 100 wt% of the foliar graphite particles (A) and the carbon black (B). % Is preferable, and 65 to 95% by weight is more preferable. Moreover, 1 to 40 weight% is preferable and, as for the ratio of carbon black (B), 5-35 weight% is more preferable.
When the proportion of carbon black (B) is lower than the above range, the conductivity is lowered, and there is a concern that contact resistance with the composite layer increases when the underlayer is formed. On the other hand, carbon black (B) If the ratio is higher than the above range, the adhesion with the composite layer may be lowered when the underlayer is formed. Moreover, in order to improve the smoothness of the interface when the underlayer is formed, it is preferable to increase the ratio of the graphite particles (A) as compared with the carbon black (B).
When the ratio of the graphite particles (A) and the carbon black (B) is in the above-mentioned range, it is possible to form an underlayer that is particularly excellent in reducing contact resistance with the composite layer and in adhesion.
The proportion of the amphoteric resin type dispersant (C) used is preferably 1% by weight to 100% by weight and preferably 2% by weight to 50% by weight with respect to 100% by weight of the total of the foliar graphite particles (A) and carbo black (B) % Is more preferable. When the ratio of the amphoteric resin type dispersant (C) is lower than the above range, there is a concern that the stability of the dispersion is lowered and the viscosity is increased. On the other hand, when the ratio of the amphoteric resin type dispersant (C) is higher than the above range, the filling rate of the foliar graphite particles (A) and the carbo black (B) is lowered, and the conductivity may be inferior.
The ratio of using the binder (D) is preferably 1% by weight to 200% by weight and more preferably 2% by weight to 100% by weight with respect to the total 100% by weight of the foliar graphite particles (A) and the carbon black (B). . When the ratio of the binder (D) is lower than the above range, there is a concern that the adhesion with the foil-like current collector or the composite material layer is lowered. On the other hand, when the ratio of the binder (D) is higher than the above range, the filling rate of the foliar graphite particles (A) and the carbo black (B) is lowered, and the conductivity may be inferior.

Next, the aqueous liquid medium (E) will be described.
As the aqueous liquid medium (E) used in the present invention, it is preferable to use water, but if necessary, for example, a liquid medium compatible with water in order to improve the coating property to the current collector. May be used.
Liquid media compatible with water include alcohols, glycols, cellosolves, amino alcohols, amines, ketones, carboxylic acid amides, phosphoric acid amides, sulfoxides, carboxylic acid esters, and phosphoric acid esters , Ethers, nitriles and the like, and may be used as long as they are compatible with water.

  Furthermore, the conductive primer composition can contain a film forming aid, an antifoaming agent, a leveling agent, a dispersing agent, a preservative, a pH adjusting agent, a viscosity adjusting agent and the like as required.

  The proper viscosity of the conductive primer composition obtained in the present invention depends on the method for applying the conductive primer composition, but generally it is preferably 10 mPa · s or more and 30,000 mPa · s or less. The conductive primer composition obtained in the present invention can be applied to a current collector and dried to obtain a secondary battery electrode underlayer.

(Method for producing primer composition)
Since graphite particles (A) and carbon black (B) have a large average particle diameter, it is preferable to use them in advance by dispersing the dispersion particle diameter in the range of 0.1 to 50 μm using water and a dispersion resin. As the dispersion resin, an amphoteric resin type dispersant (C) is preferable. The dispersed particle size referred to here is the particle size (D50) that becomes 50% when the volume fraction of the particles is integrated from the finer particle size distribution in the volume particle size distribution of the obtained dispersion. ) And measured with a general particle size distribution meter, for example, a dynamic light scattering type particle size distribution meter (“Microtrac UPA” manufactured by Nikkiso Co., Ltd.).
The graphite particles (A) and the carbon black (B) may be dispersed simultaneously, or a separately dispersed graphite particle dispersion and a carbon black dispersion may be mixed. Moreover, you may disperse | distribute by adding the other to the dispersion which disperse | distributed one.

As an apparatus used for obtaining the conductive primer composition, a disperser or a mixer that is usually used for pigment dispersion or the like can be used.
For example, mixers such as dispersers, homomixers, or planetary mixers; homogenizers such as “CLEARMIX” manufactured by M Technique Co., Ltd. or “FILMIX” manufactured by PRIMIX; paint conditioner (manufactured by Red Devil Corporation) , Ball mill, sand mill (“Dynomill” manufactured by Shinmaru Enterprises Co., Ltd.), attritor, pearl mill (“DCP mill” manufactured by Eirich Co., Ltd.), or coball mill; wet type jet mill (Genus "Genus PY" manufactured by Co., Ltd., "Starburst" manufactured by Sugino Machine Co., Ltd., "Nanomizer" manufactured by Nanomizer Co., Ltd.), "Claire SS-5" manufactured by M Technique Co., Ltd. ) Medialess dispersers such as “MICROS” manufactured by; or Other roll mill and the like, but not limited thereto. Moreover, as the disperser, it is preferable to use a disperser that has been subjected to a metal contamination prevention treatment from the disperser.

  For example, when using a media-type disperser, a disperser in which the agitator and vessel are made of a ceramic or resin disperser, or the surface of the metal agitator and vessel is treated with tungsten carbide spraying or resin coating. Is preferably used. As the media, it is preferable to use glass beads, ceramic beads such as zirconia beads or alumina beads. Moreover, also when using a roll mill, it is preferable to use a ceramic roll. Only one type of dispersion device may be used, or a plurality of types of devices may be used in combination. Further, in the case of a positive or negative electrode active material in which particles are easily broken or crushed by a strong impact, a medialess disperser such as a roll mill or a homogenizer is preferable to a media type disperser.

(Mixed material layer)
In the present invention, the composite material layer provided on the non-aqueous secondary battery electrode base layer is formed of composite material ink. The composite ink contains an active material (F) and a binder (D).
The active material (F) will be described. The positive electrode active material for the lithium ion secondary battery is not particularly limited, but metal oxides capable of doping or intercalating lithium ions, metal compounds such as metal sulfides, and conductive polymers are used. be able to.
Examples thereof include transition metal oxides 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 structure lithium nickelate, lithium cobaltate, lithium manganate, spinel structure lithium manganate, etc. Examples thereof include composite oxide powders of lithium and transition metals, lithium iron phosphate materials that are phosphate compounds having an olivine structure, transition metal sulfide powders such as TiS ₂ and FeS, and the like.
In addition, conductive polymers such as polyaniline, polyacetylene, polypyrrole, and polythiophene can also be used. Moreover, you may mix and use said inorganic compound and organic compound.

The negative electrode active material for the lithium ion secondary battery is not particularly limited as long as it can be doped or intercalated with lithium ions. For example, metal Li, alloys thereof such as tin alloy, silicon alloy, lead alloy, Li _X Fe ₂ O ₃ , Li _X Fe ₃ O ₄ , Li _X WO ₂ , lithium titanate, lithium vanadate, silicon Metal oxides such as lithium oxide, conductive polymers such as polyacetylene and poly-p-phenylene, amorphous carbonaceous materials such as soft carbon and hard carbon, artificial graphite such as highly graphitized carbon materials, or natural Examples thereof include carbonaceous powders such as graphite, carbon black, mesophase carbon black, resin-fired carbon materials, air-growth carbon fibers, and carbon fibers. These negative electrode active materials can be used alone or in combination.

  The size of these active materials (F) is preferably in the range of 0.05 to 100 μm, and more preferably in the range of 0.1 to 50 μm. And it is preferable that the dispersed particle diameter of the electrode active material (F) in compound-material ink is 0.05-30 micrometers. The dispersed particle size referred to here is a particle size (D50) that is 50% when the volume ratio of the particles is integrated from the fine particle size distribution in the volume particle size distribution. A particle size distribution meter such as a dynamic light scattering type particle size distribution meter (“Microtrack UPA” manufactured by Nikkiso Co., Ltd.).

Next, the binder (D) will be described.
The binder (D) used in the present invention is used for binding the active material (F) to the current collector when the composite material layer is formed. As the binder (D), the same material as the binder (D) used in the conductive primer composition can be used. The form of the binder is preferably an emulsion type from the viewpoint of adhesion to the current collector. The emulsion type here refers to a state in which the binder is not dissolved in the aqueous liquid solvent but is dispersed in the form of particles in the aqueous liquid solvent.

  Furthermore, a conductive material (G) can be used for the composite ink in order to increase conductivity. The conductive material (G) is preferably a carbon material, and in addition to the carbon black (B) described above, conductive carbon fibers (carbon nanotubes, carbon nanofibers, carbon fibers), fullerene, etc. alone or 2 More than one type can be used in combination. As in the case of obtaining the conductive primer composition, when the conductive material (G) is used, it is preferably used by dispersing it in a dispersed particle size of 0.1 to 10 μm using water and a dispersion resin. The dispersion resin is preferably a water-soluble cellulose resin, a water-soluble acrylic resin, a water-soluble styrene / acrylic resin, a water-soluble polyester resin, a water-soluble urethane resin, or the like, and more preferably an amphoteric dispersant (C). . The dispersed particle size referred to here is a particle size (D50) that is 50% when the volume ratio of the particles is integrated from the fine particle size distribution in the volume particle size distribution. A particle size distribution meter such as a dynamic light scattering type particle size distribution meter (“Microtrack UPA” manufactured by Nikkiso Co., Ltd.).

Furthermore, a film forming aid, an antifoaming agent, a leveling agent, a dispersant, a preservative, a pH adjuster, a viscosity adjuster, and the like can be blended in the composite ink as necessary.
The method for producing the composite ink is not particularly limited, and the above-described disperser or the like can be used.

Although it depends on the coating method, the viscosity of the composite ink is preferably 100 mPa · s or more and 30,000 mPa · s or less in the range of 30 to 90% by weight of the solid content.
The active material (F) is preferably contained as much as possible within the viscosity range that can be applied. For example, the proportion of the active material (F) in the solid content of the composite ink is 80% by weight or more and 99% by weight or less. Is preferred.
When the conductive material (G) is included, the proportion of the conductive material (G) in the solid material ink solid content is preferably 0.1 to 15% by weight.
When the binder is included, the ratio of the binder to the solid material ink solid content is preferably 0.1 to 15% by weight.

<Electrode>
The conductive primer composition of the present invention is coated and dried on a foil-like current collector to form a base layer, and a composite layer formed from a composite ink is provided on the base layer, and a non-aqueous two-component composition is provided. A secondary battery electrode can be obtained.

(Current collector)
The material and shape of the current collector used for the electrode are not particularly limited, and those suitable for various secondary batteries can be appropriately selected.
For example, examples of the material for the current collector include metals and alloys such as aluminum, copper, nickel, titanium, and stainless steel. In the case of a lithium ion battery, aluminum is particularly preferable as the positive electrode material, and copper is preferable as the negative electrode material.
In general, foil on a flat plate is used as the shape, but the surface is roughened, porous foam, perforated foil, and mesh current collector. Can also be used.

There is no particular limitation on the method for applying the conductive primer composition on the current collector and the method for applying the mixed ink on the base layer formed from the conductive primer composition, and there are no known methods. Can be used.
Specific examples include die coating method, dip coating method, roll coating method, doctor coating method, knife coating method, spray coating method, gravure coating method, screen printing method or electrostatic coating method, and the like. Examples of methods that can be used include standing drying, blower dryers, hot air dryers, infrared heaters, and far-infrared heaters, but are not particularly limited thereto.
Moreover, you may perform the rolling process by a lithographic press, a calender roll, etc. after application | coating. The thickness of the underlayer is generally from 0.1 to 10 μm, preferably from 0.5 to 5 μm. The thickness of the composite layer is generally 1 to 500 μm, preferably 10 to 300 μm.

<Secondary battery>
A non-aqueous secondary battery can be obtained by using the above electrode for at least one of a positive electrode and a negative electrode.
Secondary batteries include lithium ion secondary batteries, sodium secondary batteries, magnesium secondary batteries, lithium ion capacitors, and the like. Conventionally known non-aqueous electrolytes for each secondary battery, A separator etc. can be used suitably.

(Electrolyte)
A case of a lithium ion secondary battery will be described as an example. As the electrolytic solution, an electrolyte containing lithium dissolved in a non-aqueous solvent is used.
As the electrolyte, 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 etc. but are not limited to.

The non-aqueous solvent is not particularly limited.
Carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate;
Lactones such as γ-butyrolactone, γ-valerolactone, and γ-octanoic lactone;
Glymes such as tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,2-methoxyethane, 1,2-ethoxyethane, and 1,2-dibutoxyethane;
Esters such as methyl formate, methyl acetate, and methyl propionate;
Sulfoxides such as dimethyl sulfoxide and sulfolane; and
Nitriles such as acetonitrile are exemplified. These solvents may be used alone or in combination of two or more.

  Furthermore, the electrolyte solution may be a polymer electrolyte that is held in a polymer matrix and made into a gel. Examples of the polymer matrix include, but are not limited to, an acrylate resin having a polyalkylene oxide segment, a polyphosphazene resin having a polyalkylene oxide segment, and a polysiloxane having a polyalkylene oxide segment.

(separator)
Examples of the separator include, but are not limited to, a polyethylene nonwoven fabric, a polypropylene nonwoven fabric, a polyamide nonwoven fabric and those obtained by subjecting them to a hydrophilic treatment.

(Battery structure / configuration)
The structure of the lithium ion secondary battery using the composition of the present invention is not particularly limited, but is usually composed of a positive electrode and a negative electrode, and a separator provided as necessary, a paper type, a cylindrical type, a coin type, Various shapes can be formed according to the purpose of use, such as a button type and a laminated type.

  EXAMPLES The present invention will be described more specifically with reference to the following examples. However, the following examples do not limit the scope of rights of the present invention. In the examples and comparative examples, “part” represents “part by weight”.

(Dispersant synthesis example 1)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 200.0 parts of n-butanol and replaced with nitrogen gas. The inside of the reaction vessel was heated to 110 ° C., and a mixture of 100.0 parts of styrene, 60.0 parts of acrylic acid, 40.0 parts of dimethylaminoethyl methacrylate, and 12.0 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) The polymerization reaction was carried out dropwise over 2 hours. After completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a copolymer (1) solution. Got. The weight average molecular weight of the copolymer (1) was about 10,000, and the acid value was 219.1 (mgKOH / g).
Further, after cooling to room temperature, 74.2 parts of dimethylaminoethanol was added for neutralization. This is the amount that neutralizes 100% of acrylic acid. Furthermore, after adding 400 parts of water and making it aqueous, it heated to 100 degreeC, butanol was azeotroped with water, and butanol was distilled off.
Dilution with water gave an aqueous solution or dispersion of an amphoteric resin dispersant (1) with a nonvolatile content of 20%. Moreover, the viscosity of the aqueous solution of the amphoteric resin type dispersant (1) having a nonvolatile content of 20% was 40 mPa · s.

(Dispersant Synthesis Examples 2 to 20)
The compounding compositions shown in Table 1 were synthesized in the same manner as in Synthesis Example 1 to obtain dispersants of Synthesis Examples 2-20.

Ｓｔ：スチレン
ＡＡ：アクリル酸
ＢｚＭＡ：ベンジルメタクリレート
ＤＭ：ジメチルアミノエチルメタクリレート
ＢＭＡ：メタクリル酸ブチル

St: Styrene AA: Acrylic acid BzMA: Benzyl methacrylate DM: Dimethylaminoethyl methacrylate BMA: Butyl methacrylate

<Example 1: Conductive primer composition (1-1)>
7 parts of graphite flake CPB-3 (manufactured by Chuetsu Graphite Co., Ltd., average particle diameter 18 μm) as graphite particles (A), 4.1 parts of Synthesis Example 1 (solid content concentration 20%), 58 parts of water 9 parts were mixed in a mixer, and further placed in a sand mill and dispersed for 5 hours to obtain a graphite particle dispersion (1-1).
Next, 1.5 parts of acetylene black (Denka Black HS-100, average particle size 48 nm) as carbon black (B), 0.9 parts of Synthesis Example 1 (solid content concentration 20%) as water, 12 parts of water 6 parts were put in a mixer and mixed, and further placed in a sand mill and dispersed for 5 hours to obtain a carbon black dispersion (1-1).
CMC Daicel 1120 (carboxymethylcellulose, Daicel Finechem) of water-soluble cellulose resin as a binder with respect to 70.0 parts of the obtained graphite particle dispersion (1-1) and 15.0 parts of carbon black dispersion (1-1) Co., Ltd., 100% solid content) 1.5 parts and 50 parts of water were mixed to prepare a conductive primer composition (1-1).

<Examples 1 to 24: conductive primer compositions 1-2 to 1-15, 2 to 10>
As shown in Tables 2 and 3, a conductive primer composition was obtained in the same manner as the conductive primer composition (1-1) of Example 1 except that the type and ratio of the composition were changed.

<Comparative Examples 1-12: Conductive primer composition 1-16-1-20, 11-17>
As shown in Tables 2 and 3, a conductive primer composition was obtained in the same manner as the conductive primer composition (1-1) of Example 1 except that the type and ratio of the composition were changed.

・ＦＢＦ ：葉状黒鉛（中越黒鉛（株）製、平均粒子径８μｍ）
・ＣＮＰ−１５：葉状黒鉛（伊藤黒鉛（株）製、平均粒子径１５μｍ）
・Ｚ−１００：葉状黒鉛（伊藤黒鉛（株）製、平均粒子径６０μｍ）
・ＳＧ−ＢＨ８：球状黒鉛（伊藤黒鉛（株）製、平均粒子径８μｍ）
・ＳＰＧ：人造黒鉛（ＳＥＣカーボン（株）製、平均粒子径１０μｍ）
・＃２６００：カーボンブラック（三菱化学（株）製、平均粒子径１３ｎｍ）
・Ｗ−１６８：エマルション型アクリル樹脂（トーヨーケム（株）製、固形分５０％）

FBF: foliated graphite (manufactured by Chuetsu Graphite Co., Ltd., average particle size 8 μm)
CNP-15: foliated graphite (manufactured by Ito Graphite Co., Ltd., average particle size 15 μm)
Z-100: foliated graphite (manufactured by Ito Graphite Co., Ltd., average particle size 60 μm)
SG-BH8: Spherical graphite (manufactured by Ito Graphite Co., Ltd., average particle size 8 μm)
SPG: artificial graphite (manufactured by SEC Carbon Co., Ltd., average particle size 10 μm)
# 2600: Carbon black (Mitsubishi Chemical Corporation, average particle size 13 nm)
W-168: Emulsion type acrylic resin (Toyochem Co., Ltd., solid content 50%)

(Determination of degree of dispersion of conductive primer)
The degree of dispersion of the conductive primer was determined by determination with a grind gauge (in accordance with JISK5600-2-5). The evaluation results are shown in Table 5. The numbers in the table indicate the size of the coarse particles. The smaller the value, the better the dispersibility and the more uniform the dispersion.

<Preparation of mixed ink for positive electrode of lithium ion secondary battery>
[Composite ink for lithium ion secondary battery positive electrode (1)]
45 parts LiNi _1/3 Mn _1/3 Co _1/3 O ₂ as a positive electrode active material, 2.5 parts Denka Black HS-100 as a conductive material, 2.5 parts PVDF (polyvinylidene fluoride) as a binder, NMP ( 50 parts of (N-methylpyrrolidone) was mixed to prepare a composite ink (1) for a lithium ion secondary battery positive electrode.
[Composite ink for lithium ion secondary battery positive electrode (2)]
45 parts of LiFePO ₄ as a positive electrode active material, 2.5 parts of Denka Black HS-100 as a conductive material, 0.5 part of CMC (Daicel 1120: carboxymethylcellulose) as a binder, PTFE (polytetrafluoroethylene 30-J: Mitsui A mixture ink (2) for a positive electrode of a lithium ion secondary battery was prepared by mixing 3.5 parts of DuPont Fluorochemical Co., Ltd., 60% aqueous dispersion) and 48.5 parts of water.
[Composite ink for lithium ion secondary battery positive electrode (3)]
45 parts of LiFePO ₄ as a positive electrode active material, 2.5 parts of Denka Black HS-100 as a conductive material, 2.5 parts of an aqueous solution of the amphoteric resin-type dispersant of Synthesis Example 1, PTFE (polytetrafluoroethylene 30-J as a binder) : Mitsui / DuPont Fluoro Chemical Co., Ltd., 60% aqueous dispersion) 3.5 parts and 46.5 parts of water were mixed to prepare a mixture ink (3) for a lithium ion secondary battery positive electrode.

<Preparation of Lithium Ion Secondary Battery Positive Electrode and Evaluation Coin Type Battery>
After applying the conductive primer composition (1-1) of Example 1 onto a 20 μm-thick aluminum foil serving as a current collector using a doctor blade, it was dried under reduced pressure and dried to a thickness of 2 μm. Adjusted as follows. Further, a mixture ink for a positive electrode of a lithium ion secondary battery was applied on the underlayer, and then dried by heating under reduced pressure. Furthermore, the rolling process by a roll press was performed, the positive electrode from which thickness becomes 70 micrometers was produced, and adhesiveness was evaluated with the following method.

Next, the obtained positive electrode was punched into a diameter of 16 mm, a working electrode, a metallic lithium foil counter electrode, a separator (porous polypropylene film) inserted between the working electrode and the counter electrode, and an electrolytic solution (ethylene carbonate and diethyl carbonate). A coin-type battery for evaluation consisting of a non-aqueous electrolyte solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solvent in which the ratio of 1: 1 was mixed at a ratio of 1: 1 (volume ratio) was prepared. The coin-type battery was manufactured in a glove box substituted with argon gas, and a predetermined battery characteristic evaluation was performed after the coin-type battery was manufactured.

(Electrode adhesion)
Using the knife, the incision from the surface of the electrode to the depth reaching the current collector was cut into 6 grids in the vertical and horizontal directions at intervals of 2 mm. An adhesive tape was applied to the cut and immediately peeled off, and the degree of the active material falling off was determined by visual judgment. The evaluation criteria are shown below.
○: “No peeling (practical level)”
○ △: “Slightly peeled (problem but usable level)”
Δ: “About half peel”
×: “Peeling at most parts”

(Charge / discharge storage characteristics)
About the obtained coin-type battery, charging / discharging measurement was performed using the charging / discharging apparatus (Hokuto Denko Co., Ltd. SM-8).
The constant current charging was continued up to a charging end voltage of 4.3 V at a charging current of 1.9 mA. After the battery voltage reached 4.3V, constant current discharge was performed at a discharge current of 1.9 mA until the discharge end voltage reached 2.8V. These charge / discharge cycles are defined as one cycle, and 5 cycles of charge / discharge are repeated, and the discharge capacity at the fifth cycle is defined as the initial discharge capacity. (The initial discharge capacity is assumed to be 100% maintenance rate).

Next, after charging in the same way as the 5th cycle, after storing for 100 hours in a constant temperature bath at 60 ° C., constant current discharge is performed at a discharge current of 1 mA until the discharge end voltage reaches 2.8 V, and the change in discharge capacity The rate was calculated (the closer to 100%, the better).
A: “Change rate is 98% or more. Particularly excellent.”
○: “Change rate is 95% or more and less than 98%. Excellent”
○ △: “Change rate is 90% or more and less than 95%. No problem at all”
Δ: “Change rate is 85% or more and less than 90%.
×: “Change rate is less than 85%.

In addition, when the active material used is LiFePO ₄ , LiNi _1/3 Mn _1/3 except that the charging current is 1 mA, the charging end voltage is 4.2 V, the discharging current is 1 mA, and the discharging end voltage is 2.0 V. The charge / discharge storage characteristics can be measured as in the case of Co _1/3 O ₂ .
Further, when artificial graphite is used as an active material for the negative electrode (described later), a charging current of 0.85 mA (corresponding to 0.1 C), a charging end voltage of 0.1 V, a discharging current of 0.85 mA, a discharging end voltage of 2 The charge / discharge storage characteristics can be measured in the same manner as LiNi _1/3 Mn _1/3 Co _1/3 O ₂ except that the voltage is 0.0 V.

Using the conductive primer compositions obtained in Examples 2-12, 16-22, and Comparative Examples 1-4, 6-11, as shown in Table 4, for conductive primer compositions and positive electrode secondary battery electrodes A positive electrode secondary battery electrode was obtained and evaluated in the same manner as in Example 1 except that the combination of the mixture inks was changed.

<Production of Lithium Ion Secondary Battery Negative Electrode Ink and Evaluation Coin Type Battery>
[Lithium ion secondary battery negative electrode ink (4)]
90 parts of artificial graphite as a negative electrode active material, 2 parts of Denka Black HS-100 as a conductive material, 8 parts of PVDF (polyvinylidene fluoride) as a binder, and 100 parts of NMP (N-methylpyrrolidone) are mixed, and lithium ion secondary A composite ink for battery negative electrode was prepared.

  After applying the conductive primer compositions obtained in Examples 13 to 15, 23, and 24 and Comparative Examples 5 and 12 onto a copper foil having a thickness of 20 μm as a current collector using a doctor blade, heating under reduced pressure was performed. It dried and adjusted so that the thickness of a base layer might be set to 2 micrometers. Furthermore, after applying the mixture ink (4) for lithium ion secondary battery negative electrodes on a base layer, it dried under reduced pressure heating. Furthermore, the rolling process by a roll press was performed, and it adjusted so that the thickness of an electrode might be set to 70 micrometers by drying under reduced pressure, and evaluated similarly to the case of a positive electrode. The charge / discharge retention characteristics were evaluated using an evaluation coin-type battery having a negative electrode as a working electrode and a metal lithium foil as a counter electrode.

As shown in Table 4, when the conductive primer composition of the present invention is used, the conductive primer composition is uniformly dispersed. It is considered that good battery charge / discharge storage characteristics can be obtained because of a low contact resistance and a good conductive network in the underlayer.
On the other hand, in the comparative example, the smoothness of the surface of the underlying layer to be formed cannot be maintained, the adhesion is lowered, and as a result, sufficient battery charge / discharge characteristics cannot be obtained, and the characteristics are impaired by forming the underlying layer. It was also seen if you end up. Moreover, in the comparative example, it is thought that the battery charge / discharge characteristics were deteriorated because the conductive carbon particles of the obtained underlayer could not be packed closely or the conductive network was not sufficient.

Claims (6)

In a copolymer obtained by copolymerizing graphite particles (A) made of leaf-like natural graphite having an average particle size of 1 to 50 μm, carbon black (B) having an average particle size of 0.01 to 0.3 μm, and the following monomers: Conductive material for forming a non-aqueous secondary battery electrode containing an amphoteric resin type dispersant (C) obtained by neutralizing at least a part of a carboxyl group with a basic compound, a binder (D), and an aqueous liquid medium (E) Primer composition.
Ethylenically unsaturated monomer having an aromatic ring (c1): 5 to 70% by weight
Ethylenically unsaturated monomer having a carboxyl group (c2): 15 to 60% by weight
Ethylenically unsaturated monomer having an amino group (c3): 1 to 80% by weight
Ethylenically unsaturated monomers (c4) other than (c1) to (c3): 0 to 79% by weight
(However, the total of (c1) to (c4) is 100% by weight) Further, in the present invention, the proportion of the leaf-like graphite particles (A) is 60 to 99% by weight and the proportion of the carbon black (B) is 1 to 40 in the total 100% by weight of the leaf-like graphite particles (A) and the carbon black (B). The conductive primer composition for forming a nonaqueous secondary battery electrode according to claim 1, wherein the composition is wt%.   The secondary battery electrode base layer formed from the conductive primer composition for non-aqueous secondary battery electrode formation of Claim 1 or 2. A non-aqueous secondary battery electrode, wherein the non-aqueous secondary battery electrode base layer and the composite material layer according to claim 3 are laminated on a current collector.   The non-aqueous secondary battery electrode according to claim 4, wherein the composite layer is formed from a composite ink containing an amphoteric resin type dispersant (C). A non-aqueous secondary battery comprising a positive electrode, a negative electrode, and an electrolytic solution, wherein at least one of the positive electrode and the negative electrode is the non-aqueous secondary battery electrode according to claim 4 or 5.