JP5261935B2 - Electrode electrolyte for polymer fuel cell and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode electrolyte for polymer electrolyte fuel cell excellent in proton conductivity, dimensional stability, hot water resistance, mechanical characteristics, and low in a price. <P>SOLUTION: The electrode electrolyte for the polymer fuel cell contains a polyarylene polymer containing 0.5-100 mole% repeating structural unit represented by formula (1') and 0-99.5 mole% repeating structural unit represented by formula (A'). <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an electrode electrolyte for a polymer electrolyte fuel cell, an electrode paste, an electrode, and a membrane-electrode assembly containing a polymer composed of a specific structural unit.

  Solid polymer fuel cells have high power density and can be operated at low temperatures, so they can be reduced in size and weight, and put into practical use as power sources for automobiles, stationary power sources, and portable devices. Is expected.

  A polymer electrolyte fuel cell is provided with a pair of electrodes on both sides of a proton conductive solid polymer electrolyte membrane, supplies pure hydrogen or reformed hydrogen as a fuel gas to one electrode (fuel electrode), oxygen gas or air Is supplied as an oxidant to the other electrode (air electrode) to generate electricity.

  The electrode of such a fuel cell is composed of an electrode electrolyte in which a catalyst component is dispersed (for this reason, the electrode is sometimes referred to as an electrode catalyst layer), and the electrode catalyst layer on the fuel electrode side generates protons and electrons from the fuel gas. Water is generated from oxygen, protons and electrons in the electrode catalyst layer on the air electrode side, and the solid polymer electrolyte membrane conducts protons in ionic conduction. And electric power is taken out through this electrode catalyst layer.

  Conventionally, in a polymer electrolyte fuel cell, a perfluoroalkyl sulfonic acid polymer represented by Nafion (trademark) is used as an electrolyte of an electrode catalyst layer. Although this material has excellent proton conductivity, it is very expensive and has a large amount of fluorine atoms in the molecule, so that it has low combustibility and is used for the electrode catalyst such as platinum. There is a problem that makes it very difficult to recover and reuse expensive precious metals.

  On the other hand, various non-perfluoroalkylsulfonic acid polymers have been studied as alternative materials. In particular, an attempt has been made to use an aromatic sulfonic acid polymer having a high heat resistance as an electrolyte with the aim of using it under high temperature conditions with high power generation efficiency.

For example, Japanese Patent Application Laid-Open No. 2005-50726 (Patent Document 1) discloses the use of a sulfonated polyarylene polymer as an electrode electrolyte, and further, Japanese Patent Application Laid-Open No. 2004-253267 (Patent Document 2). Discloses the use of certain sulfonated polyarylenes.
Japanese Patent Laying-Open No. 2005-50726 JP 2004-253267 A

  However, these materials conventionally known as electrolytes sometimes cause a reversible elimination reaction of sulfonic acid groups or a crosslinking reaction involving sulfonic acid at high temperatures. As a result, there is a problem that proton conductivity is reduced, membrane embrittlement or the like occurs, power generation output of the fuel cell is reduced, or power generation is disabled when the membrane is broken.

In order to avoid such problems as much as possible, the upper limit temperature at the time of fuel cell power generation is limited and used, and the power generation output is limited.
When the sulfonic acid concentration is increased in order to increase proton conductivity, there is a problem that the swelling due to water absorption is large under high-temperature and high-humidity conditions, the gas flow path is blocked, and the power generation performance decreases.

  In addition, electrolyte membranes that have been used in the past, such as Nafion, are easy to swell in methanol aqueous solution and do not have sufficient methanol resistance. It was insufficient.

  That is, the object of the present invention is to solve the above-mentioned problem of cost and the problem of recovery of the catalytic metal, and is a solid having excellent proton conductivity, dimensional stability, resistance to hot water, and mechanical properties. Provided is an electrode electrolyte for a polymer fuel cell, and further provides an electrode paste, an electrode, and an electrolyte membrane with a catalyst containing the electrolyte.

  The present invention has been made to solve the above problems, and by copolymerizing a specific sulfonic acid imide compound, a strongly acidic copolymer can be synthesized, and a material design with high proton conductivity can be achieved. It is possible, and does not require a complicated process associated with the reaction for introducing the sulfonic acid, can improve the stability of the sulfonic acid group under high temperature conditions, and does not have the sulfonic acid group in the copolymer. It has been found that even when the composition ratio of the unit is increased, a highly proton-conductive copolymer can be synthesized, and a material design excellent in hot water resistance and mechanical properties can be achieved, thereby solving the above problems.

  Furthermore, this polymer does not contain a fluorine atom, or even if it contains it, its content has been greatly reduced, and it has been found that the above-mentioned problems relating to the recovery and reuse of catalyst metals can be solved. It came to be completed.

The configuration of the present invention is as follows.
[1] 0.5 to 100 mol% of a repeating structural unit represented by the following formula (1 ′), the formula (A ′)
A polyarylene polymer containing 0 to 99.5 mol% of repeating structural units represented by (the sum of the structures (1 ′) and (A ′) is 100 mol%):

(In the formula (1 ′), A is a divalent electron-withdrawing group, B is a divalent electron-donating group or a single bond, and ^Ma is hydrogen, an alkali metal, a tertiary ammonium, or a fourth group. A cationic species selected from quaternary ammonium cations, R ^a is a hydrocarbon or fluorinated hydrocarbon group having 1 to 20 carbon atoms, and Ar is —SO ₂ —NM ^b —SO ₂ —R ^b (wherein M ^b is hydrogen, an alkali metal or a tertiary ammonium or quaternary ammonium cation, and R ^b is from 1 to C carbon atoms.
20 is a hydrocarbon or fluorinated hydrocarbon group), m is an integer of 0 to 10, n is an integer of 0 to 10, and k is 1 It is an integer of ~ 4.

In formula (A ′), A ′ and D are each independently —CO—, —SO—, —SO ₂ —, —
CONH -, - COO -, - (CF 2) p - ( wherein, p is an integer of 1 to _{10), - (CH 2) p} - ( wherein, p is an integer of 1 to 10) , —CR ′ ₂ — (wherein R ′ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, —S—. Is a divalent group selected, B ′ is an oxygen atom or a sulfur atom, R ¹ to R ¹⁶ may be the same or different, and are a hydrogen atom, a fluorine atom, an alkyl group, partially or completely At least one atom or group selected from halogen-substituted halogenated alkyl groups, aryl groups, allyl groups, nitro groups, and nitrile groups, and s and t are each independently an integer of 0 to 4, r is 0 or a positive integer. )
An electrode electrolyte for a polymer fuel cell, comprising:
[2] The polymer electrolyte fuel cell electrode electrolyte according to [1], wherein the aromatic group constituting Ar is a group selected from a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthrenyl group.
[3] R ^a and R ^b are each a linear or branched fluorinated hydrocarbon group represented by the general formula —C _p F _{2p + 1} (wherein p is an integer of 1 to 10). 3. The polymer electrolyte fuel cell electrode electrolyte according to claim 1 or 2.
[4] The divalent electron withdrawing group is —CO—, CONH—, — (CF ₂ ) _p — (wherein p is 1 to
10 is an integer _{of), - C (CF 3)} 2 -, - COO -, - SO -, - SO 2 - is selected from the divalent electron donating group, -O -, - S-, -CH = CH-, -C≡C-,

The electrode electrolyte for polymer fuel cells according to any one of [1] to [3], which is a group selected from:
[6] An electrode paste comprising the electrolyte of [1] to [5], catalyst particles, and a solvent.

  According to the present invention, since a strongly acidic segment obtained by introducing a novel aromatic sulfonic imide into polyarylene is contained, an electrode electrolyte having high proton conductivity and improved mechanical strength can be obtained. In addition, according to the present invention, it is not necessary to sulfonate and introduce a sulfonic acid group, so that a complicated process is not required, the catalyst metal is easily recovered, and the proton conductivity and dimensional stability are excellent. An electrode electrolyte for a polymer electrolyte fuel cell excellent in hot water resistance and mechanical properties is provided. Furthermore, the present invention provides an electrode paste, an electrode, and a catalyst-attached electrolyte membrane containing the electrolyte, and contributes to improvement in power generation performance of a solid polymer fuel cell.

(Electrode electrolyte)
The electrode electrolyte for a polymer electrolyte fuel cell of the present invention includes a polyarylene polymer containing a strongly acidic segment obtained by introducing a novel aromatic sulfonic imide into polyarylene.

In the present specification, a repeating unit in a polymer is referred to as a “unit”. Hereinafter, a repeating unit having hydrophobicity may be referred to as a “hydrophobic unit”, and a structural unit having a sulfonic acid group may be referred to as a “sulfonic acid unit”.
(Polyarylene polymer)
The polyarylene polymer used in the present invention is a polyarylene composed of a repeating structural unit derived from an aromatic compound, and a polyarylene polymer containing a repeating structural unit represented by the following formulas (1 ′) and (A ′): Arylene polymer:

In the formula (1 ′), A is a divalent electron-withdrawing group, and B is a divalent electron-donating group or a single bond.
As A, —CO—, CONH—, — (CF ₂ ) _p — (wherein p is an integer of 1 to 10), —C (CF ₃ ) ₂ —, —COO—, —SO—, -SO ₂ - and the like.
As B, —O—, —S—, —CH═CH—, —C≡C—,

Etc. With such a group, the effect of the present invention becomes more apparent.
M ^a is a cation species selected from hydrogen, alkali metals such as Na and K, tertiary ammonium, or quaternary ammonium cations such as ammonium, tetramethylammonium tetraethylammonium, trimethylbenzylammonium and tetrabutylammonium.

R ^a and R ^b in the above formula (1 ′) are a hydrocarbon or fluorinated hydrocarbon group having 1 to 20 carbon atoms, and may be the same or different, preferably a hydrocarbon group having 4 to 20 carbon atoms. It is. Non-limiting examples of useful hydrocarbon groups include linear hydrocarbons, branched hydrocarbons, and alicyclic hydrocarbons. Of these hydrocarbon groups, a fluorinated alkyl group such as a trifluoromethyl group is preferred.

Ar is an aromatic group having a substituent represented by —SO ₂ —NM ^b —SO ₂ —R ^b .
When the “Ar” moiety in the above formula is an aromatic group, the “Ar” moiety is an aromatic hydrocarbon group. Non-limiting examples of suitable aromatic groups include phenyl, biphenyl, naphthyl, anthracenyl, and phenanthracenyl groups. Of these groups, phenyl and naphthyl groups are preferred.

m is an integer of 0 to 10, preferably 0 to 2. n is an integer of 0 to 10, preferably 0 to 2. k is an integer of 1 to 4, preferably 1 or 2.
As the aromatic group constituting Ar, a group selected from a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthrenyl group is preferable from the viewpoint of availability of raw materials and ease of production.

Specific examples of the repeating structural unit represented by the general formula (1 ′) are exemplified below.

  In this invention, the repeating structural unit represented by the following general formula (A ') is included with the repeating structural unit represented by the said general formula (1'). When such a polymer component is contained, the strength and chemical resistance of the electrolyte can be improved.

In the general formula (A ′), A ′ and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _l — (l is 1-10 of an _{integer), - (CH 2) l} - (l is an integer of 1 to _{10), - CR '2 - (} R' is an aliphatic hydrocarbon group,
An aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, and —S—. Here, specific examples of the structure represented by —CR ′ ₂ — include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, propyl group, octyl group, decyl group. Group, octadecyl group, phenyl group, trifluoromethyl group, and the like.

Among these, a direct bond, —CO—, —SO ₂ —, —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), cyclohexylidene Group, fluorenylidene group and -O- are preferred.

B ′ is independently an oxygen atom or a sulfur atom, preferably an oxygen atom.
R ^{1 to} R ¹⁶ may be the same as or different from each other, and are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which a part or all of them are halogenated, an allyl group, an aryl group, a nitro group, a nitrile group. At least one atom or group selected from the group consisting of

  Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group, a cyclohexyl group, and an octyl group. Examples of the halogenated alkyl group include a trifluoromethyl group, a pentafluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and a perfluorohexyl group. Examples of the allyl group include a propenyl group, and examples of the aryl group include a phenyl group and a pentafluorophenyl group.

s and t represent an integer of 0 to 4. r shows 0 or an integer greater than or equal to 1, and an upper limit is 100 normally, Preferably it is 1-80.
Preferred combinations of the values of s and t and the structures of A ′, B ′, D, and R ^{1 to} R ¹⁶ include (1) s = 1, t = 1, and A is —CR ′ ₂ — ( R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group), a cyclohexylidene group or a fluorenylidene group, B ′ is an oxygen atom, D is —CO— or — SO ₂ - a is the structure R ¹ to R ¹⁶ is a hydrogen atom or a fluorine atom, a (2) s = 1, t = 0, B ' is an oxygen atom, D is -CO- or - SO ₂ - a is the structure R ¹ to R ¹⁶ is a hydrogen atom or a fluorine atom, (3) s = 0, a t = 1, a is -CR _'2 - (R' is an aliphatic hydrocarbon group , An aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, and B ′ is an oxygen atom Ri, the structure R ¹ to R ¹⁶ is a hydrogen atom or a fluorine atom or a nitrile group.

Examples of the polyarylene polymer used in the present invention include a copolymer represented by the following (V).

In the formula, A, B, R ^a , M ^a , k, A ′, D, B ′, R ^{1 to} R ¹⁶ , s, t, r, and m are as described above.
In the copolymer, the repeating structural unit represented by the general formula (1 ′) (that is, the unit of x) is in an amount of 0.5 to 100 mol% (however, 100 mol% is not included), and (A ′) Are included at a ratio of 0 to 99.5 mol%. More preferably, the repeating structural unit represented by the formula (1 ′) is contained at a ratio of 40 to 99.99 mol%, and the repeating structural unit represented by the formula (A ′) is contained at a ratio of 60 to 0.01 mol%. It is a waste.

  Furthermore, the polyarylene polymer used in the present invention includes a copolymer represented by the following (VI).

In the formula, A, B, R ^a , M ^a , k, A ′, D, B ′, R ^{1 to} R ¹⁶ , s, t, r, m, Ar, Ar
"Is as described above.
In the copolymer represented by the formula (VI), the repeating structural unit represented by the formula (1 ′) (that is, the unit of x) is 0.5 to 100 mol%, and is represented by the formula (A ′). 0 to 99.5 mol% of repeating structural units (that is, units of y), 0 to 99.5 mol% of repeating structural units represented by the formula (2 ″) (that is, units of z) (the structure (1 ′ ), (2 ″), and (A ′) are 100 mol%). More preferably, the repeating structural unit represented by the formula (1 ′) is represented by (40) to (99.99). ) Mol%, 0.1 to 60 mol% of the repeating structural unit represented by the formula (A ′), and 0 to 59.9 mol% of the repeating structural unit represented by the following formula (2 ″). It is a waste.

  The ion exchange capacity of the polyarylene polymer is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, and more preferably 0.8 to 2.8 meq / g. If it is less than 0.3 meq / g, the proton conductivity is low and the power generation performance is low. On the other hand, if it exceeds 5 meq / g, the water resistance may be significantly lowered, which is not preferable.

  In particular, as an ion conductive polymer in the anode electrode, the ion exchange capacity is usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably 0.8 to 2.8 meq / g. . When the content of the aromatic sulfonic acid derivative is less than 0.3 meq / g, proton conductivity decreases. On the other hand, if the ion exchange capacity exceeds 5.0 meq / g, the hydrophilicity may increase and the solvent resistance may decrease significantly.

  The molecular weight of the polyarylene polymer thus obtained is 10,000 to 1,000,000, preferably 20,000 to 800,000 in terms of polystyrene-equivalent weight average molecular weight by gel permeation chromatography (GPC).

  Such a polyarylene polymer includes a strongly acidic segment obtained by introducing a novel aromatic sulfonic imide into the polyarylene, so that an electrode electrolyte having high proton conductivity and improved mechanical strength is obtained. Is obtained. Therefore, it is possible to design a material with high proton conductivity, improve the stability of sulfonic acid groups under high temperature conditions, and increase the composition ratio of units having no sulfonic acid groups in the copolymer. Therefore, a copolymer having a high sulfonic acid concentration can be synthesized, and a material design excellent in hot water resistance and mechanical properties can be achieved. Such a polymer can be suitably used as a proton conductive membrane, an electrode electrolyte, and a binder for a fuel cell. An electrode electrolyte containing such a polyarylene polymer is also suitable as a membrane electrode assembly.

The electrode electrolyte according to the present invention only needs to include the above-described polymer, and therefore, the electrode electrolyte may be composed of only the above-described polymer or may further include another electrolyte. Other electrolytes include perfluorocarbon polymers such as Nafion, Flemion, and Aciplex that have been used in the past, sulfonated products of vinyl polymers such as polystyrene sulfonic acid, polybenzimidazole, polyether ether ketone, and other heat resistance Examples of the polymer include organic polymers such as a polymer having a sulfonic acid group or a phosphoric acid group introduced. When other electrolytes are included, the ratio of use is desirably 50% by weight or less, preferably 30% by weight in the total electrode electrolyte.
(Electrode paste)
The electrode paste of the present invention is composed of the above-mentioned electrode electrolyte, catalyst particles, and solvent, and may contain other components such as a dispersant and carbon fiber as necessary.

Catalyst particles The catalyst particles are composed of a catalyst supported on carbon or a metal oxide support, or a single catalyst.

  Platinum or a platinum alloy is used as the catalyst. When a platinum alloy is used, stability and activity as an electrode catalyst can be further imparted. Such platinum alloys include platinum group metals other than platinum (ruthenium, rhodium, palladium, osmium, iridium), iron, cobalt, titanium, gold, silver, chromium, manganese, molybdenum, tungsten, aluminum, silicon, rhenium. An alloy of platinum and one or more selected from zinc and tin is preferable, and the platinum alloy may contain an intermetallic compound of a metal alloyed with platinum.

The catalyst forms catalyst particles, either alone or supported on a carrier.
As the carrier for supporting the catalyst, carbon black such as oil furnace black, channel black, lamp black, thermal black and acetylene black is preferably used in view of the electron conductivity and the specific surface area. Further, artificial graphite or carbon obtained from organic compounds such as natural graphite, pitch, coke, polyacrylonitrile, phenol resin, furan resin, and the like may be used.

  Examples of the oil furnace black include “Vulcan XC-72”, “Vulcan P”, “Black Pearls 880”, “Black Pearls 1100”, “Black Pearls 1300”, “Black Pearls 2000”, and “Regal 400” manufactured by Cabot Corporation. “Ketjen Black EC” manufactured by Lion Corporation, “# 3150, # 3250” manufactured by Mitsubishi Chemical Corporation, and the like. Examples of the acetylene black include “DENKA BLACK” manufactured by Denki Kagaku Kogyo.

As the form of these carbons, in addition to particles, fibers can also be used. Further, the amount of the catalyst supported on the carbon is not particularly limited as long as the catalyst activity can be effectively exhibited, but the supported amount is 0.1 to 9.0 g- with respect to the carbon weight. Metal / g-carbon, preferably in the range of 0.25 to 2.4 g-metal / g-carbon.

  In addition to carbon, the carrier may be a metal oxide such as titania, zinc oxide, silica, ceria, alumina, alumina spinel, magnesia, zirconia, and the like.

Solvent The solvent of the electrode paste of the present invention is not particularly limited as long as it can dissolve or disperse the electrolyte. Further, not only one type but also two or more types of solvents can be used.

Specifically, water,
Methanol, ethanol, n-propyl alcohol, 2-propanol, 2-methyl-2-propanol, 2-butanol, n-butyl alcohol, 2-methyl-1-propanol, 1-pentanol, 2-pentanol, 3- Pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl 1-propanol, cyclohexanol, 1-hexanol 2-methyl-1-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3- Methylcyclohexanol, 4-methylcyclohexanol, 1-octanol, 2-octa Nord, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, Alcohols such as
Polyhydric alcohols such as ethylene glycol, propylene glycol and glycerol,
Dioxane, tetrahydrofuran, tetrahydropyran, diethyl ether, diisopropyl ether, di-n-propyl ether, butyl ether, phenyl ether, isopentyl ether, 1,2-dimethoxyethane, diethoxyethane, bis (2-methoxyethyl) ether, bis Ethers such as (2-ethoxyethyl) ether, cineol, benzyl ethyl ether, anisole, phenetole, acetal,
Ketones such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, 2-hexanone, 4-methyl-2-pentanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone Kind,
γ-butyrolactone, ethyl acetate, propyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, lactic acid Esters such as butyl,
Aprotic polar solvents such as dimethyl sulfoxide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, tetramethylurea,
Examples thereof include hydrocarbon solvents such as toluene, xylene, heptane, hexane, heptane, and octane, and these can be used in combination of one or more.

Dispersants Dispersants that may be included as necessary include oleic acid / N-methyltaurine, potassium oleate / diethanolamine salt, alkyl ether sulfate / triethanolamine salt, polyoxyethylene alkyl ether sulfate / triethanolamine salt , Amine salt of special modified polyether ester acid, amine salt of higher fatty acid derivative, amine salt of special modified polyester acid, amine salt of high molecular weight polyether ester acid, amine salt of special modified phosphoric acid ester, high molecular weight polyester acid amidoamine salt , Amidoamine salts of special fatty acid derivatives, alkylamine salts of higher fatty acids, amidoamine salts of high molecular weight polycarboxylic acids, sodium laurate, sodium stearate, sodium oleate sodium lauryl sulfate, Chyl sulfate sodium salt, stearyl sulfate sodium salt, oleyl sulfate sodium salt, lauryl ether sulfate ester salt, sodium alkylbenzene sulfonate, oil-soluble alkylbenzene sulfonate, α-olefin sulfonate, higher alcohol phosphate monoester di Anionic surfactants such as sodium salt, higher alcohol phosphate diester disodium salt, zinc dialkyldithiophosphate, benzyldimethyl {2- [2- (P-1,1,3,3-tetramethylbutylphenoxy) ethoxy] Ethyl} ammonium chloride, octadecylamine acetate, tetradecylamine acetate, octadecyltrimethylammonium chloride, tallow trimethylammonium chloride, dodecyltrimethylammonium Chloride, palm trimethylammonium chloride, hexadecyltrimethylammonium chloride, behenyltrimethylammonium chloride, palm dimethylbenzylammonium chloride, tetradecyldimethylbenzylammonium chloride, octadecyldimethylbenzylammonium chloride, dioleyldimethylammonium chloride, 1-hydroxyethyl-2- Addition of tallow imidazoline quaternary salt, 2-heptadecenyl-hydroxyethyl imidazoline, stearamide ethyl diethylamine acetate, stearamide ethyl diethylamine hydrochloride, triethanolamine monostearate formate, alkyl pyridium salt, higher alkylamine ethylene oxide addition , Polyacrylamide amine salt, modified polyacrylamide Min salts, cationic surfactants such as perfluoroalkyl quaternary ammonium iodide,
And dimethyl coconut betaine, dimethyl lauryl betaine, sodium laurylaminoethylglycine, sodium laurylaminopropionate, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, amide betaine, imidazolinium betaine, lecithin, 3- [ω-fluoroaccanoyl N -Amphoteric surfactants such as sodium ethylamino] -1-propanesulfonate, N- [3- (perfluorooctanesulfonamido) propyl] -N, N-dimethyl-N-carboxymethyleneammonium betaine, and coconut fatty acid diethanolamine (1: 2 type), coconut fatty acid diethanolamide (1: 1 type), bovine fatty acid diethanolamide (1: 2 type), bovine fatty acid diethanolamide (1: 1 type), oleic acid diethanolamide (1: 1 type) ) Hydroxyethyl lauryl amine, polyethylene glycol lauryl amine, polyethylene glycol coconut amine, polyethylene glycol stearyl amine, polyethylene glycol beef tallow amine, polyethylene glycol beef tallow propylene diamine, polyethylene glycol dioleyl amine, dimethyl lauryl amine oxide, dimethyl stearyl amine oxide, dihydroxyethyl lauryl amine Oxide, perfluoroalkylamine oxide, polyvinylpyrrolidone, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, fatty acid ester of glycerin, fatty acid ester of pentaerythlit Nonionic surfactants such as sorbite fatty acid ester, sorbitan fatty acid ester, sugar fatty acid ester, and amphoteric surfactants such as sodium laurylaminopropionate, stearyldimethylbetaine, lauryldihydroxyethylbetaine, etc. it can. These can be used alone or in combination of two or more. Among these, a surfactant having a basic group is preferable, an anionic or cationic surfactant is more preferable, and a surfactant having a molecular weight of 5,000 to 30,000 is more preferable. is there.

When the above dispersant is added to the electrode paste, the storage stability and fluidity are excellent, and the productivity during coating is improved.
Carbon fiber In the electrode paste according to the present invention, a carbon fiber on which a catalyst is not supported can be added as necessary.

As carbon fibers used as necessary in the present invention, rayon-based carbon fibers, PAN-based carbon fibers, lignin pover-based carbon fibers, pitch-based carbon fibers, vapor-grown carbon fibers, and the like can be used, preferably Vapor grown carbon fiber.

  When carbon fiber is added to the electrode paste, the pore volume in the electrode increases, thereby improving the diffusibility of fuel gas and oxygen gas, and improving the flooding caused by the generated water, thereby improving the power generation performance. .

Other Additives In the electrode paste according to the present invention, other components can be added as necessary. For example, a water repellent such as a fluorine polymer or a silicon polymer may be added. The water repellent has an effect of efficiently discharging generated water and contributes to improvement of power generation performance.

Composition The usage ratio of the catalyst particles in the paste according to the present invention is 1 to 20% by weight, preferably 3 to 15% by weight. Further, the usage ratio of the electrode electrolyte is 0.5 to 30% by weight, and preferably 1 to 15% by weight. Further, the ratio of the solvent used is 5 to 95% by weight, preferably 15 to 90% by weight.

The use ratio of the dispersant used as necessary is 0% by weight to 10% by weight, preferably 0% by weight to 2% by weight, and the use ratio of the carbon fiber used as necessary is The ratio is 0 to 20% by weight, preferably 1 to 10% by weight. (The total amount does not exceed 100% by weight)
When the use ratio of the catalyst particles is less than the above range, the electrode reaction rate may be lowered. On the other hand, if it is larger than the above range, the viscosity of the electrode paste increases and uneven coating may occur during coating.

  When the use ratio of the electrolyte is less than the above range, the proton conductivity decreases. Furthermore, it cannot play the role of a binder, and an electrode cannot be formed. Moreover, when larger than the said range, the pore volume in an electrode will reduce.

When the use ratio of the solvent is within the above range, a sufficient pore volume in the electrode necessary for power generation can be secured. Moreover, if it exists in the said range, it is suitable for the handling as a paste.
When the use ratio of the dispersant is within the above range, an electrode paste having excellent storage stability can be obtained. When the use ratio of the carbon fiber is less than the above range, the effect of increasing the pore volume in the electrode is low. Moreover, when larger than the said range, an electrode reaction rate may fall.

Preparation of Paste The electrode paste according to the present invention can be prepared , for example, by mixing the above-mentioned components at a predetermined ratio and kneading by a conventionally known method.

The order of mixing each component is not particularly limited. For example, all components are mixed and stirred for a certain period of time, or components other than the dispersant are mixed and stirred for a certain period of time, and then a dispersant is added as necessary. It is preferable to add and stir for a certain time. Moreover, you may adjust the quantity of a solvent as needed and may adjust the viscosity of a paste.
(Electrode and membrane-electrode assembly)
When the electrode paste according to the present invention as described above is applied onto a transfer substrate and the solvent is removed, the electrode of the present invention is obtained. By forming such an electrode on at least one surface of the polymer electrolyte, the membrane-electrode assembly of the present invention can be obtained.

  As the transfer substrate, a sheet made of a fluoropolymer such as polytetrafluoroethylene (PTFE), a glass plate or a metal plate whose surface is treated with a release agent, a polyethylene terephthalate (PET) sheet, or the like can be used.

Examples of the coating method include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.
When the electrode applied on the transfer substrate is dried to remove the solvent and then transferred to at least one surface of the solid polymer electrolyte membrane, the membrane-electrode assembly of the present invention is obtained.

The solid polymer electrolyte membrane used for the membrane electrode assembly of the present invention is not particularly limited as long as it is a proton conductive solid polymer membrane.
For example, an electrolyte membrane made of a perfluoroalkyl sulfonic acid polymer such as Nafion (DuPont), Flemion (Asahi Glass), Aciplex (Asahi Kasei),
Reinforced electrolyte membrane combined with polytetrafluoroethylene fiber and porous membrane to perfluoroalkylsulfonic acid polymer,
An electrolyte membrane comprising a partially fluorinated sulfonated polymer such as polytetrafluoroethylene graft sulfonated polystyrene,
Sulfonated polyarylene, sulfonated polyphenylene, sulfonated polyether ketone, sulfonated polyether sulfone, sulfonated polyether nitrile, sulfonated polyphenylene ether, sulfonated polyphenylene sulfide, sulfonated polybenzimidazole, sulfonated polybenzoxazole, sulfone Electrolyte membranes made of aromatic sulfonated polymers such as modified polybenzthiazole,
Electrolyte membranes composed of aliphatic sulfonated polymers such as sulfonated polystyrene and sulfonic acid-containing acrylic polymers,
A pore filling type electrolyte membrane in which these are combined with a porous membrane,
Examples thereof include an electrolyte membrane made of an acid-impregnated polymer in which a polymer such as polybenzoxazole, polybenzimidazole, or polybenzthiazole is impregnated with phosphoric acid or sulfuric acid. Among these, an electrolyte membrane made of an aromatic sulfonated polymer is preferable.

Moreover, the polymer which comprises the said electrolyte for electrodes can also be used as a solid polymer electrolyte.
In order to transfer the electrode to the solid polymer electrolyte membrane, a hot press method can be used. In the hot press method, the electrode paste is applied to carbon paper or a release sheet, but the electrode paste application surface and the electrolyte membrane are pressure-bonded. Hot pressing is usually performed in a temperature range of 50 to 250 ° C. and a pressure of 10 to 500 kg / cm ² for a period of 1 minute to 180 minutes.

As another method for obtaining the membrane-electrode assembly of the present invention, there is a method of repeatedly applying and drying the electrode layer and the electrolyte membrane stepwise. There is no restriction | limiting in particular in the order of application | coating and drying.
For example, an electrolyte membrane solution is applied on a substrate such as a PET film and dried to form an electrolyte membrane, and then the electrode paste of the present invention is applied thereon. Next, the substrate is peeled off, and the electrode paste is applied to the other surface. Finally, the solvent is removed to obtain a membrane-electrode assembly (this membrane-electrode assembly may be referred to as an electrolyte membrane with catalyst). Examples of the application method include the same methods as described above.

The removal of the solvent is performed at a drying temperature of 20 ° C to 180 ° C, preferably 50 ° C to 160 ° C, and a drying time of 5
The time is from min to 600 min, preferably from 30 min to 400 min.
If necessary, the electrolyte membrane may be immersed in water to remove the solvent. The water temperature is 5 ° C to 120 ° C, preferably 15 ° C to 95 ° C, and the water immersion time is 1 minute to 72 hours, preferably 5 minutes to 48 hours.

  Contrary to the above method, the electrode paste is first applied to form the electrode layer, and then the electrolyte membrane solution is applied to create the electrolyte membrane, and then the other electrode layer (catalyst layer). May be formed in the same manner to form an electrolyte membrane with a catalyst.

The thickness of the electrode layer is not particularly limited, but the metal supported as a catalyst is 0.05 to 4.0 mg / cm ² , preferably 0.1 to 2.0 mg / cm ² per unit area. It is desirable to be in the range of ² . Within this range, sufficiently high catalytic activity is exhibited and protons can be efficiently conducted.

  The pore volume of the electrode layer is 0.05 to 3.0 ml / g, preferably 0.1 to 2.0 ml / g. The pore volume of the electrode layer is measured by a method such as a mercury intrusion method or a gas adsorption method.

The thickness of the electrolyte membrane is not particularly limited, but if the thickness is increased, the power generation efficiency is reduced or it is difficult to reduce the weight, so that the thickness may be about 10 to 200 μm. is not.
[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. Various measurement items in the examples were determined as follows.

(Molecular weight)
For the number average molecular weight (Mn) of the hydrophobic unit before sulfonation, tetrahydrofuran (THF) was used as a solvent, and the molecular weight in terms of polystyrene was determined by GPC. The weight average molecular weight (Mw) of the sulfonated polymer was determined by GPC using polystyrene as a molecular weight using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent.

(Ion exchange capacity)
Wash the resulting sulfonated polymer until the pH of the sulfonated polymer is 4 to 6, remove free residual acid, thoroughly wash with water, dry, weigh a predetermined amount, and mix THF / water It melt | dissolved in the solvent and titrated with the standard solution of NaOH by making phenolphthalein into an indicator, and calculated | required the ion exchange capacity from the neutralization point.

(Glass-transition temperature)
The glass transition temperature of the sulfonated polymer was measured with a dynamic viscoelasticity measuring device.
(Measurement of membrane resistance)
The membrane was sandwiched between conductive carbon plates from above and below via sulfuric acid having a concentration of 1 mol / l, the AC resistance between the carbon plates was measured at room temperature, and the following formula was obtained.
Membrane resistance (Ω · cm ² ) = resistance value between carbons across the membrane (Ω) −blank value (Ω) × contact area (cm ² )
(Power generation evaluation)
The catalyst-attached electrolyte membrane is sandwiched between carbon papers and 160 ° C under a pressure of 100 kg / cm ^2.
A membrane electrode assembly (MEA) was formed by hot press molding under conditions of × 15 min. This MEA is sandwiched between two titanium current collectors, and a heater is placed on the outside of the current collector, with an effective area of 25c.
An m ² fuel cell was assembled.

The temperature of the fuel cell was maintained at 85 ° C., and hydrogen and oxygen were supplied at 2 atm at a humidity of 35% RH and 100% RH. Under each condition, the voltage between terminals at current densities of 0.5 A / cm ² and 1.0 A / cm ² was measured.

Further, the temperature of the fuel cell was kept at 85 ° C., hydrogen and oxygen were supplied at 2 atm at a humidity of 35% RH, and the voltage between terminals at a current density of 0.5 A / cm ² was measured for 150 hours.
(Molecular weight)
For the number average molecular weight (Mn) of the hydrophobic unit before sulfonation, tetrahydrofuran (THF) was used as a solvent, and the molecular weight in terms of polystyrene was determined by GPC. The weight average molecular weight (Mw) of the sulfonated polymer was determined by GPC using polystyrene as a molecular weight using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent.

(Ion exchange capacity)
Wash the resulting sulfonated polymer until the pH of the sulfonated polymer is 4 to 6, remove free residual acid, thoroughly wash with water, dry, weigh a predetermined amount, and mix THF / water It melt | dissolved in the solvent and titrated with the standard solution of NaOH by making phenolphthalein into an indicator, and calculated | required the ion exchange capacity from the neutralization point.

(Glass-transition temperature)
The glass transition temperature of the sulfonated polymer was measured with a dynamic viscoelasticity measuring device.
(Measurement of membrane resistance)
The membrane was sandwiched between conductive carbon plates from above and below via sulfuric acid having a concentration of 1 mol / l, the AC resistance between the carbon plates was measured at room temperature, and the following formula was obtained.
Membrane resistance (Ω · cm ² ) = resistance value between carbons across the membrane (Ω) −blank value (Ω) × contact area (cm ² )
(Power generation evaluation)
The catalyst-attached electrolyte membrane is sandwiched between carbon papers and 160 ° C under a pressure of 100 kg / cm ^2.
A membrane electrode assembly (MEA) was formed by hot press molding under conditions of × 15 min. The MEA was sandwiched between two titanium current collectors, and a heater was placed outside the MEA to assemble a fuel cell having an effective area of 25 cm ² .

The temperature of the fuel cell was maintained at 85 ° C., and hydrogen and oxygen were supplied at 2 atm at a humidity of 35% RH and 100% RH. Under each condition, the voltage between terminals at current densities of 0.5 A / cm ² and 1.0 A / cm ² was measured.

Further, the temperature of the fuel cell was kept at 85 ° C., hydrogen and oxygen were supplied at 2 atm at a humidity of 35% RH, and the voltage between terminals at a current density of 0.5 A / cm ² was measured for 150 hours.
Synthesis Example 1: Synthesis of N-trifluoromethylsulfonyl-3- (2,5-dichlorobenzoyl) benzenesulfonic acid imide (1)

Triethylamine (27 mL, 200 mmol), 3- (2,5-dichlorobenzoyl) benzenesulfonyl chloride (27.97 g, 80 mmol) and trifluoromethanesulfonamide (13.30 g, 87 mmol) dissolved in dry acetone (250 mL) The cold solution was added dropwise under nitrogen and the reaction mixture was stirred at room temperature for 24 hours. After the triethylammonium chloride precipitate was separated by filtration, the filtrate was concentrated by rotary evaporator, diluted with ethyl acetate (400 mL) and washed with 1N HCl (2 × 200 mL).
The organic phase was dried over MgSO ₄ and the solvent removed to give the acidic sulfonic acid imide crude product as a brown oil. The product was redissolved in methanol / water (200/75 mL) and treated with K ₂ CO ₃ (6.91 g, 50 mmol, dissolved in 7 ml of water).

The solution was filtered off, concentrated to about 100 mL and slowly cooled. The precipitate was collected by filtration, washed with water, dried, and recrystallized with ethanol using activated carbon to obtain potassium sulfonate imide 1 as colorless crystals. Yield: 30.83 g (77%)
Synthesis Example 2: Synthesis of sulfonic acid imide-containing block copolymer Dry DMAc (45 mL) was mixed with the compound of Synthesis Example 1 (14.01 g, 28.00 mmol), 2-chlorobenzonitrile-terminated poly (ether nitrile) oligomer (M _n = 8200, 8.50 g, 1.04 mmol), Ni (PPh ₃ ) ₂ Cl ₂ (0.57 g, 0.87 mmol), PPh ₃ (3.05 g, 11.61 mmol), NaI (0.13 g, 0 .87 mmol), Zn dust (4.74 g, 72.6 g) was added under a dry nitrogen stream and the reaction mixture was mechanically stirred at 80 ° C. for 4 hours. The resulting thick suspension was diluted with THF and filtered through a celite pad to remove excess Zn. Toluene and hexane were sequentially added to the filtrate to precipitate the crude polymer as the potassium salt. The powdered product is stirred with 2N H ₂ SO ₄ at high temperature (80 ° C.) for 2 hours, filtered at high temperature, washed repeatedly until pH> 6, stirred in boiling water for 20 hours, filtered and dried. did. Yield: 16.20 g (84%); GPC: M _n = 75100; M _w = 159000. The isolated acidic polymer (3.90 g) was dissolved in a mixture of NMP (17.35 g) and methanol (8.69). The film is cast on a PET substrate using a doctor blade, dried in an oven at 80 ° C. for 30 minutes, peeled from the substrate, dried at 140 ° C. for 30 minutes, and stored in deionized water for 24 hours. And dried to constant weight in the atmosphere. The resulting membrane is 1.42 mequiv. At a temperature of 85 ° C. and a relative humidity of 90%. / G ion exchange capacity and a proton conductivity of 0.132 S / cm comparable to Nafion 117 membrane (0.127 S / cm).

Synthesis Example 3: Synthesis of sulfonic acid imide-sulfonic acid copolymer The sulfonic acid imide monomer (6.00 g, 12 mmol) of Synthesis Example 1 and neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate (14.45 g) The polymerization operation of Synthesis Example 2 was performed on a mixture of 2-chlorobenzonitrile-terminated poly (ether nitrile) oligomers (M _n = 8200, 6.51 g, 0.79 mmol). The crude polymer, which is a neopentyl ester, is dissolved in DMAc, reacted with excess LiBr at 135 ° C., and treated in the same manner as in Synthesis Example 2 to treat 25 mol% sulfonic acid imide and 75 mol% sulfonic acid units as acidic blocks. To obtain a segmented copolymer. Yield: 15.25 g (74%); GPC:
M _n = 76,800; M _w = 200,000. A membrane was prepared according to Synthesis Example 2. The resulting membrane is 2.25 mequiv. At a temperature of 85 ° C. and a relative humidity of 90%. / G ion exchange capacity and 0.313 S / cm proton conductivity over Nafion 117. Conductivity (0.029 S / cm) at 85 ° C. and 50% relative humidity was comparable to Nafion 117 (0.032 S / cm).

[Example 1]
[Preparation of Paste 1]
Put 50 g of zirconia balls (trade name: YTZ ball, manufactured by Nikkato Co., Ltd.) 25 g in a 50 ml glass bottle, and carry platinum-supported carbon particles (Pt: 46 wt%, (Tanaka Kikinzoku Kogyo Co., Ltd .: TEC10E50E) 1.51 g. 0.88 g of distilled water, 3.23 g of a 15% water-1,2-dimethoxyethane solution (weight ratio 10:90) of the sulfonated polymer synthesized in Synthesis Example 3 and 13.97 g of 1,2-dimethoxyethane were added. The mixture was stirred for 60 minutes with a wafer blower to obtain a paste having a viscosity of 50 cp (25 ° C.).
[Production of gas diffusion layer]
Carbon black and polytetrafluoroethylene (PTFE) particles are mixed at a weight ratio of carbon black: PTFE particles = 4: 6, and a slurry in which the resulting mixture is uniformly dispersed in ethylene glycol is mixed on one side of carbon paper. The base layer was applied and dried to prepare two diffusion layers 3 composed of the base layer and carbon paper.
[Production of gas diffusion electrode]
On the diffusion layer produced above, paste 1 was applied using a doctor blade so that the amount of platinum applied was 0.5 mg / cm ² . This was heated and dried at 95 ° C. for 10 minutes to form a gas diffusion electrode layer.
[Production of membrane-electrode assembly]
One electrolyte membrane (thickness 30 μm) made of the sulfonated polymer of Synthesis Example 2 was prepared, sandwiched between the pair of gas diffusion electrode layers prepared above, and under a pressure of 100 kg / cm ² , 16
A membrane-electrode assembly was prepared by hot press molding under the condition of 0 ° C. × 15 min.
[Power generation evaluation]
A polymer electrolyte fuel cell was constructed by laminating a separator also serving as a gas flow path on both sides of the membrane-electrode assembly obtained above. Using this as a single cell, one was supplied with air as an oxygen electrode, and the other was supplied with pure hydrogen as a fuel electrode to generate electricity. Initial power generation characteristics were evaluated under the conditions of power generation: cell temperature 95 ° C., air electrode side relative humidity 75%, air electrode side flow rate 4 L / min, fuel electrode side relative humidity 40%, fuel electrode side flow rate 1 L / min. Table 2 shows the output voltage at a current density of 1.0 A / cm ² . After initial characteristic evaluation, the current density was measured at a cell temperature of 95 ° C., an air electrode side relative humidity of 75%, an air electrode side flow rate of 0.2 L / min, a fuel electrode side relative humidity of 40%, and a fuel electrode side flow rate of 0.6 L / min. Holding at 0.1 A / cm ² , continuous power generation was performed for 500 hours. After 500 hours, the output voltage at a current density of 1.0 A / cm ² was measured under the same conditions as the initial power generation characteristic evaluation conditions. The measurement results are shown in Table 1.
[Comparative Example 1]
An electrode paste, a gas diffusion layer, a gas diffusion electrode, and a membrane-electrode junction were obtained in the same manner except that the polymer used in the electrode paste of Example 1 was changed to a Nafion solution (2020CS, 20.1 wt% solution manufactured by Dupont). A body was prepared and power generation was evaluated under the same conditions.

Claims (7)

0.5 to 100 mol% (excluding 100 mol% ) of repeating structural units represented by the following formula (1 '), 0 to 99.5 mol% of repeating structural units represented by the formula (A') ( The polyarylene polymer containing the structures (1 ′) and (A ′) is 100 mol%:

(In the formula (1 ′), A is a divalent electron-withdrawing group, B is a divalent electron-donating group or a single bond, and ^Ma is hydrogen, an alkali metal, a tertiary ammonium, or a fourth group. A cationic species selected from quaternary ammonium cations, R ^a is a hydrocarbon or fluorinated hydrocarbon group having 1 to 20 carbon atoms, and Ar is —SO ₂ —NM ^b —SO ₂ —R ^b (wherein M ^b is hydrogen, an alkali metal or a tertiary ammonium or quaternary ammonium cation, and R ^b is a hydrocarbon or fluorinated hydrocarbon group having 1 to 20 carbon atoms. A group (not including a fluorine atom) , m is an integer of 0 to 10, n is an integer of 0 to 10, and k is an integer of 1 to 4.
In formula (A ′), A ′ and D are each independently —CO—, —SO—, —SO ₂ —, —CONH—, —COO—, — (CF ₂ ) _p — (wherein p is an integer of 1 to 10), — (CH ₂ ) _p — (wherein p is an integer of 1 to 10), —CR ′ ₂ — (wherein R ′ is an aliphatic hydrocarbon group) , An aromatic hydrocarbon group or a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, -O-, -S-, and B 'is an oxygen atom or sulfur R ¹ to R ^{16, which} may be the same or different, are a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group partially or completely halogen-substituted, an aryl group, an allyl group, a nitro group, And at least one atom or group selected from nitrile groups, and s and t are each independently 0 to 0 Is an integer, r is 0 or a positive integer. )
An electrode electrolyte for a polymer fuel cell, comprising:   2. The polymer electrolyte fuel cell electrode electrolyte according to claim 1, wherein the aromatic group constituting Ar is a group selected from a phenyl group, a naphthyl group, an anthracenyl group, and a phenanthrenyl group. R ^a and R ^b are linear or branched fluorinated hydrocarbon groups represented by the general formula —C _p F _{2p + 1} (wherein p is an integer of 1 to 10). The electrode electrolyte for polymer fuel cells according to claim 1 or 2. The divalent electron withdrawing group, -CO-, CONH -, - ( CF 2) p - ( wherein, p is an integer of 1 to _{10), - C (CF 3)} 2 -, - COO -, - SO -, - SO 2 - is selected from the divalent electron donating group, -O -, - S -, - CH = CH -, - C≡C-,

The electrode electrolyte for polymer fuel cells according to any one of claims 1 to 3, wherein the electrode electrolyte is a group selected from the group consisting of:   An electrode paste comprising the electrolyte according to claim 1, catalyst particles, and a solvent. An electrode for a polymer electrolyte fuel cell comprising the electrolyte according to any one of claims 1 to 4 and catalyst particles.   A membrane-electrode assembly comprising the electrode according to claim 6 on at least one surface of a polymer electrolyte membrane.