JP4879639B2 - Electrode electrolyte for polymer fuel cell and use thereof - Google Patents

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 comprising a polymer composed of a specific repeating 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 conventional materials known as electrolytes have a problem that the conductivity of hydrogen ions is significantly reduced by freezing of water below freezing point. Considering the widespread use including cold regions, it is an important issue in this field to stably start or operate the fuel cell particularly at 0 ° C. or below where water freezes.

  That is, the object of the present invention is to solve the above-mentioned problem of cost and the problem of recovery of catalytic metal, and to exhibit a sufficient function even in a low temperature environment, and an electrode for a polymer electrolyte fuel cell The present invention provides an electrolyte, and further provides an electrode paste, an electrode, and a catalyst-attached electrolyte membrane containing the electrolyte.

  The present invention has been made in order to solve the above-mentioned problems. The amount of non-frozen water contained in the proton conducting membrane at low temperature and its self-diffusion coefficient are measured using a pulsed NMR method. I found a way to measure. Next, as a result of examining the correlation between each value and proton conductivity at low temperature, by designing a polymer in which the value obtained by multiplying the amount of unfrozen water and the self-diffusion coefficient falls within a specific range. The inventors have found that an electrode electrolyte membrane having excellent low-temperature power generation characteristics can be obtained.

  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] Ion conductive polymer segment (A) and non-ion conductive polymer segment (
An electrode electrolyte comprising a copolymer having B),
The electrolyte was immersed in water, heated at 90 ° C. for 30 minutes to absorb water, and then cooled to −20 ° C. When the water was absorbed, the weight of the water that was not frozen [g] (both High per 1 g of polymer) and a multiplier (multiplied value) of self-diffusion coefficient [× 10 ⁻¹⁰ m ² / s] measured at −20 ° C. in the range of 0.2 to 1.5. Electrode electrolyte for molecular fuel cells.
[2] The polymer electrolyte fuel cell electrode electrolyte according to [1], wherein the self-diffusion coefficient of water not frozen at −20 ° C. is 0.40 × 10 ⁻¹⁰ m ² / s or more.
[3] The ion conductive polymer segment (A) includes a structural unit represented by the following general formula (A):
The polymer electrolyte fuel cell electrode electrolyte of [1] to [2], wherein the non-ion conductive polymer segment (B) includes a structural unit represented by the following general formula (B):

Wherein Y is —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C (CF ₃ ) represents at least one structure selected from the group consisting of ₂ —, Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ represents at least one structure selected from the group consisting of —, —O—, and —S—, and Ar represents —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p An aromatic group having a substituent represented by SO ₃ H. m represents an integer of 0 to 10, n represents an integer of 0 to 10, k represents an integer of 1 to 4, and p represents 1 Represents an integer of ~ 12)

... (B)
(In the formula, A is independently a direct bond or —CO—, —SO ₂ —, —SO—, —CONH—,
_{-COO -, - (CF 2)} l - (l is an integer of 1 to _{10), - (CH 2) l} - (l is an integer of 1 to 10), - C (R ') 2 - (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), at least one selected from the group consisting of a cyclohexylidene group, a fluorenylidene group, —O—, and —S—. Wherein B is independently an oxygen atom or a sulfur atom, R ^{1 to} R ¹¹ may be the same as or different from each other, and a hydrogen atom, a fluorine atom, an alkyl group, part or all of which are halogenated And at least one atom or group selected from the group consisting of a halogenated alkyl group, an allyl group, an aryl group, a nitro group, and a nitrile group. X represents —CO— or —SO ₂ —, Ar ′ represents an aromatic group,
t represents an integer of 0 to 4, and r represents an integer of 1 or more. )
[4] In the structural unit represented by the general formula (A), Y is —CO—, Ar is an aromatic ring having a substituent represented by —SO ₃ H, m is 0, and n is An ion conducting polymer segment (A ′) that is 0,
In the structural unit represented by the general formula (B), A is independently a direct bond or —C (R ′) ₂ — (R ′ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a halogenated hydrocarbon group. And at least one group selected from the group consisting of cyclohexylidene group, fluorenylidene group, and -O-, B is an oxygen atom, R ¹ to R ¹⁶ is a non-ion conductive segment of a hydrogen atom (B ') [1] ~ polymer fuel cell electrode electrolyte [3].
[5] An electrode paste comprising the electrolyte of [1] to [4], catalyst particles, and a solvent.
[6] An electrode for a polymer electrolyte fuel cell, comprising the electrolyte of [1] to [4] and catalyst particles.
[7] A membrane-electrode assembly comprising the electrode of [6] on at least one surface of a polymer electrolyte membrane.

According to the present invention, there is provided an electrode electrolyte for a polymer electrolyte fuel cell that is inexpensive, easily recovers a catalytic metal, has excellent proton conductivity and dimensional stability, and has excellent low-temperature power generation characteristics. 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)
An electrode electrolyte for a polymer electrolyte fuel cell of the present invention is an electrode electrolyte membrane comprising a copolymer having an ion conductive polymer segment (A) and a non-ion conductive polymer segment (B),
The electrolyte was immersed in water, heated at 90 ° C. for 30 minutes, and then cooled to −20 ° C. When the electrolyte was cooled to −20 ° C., the weight of non-frozen water measured at −20 ° C. (per 1 g of copolymer) And a self-diffusion coefficient [× 10 ⁻¹⁰ m ² / s] measured at −20 ° C. (multiplied value) is in the range of 0.2 to 1.5, preferably 0.20. ~ 1.00.

If the multiplication value is within the above range, the water does not freeze, and hydrogen ions diffuse in the membrane, so that sufficient proton conductivity can be obtained even at low temperatures.
On the other hand, if the amount is less than the above range, the amount of water adsorbed on the ion conductive group is small and sufficient proton conductivity cannot be exhibited. On the other hand, if the above range is exceeded, swelling and dimensional changes of the proton conducting membrane are large, and there is a tendency for peeling from the electrode layer surface and cracking of the electrode layer during power generation of the fuel cell.

The self-diffusion coefficient [× 10 ⁻¹⁰ m ² / s] is 0.40 or more, preferably 0.50 or more. When the self-diffusion coefficient is within the above range, the water does not freeze and hydrogen ions are diffused in the membrane, so that sufficient proton conductivity can be obtained even at a low temperature.

On the other hand, if the amount is less than the above range, the amount of water adsorbed on the ion conductive group is small, and a sufficient diffusion rate of hydrogen ions cannot be obtained, so that sufficient ion conductivity cannot be expressed.
The measurement of the amount of unfrozen water in the electrode electrolyte at −20 ° C. and the self-diffusion coefficient of water is performed as follows.

  In any measurement, the electrode electrolyte is immersed in water, heated at 90 ° C. for 30 minutes, and then taken out of the water to completely remove the water on the membrane surface. Thereafter, the membrane was rapidly cooled to −80 ° C., left at −80 ° C. for 30 minutes, then increased by 10 ° C. every 5 minutes, and after reaching −20 ° C., kept at −20 ° C. for 60 minutes. And

The amount of moisture that is not frozen at −20 ° C. in the electrode electrolyte is measured using pulsed NMR, and is calculated using a calibration curve from the intensity of the FID (free decay) signal observed by NMR.
The self-diffusion coefficient of water at −20 ° C. in the electrode electrolyte is obtained by measurement using a known magnetic field gradient NMR method using a magnetic field gradient and a spin echo method.

Copolymer In the present invention, the material for forming the electrode electrolyte is a copolymer having an ion conductive polymer segment (A) and a non-ion conductive polymer segment (B).

  In the present invention, the copolymer forming the electrode electrolyte includes a repeating structural unit represented by the following general formula (A) (segment (A)) and a repeating structural unit represented by the following general formula (B) ( A polyarylene having a sulfonic acid group containing a segment (B)), for example, a polyarylene having a sulfonic acid group represented by the following general formula (C) is preferable.

  When a copolymer represented by the following general formula (C) is used, water resistance and mechanical strength are improved, so that the ion exchange capacity can be improved, and accordingly, the moisture content of unfrozen water at −20 ° C. Further, the self-diffusion coefficient of water is increased, and the proton conductivity is also improved.

(Polyarylene having a sulfonic acid group)
The polyarylene having a sulfonic acid group suitably used in the present invention includes a repeating structural unit represented by the following general formula (A) and a structural unit represented by the following general formula (B).

In the formula, Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _l.
It represents at least one structure selected from the group consisting of — (l is an integer of 1 to 10) and —C (CF ₃ ) ₂ —. Preferably Y is -CO-.

Z is a direct bond or at least one selected from the group consisting of — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CH ₃ ) ₂ —, —O—, and —S—. The structure of the species is shown.
Ar represents an aromatic group having a substituent represented by —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H. Preferably Ar is —SO ₃ H.

  m and n represent an integer of 0 to 10. Preferably, m = n = 1. k shows the integer of 1-4. p represents an integer of 1 to 12.

In the formula, A is independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —
COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), — (CH ₂ ) ₁ — (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-. . Preferably, a direct bond, or —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, —O—, — It is at least one structure selected from the group consisting of S-.

B is independently an oxygen atom or a sulfur atom, preferably an oxygen atom.
R ^{1 to} R ¹¹ may be the same as or different from each other, and may be a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group partially or wholly halogenated, an allyl group, an aryl group, a nitro group, or a nitrile group. At least one atom or group selected from the group consisting of Preferably it is a hydrogen atom.

X represents —CO— or —SO ₂ —, preferably —CO—.
Ar ′ represents an aromatic group, and specific examples include a phenyl group and a naphthyl group.
t shows the integer of 0-4.

r represents an integer of 1 or more.
Specifically, the polyarylene having a sulfonic acid group is a polymer represented by the following general formula (C).

(In the formula (C), Ar, Ar ′, A, B, X, Y, Z, k, m, n, r, t, and R ¹ to
R ¹¹ is synonymous with Ar, Ar ′, A, B, X, Y, Z, k, m, n, r, t, and R ^{1 to} R ^{11 in the} general formulas (A) and (B), respectively. It is. )
The polyarylene having a sulfonic acid group used in the present invention contains 0.5 to 99.999 mol%, preferably 10 to 99.999 mol, of the structural unit represented by the general formula (A) (ratio of x). The structural unit represented by the above general formula (B) (ratio of y) is contained in a ratio of 99.5 to 0.001 mol%, preferably 90 to 0.001 mol%.
<Method for producing polymer>
For the production of polyarylene having a sulfonic acid group, for example, the following three methods, Method A, Method B and Method C, can be used.

(Method A)
For example, in the method described in JP-A No. 2004-137444, a monomer having a sulfonate group that can be a structural unit represented by the general formula (A), and a structural unit represented by the general formula (B) A polyarylene having a sulfonic acid ester group is produced by copolymerization with a monomer or oligomer that can be synthesized, and the sulfonic acid ester group is deesterified, and then the sulfonic acid ester group is converted into a sulfonic acid group. be able to.

(Method B)
For example, in the method described in JP-A No. 2001-342241, a monomer having a skeleton represented by the general formula (A) and having no sulfonic acid group or sulfonic acid ester group, and the general formula (B) It is also possible to synthesize this polymer by copolymerizing a monomer or oligomer that can be a structural unit represented and sulfonating the polymer using a sulfonating agent.

(Method C)
In the general formula (A), when Ar is an aromatic group having a substituent represented by —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H, for example, A precursor monomer that can be a structural unit represented by the general formula (A) and a monomer or oligomer that can be a structural unit represented by the general formula (B) by the method described in Japanese Unexamined Patent Application Publication No. 2005-60625 Can be synthesized by a method in which an alkylsulfonic acid or a fluorine-substituted alkylsulfonic acid is introduced.
As specific examples of the monomer having a sulfonic acid ester group that can be used in (Method A) and can be the structural unit represented by the general formula (A), JP-A Nos. 2004-137444 and 2004-345997 are disclosed. Examples thereof include sulfonic acid esters described in JP-A-2004-346163.
As a specific example of a monomer having no sulfonic acid group or sulfonic acid ester group that can be a structural unit represented by the above general formula (A) that can be used in (Method B), JP-A-2001-342241 Examples thereof include dihalides described in Japanese Patent Laid-Open No. 2002-293889.
Specific examples of precursor monomers that can be used in (Method C) and can be structural units represented by the above general formula (A) include dihalides described in JP-A-2005-36125. Can be mentioned.

  Moreover, the following compounds can be mentioned as a specific example of the monomer or oligomer which can be used in any method and can be the structural unit represented by the general formula (B). Here, D represents a chlorine atom, a bromine atom, or an iodine atom.

  Furthermore, for example, the following copolymers can also be used.

  In order to obtain a polyarylene having a sulfonic acid group, first, a monomer that can be a structural unit represented by the general formula (A) and a monomer that can be a structural unit represented by the general formula (B), Alternatively, it is necessary to copolymerize with an oligomer to obtain a precursor polyarylene. This copolymerization is carried out in the presence of a catalyst, and the catalyst used in this case is a catalyst system containing a transition metal compound. This catalyst system is (1) a transition metal salt and a ligand. A compound (hereinafter referred to as “ligand component”) or a transition metal complex coordinated with a ligand (including a copper salt) and (2) a reducing agent as essential components, and further increase the polymerization rate. Therefore, “salt” may be added.

  Specific examples of these catalyst components, the use ratio of each component, the polymerization conditions such as the reaction solvent, concentration, temperature, time, etc. include the compounds described in JP-A No. 2001-342241.

The polyarylene having a sulfonic acid group can be obtained by converting the precursor polyarylene to a polyarylene having a sulfonic acid group. As this method, there are the following three methods.
(Method A)
A method of deesterifying a polyarylene having a sulfonate group of a precursor by a method described in JP-A-2004-137444.
(Method B)
A method of sulfonating a precursor polyarylene by a method described in JP-A No. 2001-342241.
(Method C)
A method of introducing an alkylsulfonic acid group into the precursor polyarylene by the method described in JP-A-2005-60625.

  The polyarylene having a sulfonic acid group of the general formula (C) produced by the above method has an ion exchange capacity of usually 0.3 to 5 meq / g, preferably 0.5 to 3 meq / g, more preferably Is 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.

  The ion exchange capacity is, for example, a precursor monomer that can be a structural unit represented by the general formula (A), a monomer that can be a structural unit represented by the general formula (B), or the kind of oligomer, and the use ratio. It can be adjusted by changing the combination. Specifically, the monomer ratio may be changed so that the composition ratio is as described above.

  The molecular weight of the polyarylene having a sulfonic acid group 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).

(Manufacture of electrode electrolyte)
In order to produce an electrode electrolyte from the copolymer, for example, a composition comprising the copolymer and an organic solvent is prepared, cast on the substrate by casting using the composition, and formed into a film shape. There is a method for producing a film, such as a casting method.

  In addition, the said composition contains inorganic acid, such as a sulfuric acid and phosphoric acid, organic acid containing carboxylic acid, appropriate amount of water, etc. other than the copolymer and organic solvent which consist of segment (A) and segment (B). Also good.

  The polymer concentration in the composition is usually 5 to 40% by weight, preferably 7 to 25% by weight, although it depends on the molecular weight of the copolymer comprising the segment (A) and the segment (B). If it is less than 5% by weight, it is difficult to increase the film thickness, and pinholes may be easily generated. On the other hand, if it exceeds 40% by weight, the solution viscosity is so high that it is difficult to form a film, and surface smoothness may be lacking.

  The solution viscosity of the composition is usually 2,000 to 100,000 mPa · s, preferably 3,000 to 50,000 mPa · s, although it depends on the molecular weight of the copolymer and the polymer concentration. If it is less than 2,000 mPa · s, the retention of the solution during processing is poor, and it may flow from the substrate. On the other hand, when it exceeds 100,000 mPa · s, the viscosity is too high to be extruded from the die, and it may be difficult to form a film by the casting method.

  The composition can be prepared, for example, by mixing the above-described components at a predetermined ratio and mixing them using a conventionally known method, for example, a mixer such as a wafer blower, homogenizer, disperser, paint conditioner, or ball mill. .

As an organic solvent used, methanol, ethanol, 1-propanol, 2-propanol, 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, dicyclohexanol, 1-hexanol, 2 -Methyl-1-pentanol, 2-methyl-2-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-methylcyclohexanol, 2-methylcyclohexanol, 3-methylcyclo Hexanol, 4-methylcyclohexanol, 1-octanol, 2-octa 2-ethyl-1-hexanol, ethylene glycol, propylene glycol, 1.3-butanediol, glycerol, m-cresol, diethylene glycol, dipropylene glycol, ethyl lactate, n-butyl lactate, diacetone alcohol, dioxane, Butyl ether, phenyl ether, isopentyl ether, dimethoxyethane, diethoxyethane, bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether, cineol, benzylethyl ether, furan, tetrahydrofuran, anisole, phenetole, acetal, Acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, 2-hexanone, 4-methyl-2-pentanone, 2- Butanone, 2,4-dimethyl-3-pentanone, 2-octanone, acetophenone, mesityl oxide, benzaldehyde, ethyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, isoamyl acetate, pentyl acetate, isopentyl acetate, 3-methoxybutyl acetate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, butyl lactate, γ-butyrolactone, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dimethyldiethylene glycol, dimethyl sulfoxide, dimethyl sulfone, diethyl sulfide, acetonitrile, butyronitrile, nitromethane, nitroethane, -Nitropropane, nitrobenzene, benzene, toluene, xylene, hexane, cyclohexane, dimethylaceamide, dimethylformamide, N-methyl-2-pyrrolidone, dimethylsulfoxide, tetramethylurea, 1,3-dimethyl-2-imidazolidinone and the like can be illustrated, it can also be used in combination of one or more, of which one or more, -O -, - OH, -CO -, - SO 2 -, - SO 3 -, - CN and An organic solvent having at least one group composed of —CO ₂ — is preferable.

  Examples of the substrate include a polyethylene terephthalate (PET) film, but are not limited to this, and any material may be used as long as it is a substrate used in a normal solution casting method. Even if it is manufactured, it is not particularly limited.

  After film formation by the above casting method, a film (electrode electrolyte) can be obtained by drying at 30 to 160 ° C., preferably 50 to 150 ° C. for 3 to 180 minutes, preferably 5 to 120 minutes. The dry film thickness is usually 10 to 100 μm, preferably 20 to 80 μm. If the solvent remains in the membrane after drying, the solvent may be removed by water extraction as necessary.

  The electrode electrolyte according to the present invention may be composed of only the polymer composed of the segment (A) and the segment (B), or may further contain 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 in which a sulfonic acid group or a phosphoric acid group is 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.

The electrode electrolyte of the present invention can be used for proton conductive conductive membranes that can be used for, for example, primary battery electrolytes, secondary battery electrolytes, display elements, various sensors, signal transmission media, solid capacitors, ion exchange membranes, and the like. is there.
(Electrode paste)
The electrode paste of the present invention comprises the above electrode electrolyte, catalyst particles, and a 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- Beef tallow imidazoline quaternary salt, 2-heptadecenyl-hydroxyethyl imidazoline,
Stearamide ethyl diethylamine acetate, stearamide ethyl diethylamine hydrochloride, triethanolamine monostearate formate, alkyl pyridium salt, higher alkyl amine ethylene oxide adduct, polyacrylamide amine salt, modified polyacrylamide amine salt, perfluoroalkyl Cationic surfactants such as quaternary ammonium iodides,
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 membrane with electrode and catalyst)
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.

  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 both surfaces of the solid polymer electrolyte membrane, the electrolyte membrane with catalyst of the present invention is obtained.

The solid polymer electrolyte membrane used for the catalyst-attached electrolyte membrane 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 catalyst-attached electrolyte membrane of the present invention, there is a method of repeatedly applying and drying the catalyst 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, when the solvent is removed, an electrolyte membrane with catalyst is obtained. Examples of the application method include the same methods as described above.

The solvent is removed at a drying temperature of 20 ° C. to 180 ° C., preferably 50 ° C. to 160 ° C., and a drying time of 5 minutes to 600 minutes, preferably 30 minutes to 400 minutes.
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 and the electrode layer is formed, and then the electrolyte membrane solution is applied to create the electrolyte membrane, and then the other catalyst layer is applied. It is good also as an electrolyte membrane with a catalyst by drying.

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.

In Examples, sulfonic acid equivalent weight, molecular weight, weight per gram of unfrozen water copolymer [g], water self-diffusion coefficient and proton conductivity were determined as follows.
1. Sulfonic acid equivalent The polymer having the sulfonic acid group was washed with water until the water was neutral, thoroughly washed with water except for free remaining acid, dried, weighed a predetermined amount, THF / Phenolphthalein dissolved in a mixed solvent of water was used as an indicator, titration was performed using a standard solution of NaOH, and the sulfonic acid equivalent was determined from the neutralization point.
2. Measurement of molecular weight The polyarylene weight average molecular weight having no sulfonic acid group was determined by GPC using tetrahydrofuran (THF) as a solvent, and the molecular weight in terms of polystyrene was obtained. The molecular weight of the polyarylene having a sulfonic acid group was determined by GPC using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as a solvent as an eluent.
3. Measurement of weight [g] per 1 g of unfrozen water copolymer and self-diffusion coefficient of water in the proton conducting membrane The proton conducting membrane to be measured was thoroughly washed. Several to several tens of proton conducting membranes were put in a dedicated glass sample tube for pulsed NMR, and after water absorption, heated at 90 ° C. for 30 minutes. Excess water was removed after heating, and measurement was performed using pulsed NMR.

In the measurement, the sample was first rapidly cooled to −80 ° C. and placed for 30 minutes. The temperature was increased by 10 ° C. every 5 minutes, and after reaching −20 ° C., the sample was placed for 60 minutes before starting the measurement.
The signal intensity was measured in a region where the signal of the solid component attenuates after 70 μs from the start of signal observation and only the signal of the solution component is observed.

  The water content was calculated using a calibration curve prepared in advance using a liquid sample with a known water content. The change in the device detection sensitivity due to the measurement temperature was corrected using the ratio of the respective signal intensities observed at the calibration curve creation temperature and the sample measurement temperature of the same sample.

The calculated water content (g) was compared as the weight of water contained in 1 g of dry membrane weight by dividing the measured membrane by the dry membrane weight (g) after vacuum drying at 110 ° C. for 1 hour.
The self-diffusion coefficient of water was measured using a known magnetic field gradient NMR method using a spin echo method. The measurement was performed at 3 T / m and 256 times.
4). Measurement of proton conductivity AC resistance was measured by pressing a platinum wire (f = 0.5 mm) against the surface of a 5 mm wide strip-shaped proton conducting membrane sample, holding the sample in a constant temperature and humidity device, and between the platinum wires It was obtained from AC impedance measurement. That is, the impedance at an alternating current of 10 kHz was measured in an environment of 25 ° C., 0 ° C., −10 ° C., −20 ° C., −30 ° C., and relative humidity 50%. A chemical impedance measurement system manufactured by NF Circuit Design Block Co., Ltd. was used as the resistance measurement device, and JW241 manufactured by Yamato Scientific Co., Ltd. was used as the constant temperature and humidity device. Five platinum wires were pressed at intervals of 5 mm, the distance between the wires was changed to 5 to 20 mm, and the AC resistance was measured. The specific resistance of the membrane was calculated from the distance between the lines and the resistance gradient, the alternating current impedance was calculated from the reciprocal of the specific resistance, and the proton conductivity was calculated from this impedance.

Specific resistance R (Ω · cm) = 0.5 (cm) × film thickness (cm) × resistance-to-resistance gradient (Ω / cm)
5. Hot Water Resistance The above membrane was immersed in hot water at 120 ° C. for 24 hours, and the weight and size of the membrane immediately after taking out were compared with the membrane before immersion to determine the moisture content and the dimensional change rate.
6). Power generation evaluation A catalyst-attached electrolyte membrane is sandwiched between carbon papers at 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.
<Example 1>
In a 1 L three-necked flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube, 135.2 g (337 mmol) of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate, represented by the following formula (I), Mn9, 500 oligomers 48.7 g (5.1 mmol), bis (triphenylphosphine) nickel dichloride 6.71 g (10.3 mmol), sodium iodide 1.54 g (10.3 mmol), triphenylphosphine 35.9 g (137 mmol) Then, 53.7 g (821 mmol) of zinc was weighed and replaced with dry nitrogen. 430 mL of N, N-dimethylacetamide (DMAc) was added thereto, and stirring was continued for 3 hours while maintaining the reaction temperature at 80 ° C. Then, 730 mL of DMAc was added for dilution, and insoluble matters were filtered off.

  The obtained solution was put into a 2 L three-necked flask equipped with a stirrer, a thermometer, and a nitrogen introduction tube. The mixture was heated and stirred at 115 ° C., and 44 g (506 mmol) of lithium bromide was added. After stirring for 7 hours, the product was precipitated by pouring into 5 L of acetone. Subsequently, it was washed with 1N hydrochloric acid and pure water in this order, and then dried to obtain 122 g of the target polymer. The weight average molecular weight (Mw) of the obtained polymer was 135,000. The obtained polymer is presumed to be a sulfonated polymer represented by the formula (II). The ion exchange capacity of this polymer was 2.3 meq / g.

(I)
(II)
<Synthesis Example 2>
The same operation as in Synthesis Example 1 was performed except that the oligomer represented by the formula (III) was used instead of the oligomer represented by the formula (I) to obtain 128 g of the target polymer. The weight average molecular weight (Mw) of the obtained polymer was 140,000. The obtained polymer is presumed to be a sulfonated polymer represented by the formula (IV). The ion exchange capacity of this polymer was 2.3 meq / g.

[Comparative Synthesis Example 1]
The same operation as in Synthesis Example 1 was performed except that the oligomer represented by the formula (V) was used instead of the oligomer represented by the formula (I) to obtain 123 g of a target polymer. The weight average molecular weight (Mw) of the obtained polymer was 137,000. The obtained polymer is presumed to be a sulfonated polymer represented by the formula (VI). The ion exchange capacity of this polymer was 2.2 meq / g.

[Examples 1 and 2, Comparative Example 1]
Copolymers obtained in Synthesis Examples 1 and 2 and Comparative Synthesis Example 1 (corresponding to Examples 1 and 2 and Comparative Example 1, respectively) in a mixed solvent of methanol / NMP = 50/50 to 15% by weight It melt | dissolved so that the varnish of an electrode electrolyte might be prepared. A film having a thickness of 40 μm was produced from this varnish by a casting method. Weight [g] per 1 g of water copolymer not frozen at −20 ° C. in the obtained film, and self-diffusion coefficient of water measured at −20 ° C. [× 10 ⁻¹⁰ m ² / s] Table 1 shows the value of the self-diffusion coefficient [× 10 ⁻¹⁰ m ² / s] measured at −20 ° C. The results of proton conductivity measurement are shown in Table 2.

[Example 3]
[Preparation of paste A]
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 15% water-1,2 dimethoxyethane solution (weight ratio 10:90) of the polymer of Synthesis Example 1, 13.97 g of 1,2-dimethoxyethane, vapor grown carbon fiber (Product name: VGCF, manufactured by Showa Denko Co., Ltd.) 0.1 g and a dispersant (trade name: DA234, manufactured by Enomoto Kasei Co., Ltd.) 0.028 g were added, and the mixture was stirred for 60 minutes with a wave blower, and the viscosity was 50 cp (25 ° C.). Paste A was obtained.

[Create electrode]
On the PET film treated with a release agent, paste A was applied using a doctor blade so that the platinum coating amount was 0.5 mg / cm ² . This was heated and dried at 95 ° C. for 10 minutes to form an electrode layer.

[Creating electrolyte membrane with catalyst]
One electrolyte membrane having a film thickness of 50 μm made of a polymer having a weight average molecular weight (Mw) of 170,000 having a structure represented by the following general formula is prepared, sandwiched between two electrode layers, and under a pressure of 100 kg / cm ² . The catalyst-attached electrolyte membrane was prepared by hot press molding under the conditions of 160 ° C. × 15 min.

[Example 4]
[Preparation of paste B]
In a 50 ml glass bottle, 25 g of zirconia balls having a diameter of 10 mm (trade name: YTZ ball, manufactured by Nikkato Co., Ltd.), 1.51 g of platinum-supported carbon particles (Pt: 46 wt% supported) as in Example 3 and distilled water of 0. 88 g, 3.23 g of a 15% water-N-methyl-2-pyrrolidone solution of the sulfonated polyarylene of Synthesis Example 2 (weight ratio 10:90), N-methyl-2-pyrrolidone (bp. 202, δ 11.17) 13.97 g, 0.1 g of vapor grown carbon fiber (trade name: VGCF, Showa Denko KK) and 0.028 g of dispersant (trade name: DA234, manufactured by Enomoto Kasei Co., Ltd.) are added, and the mixture is stirred for 60 minutes with a wafer blaster. As a result, a paste B having a viscosity of 65 cp (25 ° C.) was obtained.

[Create electrode]
Paste B was applied on a PET film treated with a release agent using a doctor blade so that the platinum coating amount was 0.5 mg / cm ² . This was heated and dried at 95 ° C. for 10 minutes to form an electrode layer.

[Creating electrolyte membrane with catalyst]
One electrolyte membrane similar to that used in Example 3 was prepared, sandwiched between two electrode layers, and hot press molded under a pressure of 100 kg / cm ² under the conditions of 160 ° C. × 15 min, and the electrolyte with catalyst A membrane was created.

[Comparative Example 2]
[Preparation of paste B]
In a 50 ml glass bottle, 25 g of zirconia balls having a diameter of 10 mm (trade name: YTZ ball, manufactured by Nikkato Co., Ltd.), 1.51 g of platinum-supported carbon particles (Pt: 46 wt% supported) as in Example 3 and distilled water of 0. 88 g, 3.23 g of a 15% water-N-methyl-2-pyrrolidone solution of the sulfonated polyarylene of Comparative Synthesis Example 1 (weight ratio 10:90), N-methyl-2-pyrrolidone (bp 202, δ 11.17) 13.97 g, 0.1 g of vapor grown carbon fiber (trade name: VGCF, manufactured by Showa Denko KK) and 0.028 g of a dispersant (trade name: DA234, manufactured by Enomoto Kasei Co., Ltd.) are added, and a wafer blower is used for 60 minutes. The mixture was stirred to obtain paste C having a viscosity of 65 cp (25 ° C.).

[Create electrode]
Paste C was applied onto a PET film treated with a release agent using a doctor blade so that the platinum coating amount was 0.5 mg / cm ² . This was heated and dried at 95 ° C. for 10 minutes to form an electrode layer.

[Creating electrolyte membrane with catalyst]
One electrolyte membrane similar to that used in Example 3 was prepared, sandwiched between two electrode layers, and hot press molded under a pressure of 100 kg / cm ² under the conditions of 160 ° C. × 15 min, and the electrolyte with catalyst A membrane was created.

  The results are also shown in Table 3.

Claims (7)

An electrode electrolyte comprising a copolymer having an ion conductive polymer segment (A) and a non-ion conductive polymer segment (B),
The electrolyte was immersed in water, heated at 90 ° C. for 30 minutes to absorb water, and then cooled to −20 ° C. When the water was absorbed, the weight of the water that was not frozen [g] (both The multiplier (multiplied value) of the self-diffusion coefficient [× 10 ⁻¹⁰ m ² / s] measured at −20 ° C. is in the range of 0.2 to 1.5. A polymer electrolyte fuel cell electrode electrolyte. ^2. The polymer electrolyte fuel cell electrode electrolyte according to claim 1, wherein the self-diffusion coefficient of water not frozen at −20 ° C. is 0.40 × 10 ⁻¹⁰ m ² / s or more. The ion conductive polymer segment (A) includes a structural unit represented by the following general formula (A),
The polymer electrolyte fuel cell electrode electrolyte according to claim 1 or 2, wherein the non-ion conductive polymer segment (B) includes a structural unit represented by the following general formula (B):

Wherein Y is —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10), —C (CF ₃ ) represents at least one structure selected from the group consisting of ₂ —, Z is a direct bond, or — (CH ₂ ) ₁ — (l is an integer of 1 to 10), —C (CH ₃ ) ₂ represents at least one structure selected from the group consisting of —, —O—, and —S—, and Ar represents —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p An aromatic group having a substituent represented by SO ₃ H. m represents an integer of 0 to 10, n represents an integer of 0 to 10, k represents an integer of 1 to 4, and p represents 1 Represents an integer of ~ 12)

(In the formula, A is independently a direct bond or —CO—, —SO ₂ —, —SO—, —CONH—,
_{-COO -, - (CF 2)} l - (l is an integer of 1 to _{10), - (CH 2) l} - (l is an integer of 1 to 10), - C (R ') 2 - (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group), at least one selected from the group consisting of a cyclohexylidene group, a fluorenylidene group, —O—, and —S—. Wherein B is independently an oxygen atom or a sulfur atom, R ^{1 to} R ¹¹ may be the same as or different from each other, and a hydrogen atom, a fluorine atom, an alkyl group, part or all of which are halogenated And at least one atom or group selected from the group consisting of a halogenated alkyl group, an allyl group, an aryl group, a nitro group, and a nitrile group. X represents —CO— or —SO ₂ —, Ar ′ represents an aromatic group,
t represents an integer of 0 to 4, and r represents an integer of 1 or more. ) In the structural unit represented by the general formula (A), Y is —CO—, and Ar is —SO _3.
An aromatic ring having a substituent represented by H, m is an ion-conductive polymer segment (A ′) in which n is 0 and n is 0;
In the structural unit represented by the general formula (B), A is independently a direct bond or —C (R ′) ₂ — (R ′ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a halogenated hydrocarbon group. And at least one group selected from the group consisting of cyclohexylidene group, fluorenylidene group, and -O-, B is an oxygen atom, R ¹ to R ¹⁶ is a polymer electrolyte fuel cell electrode electrolyte according to claim 1, characterized in that a non-ion conductive segment of a hydrogen atom (B ').   An electrode paste comprising the electrolyte according to claim 1, catalyst particles, and a solvent.   A solid polymer fuel cell electrode comprising the electrolyte according to claim 1 and catalyst particles. A membrane-electrode assembly comprising the electrode according to claim 6 on at least one surface of a polymer electrolyte membrane.