JP6182995B2 - Composition for current collector coating for catalyst electrode, current collector with coat layer, catalyst electrode, fuel cell and air cell - Google Patents

Description

  The present invention relates to a current collector coating composition for a catalyst electrode, a current collector with a coat layer obtained using the composition, a catalyst electrode, a fuel cell and an air battery obtained using the catalyst 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 a large-sized secondary battery for use in automobiles or the like, it is desired to realize a large-sized secondary battery instead of a conventional lead storage battery.

  Therefore, in recent years, fuel cells and air cells have been actively developed, in which oxygen in the air or the like is used as a positive electrode active material, and energy of a chemical reaction with a compound serving as a fuel or a negative electrode active material can be extracted as electric energy. These batteries are known to have a higher theoretical energy capacity than lithium ion secondary batteries and the like, and there are great expectations for their realization.

In a battery using a catalyst electrode such as a fuel cell or an air battery, the basic configuration of the air electrode is a stack of a catalyst layer on a current collector (Patent Document 1). There is also a configuration in which a conductive water repellent layer is laminated (Patent Document 2).
Moreover, since oxygen must spread over the catalyst layer in order to cause a catalytic reaction, the current collector preferably has gas permeability. Therefore, many porous current collectors have been studied so far. Specifically, carbon fiber current collectors, metal mesh current collectors, and the like have been developed.

In a metal mesh-shaped current collector, a metal mesh made of a stainless steel wire, a nickel wire, or a nickel-plated stainless steel wire is used as a substrate in terms of conductivity and stability to an electrolytic solution. When these current collectors are incorporated in a battery as gas diffusion electrodes, a thin oxide film is formed on the surface of the current collector due to the oxidizing action of oxygen, or the alkali used as an electrolyte is relatively wettable during battery storage. May penetrate into high metal surface and promote surface oxidation. As this surface oxidation progresses, the electrical contact state decreases, which may cause problems such as an increase in internal resistance. Further, due to surface oxidation, the adhesion with the conductive water-repellent layer and the catalyst layer is deteriorated, which adversely affects battery characteristics.

In order to solve the above problems, for example, Patent Documents 3 and 4 disclose a technique of applying a conductive paint made of graphite on a current collector. By using a graphite material with high water repellency, adverse effects on the current collector surface are suppressed. Patent Document 5 proposes a technique using a conductive paint made of metal powder and graphite. However, in these inventions, the dispersibility of the conductive coating material is poor, and the effect of suppressing the oxidation of the current collector is insufficient.
On the other hand, Patent Document 6 proposes a method of adjusting the roughness of the surface by performing plating on the current collector and strengthening the adhesion with the catalyst layer.
However, the above-mentioned problem has not been completely solved, and further improvement has desired the development of a battery having low internal resistance and excellent long-term durability.

JP 58-1003003 A International Publication WO2010 / 131535 Pamphlet JP-A-7-220726 JP 2005-19146 A JP-A-8-273672 JP 11-339864 A

  An object of the present invention is a composition for a current collector coating for forming a fuel cell and an air cell using a catalyst electrode excellent in long-term durability such as cycle retention rate and voltage retention rate, and a dispersion of a carbon material It is to provide a current collector coating composition that is excellent in the properties, adhesion to the surface of the current collector, and water resistance.

In the present invention, the dispersibility of the carbon material (A) and the barrier property of the current collector surface can be improved by using the aqueous resin type dispersant (B).
That is, the present invention provides a current collector for a catalyst electrode, which contains a carbon material (A), an aqueous resin dispersant (B) obtained by copolymerizing the following monomers, and an aqueous liquid medium (C). The present invention relates to a body coating composition.
Ethylenically unsaturated monomer (b1) having at least one of aromatic ring and aliphatic skeleton: 10 to 90% by weight
Ethylenically unsaturated monomer having acidic functional group (b2): 10 to 90% by weight
Other monomers (b3) other than (b1) to (b2): 0 to 80% by weight
(However, the sum of (b1) to (b3) is 100% by weight)

  Furthermore, this invention relates to the said composition for collector coating in which at least one part of the acidic functional group of an aqueous resin type dispersing agent (B) is neutralized with the basic compound.

  Furthermore, this invention relates to the said composition for collector coating in which the other monomer (b3) contains the ethylenically unsaturated monomer which has an amino group.

  Furthermore, this invention relates to the collector with a coating layer for catalyst electrodes which comprises the collector which has gas permeability, and the collector coating layer formed from the said collector coating composition.

  Furthermore, this invention relates to the catalyst electrode which comprises the said collector with a coating layer, and a catalyst layer.

  Furthermore, the present invention relates to a fuel cell or air cell using the catalyst electrode.

  By using the aqueous resin type dispersant, it was possible to obtain a current collector coating composition with improved carbon material dispersibility and current collector surface barrier properties. The composition for current collector coating of the present invention can form a coating layer having excellent water resistance and adhesion to the current collector, and is excellent in the catalyst electrode excellent in adhesion to the catalyst layer and the water repellent layer, and thus excellent in durability. A catalyst battery can be provided.

The current collector coating composition of the present invention is for forming a coating layer of a gas-permeable current collector used for a catalyst electrode of a fuel cell or an air cell.
The catalyst electrode generally has the following configuration.
For example, on the surface of a gas permeable current collector,
(1) a catalyst electrode directly provided with a catalyst layer,
(2) a catalyst electrode provided with a conductive water-repellent layer between the catalyst layer,
The catalyst layer and the conductive water-repellent layer can form a predetermined electrode by preparing and applying a dispersion in which necessary materials are dispersed in a liquid medium or the like.

In order to improve the durability of the battery, the surface of the current collector is coated on the surface of the current collector using a current collector coating composition containing a carbon material, an aqueous resin-type dispersant, and an aqueous liquid medium. An electrode can be obtained by forming a layer and applying the above-described catalyst layer or a dispersion for forming a conductive water-repellent layer on the coating layer.
Since the composition for current collector coating of the present invention is excellent in dispersibility of the carbon material, it can be uniformly coated on the surface of a gas-permeable current collector, which will be described later, which is a porous shape. It is possible to form a coat layer having excellent properties and water resistance.
Moreover, the current collector coating layer formed from the current collector coating composition of the present invention has excellent water resistance and excellent adhesion to the current collector.

<Aqueous resin type dispersant (B)>
The aqueous resin dispersant (B) used in the current collector coating composition of the present invention functions effectively as a dispersant for the carbon material and can alleviate aggregation of the carbon material.
First, the aqueous resin type dispersant (B) in the present invention will be described.
The aqueous resin dispersant (B) in the present invention comprises an ethylenically unsaturated monomer (b1) having at least one of an aromatic ring and an aliphatic skeleton, and an ethylenically unsaturated monomer having an acidic functional group ( b2) and an essential component.
The aqueous resin dispersant (B) is preferably one obtained by neutralizing at least a part of the acidic functional group with a basic compound.

<Monomer (b1)>
Examples of the ethylenically unsaturated monomer (b1) having at least one of an aromatic ring and an aliphatic skeleton include an ethylenically unsaturated monomer (b1-1) having an aromatic ring and an ethylenically unsaturated monomer having an aliphatic skeleton. Examples thereof include a saturated monomer (b1-2) and an ethylenically unsaturated monomer having both an aromatic ring and an aliphatic skeleton. These can be used alone or in combination of two or more.
The ethylenically unsaturated monomer (b1-1) having an aromatic ring is not particularly limited as long as it has an aromatic ring. For example, styrene, α-methylstyrene, benzyl (meth) acrylate and the like can be exemplified.

  The ethylenically unsaturated monomer (b1-2) having an aliphatic skeleton is not particularly limited as long as it has an aliphatic skeleton. Examples of the aliphatic skeleton include saturated or unsaturated hydrocarbon groups, and aliphatic groups that are saturated or unsaturated hydrocarbons bonded by one or more heteroatoms, among which saturated hydrocarbons. And saturated aliphatic groups having an ether bond are preferred.

Examples of the saturated hydrocarbon group include a chain saturated hydrocarbon group and a cyclic saturated hydrocarbon group.
Specific examples of the monomer having a chain saturated hydrocarbon group include 1 to 22 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. There are alkyl (meth) acrylates having an alkyl group, preferably an alkyl (meth) acrylate having an alkyl group having 2 to 12 carbon atoms, more preferably 3 to 8 carbon atoms. These alkyl groups may be branched, and specific examples include isopropyl (meth) acrylate, isobutyl (meth) acrylate, tertiary butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2-butylhexyl ( And (meth) acrylate.
Examples of the α-olefin compound include 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene and the like.

  Examples of the monomer having a cyclic saturated hydrocarbon group include isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, 1-adamantyl (meth) acrylate, and the like. Can be mentioned.

  Examples of the saturated aliphatic group having an ether bond include a polyoxyalkylene structure. Specific examples of the monomer having a polyoxyalkylene structure include diethylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, and polypropylene glycol mono (meth) acrylate, which have a hydroxyl group at the terminal, Alkoxy groups at the end, such as monoacrylate or monomethacrylate having an alkylene chain, methoxyethylene glycol (meth) acrylate, methoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, and methoxypolypropylene glycol (meth) acrylate And monoacrylate or monomethacrylate having a polyoxyalkylene chain. Examples of the alkyl vinyl ether compound include butyl vinyl ether and ethyl vinyl ether.

  The saturated aliphatic compound having an ether bond may be cyclic, and specific examples include glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and the like.

<Monomer (b2)>
Examples of the acidic functional group possessed by the ethylenically unsaturated compound (b2) having an acidic functional group include a carboxyl group, a sulfo group, and a phosphoric acid group. These alkali metal salts or alkaline earth metal salts or Ammonium salts can also be used.

  Examples of the monomer having a carboxyl group include maleic acid, fumaric acid, itaconic acid, citraconic acid, or alkyl or alkenyl monoesters thereof, phthalic acid β- (meth) acryloxyethyl monoester, isophthalic acid β- ( Examples include meth) acryloxyethyl monoester, terephthalic acid β- (meth) acryloxyethyl monoester, succinic acid β- (meth) acryloxyethyl monoester, acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and the like. I can do it. In particular, methacrylic acid and acrylic acid are preferable.

  Examples of the monomer having a sulfo group include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acryloyloxyethyl sulfonic acid, isoprene sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfone. Examples include acid and allyloxybenzene sulfonic acid.

Monomers having a phosphoric acid group include mono (2-acryloyloxyethyl) acid phosphate, mono (2-methacryloyloxyethyl) acid phosphate, diphenyl (2-acryloyloxyethyl) phosphate, diphenyl (2-methacryloyloxyethyl). ) Phosphate, phenyl (2-acryloyloxyethyl) phosphate, acid phosphooxyethyl methacrylate, methacryloyl oxyethyl acid phosphate monoethanolamine salt, 3-chloro-2-acid phosphooxypropyl methacrylate, acid phosphooxypoly Oxyethylene glycol monomethacrylate, acid phosphooxypolyoxypropylene glycol methacrylate, (meth) acryloyloxyethyl Cyd phosphate, (meth) acryloyloxypropyl acid phosphate, (meth) acryloyloxy-2-hydroxypropyl acid phosphate, (meth) acryloyloxy-3-hydroxypropyl acid phosphate, (meth) acryloyloxy-3-chloro-2- Examples thereof include hydroxypropyl acid phosphate, allyl alcohol acid phosphate, and the like.

<Monomer (b3)>
Other monomers (b3) other than (b1) to (b2) are not particularly limited, and examples thereof include the following.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, glycerol mono (meth) acrylate, and allyl alcohol.

As nitrogen-containing unsaturated compounds, 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 ethylenically unsaturated monomer having an amino group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, methylethylaminoethyl (meth) acrylate, dimethylaminostyrene, diethylaminostyrene and the like.

Among the other monomers (b3), an ethylenically unsaturated monomer having an amino group is preferable.

<Composition ratio and function of monomers (b1) to (b3)>
The ratio of the monomers constituting the copolymer in the aqueous resin dispersant (B) used in the present invention is as follows when the total of the monomers (b1) to (b3) is 100% by weight:
Ethylenically unsaturated monomer (b1) having at least one of aromatic ring and aliphatic skeleton: 10 to 90% by weight
Ethylenically unsaturated monomer having acidic functional group (b2): 10 to 90% by weight
Other monomers (b3) other than (b1) to (b2): 0 to 80% by weight
Preferably, (b1): 15-70 wt%, (b2): 15-70 wt%, (b3): 1-70 wt%.
More preferably, they are (b1): 30-70 weight%, (b2): 15-50 weight%, (b3): 1-40 weight%.

It is presumed that the aromatic ring or aliphatic skeleton derived from the ethylenically unsaturated monomer (b1) having at least one of an aromatic ring and an aliphatic skeleton becomes the main adsorption site to the carbon material (A) described later. When the ethylenically unsaturated monomer having an amino group (b3) is contained, the amino group is also an adsorption site for the carbon material (A), which is preferable.
The ethylenically unsaturated monomer (b2) having an acidic functional group has a function of dissolving or dispersing the copolymer in an aqueous liquid medium. The neutralization of the acidic functional group is preferable because the effect becomes greater.
Then, the copolymer is adsorbed to the carbon material (A) through an aromatic ring or an aliphatic skeleton, preferably neutralized, and in the aqueous liquid medium of the carbon material (A) by charge repulsion of the ionized acidic functional group. It is considered that the dispersion state in can be kept stable.

The molecular weight of the copolymer obtained by copolymerizing the above monomers (b1) to (b3) is not particularly limited, but the viscosity of the aqueous resin dispersant (B) in a 20% solid content aqueous solution is preferably 5 ~ 100,000 mPa · s, more preferably 10 ~ 50,000 mPa · s. When the molecular weight of the aqueous resin type dispersant (B) is lower than the predetermined range and the molecular weight of the aqueous resin type dispersant (B) is higher than the predetermined range and the molecular weight of the aqueous resin type dispersant (B) is too high, the carbon material ( A) may result in poor dispersion.
In addition, the viscosity in this invention is the value measured on 25 degreeC conditions using the B-type viscosity meter.

The acid value of the aqueous resin dispersant (B) is preferably in the range of 50 mgKOH / g to 400 mgKOH / g, and more preferably in the range of 80 mgKOH / g to 300 mgKOH / g. .
If the acid value of the aqueous resin dispersant (B) is lower than the above range, the dispersion stability of the dispersion tends to decrease and the viscosity tends to increase. In addition, when the acid value of the aqueous resin dispersant (B) is higher than the above range, the adhesion of the aqueous resin dispersant (B) to the carbon surface tends to decrease, and the storage stability of the dispersion tends to decrease. .
The acid value of the aqueous resin dispersant (B) in the present invention is a value obtained by converting the measured acid value (mgKOH / g) into a solid content in accordance with the potentiometric titration method of JIS K0070.

<Manufacturing method>
The aqueous resin dispersant (B) can be obtained by various production methods.
For example, the monomers (b1) to (b3) are polymerized in an organic solvent that can be azeotroped with water. Thereafter, an aqueous liquid medium typified by water and preferably a neutralizing agent are added to neutralize at least a part of the acidic functional groups, the azeotropic solvent is distilled off, and an aqueous resin-type dispersant (B ) Aqueous solution or dispersion.
As the organic solvent at the time of polymerization, any solvent that azeotropes with water may be used, but those having high solubility in the copolymer are preferable, and ethanol, 1-propanol, 2-propanol, and 1-butanol are preferable. Preferably 1-butanol.

Alternatively, it is copolymerized in a hydrophilic organic solvent, neutralized with water, preferably by adding a neutralizing agent, the hydrophilic organic solvent is not distilled off, and an aqueous liquid medium containing the hydrophilic organic solvent and water is used. A liquid in which the aqueous resin dispersant (B) 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 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, alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide, organic acids and mineral acids Etc. can be used. The copolymer as described above is dispersed or dissolved in an aqueous liquid medium.

<Carbon material (A)>
The carbon material (A) in the present invention is not particularly limited as long as it is a carbon material having conductivity, but graphite, carbon black, conductive carbon fiber (carbon nanotube, carbon nanofiber, carbon fiber), Fullerenes or the like can be used alone or in combination of two or more. From the viewpoint of conductivity, availability, and cost, it is preferable to use carbon black.

  Carbon black is a furnace black produced by continuously pyrolyzing a gas or liquid raw material in a reactor, especially ketjen black using ethylene heavy oil as a raw material. Channel black that has been rapidly cooled and precipitated, thermal black obtained by periodically repeating combustion and thermal decomposition using gas as a raw material, and particularly various types such as acetylene black using acetylene gas as a raw material, or 2 More than one type can be used in combination. Ordinarily oxidized carbon black, hollow carbon and the like can also be used.

  The oxidation treatment of carbon is performed by treating carbon at a high temperature in the air or by secondary treatment with nitric acid, nitrogen dioxide, ozone, etc., for example, such as phenol group, quinone group, carboxyl group, carbonyl group. This is a treatment for directly introducing (covalently bonding) an oxygen-containing polar functional group to the carbon surface, and is generally performed to improve the dispersibility of carbon. However, since it is common for the conductivity of carbon to fall, so that the introduction amount of a functional group increases, it is preferable to use the carbon which has not been oxidized.

As the specific surface area of the carbon black used increases, the contact point between the carbon black particles increases, which is advantageous for lowering 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.

  Further, the particle size of the carbon black to be used is preferably 0.005 to 1 μm, particularly preferably 0.01 to 0.2 μm in terms of primary particle size. However, the primary particle diameter here is an average of the particle diameters measured with an electron microscope or the like.

The dispersed particle diameter of the carbon material (A) in the current collector coating composition is desirably refined to 0.03 μm or more and 5 μm or less. A composition having a carbon material having a dispersed particle size of less than 0.03 μm may be difficult to produce. In addition, when a composition having a dispersed particle diameter of the carbon material exceeding 2 μm is used, problems such as variations in the material distribution of the coat layer coating film and variations in the resistance distribution of the electrode may occur.
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.).

  Examples of commercially available carbon black include Toka Black # 4300, # 4400, # 4500, # 5500 (Tokai Carbon Co., Furnace Black), Printex L and the like (Degussa Co., Furnace Black), Raven 7000, 5750, 5250, 5000 ULTRA III, 5000 ULTRA, etc., Conductex SC ULTRA, Conductex 975 ULTRA, etc., PUER BLACK100, 115, 205, etc. (manufactured by Colombian, Furnace Black), # 2350, # 2400B, # 2600B, # 30050B, # 3030B, # 3030B, # 3030B 3350B, # 3400B, # 5400B, etc. (Mitsubishi Chemical Corporation, furnace black), MONARCH1400, 1300, 900, VulcanXC-7 2R, BlackPearls2000, etc. (Cabot, Furnace Black), Ensaco 250G, Ensaco 260G, Ensaco 350G, SuperP-Li (manufactured by TIMCAL), Ketjen Black EC-300J, EC-600JD (manufactured by Akzo), Denka Black, Denka Black HS Examples of graphite such as -100, FX-35 (manufactured by Denki Kagaku Kogyo Co., Ltd., acetylene black) include natural graphite such as artificial graphite, flake graphite, lump graphite, and earth graphite, but are not limited thereto. They may be used in combination of two or more.

  As the conductive carbon fibers, those obtained by firing from petroleum-derived raw materials are preferable, but those obtained by firing from plant-derived raw materials can also be used. For example, VGCF manufactured by Showa Denko Co., Ltd. manufactured with petroleum-derived raw materials can be mentioned.

<Aqueous liquid medium (C)>
As the aqueous liquid medium (C) 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.

<Composition for current collector coating>
The composition for current collector coating contains at least a carbon material (A), an aqueous resin dispersant (B) obtained by copolymerizing the following monomers, and an aqueous liquid medium (C). .
The current collector coating composition may further contain a binder in order to improve adhesion to the current collector and improve the durability of the current collector.
The binder in the present invention is used for binding particles such as a carbon material, and the effect of dispersing these particles in a solvent is small.

  Examples of the binder include acrylic resins, polyurethane resins, polyester resins, phenol resins, epoxy resins, phenoxy resins, urea resins, melamine resins, alkyd resins, formaldehyde resins, silicone resins, fluororesins, carboxymethylcellulose and other cellulose resins, styrene -Synthetic rubbers such as butadiene rubber and fluorine rubber, conductive resins such as polyaniline and polyacetylene, and the like, 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, which may be a water-soluble resin or a water-dispersed resin. These binders can be used alone or in combination.

  Furthermore, a film-forming auxiliary, an antifoaming agent, a leveling agent, a preservative, a pH adjusting agent, a viscosity adjusting agent and the like can be blended in the current collector coating composition as necessary.

The proportion of the carbon material (A) in the total solid content of the current collector coating composition is preferably 20% by weight or more and 80% by weight or less, and more preferably 30% by weight or more and 60% by weight or less. If the amount of the carbon material (A) is small, the conductivity of the underlayer may not be maintained. On the other hand, if the amount of the carbon material (A) that is a conductive auxiliary agent is too large, the resistance of the coating film may be reduced.
Moreover, it is preferable that the ratio of the aqueous resin type dispersing agent (B) to solid content in the composition for collector coating is 1 to 70 weight% or less.
Furthermore, when a binder is included, the ratio of the binder to the solid content in the current collector coating composition is preferably 19 to 79% by weight.
Moreover, although it depends on the coating method, the viscosity of the current collector coating composition is preferably 1 mPa · s or more and 20,000 mPa · s or less in the range of 5 to 50% by weight of the solid content.
The thickness of the coat layer of the current collector is generally 0.2 μm or more and 20 μm or less, preferably 0.5 μm or more and 5 μm or less.

Such a current collector coating composition can be obtained by various methods.
A case of a current collector coating composition containing a carbon material (A), an aqueous resin type dispersant (B), a binder, and an aqueous liquid medium (C) will be described as an example.
For example,
(X-1) Obtaining an aqueous dispersion of a carbon material containing the carbon material (A), the aqueous resin dispersant (B), and the aqueous liquid medium (C), adding a binder to the aqueous dispersion, A composition for current collector coating can be obtained.
(X-2) Obtaining an aqueous dispersion of the active material containing the carbon material (A), the aqueous resin dispersant (B), the binder, and the aqueous liquid medium (C) to obtain a composition for current collector coating Can do.
(X-3) Obtaining a solution containing the aqueous resin dispersant (C), the binder, and the aqueous liquid medium (D), and further adding the carbon material (A) to obtain a current collector coating composition. it can.

(Disperser / Mixer)
As an apparatus used for obtaining the current collector coating composition, a disperser or a mixer 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, or “fillmix” manufactured by PRIMIX; paint conditioner (manufactured by Red Devil), ball mill, sand mill (Shinmaru Enterprises "Dynomill", etc.), Attritor, Pearl Mill (Eirich "DCP Mill", etc.), or Coball Mill, etc .; Media type dispersers; Wet Jet Mill (Genus, "Genus PY", Sugino Media-less dispersers such as “Starburst” manufactured by Machine, “Nanomizer” manufactured by Nanomizer, etc., “Claire SS-5” manufactured by M Technique, or “MICROS” manufactured by Nara Machinery; or other roll mills, etc. Although The present invention is not limited to these. 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.

<Current collector with coat layer>
The current collector with a coat layer of the present invention includes a current-permeable current collector and a current collector coat layer formed from the current collector coating composition.
(Current collector)
The material of the current collector used for the catalyst electrode is not particularly limited, but a shape having gas permeability is required, and the corresponding current collector can be appropriately selected.
For example, examples of the material of the current collector include metals such as aluminum, copper, nickel, titanium, and stainless steel, alloys, and resins. In the case of a fuel cell and an air cell, stainless steel, nickel, and aluminum are preferable.
As the shape, a porous material is generally selected, and a perforated foil shape such as a punching metal or an expanded metal, a foam metal foil, a nonwoven fabric, or a mesh current collector can be used.

(Coating method)
The method for applying the current collector coating composition on the current collector is not particularly limited, and a known method can be used.
Specific examples include a gravure coating method, 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 screen printing method, or an electrostatic coating method.
As the drying method, standing drying, blow dryer, hot air dryer, infrared heater, far infrared heater and the like can be used, but not particularly limited thereto.
Moreover, you may perform the rolling process by a lithographic press, a calender roll, etc. after application | coating.

<Catalyst electrode>
The catalyst electrode of the present invention comprises at least a current collector with a coat layer and a catalyst layer, and can be used for a fuel cell or an air cell. The catalyst electrode may have a water repellent layer between the current collector with a coat layer and the catalyst layer.
The catalyst layer included in the catalyst electrode includes at least a catalyst material, and may further include a binder. Although the formation method of a catalyst layer is not specifically limited, For example, it can form on a collector with a coating layer using the catalyst ink composition which contains a catalyst material, a binder, and a solvent at least.
As the coating method and the drying method of the catalyst ink composition, a conventionally known coating method can be used, and the same method as the method exemplified for the current collector coating composition can be used.

<Fuel cell>
The current collector with a coat layer and the catalyst electrode of the present invention can be used for a cathode and an anode of a fuel cell.
(Catalyst material for fuel cells)
A known or commercially available catalyst material for the fuel cell can be used. For example, the catalyst particles may be those supported on carbon particles, oxide particles, or nitride particles as a catalyst support.

Examples of the catalyst particles include platinum, gold, silver, palladium, iridium, rhodium, ruthenium, and alloys thereof.
Examples of the catalyst carrier include the following.
Examples of the carbon particles include those similar to the carbon material (A).
Examples of the oxide particles include indium oxide, tin oxide, zinc oxide, titanium oxide, silica, and alumina.
Examples of the nitride particles include titanium nitride, zirconium nitride, niobium nitride, tantalum nitride, chromium nitride, vanadium nitride, and the like.
For these catalyst supports, an optimum material can be selected according to the required performance.

The loading rate of the catalyst particles on the catalyst carrier is not particularly limited. When platinum is used as the catalyst particles and carbon particles are used as the catalyst carrier, the catalyst particles can normally be loaded up to about 1 to 70% by weight with respect to 100% by weight of the catalyst particles.

Examples of commercially available fuel cell catalyst materials include:
Platinum-supported carbon particles such as TEC10E50E, TEC10E70TPM, TEC10V30E, TEC10V50E, TEC66E50;
Platinum-ruthenium alloy-supported carbon particles such as TEC66E50 and TEC62E58;
Can be purchased from Tanaka Kikinzoku Kogyo Co., Ltd., but is not limited thereto.

(Fuel cell binder)
As the binder for the fuel cell, a proton conductive polymer is preferable. As the proton conductive polymer, a conventionally known one can be used as a binder for binding the catalyst material. Examples of the proton conductive polymer include a fluorine-based ion exchange resin such as perfluorosulfonic acid, an olefin resin into which a strongly acidic functional group such as a sulfonic acid group is introduced, and a polyimide resin. For example, by introducing a fluorine atom having a high electronegativity, it is chemically very stable, a sulfonic acid group has a high degree of detachment, and high ionic conductivity can be realized. Specific examples of such proton conductive polymers include “Nafion” manufactured by DuPont. Usually, the proton conductive polymer is used as an alcohol aqueous solution containing about 5 to 30% by weight of the polymer. As the alcohol, for example, methanol, propanol or the like is used.

(Catalyst ink composition for fuel cells)
The types and ratios of the catalyst material, the proton conductive polymer, and the solvent contained in the catalyst ink composition are not limited and can be appropriately selected within a wide range. As a preferable range, for example, the proton conductive polymer is 10 to 300 parts by weight, preferably 20 to 250 parts by weight with respect to 100 parts by weight of the catalyst material.

  The method for preparing the catalyst ink composition is not particularly limited. Preparation can be carried out by dispersing each component at the same time, or after dispersing the catalyst paste composition, a proton-conductive polymer component may be added, and is optimized depending on the catalyst material, proton-conductive polymer, and solvent type used. can do.

(Fuel cell electrode membrane assembly)
The fuel cell of the present invention includes a fuel cell electrode membrane assembly, and is composed of a separator and a current collector plate disposed so as to sandwich the fuel cell electrode membrane assembly.
A fuel cell electrode membrane assembly is formed by adhering a fuel cell catalyst layer to one or both sides of a proton-conducting solid polymer electrolyte membrane, and a current collector adhering to one or both sides thereof It is provided.

Examples of the method for producing a fuel cell electrode membrane assembly include a method in which the catalyst electrode is thermocompression bonded to one or both sides of a solid polymer electrolyte membrane. Moreover, after forming the catalyst layer previously formed on the transfer base material on the solid polymer electrolyte membrane by transfer, the above-mentioned current collector with a coat layer may be thermocompression bonded.

(Solid polymer electrolyte membrane)
Examples of the solid polymer electrolyte membrane include perfluorosulfonic acid-based fluorine ion exchange resins. By introducing a fluorine atom having a high electronegativity, it is chemically very stable, the degree of sulfonic acid group dissociation is high, and high ionic conductivity can be realized. Specific examples include “Nafion” manufactured by DuPont, “Flemion” manufactured by Asahi Glass, “Aciplex” manufactured by Asahi Kasei, “Gore Select” manufactured by Gore, and the like. The thickness of the electrolyte membrane is usually about 20 μm to 250 μm, preferably about 10 μm to 80 μm.

(Conductive water repellent layer)
The electrode membrane assembly of the present invention may include a microporous layer on the side of the catalyst layer that contacts the current collector. This layer is handled as a part of the catalyst layer, or is also referred to as a conductive water repellent layer, a water repellent layer, or MPL (micro porous layer), and uniform gas supply to the catalyst layer, In addition to improving conductivity, it has the role of improving the drainage of water generated during power generation on the cathode side. The conductive water-repellent layer can be formed by, for example, applying a carbon material and a paste composition containing a water-repellent material on a current collector, and then baking the material at about 300 ° C. in the atmosphere.

(Transfer substrate)
The transfer substrate is a film substrate for applying a catalyst ink composition to form a fuel cell catalyst layer and transferring the catalyst layer on the transfer substrate to a solid polymer electrolyte membrane such as Nafion. As the transfer substrate, a polymer film that is inexpensive and easily available is preferable, and polytetrafluoroethylene, polyimide, polyethylene terephthalate, and the like are more preferable. Specific examples include a Teflon sheet.

(Separator)
The separator supplies and discharges a reaction gas such as a fuel gas (hydrogen) and an oxidant gas (oxygen). When the reaction gas is uniformly supplied to the anode and cathode catalyst particles through the gas diffusion base material (current collector), a gas phase is formed at the boundary between the catalyst particles and the proton conductive polymer provided in both electrodes. (Reactive gas), liquid phase (proton conducting polymer), solid phase (three-phase interface of catalyst particles possessed by both electrodes) is formed, and a direct current is generated by causing an electrochemical reaction.

In the above electrochemical reaction,
Cathode side: O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O
Anode side: H ₂ → 2H ⁺ + 2e ⁻
H ⁺ (proton) generated on the anode side moves toward the cathode side through the solid polymer electrolyte membrane, and e ⁻ (electron) moves to the cathode side through an external load.

On the other hand, on the cathode side, oxygen contained in the oxidant gas reacts with H ⁺ and e ⁻ moving from the anode side to generate water. As a result, the above-described fuel cell generates direct-current power from hydrogen and oxygen to generate water.

<Air battery>
The current collector with a coat layer and the catalyst electrode of the present invention can be used for a cathode of an air battery.
The air battery includes a cathode electrode composed of the catalyst electrode, an anode electrode having a negative electrode active material, an electrolyte layer that conducts metal ions between the cathode electrode and the anode electrode, and a separator.

(Catalyst material for cathode of air battery)
The catalyst material for an air battery includes catalyst particles and, if necessary, a conductive catalyst support that supports the catalyst particles.
Examples of the catalyst particles include inorganic ceramic materials such as MnO ₂ , CeO ₂ , TiO ₂ , Co ₃ O ₄ , and Fe ₃ O ₄ , organic complexes such as cobalt phthalocyanine and iron porphyrin, and composite materials thereof. it can. In addition, the same catalyst materials as exemplified in the fuel cell can be used.

(Binder for air battery)
As the binder for the air battery, the same binders as exemplified in the above-mentioned current collector coating composition can be used.

(Anode for air battery)
The air battery anode electrode has a negative electrode layer having a negative electrode active material, and a negative electrode current collector may be used as necessary. An electrolyte layer is disposed in contact with the negative electrode layer. The negative electrode active material usually has a metal element that becomes conductive ions. Examples of the metal element include lithium (Li), sodium (Na), zinc (Zn), iron (Fe), aluminum (Al), magnesium (Mg), manganese (Mn), silicon (Si), titanium ( Ti), chromium (Cr), vanadium (V), and the like. Among these, Li is preferable because a battery having a high energy density can be obtained. Moreover, not only a metal simple substance but an alloy, a metal oxide, a metal nitride etc. can be mentioned, However It is not limited to these, The conventionally well-known thing applied to an air battery can be applied. .

(Electrolyte layer)
The electrolyte layer conducts metal ions between the air battery cathode electrode and the air battery anode electrode. The type of metal ion varies depending on the type of the negative electrode active material described above, and the form thereof is not particularly limited as long as it has metal ion conductivity. For example, an aqueous solution or a non-aqueous solution can be applied, or a gel polymer electrolyte in which they are held by a polymer matrix, a polymer electrolyte, and an inorganic solid electrolyte may be used. Further, different electrolytes may be used on the cathode side and the anode side using a solid electrolyte or a separator.

In consideration of lithium ion conduction, an electrolytic solution in which an electrolyte containing lithium is dissolved in water or 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, when the electrolyte solution is a polymer electrolyte held in a polymer matrix and made into a gel, the polymer matrix includes an acrylate resin having a polyalkylene oxide segment, a polyphosphazene resin having a polyalkylene oxide segment, and a polyelectrolyte. Examples include, but are not limited to, a polysiloxane having an alkylene 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 subjected to hydrophilic treatment.

  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”.

(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 140.0 parts of styrene, 60.0 parts of acrylic acid, and 12.0 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 2 hours. A polymerization reaction was performed. 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 ) A solution was obtained. Moreover, the acid value of the copolymer (1) 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 aqueous resin dispersant (1) with a nonvolatile content of 20%. Further, the viscosity of the aqueous solution of the aqueous resin dispersant (1) having a nonvolatile content of 20% was 40 mPa · s.

(Synthesis Examples 2-14)
The compounding compositions shown in Table 1 were synthesized in the same manner as in Synthesis Example 1 to obtain dispersants of Synthesis Examples 2-14.

Ｓｔ：スチレン
ＢＡ：ブチルアクリレート
ＡＡ：アクリル酸
ＭＡＡ：メタクリル酸
２−ＳＥＭＡ：２−スルホエチルメタクリレート
ＨＥＭＡ：ヒドロキシルエチルメタクリレート
ＤＭ：ジメチルアミノエチルメタクリレート

ＤＭＡＥ：ジメチルアミノエタノール
ＮａＯＨ：水酸化ナトリウム

St: Styrene BA: Butyl acrylate AA: Acrylic acid MAA: Methacrylic acid 2-SEMA: 2-Sulfoethyl methacrylate HEMA: Hydroxyethyl methacrylate DM: Dimethylaminoethyl methacrylate

DMAE: Dimethylaminoethanol NaOH: Sodium hydroxide

<Preparation of current collector coating composition>
[Example 1: Composition for current collector coating (1)]
10 parts of acetylene black (DENKA BLACK HS-100) as a carbon material, 10 parts (2 parts as a solid content) of an aqueous solution or dispersion of the aqueous resin type dispersant (1) described in Synthesis Example (1), water 66 7 parts were mixed in a mixer and further dispersed in a sand mill. Next, 13.3 parts (8 parts as a solid content) (polytetrafluoroethylene 30-J: made by Mitsui / Dupont Fluorochemical Co., Ltd., 60% aqueous dispersion) is added as a binder, and stirred and mixed with a disper. A body coating composition (1) was obtained.

[Examples 2 to 13, Comparative Examples 1 to 4: Current collector coating compositions (2) to (17)]

Using the carbon material and dispersant shown in Table 2, the amount of water added was adjusted to the same solid content by the same method as the current collector coating composition (1), and the current collector coating composition Products (2) to (17) were obtained, and the dispersity as a current collector coating composition was determined by the following method.

(Determining the degree of dispersion)
The degree of dispersion of the current collector coating composition was determined by determination with a grind gauge (according to JISK5600-2-5).
The evaluation results are shown in Table 2. The numbers in the table indicate the size of coarse particles, and the smaller the value, the better the dispersibility and the more uniform current collector coating composition.

  As shown in Table 2, it is clear that the collector coating compositions (1) to (13) of the present invention are excellent in dispersibility of the carbon material and are uniform collector coating compositions. It was.

<Preparation of current collector with coat layer>
[Example 14: Current collector with coat layer (1)]
A collector coating composition (1) is added to a container, and a punching metal foil (thickness 30 μm) made of an aluminum material is immersed in the container for a certain period of time, and then dried at 120 ° C. for 30 minutes. A layered current collector (1) was obtained. The thickness of the coat layer was 1.5 μm.

[Examples 15 to 26, Comparative Examples 5 to 8: Current collector with coat layer (2) to (17)]
The current collector coating compositions (2) to (17) were used to obtain current collectors with coat layers (2) to (17) in the same manner as the current collector with coat layer (1).

(Water resistance evaluation)
With respect to the current collectors (1) to (17) prepared as described above, the surface of the current collector was rubbed with a cotton cloth containing water to evaluate the water resistance. The evaluation criteria are shown below, and the results are shown in Table 3.

○: “No shaving is seen (a level where there is no practical problem)”
○ △: “The foundation layer is slightly scraped and attached to the cotton cloth, but the surface of the current collector is not exposed (although there is a problem, it can be used)”
Δ: “Underlayer is shaved and the current collector surface is partially exposed”
×: “Underly layer is completely scraped off”

(Adhesion evaluation)
A cellophane tape was applied to the current collectors with coat layer (1) to (17) produced above and peeled off, and the degree of drop-off of the coat layer was determined by visual judgment. The evaluation criteria are shown below, and the results are shown in Table 3.

○: “No peeling (practical level)”
○ △: “Slightly peeled (problem but usable level)”
Δ: “About half peel”
×: “Peeling at most parts”

  As shown in Table 3, it was clear that the current collectors with coat layer (1) to (14) of the present invention were excellent in water resistance. Water resistance is important because the coating layer does not collapse when a gas containing water vapor passes through or when an aqueous paste for forming a catalyst layer or a conductive water repellent layer is prepared.

<Preparation of catalyst electrode for air battery>
[Example 27]
As a conductive carbon material, 75 parts of furnace black (manufactured by Cabot, vulcan xc-72), 25 parts of PTFE powder, and 20 parts of N-methylpyrrolidone are mixed in a mortar, and the basis weight of the conductive carbon material is 2 mg / cm ² . Thus, after thermocompression bonding to the current collector with a coat layer (1), a conductive water-repellent layer was formed on the current collector with a coat layer by heating and vacuum drying.

Subsequently, 4 parts by weight of platinum catalyst-supporting carbon (manufactured by Tanaka Kikinzoku Co., Ltd., 46% platinum, TEC10E50E) as a catalyst material, 56 parts by weight of propanol as a solvent, and 20 parts by weight of ion-exchanged water are stirred and mixed with a disper. After preparing a catalyst paste composition (solid content concentration 4% by weight), a 20% PTFE dispersion solution (PTFE 30-J; made by Mitsui DuPont Fluoro Chemical Co., Ltd., 60% polytetrafluoroethylene aqueous dispersion was ionized as a binder. 20 parts by weight are added and diluted with a disperser to mix and mix with a catalyst ink composition for an air battery (when the solid content concentration is 8% by weight and the catalyst ink composition is 100% by weight) Of carbon-based catalyst material and binder). The obtained catalyst ink composition has a basis weight of platinum catalyst-supported carbon of 0.46 mg / cm on the conductive water-repellent layer of the current collector with a coat layer on which the conductive water-repellent layer prepared above is formed. The catalyst electrode (1) for an air battery was produced by applying to ² and heating and vacuum drying.

<Production of evaluation cell for air battery>
A separator (porous polypropylene film) containing a non-aqueous electrolyte solution (1M LiPF ₆ , ethylene carbonate / diethyl carbonate = 1/1, volume ratio) on a Li foil, a solid electrolyte (manufactured by OHARA, LiCGC Plate 1 inch × 150 μmt), and fixed with an aluminum laminate film. At this time, the aluminum laminate film on the solid electrolyte side was cut out to a size of 16 mm square to produce an exposed surface of the solid electrolyte, and an anode electrode for an air battery was produced.
A non-woven fabric impregnated with a 1M LiCl aqueous solution as an aqueous electrolyte on the solid electrolyte of the anode electrode for an air battery, and then the catalyst electrode (1) is placed, fixed with an aluminum laminate film, and thermocompression bonded. A battery evaluation cell was obtained.

[Examples 28 to 39, Comparative Examples 9 to 12]
Except having used the collector (2)-(17) with a coating layer, it carried out similarly to Example 27, and produced the catalyst electrode (2)-(17) for air batteries, and the evaluation cell for air batteries.

(Characteristic evaluation of air battery: capacity retention)
Using the obtained air battery evaluation cell, a 3-cycle break-in operation was performed under the conditions of a cut voltage of 2.0 V to 4.8 V and a current density of 0.5 mA / cm ² . Then, the capacity | capacitance retention was calculated | required by performing the charge / discharge test of 30 cycles on the same conditions. The evaluation results are shown in Table 4.

As shown in Table 3, it was found that the catalyst electrode using the current collector with a coating layer of the present invention was excellent in capacity retention after 30 cycles in charge and discharge of the air battery. It was also found that the better the water resistance and adhesion of the coat layer, the better the capacity retention of the battery. On the other hand, there is a correlation between the dispersibility of the current collector coating composition and the water resistance and adhesion of the coating layer. Therefore, if the dispersibility of the current collector coating composition is good, the current collector coat layer has a dense internal structure, and the current collector surface can be protected, leading to an improvement in capacity retention. I think that.

<Fabrication of catalyst electrode for fuel cell>

[Example 40]
In the same manner as in Example 27, a conductive water-repellent layer was formed on the current collector with coat layer (1). Subsequently, 4 parts by weight of platinum catalyst-supporting carbon (manufactured by Tanaka Kikinzoku Co., Ltd., 46% platinum, TEC10E50E) as a catalyst material, 56 parts by weight of propanol as a solvent, and 20 parts by weight of ion-exchanged water are stirred and mixed with a disper. After preparing a catalyst paste composition (solid content concentration of 4% by weight), 20 parts by weight of 20% by weight Nafion dispersion (DuPont Ctype DE2020) is added as a proton conductive polymer, and the mixture is stirred and mixed with a disper. Thus, a catalyst ink composition for a fuel cell (a total ratio of the carbon-based catalyst material and the proton conductive polymer when the solid content concentration was 8% by weight and the catalyst ink composition was 100% by weight) was produced. The obtained catalyst ink composition for a fuel cell has a weight per unit area of platinum catalyst-supporting carbon of 0. 0 on the conductive water-repellent layer of the current collector with the coating layer formed with the conductive water-repellent layer prepared above. The catalyst electrode (18) for a fuel cell was produced by applying to 46 mg / cm ² and drying by heating under vacuum.

By applying the catalyst ink composition for a fuel cell used at the time of preparing the catalyst electrode (18) onto a Teflon film so that the weight per unit area of the platinum catalyst-supported carbon is 0.46 mg / cm ² , and heating and vacuum drying, A fuel cell anode catalyst sheet was prepared.

<Production of evaluation cell for fuel cell>
The catalyst electrode (18) for the fuel cell and the anode catalyst sheet for the fuel cell were adhered to both surfaces of the solid polymer electrolyte membrane (Nafion NR-212, DuPont, film thickness 51 μm), respectively, After nipping under the condition of 5 MPa, the Teflon film of the anode catalyst sheet for fuel cells is peeled off, and a carbon paper substrate made of carbon fiber (TGP-H-090, manufactured by Toray Industries, Inc.) is adhered to the surface. A fuel cell electrode membrane assembly was prepared.
The obtained fuel cell electrode membrane assembly was used as a sample of 5 cm square, sandwiched between two gaskets from both sides and then two separators, which were graphite plates, and two current collector plates were attached from both sides. Single cell).

[Examples 41 to 52, Comparative Examples 13 to 16]
Fuel cell catalyst electrodes (18) to (34) and a fuel cell (single cell) were produced in the same manner as in Example 40 except that the collectors with coat layer (2) to (17) were used.

(Fuel cell (single cell) characteristics evaluation: voltage maintenance rate)
Using the obtained evaluation cell for a fuel cell, the cell temperature was set to 80 ° C., and air humidified at a temperature of 60 ° C. and a relative humidity of 42% was supplied from the cathode side (catalyst electrode side) at a flow rate of 160 mL / min. Then, a hydrogen gas humidified at a temperature of 77 ° C. and a relative humidity of 88% was supplied at a flow rate of 110 mL / min, and the voltage after maintaining at a current density of 500 mA / cm ² for 3 hours was defined as the initial voltage. Moreover, the voltage after 24 hours holding | maintenance was recorded on the same conditions, and the voltage maintenance factor was computed. The evaluation results are shown in Table 5.

As shown in Table 5, it was found that the catalyst electrode using the current collector with a coat layer of the present invention has an excellent voltage maintenance ratio in the power generation characteristics of the fuel cell. It was also found that the better the water resistance and adhesion of the coat layer, the better the voltage retention rate of the battery. On the other hand, there is a correlation between the dispersibility of the current collector coating composition shown in Table 2 and the water resistance and adhesion of the coat layer. If the dispersibility is good, the internal structure of the current collector coating layer becomes dense, and the current collector surface can be protected, which may lead to an improvement in the voltage maintenance ratio.

  As described above, by using an aqueous resin type dispersant, a composition for a current collector coat having a high dispersibility of the carbon material, a current collector with a coat layer having excellent water resistance and adhesion, and a catalyst electrode having excellent durability can be obtained. It is possible to produce an air battery having a high capacity retention rate and a fuel cell having a high voltage maintenance ratio.

Claims (6)

A current collector coating composition for a catalyst electrode, comprising a carbon material (A), an aqueous resin type dispersant (B) obtained by copolymerizing the following monomers, and an aqueous liquid medium (C).
Ethylenically unsaturated monomer (b1) having at least one of aromatic ring and aliphatic skeleton: 10 to 90% by weight
Ethylenically unsaturated monomer having acidic functional group (b2): 10 to 90% by weight
Other monomers (b3) other than (b1) to (b2): 0 to 80% by weight
(However, the sum of (b1) to (b3) is 100% by weight)   The composition for collector coating according to claim 1, wherein at least a part of the acidic functional group of the aqueous resin dispersant (B) is neutralized with a basic compound.   The collector coating composition according to claim 1 or 2, wherein the other monomer (b3) comprises an ethylenically unsaturated monomer having an amino group. A current collector with a coat layer for a catalyst electrode, comprising a current collector having gas permeability and a current collector coat layer formed from the current collector coat composition according to claim 1. A catalyst electrode comprising the current collector with a coat layer according to claim 4 and a catalyst layer. A fuel cell or an air cell using the catalyst electrode according to claim 5.