JP2010238373A - Polymer electrolyte membrane, its manufacturing method, and membrane electrode assembly as well as solid polymer fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a protonic conductive film for a solid polymer fuel cell with high hydrogen peroxide and radical resistance, high initial output voltage, and capable of obtaining high output voltage over a long period of time. <P>SOLUTION: The polymer electrolyte membrane contains (A) a polyarylene system copolymer with a sulfonic acid group, and (B) manganese-content oxide with a specific surface area of 55 m<SP>2</SP>/g or less measured in the BET method. The (B) manganese-content oxide is at least one of the complex oxides containing manganese oxide or at least one element out of Mn, Ni, Bi, and Ce, and further, (B) the manganese-content oxide is at least either the complex oxide containing MnO<SB>2</SB>, Mn<SB>2</SB>O<SB>3</SB>, Mn, and Bi or that containing Mn and Ni. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a proton conducting membrane for a polymer electrolyte fuel cell that has high resistance to hydrogen peroxide and radicals, a high initial output voltage, and a high output voltage over a long period of time.

In the solid polymer fuel cell, an anode electrode and a cathode electrode are arranged on both sides of a polymer electrolyte membrane, and a cell in which both sides are sandwiched by separators is configured as a unit.
The electrode includes an electrode base material that promotes gas diffusion and collects current, and a catalyst layer that actually becomes an electrochemical reaction field. Specifically, in the anode electrode, the fuel gas reacts in the catalyst layer to generate protons and electrons, the electrons are conducted to the electrode base material and sent to the external circuit, and the protons are passed through the electrode electrolyte to the solid polymer electrolyte membrane. Conducted to. On the other hand, in the cathode electrode, the oxidizing gas in the catalyst layer, protons conducted from the solid polymer electrolyte membrane, and electrons conducted from the electrode substrate through an external circuit react to generate water.

  By the way, in these polymer electrolyte fuel cells, peroxide is generated in the catalyst layer formed at the interface between the polymer electrolyte membrane and the electrode by the cell reaction, and the peroxide is generated while diffusing the peroxide. This degrades the electrolyte. Hydrogen peroxide generated on these electrodes moves away from the electrodes due to diffusion or the like and moves into the electrolyte. This hydrogen peroxide is a substance having a strong oxidizing power and oxidizes many organic substances constituting the electrolyte. In many cases, it is considered that hydrogen peroxide is radicalized and the generated hydrogen peroxide radical is a direct reactant of the oxidation reaction.

  Perfluorinated sulfonic acid polymers, such as DuPont's Nafion, which are often used as electrolytes, generally have high radical resistance, but they have low mechanical strength and cannot be used at high temperatures to improve power output. have. On the other hand, non-perfluorosulfonic acid polymers have high mechanical strength and can be used at high temperatures, but have a problem of low radical resistance.

  Technology for adding metal oxides such as manganese dioxide as a hydrogen peroxide decomposition catalyst to sulfonated polystyrene-graft-ETFE membranes in order to improve the low radical resistance, which is a problem in non-perfluorosulfonic acid polymers (Patent Literature) 1) Further, a technique (Patent Document 2) is disclosed in which a metal oxide such as manganese dioxide is added to a sulfonated polyether ether ketone to improve the radical resistance of the electrolyte membrane.

Furthermore, in Patent Document 3, the durability is improved by adding MnO ₂ to a polyarylene copolymer having a sulfonic group composed of a segment having a sulfonic acid group and a segment having no sulfonic acid. In addition, since the average size of MnO ₂ used was large, the dispersion state of MnO _{2 in} the polymer electrolyte membrane was poor, and the durability was not sufficient.

JP 2000-106203 A JP 2001-118591 A JP 2005-135651 A

  An object of the present invention is to provide a polymer electrolyte membrane from which a fuel cell having a high resistance to hydrogen peroxide and radicals, a high initial output voltage, and a high output voltage over a long period of time can be obtained.

The configuration of the present invention is as follows.
[1] A polymer electrolyte membrane comprising (A) a polyarylene copolymer having a sulfonic acid group and (B) a manganese-containing oxide having a specific surface area of 55 m ² / g or less measured by the BET method.
[2] The polymer electrolyte membrane according to [1], wherein the (B) manganese-containing oxide is at least one of a manganese oxide or a complex oxide containing at least one element of Mn and Ni, Bi, and Ce.
[3] The polymer according to [2], wherein (B) the manganese-containing oxide is at least one of a composite oxide containing MnO ₂ , Mn ₂ O ₃ , Mn and Bi, and a composite oxide containing Mn and Ni. Electrolyte membrane.
[4] (A) The polyarylene copolymer having a sulfonic acid group includes a structural unit represented by the following general formula (3) and a structural unit represented by the following general formula (4) [1] ~ [3] polymer electrolyte membrane.

（式中、Ｙは−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−Ｃ（ＣＦ₃）₂−からなる群より選ばれた少なくとも１種の構造を示し、Ｚは直接結合または、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、−Ｃ（ＣＨ₃）₂−、−Ｏ−、−Ｓ−からなる群より選ばれた少なくとも１種の構造を示し、Ａｒは−ＳＯ₃Ｈまたは−Ｏ（ＣＨ₂）_pＳＯ₃Ｈまたは−Ｏ（ＣＦ₂）_pＳＯ₃Ｈで表される置換基を有する芳香族基を示す。ｐは１〜１２の整数を示し、ｍは０〜１０の整数を示し、ｎは０〜１０の整数を示し、ｋは１〜４の整数を示す。）

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. p represents an integer of 1 to 12, m represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents 1 Represents an integer of ~ 4.)

（式中、Ａ、Ｄは独立に直接結合または、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基およびハロゲン化炭化水素基を示す）、シクロヘキシリデン基、フルオレニリデン基、−Ｏ−、−Ｓ−からなる群より選ばれた少なくとも１種の構造を示し、Ｂは独立に酸素原子または硫黄原子であり、Ｒ¹〜Ｒ¹⁶は、互いに同一でも異なっていてもよく、水素原子、フッ素原子、アルキル基、一部またはすべてがハロゲン化されたハロゲン化アルキル基、アリル基、アリール基、ニトロ基、ニトリル基からなる群より選ばれた少なくとも１種の原子または基を示す。ｓ、ｔは０〜４の整数を示し、ｒは、０または１以上の整数を示す。）
[5]（Ａ）スルホン酸基を有するポリアリーレン系共重合体が、下記一般式（１）で表される構造を含む[4]の高分子電解質膜。

(In the formula, A and D are 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 — (wherein 1 is an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group and a halogenated hydrocarbon group. ), At least one structure selected from the group consisting of cyclohexylidene group, fluorenylidene group, —O—, and —S—, B is an oxygen atom or a sulfur atom, and R ^{1 to} R ¹⁶ May be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which some or all are halogenated, an allyl group, an aryl group, a nitro group, and a nitrile group At least one atom or group selected, s, t Represents an integer of 0 to 4, r represents 0 or an integer of 1 or more.)
[5] (A) The polymer electrolyte membrane according to [4], wherein the polyarylene-based copolymer having a sulfonic acid group includes a structure represented by the following general formula (1).

［式（１）中、Ｙは、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_i−（ｉは１〜１０の整数を示す。）または−Ｃ（ＣＦ₃）₂−を示し、Ｚは、独立に直接結合、−（ＣＨ₂）_j−（ｊは１〜１０の整数を示す。）、−Ｃ（ＣＨ₃）₂−、−Ｏ−または−Ｓ−を示し、Ａｒは、−ＳＯ₃Ｈ、−Ｏ（ＣＨ₂）_pＳＯ₃Ｈまたは−Ｏ（ＣＦ₂）_pＳＯ₃Ｈ（ｐは１〜１２の整数を示す。）で表される置換基を有する芳香族基を示し、ｍは０〜１０の整数を示し、ｎは０〜１０の整数を示し、ｋは１〜４の整数を示す。

[In the formula (1), Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _i — (i represents an integer of 1 to 10). Or —C (CF ₃ ) ₂ —, Z is independently a direct bond, — (CH ₂ ) _j — (j represents an integer of 1 to 10), —C (CH ₃ ) ₂ —, — O— or —S— is represented, and Ar represents —SO ₃ H, —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H (p represents an integer of 1 to 12). The aromatic group which has a substituent represented by this is shown, m shows the integer of 0-10, n shows the integer of 0-10, k shows the integer of 1-4.

A and D are each independently a direct bond, —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _i — (i represents an integer of 1 to 10. ), — (CH ₂ ) _j — (j represents an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group. .), cyclohexylidene group, a fluorenylidene group, -O- or -S-, B is an oxygen atom or a sulfur atom independently, R ¹ to R ¹⁶ each independently represent a hydrogen atom, a fluorine atom, an alkyl Group, a halogenated alkyl group, allyl group, aryl group, nitro group or nitrile group partially or wholly halogenated, s and t each represent an integer of 0 to 4, and r is 0 or 1 or more Indicates an integer. ]
Z represents a direct bond or at least one structure selected from the group consisting of —O— and —S—, and Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO. —, — (CF ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CF ₃ ) ₂ —, at least one structure selected from the group consisting of — and R ²⁰ is a nitrogen-containing complex A ring group is shown. q represents an integer of 1 to 5, and p represents an integer of 0 to 4.
x, y, z represents a molar ratio when x + y + z = 100 mol%. ]

[6] (A) A step of dissolving or dispersing a polyarylene copolymer having a sulfonic acid group in an organic solvent, and (B) a manganese-containing oxide having a specific surface area measured by the BET method of 55 m ² / g or less. And (B) a step of dispersing the manganese-containing oxide by high-speed stirring at a rotational speed of 5000 times / minute or more, and a method for producing a polymer electrolyte membrane.
[7] An electrode-membrane assembly including the polymer electrolyte membrane of [1] to [5].
[8] A polymer electrolyte fuel cell comprising the electrode-membrane assembly according to [7].

Hereinafter, the polymer electrolyte membrane according to the present invention will be described in detail.
[Molecular electrolyte membrane]
The polymer electrolyte membrane of the present invention contains (A) a protonic acid group-containing aromatic polymer and a manganese-containing oxide having a specific surface area measured by the BET method of 55 m ² / g or less. The (A) protonic acid group-containing aromatic polymer in the polymer electrolyte membrane of the present invention comprises a sea-like continuous phase comprising a polymer segment having a protonic acid group, which will be described later, and a polymer having no protonic acid group. It is preferable to constitute a so-called sea-island microphase separation structure composed of segmented island-like discontinuous phases. Such a continuous phase is confirmed by TEM observation.

  In the polymer electrolyte membrane having such a microphase separation structure, (A) the protonic acid group-containing aromatic polymer is a block copolymer, and the protonic acid group-containing aromatic polymer has an ion exchange capacity of 1 0.5 to 3.5 meq / g is preferably realized. Since the polymer electrolyte membrane of the present invention has such a micro-separated structure, even when (B) a manganese-containing oxide is added, the decrease in proton conductivity is small, and the swelling due to hot water is small. No elution of the manganese-containing oxide is observed. In addition, since the polymer segment having an ion conduction component is a continuous phase, the probability that the proton conduction path is cut is low, and the decrease in the initial output voltage tends to be small.

[(A) Protonic acid group-containing aromatic polymer]
(A) The protonic acid group-containing aromatic polymer has a protonic acid group composed of an ionic group composed of a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, or a phosphoric acid group. Among these, a polyarylene copolymer having a sulfonic acid group in which the proton acid group is a sulfonic acid group is most preferable because it is excellent in proton conduction efficiency in the fuel cell.

  The main chain skeleton in the protonic acid group-containing aromatic polymer includes polyether ether ketone, polyether sulfone, polyimide, polybenzo having a skeleton formed by covalently bonding aromatic rings excellent in heat resistance and mechanical strength. Those containing oxazole, polyarylene and the like are used, and the polymer segment having a proton acid group and the polymer segment having no proton acid group are preferably covalently bonded. By adopting these structures, heat resistance and mechanical strength are improved, and operation at high temperatures is possible.

  In addition, in the case where a polymer segment having a proton acid group and a polymer segment not having a proton acid group are covalently bonded, expansion due to hot water is suppressed, and oxide elution is suppressed. Furthermore, it is preferable that the polymer electrolyte membrane has a microphase separation structure and the polymer segment having an ion conductive component is a continuous phase. In such a microphase separation structure, the proton acid group-containing aromatic polymer has an ion exchange capacity of 1.5 to 3.5 meq / g, and a polymer segment having a proton acid group and a polymer segment having no proton acid group are It tends to be expressed easily by using a block copolymer that is covalently bonded.

  Next, the polyarylene copolymer having a sulfonic acid group will be specifically described. The polyarylene-based copolymer having a sulfonic acid group used in the present invention includes a structural unit having a sulfonic acid group represented by the following general formula (1) and an aromatic represented by the following general formula (2). The polymer is characterized by containing a structural unit having a structure, and is a polymer represented by the following general formula (3).

[Structural unit having sulfonic acid group]
The structural unit having a sulfonic acid group has a structure represented by the following formula (1).

一般式（１）において、Ｙは−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−Ｃ（ＣＦ₃）₂−からなる群より選ばれた少なくとも１種の構造を示す。このうち、−ＣＯ−、−ＳＯ₂−が好ましい。

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

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. Among these, a direct bond and -O- are preferable.

Ar is 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 (p represents an integer of 1 to 12). Indicates.
Specific examples of the aromatic group include a phenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Of these groups, a phenyl group and a naphthyl group are preferable. At least one substituent represented by —SO ₃ H or —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H (p represents an integer of 1 to 12) is substituted. When it is a naphthyl group, it is preferable to substitute two or more.

m is an integer of 0 to 10, preferably 0 to 2, n is an integer of 0 to 10, preferably 0 to 2, and k is an integer of 1 to 4.
As a preferred combination of the values of m and n and the structures of Y, Z and Ar, (1) m = 0, n = 0, Y is —CO—, and Ar is substituted with —SO ₃ H. (2) m = 1, n = 0, Y is —CO—, Z is —O—, and Ar is a phenyl group having —SO ₃ H as a substituent. A structure, (3) m = 1, n = 1, k = 1, Y is —CO—, Z is —O—, and Ar is a phenyl group having —SO ₃ H as a substituent. A structure, (4) m = 1, n = 0, Y is —CO—, and Ar is a naphthyl group having two —SO ₃ H as substituents; (5) m = 1 a n = 0, Y is -CO-, Z is -O-, and phenyl group Ar has an _{-O (CH 2) 4 SO 3} H as a substituent Or the like can be given a certain structure.

[Structural unit having aromatic structure]
The structural unit having an aromatic structure has a structure represented by the following formula (2).

一般式（２）において、Ａ、Ｄは独立に直接結合または、−ＣＯ−、−ＳＯ₂−、−ＳＯ−、−ＣＯＮＨ−、−ＣＯＯ−、−（ＣＦ₂）_l−（ｌは１〜１０の整数である）、−（ＣＨ₂）_l−（ｌは１〜１０の整数である）、−ＣＲ’₂−（Ｒ’は脂肪族炭化水素基、芳香族炭化水素基およびハロゲン化炭化水素基を示す）、シクロヘキシリデン基、フルオレニリデン基、−Ｏ−、−Ｓ−からなる群より選ばれた少なくとも１種の構造を示す。ここで、−ＣＲ’₂−で表される構造の具体的な例として、メチル基、エチル基、プロピル基、イソプロピル基、ブチル基、イソブチル基、ｔ−ブチル基、プロピル基、オクチル基、デシル基、オクタデシル基、フェニル基、トリフルオロメチル基、などが挙げられる。

In the general formula (2), A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (1 is 1 to 1). Is an integer of 10), — (CH ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —CR ′ ₂ — (R ′ is an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a halogenated carbon. A hydrogen group), at least one structure selected from the group consisting of 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 and a halogenated hydrocarbon group), a cyclohexylidene group, a fluorenylidene group, B is an oxygen atom, D is —CO— or —SO ₂ —. Wherein R ^{1 to} R ¹⁶ are hydrogen atoms or fluorine atoms, (2) s = 1, t = 0, B is an oxygen atom, D is —CO— or —SO ₂ —. A structure in which R ^{1 to} R ¹⁶ are a hydrogen atom or a fluorine atom, (3) s = 0, t = 1, and A is —CR ′ ₂ — (R ′ is an aliphatic hydrocarbon group, aromatic carbonization. Hydrogen group and halogenated hydrocarbon group), cyclohexylidene group, fluorenylidene group, B is an oxygen atom The structure R ¹ to R ¹⁶ is a hydrogen atom or a fluorine atom or a nitrile group.

[Structure of polyarylene copolymer having sulfonic acid group]
(A) The polyarylene copolymer having a sulfonic acid group includes a structure represented by the following formula (3).

一般式（３）において、Ａ、Ｂ、Ｄ、Ｙ、Ｚ、Ａｒ、ｋ、ｍ、ｎ、ｒ、ｓ、ｔおよびＲ¹〜Ｒ¹⁶は、それぞれ上記一般式（１）および（２）中のＡ、Ｂ、Ｄ、Ｙ、Ｚ、Ａｒ、ｋ、ｍ、ｎ、ｒ、ｓ、ｔおよびＲ¹〜Ｒ¹⁶と同義である。ｘ、ｙはｘ＋ｙ＝１００モル％とした場合のモル比を示す。

In the general formula (3), A, B, D, Y, Z, Ar, k, m, n, r, s, t and R ^{1 to} R ¹⁶ are respectively in the general formulas (1) and (2). A, B, D, Y, Z, Ar, k, m, n, r, s, t, and R ^{1 to} R ¹⁶ . x and y represent molar ratios when x + y = 100 mol%.

  The polyarylene copolymer having a sulfonic acid group used in the present invention contains 0.5 to 100 mol%, preferably 10 to 99.999 mol, of a structural unit having a sulfonic acid group represented by the formula (1). %, The structural unit having an aromatic structure represented by the formula (2) is contained in an amount of 99.5 to 0 mol%, preferably 90 to 0.001 mol%.

  (A) The polyarylene copolymer having a sulfonic acid group is preferably a proton composed of a polymer segment having a proton acid group composed of a structural unit having a sulfonic acid group and a structural unit having an aromatic structure. It is a block copolymer in which polymer segments having no acid group are covalently bonded.

  (A) The ion exchange capacity of the polyarylene copolymer having a sulfonic acid group is preferably 1.5 to 3.5 meq / g, more preferably 1.9 to 3.0 meq / g, Preferably, it is 1.8 to 2.7 meq / g. When the ion exchange capacity is within the above range, the polymer segment having a proton acid group tends to form a continuous phase, and even when the manganese-containing oxide is added, the decrease in proton conductivity is small, and also due to hot water Swelling is small and elution of the manganese-containing oxide is not observed.

  (A) The molecular weight of the protonic acid group-containing aromatic polymer 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).

[Method for producing polyarylene copolymer having sulfonic acid group]
The polyarylene-based copolymer having a sulfonic acid group can be produced by, for example, the following method A, method B or method C.

  (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 (1) and the general formula (2) Monomers or oligomers that can be structural units are copolymerized to produce a polyarylene copolymer having a sulfonic acid ester group, and the sulfonic acid ester group is converted into a sulfonic acid group by deesterification. It can be synthesized by conversion.

  (Method B) For example, in the method described in JP-A-2001-342241, a monomer having a skeleton represented by the general formula (1) and not having a sulfonic acid group or a sulfonic acid ester group, and the general formula (2) It is also possible to synthesize the polymer by copolymerizing with a monomer or oligomer that can be a structural unit represented by formula (I) and sulfonating the polymer using a sulfonating agent.

(Method C) In the general formula (1), 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, by a method described in Japanese Patent Application No. 2003-295974 (Japanese Patent Laid-Open No. 2005-060625), a precursor monomer that can be a structural unit represented by the above general formula (2), and the above general formula (2) It is also possible to synthesize by a method in which a monomer or an oligomer that can be a structural unit represented by the formula (1) is copolymerized and then 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 above general formula (1), Japanese Patent Application Laid-Open No. 2004-137444 and Japanese Patent Application No. 2003 Examples thereof include sulfonic acid esters described in Japanese Patent Application No. 143903 (Japanese Patent Laid-Open No. 2004-345997) and Japanese Patent Application No. 2003-143904 (Japanese Patent Laid-Open No. 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 (1) that can be used in (Method B), JP-A-2001-342241 Examples thereof include dihalides described in Japanese Patent Laid-Open No. 2002-293889.

  As a specific example of a precursor monomer that can be a structural unit represented by the above general formula (1) that can be used in (Method C), Japanese Patent Application No. 2003-275409 (JP 2005-36125 A) Can be mentioned.

Moreover, as a specific example of a monomer or oligomer that can be a structural unit represented by the general formula (2) used in any method,
When r = 0, for example, 4,4′-dichlorobenzophenone, 4,4′-dichlorobenzanilide, 2,2-bis (4-chlorophenyl) difluoromethane, 2,2-bis (4-chlorophenyl) -1, 1,1,3,3,3-hexafluoropropane, 4-chlorobenzoic acid-4-chlorophenyl ester, bis (4-chlorophenyl) sulfoxide, bis (4-chlorophenyl) sulfone, 2,6-dichlorobenzonitrile It is done. In these compounds, a compound in which a chlorine atom is replaced with a bromine atom or an iodine atom is exemplified.

In the case of r = 1, for example, compounds described in JP-A No. 2003-113136 can be exemplified.
In the case of r ≧ 2, for example, JP 2004-137444, JP 2004-244517, JP 2004-346164, JP 2005-112985, JP 2006-028414, JP 2006 -028415 and JP-A-2005-133081 can be mentioned.

  In order to obtain a polyarylene copolymer having a sulfonic acid group, first, a monomer that can be a structural unit represented by the general formula (1) and a structural unit represented by the general formula (2). It is necessary to obtain a precursor polyarylene-based copolymer by copolymerizing with a monomer or oligomer that can be obtained. This copolymerization is carried out in the presence of a catalyst, and the catalyst used here is a catalyst system containing a transition metal compound, and this catalyst system is preferably a transition metal salt and a ligand. A compound (hereinafter referred to as “ligand component”) or a transition metal complex (including a copper salt) in which a ligand is coordinated is used.

  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 copolymer having a sulfonic acid group can be obtained by converting the precursor polyarylene copolymer to a polyarylene copolymer having a sulfonic acid group. As this method, there are the following three methods.

(Method A) A method in which a polyarylene copolymer having a sulfonate group as a precursor is deesterified by the method described in JP-A-2004-137444.
(Method B) A method in which a precursor polyarylene copolymer is sulfonated by the method described in JP-A-2001-342241.
(Method C) A method of introducing an alkylsulfonic acid group into the precursor polyarylene copolymer by the method described in Japanese Patent Application No. 2003-295974 (Japanese Patent Laid-Open No. 2005-60625).

(B) Manganese-containing oxide Examples of the manganese-containing oxide of the present invention include manganese oxides such as MnO ₂ , Mn ₂ O ₃ , and Mn ₃ O ₄ , and composite oxides composed of manganese and other elements. The composite oxide composed of manganese and other elements has a metal-converted molar ratio (Mn: other than Mn), and 99.9: 0.1 to 5:95, preferably 99.9: 0.1 to 30:70. . More preferably, it is 95: 5 to 40:60. Within this range, the decomposition rate of hydrogen peroxide tends to be faster than that of the simple substance. Further, the other metal element may be one or more, and examples thereof include Ni, Bi, and Ce. Preferably, a composite oxide containing MnO ₂ , Mn ₂ O ₃ , Mn and Bi, or a composite oxide containing Mn and Ni is used. These manganese-containing oxides may be used alone or in combination of two or more. The polymer electrolyte membrane of the present invention includes (B) a manganese-containing oxide, so that hydrogen peroxide and radical resistance are improved, a decrease in initial output voltage is small, and deterioration of the polymer electrolyte membrane is suppressed, A high output voltage can be obtained over a long period of time. Although the detailed mechanism is not clear, it is considered that hydrogen peroxide diffused from the electrode layer to the polymer electrolyte membrane by the oxide was inactivated before being present in the radical. The composite oxide in the present invention means an oxide containing two or more kinds of metal atoms.

  Further, the manganese-containing oxide may be a hydrated substance, and may be a crystalline body or an amorphous body. Further, it may be powder or fibrous. From the viewpoint of dispersibility in the polymer electrolyte membrane, powder is preferred. Furthermore, from the viewpoint of dispersibility in the polymer electrolyte membrane, the average size (average aggregate size) of the manganese-containing oxide measured by the laser diffraction / scattering method is 55 μm or less, preferably the average size is 20 μm or less, preferably Is 10 μm or less, more preferably 5 m or less. Moreover, the form carry | supported by carriers, such as an alumina, a silica, a titania, a zirconia, may be sufficient.

The specific surface area of the manganese-containing oxide is preferably a 1~55m ² / g, more preferably from 20 to 50 m ² / g, particularly preferably 25~45m ² / g. If it is less than the above range, it is necessary to add a large amount in order to sufficiently suppress the deterioration of the polymer electrolyte membrane, and a sufficient initial output voltage cannot be secured. On the other hand, when the above range is exceeded, the deterioration suppressing effect of the polymer electrolyte membrane is saturated, and the initial output voltage may be significantly reduced. Here, the specific surface area of the manganese-containing oxide is measured by the BET method (JIS R 1626; a method for measuring the specific surface area of the fine ceramic powder by the gas adsorption BET method).

Further, the content of the manganese oxide in the manganese-containing oxide is preferably 70 to 100% by mass as the MnO ₂ conversion amount calculated on the assumption that all the manganese atoms are MnO ₂ . Preferably, it is 80-100 mass%, More preferably, it is 90-100 mass%. Here, the MnO ₂ content can be obtained by dissolving a manganese-containing oxide powder, an oxalic acid aqueous solution, and sulfuric acid and titrating with a potassium permanganate aqueous solution. When the MnO ₂ content is less than the above range, the durability improving effect is not sufficient.

  The compounding amount of the manganese-containing oxide is preferably 0.1 to 5% by mass with the total mass of the polymer electrolyte membrane being 100% by mass. Preferably, it is 0.5-3 mass%, More preferably, it is 0.5-2 mass%. If it is less than the above range, the effect of suppressing deterioration of the polymer electrolyte membrane is small, and a high output voltage cannot be maintained over a long period of time. On the other hand, exceeding the above range is not preferable because the proton conduction path is cut and the initial output voltage may be lowered. Furthermore, it becomes difficult to uniformly disperse in the polymer electrolyte membrane.

  The manganese-containing oxide is preferably dispersed uniformly in the polymer electrolyte membrane, but it may be arranged only at a site where the polymer electrolyte is severely deteriorated or more at such a site. For example, many may be arranged on the electrode side of the polymer electrolyte membrane.

Method for Producing Polymer Electrolyte Membrane The method for producing the polymer electrolyte membrane of the present invention is not particularly limited. For example, (A) after dissolving or dispersing the proton acid-containing aromatic polymer in an organic solvent, (B) A composition containing a manganese-containing oxide can be prepared, and the composition can be cast by casting on a substrate to form a film. In addition to the polymer electrolyte, oxide, and organic solvent, the composition may contain an inorganic acid such as sulfuric acid and phosphoric acid, an organic acid containing a carboxylic acid, an appropriate amount of water, and the like. Furthermore, in order to improve the dispersibility of the oxide in the composition, the following dispersant may be added.

  The polymer concentration in the composition is usually 5 to 40% by mass, preferably 7 to 25% by mass, although it depends on the molecular weight of the polymer electrolyte. If the polymer concentration is lower than the above range, it is difficult to increase the film thickness, and pinholes tend to be easily generated. On the other hand, if the polymer concentration exceeds the above range, the solution viscosity is too high to form a film, and the surface smoothness is reduced. May lack sexuality.

  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 the solution viscosity is lower than the above range, the retention of the solution during processing is poor and may flow from the substrate.On the other hand, if it exceeds the above range, the viscosity is too high to be extruded from the die, Film formation by the casting method may be difficult.

  The composition is, for example, mixing the above-mentioned components at a predetermined ratio, and using a conventionally known method, for example, a mixer such as a homomixer, homodisper, wafer blower, homogenizer, disperser, paint conditioner, or ball mill. Can be prepared. The rotational speed of the rotary mixer is preferably 5,000 times / minute or more, and more preferably 10,000 times / minute or more. Although there is no particular upper limit for the number of revolutions, in practice, 20,000 times / minute or 30,000 times / minute is often the upper limit on the performance of the mixer. In the polymer electrolyte solution produced by such a production method, the manganese-containing oxide is uniformly dispersed in the organic solvent, there is little aggregation, and precipitation of the manganese-containing oxide is observed even when left for a long time. Absent.

  If the rotational speed is too low, the manganese-containing oxide cannot be uniformly dispersed in the polymer electrolyte membrane, and sufficient power generation durability cannot be obtained. In addition, after the polymer electrolyte solution is allowed to stand, the manganese-containing oxide is precipitated, and the power generation performance may vary.

  The mixing time by the mixer is 5 seconds to 60 minutes, preferably 5 seconds to 5 minutes, and more preferably 5 seconds to 3 minutes. Within this range, the manganese-containing oxide is dispersed in a uniform polymer electrolyte solution, and no sedimentation of the manganese-containing oxide is observed after standing.

  The substrate is not particularly limited as long as it is a substrate used in a usual solution casting method. For example, a substrate made of plastic or metal is used, and preferably a thermoplastic resin such as a polyethylene terephthalate (PET) film. A substrate is used. In addition, the electrode layer can be used as a substrate.

  After film formation by the above casting method, a polymer electrolyte membrane can be obtained by drying at a temperature of 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. In addition to the polymer electrolyte, the polymer electrolyte membrane may contain a dispersant, an inorganic acid such as sulfuric acid or phosphoric acid, an organic acid containing a carboxylic acid, an appropriate amount of water, and the like.

Organic solvent (A) Organic solvents used for dispersing or dissolving the protonic acid-containing aromatic polymer include 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-octanol, 2-ethyl-1-hexanol, dioxane, butyl ether, phenyl ether, isopentyl ether, 1,2-dimethoxyethane, diethoxyethane, Bis (2-methoxyethyl) ether, bis (2-ethoxyethyl) ether, cineol, benzyl ethyl ether, anisole, phenetole, acetal, methyl ethyl ketone, 2-pentanone, 3-pentanone, cyclopentanone, cyclohexanone, 2-hexanone, 4-methyl-2-pentanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2-octanone, γ-butyrolactone, acetic acid-n-butyl, isobutyl acetate, sec-butyl acetate, pentyl acetate , Isopentyl acetate, 3-methoxybutyl acetate, methyl butyrate, ethyl butyrate, methyl lactate, ethyl lactate, butyl lactate, 2-methoxyethanol, 2-ethoxyethanol, 2- (methoxymethoxy) ethanol, 2-isopropoxyethanol 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dimethyl sulfoxide, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl- Examples include hydrocarbon organic solvents such as 2-pyrrolidone (NMP), tetramethylurea, toluene, xylene, heptane, and octane, and polyhydric alcohol organic solvents such as ethylene glycol, propylene glycol, and glycerol. Among these, a nitrogen-containing solvent is preferable because it easily forms a micro-separated structure due to acid-base interaction with the protonic acid of the polymer electrolyte. Examples of such nitrogen-containing solvents include dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide, tetramethylurea, 1,3-dimethyl-2-imidazolidinone, and γ-butyrolactone. Can be mentioned.

  The organic solvent may be used alone or in combination of two or more, but preferably contains a water-soluble aprotic dipolar organic solvent from the viewpoint of solubility of the ion exchange resin. More preferably, it is desirable to contain 10% by mass or more of a water-soluble aprotic dipolar organic solvent.

If necessary, a dispersant may be further added to the composition for forming the dispersant polymer electrolyte membrane. Examples of such a dispersant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

[Membrane electrode assembly]
The membrane electrode assembly of the present invention includes the polymer electrolyte membrane, and includes the polymer electrolyte membrane, a catalyst layer, and a gas diffusion layer.

  Typically, a catalyst layer for a cathode electrode is provided on one side and a catalyst layer for an anode electrode is provided on the other side of the polymer electrolyte membrane, and ions of each catalyst layer on the cathode side and the anode side are provided. Gas diffusion layers are provided on the cathode side and the anode side, respectively, in contact with the side opposite to the exchange resin film. A well-known structure can be employ | adopted for a catalyst layer and a gas diffusion layer. Hereinafter, each of the gas diffusion layer and the catalyst layer will be described.

[Gas diffusion layer]
The gas diffusion layer is composed of a porous substrate or a laminated structure of a porous substrate and a microporous layer. When the gas diffusion layer is composed of a laminated structure of a porous substrate and a microporous layer, the microporous layer is provided in contact with the catalyst layer. Although a gas diffusion layer is not specifically limited, It is preferable to consist of a laminated structure of a porous base material and a microporous layer.

(1) Microporous layer The microporous layer can contain carbon powder, fluorine-containing resin, and the like. The microporous layer is formed using a microporous layer forming paste in which carbon powder or the like is dispersed in a solvent.

  In the microporous layer composition used in the present invention, the carbon powder and the resin are preferably present in a weight ratio of 20 to 95:80 to 5, more preferably in a weight ratio of 40 to 90:60 to 10. preferable. When the content of the carbon powder is less than 20% by weight, it is difficult to form fine pores in the microporous layer, and the reactants are not easily diffused. When the content of the carbon powder exceeds 95% by weight, the carbon powder may fall off, which is not preferable.

(1-1) Carbon powder Examples of the carbon powder include carbon powder, carbon fiber, fullerene, carbon nanotube, carbon nanofiber, and silicon carbide whisker whose surface is coated with a carbon film. These may be used alone or in combination of two or more.

  The carbon powder is preferably carbon black such as oil furnace black, channel black, lamp black, thermal black, and acetylene black from the viewpoint of electron conductivity and specific surface area.

(1-2) Fluorine-containing resin The microporous material may contain a fluorine-containing resin. The fluorine-containing resin imparts water repellency to the porous substrate. Specific examples include polytetrafluoroethylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, silane coupling agent, silicone resin, wax, polyphosphazene, and perfluorocarbon having an aliphatic ring structure in the molecule. Polymer, copolymer of fluorine-containing olefin and hydrocarbon olefin, copolymer of fluorine-containing acrylate and acrylate or / and methacrylate, polyvinylidene fluoride, polychlorotrifluoroethylene, polyhexafluoropropylene, tetrafluoro Ethylene-perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-ethylene copolymer, poly Fluoride - hexafluoropropane, or their copolymers. Among these, a fluororesin is preferable from the viewpoint of durability of water repellency and ease of handling in use, and polytetrafluoroethylene and a tetrafluoroethylene-hexafluoropropylene copolymer are more preferable.

(1-3) Microporous layer forming paste The microporous layer used in the present invention is formed using the following microporous layer forming paste.

  In the present invention, the total weight of the carbon powder and the fluorine-containing resin in the paste is 3% by mass to 50% by mass, preferably 10% by mass to 40% by mass, and the use ratio of the solvent is 50% by mass to 97% by weight. % By mass, preferably 60% by mass to 90% by mass, and the proportion of the dispersant used as necessary is 0% by mass to 45% by mass, preferably 0% by mass to 20% by mass. . When the use ratio of the carbon powder is less than the above range, it is difficult to form micropores in the microporous layer, and the reactant is not easily diffused. If it is larger than the above range, the carbon powder may fall off. If the ratio of the water repellent used is less than the above range, the carbon powder may fall off, which is not preferable.

(1-4) Formation method of microporous layer As a formation method of the microporous layer used by this invention, it is possible to form by directly drying after apply | coating the said paste on a porous base material or a catalyst layer. The microporous layer forming paste may be applied on another transfer substrate and then dried to form a microporous layer, which may be transferred onto the porous substrate or the catalyst layer by hot pressing. Moreover, you may form by laminating | stacking the said microporous layer in several times.
Examples of the method for applying the microporous layer forming paste include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.

(2) Porous base material As the porous base material used in the present invention, a porous base material generally used for fuel cells, for example, a porous conductive sheet mainly composed of a conductive substance, is particularly limited. It can be used without being done.

  Examples of the conductive substance include a fired body from polyacrylonitrile, a fired body from pitch, carbon powders such as graphite and expanded graphite, stainless steel, molybdenum, and titanium. Although the form of the said conductive substance is not specifically limited, such as fibrous form or particle form, Preferably it is a fibrous conductive inorganic substance (inorganic conductive fiber), Most preferably, it is a carbon fiber.

  As a porous conductive sheet using inorganic conductive fibers, either a woven fabric or a non-woven fabric structure can be used. As the woven fabric, plain weaving, oblique weaving, satin weaving, crest weaving, binding weaving and the like can be used without particular limitation. Moreover, as a nonwoven fabric, what was manufactured by methods, such as a papermaking method, a needle punch method, a spun bond method, a water jet punch method, a melt blow method, can be used without being specifically limited. The porous conductive sheet using inorganic conductive fibers may be a knitted fabric.

(2-1) Method for treating porous substrate The porous substrate is preferably used after subjecting the conductive material in the porous substrate to a water repellent treatment. In order to perform the water repellent treatment of the porous substrate, a dispersion in which a fluorine-containing resin is dispersed in water or a water repellent solution dissolved in an organic solvent (hereinafter also referred to as a water repellent treatment resin) is used. Then, it can be produced by coating the water repellent with the method described later and drying and thermally decomposing components other than the water repellent (solvent, dispersant, etc.). As the water repellent coating method, a dip coating method, a screen printing method, a spray coating method or a coating method using a doctor blade, a gravure coating method, a silk screen method, a painting method, etc. are used depending on the viscosity of the composition. It is not limited to this. Among these, the dip coating method is preferable. In the case of the dip coating method, the coating amount of the water repellent resin can be adjusted by the concentration of the dispersion or the water repellent solution. The coating amount of the water-repellent treatment resin on the porous substrate is preferably such that the weight ratio of the water-repellent agent to the water-repellent treated porous substrate is 1% by mass to 50% by mass, more preferably 2% by mass. -30 mass%, 5 mass%-20 mass% are suitable. It is preferable that the coating amount of the water-repellent treatment resin is in the above-mentioned range because the drainage is good and the power generation characteristics are improved.

[Catalyst layer]
The catalyst layer constituting the membrane electrode assembly includes a catalyst and an ion exchange resin electrolyte, and further includes carbon fiber, a resin having no ion exchange group, a dispersant, and the like as necessary. Such a catalyst layer can be formed using a catalyst paste. The catalyst paste contains a catalyst, an ion exchange resin electrolyte, and a solvent. Preferably, in addition to the catalyst, the ion exchange resin electrolyte and the solvent, carbon fiber, a resin having no ion exchange group, water, a dispersant, and the like. To do.

(1) Catalyst As the catalyst, a noble metal catalyst such as platinum, palladium, gold, ruthenium or iridium is preferably used. The noble metal catalyst may contain two or more elements such as an alloy or a mixture.

  From the viewpoint of effectively using the catalyst, a catalyst in which the above catalyst is supported on carbon fine particles having a high specific surface area can be used. As the carbon support, carbon black such as oil furnace black, channel black, lamp black, thermal black, acetylene black and the like is preferable from the viewpoint of electron conductivity and specific surface area.

  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 catalyst content in the catalyst-supported carbon is 10 to 95% by mass. Desirably, it is more suitable in it being 20-85 mass%. If the catalyst content is higher than the above range, the number of catalysts that are not used effectively increases, resulting in an inefficient electrode. Further, when the catalyst content is smaller than the above, a sufficient amount of catalyst cannot be obtained, so that the battery performance is lowered.

(2) Ion exchange resin electrolyte The ion exchange resin electrolyte functions as a binder component for binding the carbon carrying the catalyst, and efficiently supplies ions generated by the reaction on the catalyst to the ion conductive membrane at the fuel electrode. In addition, the air electrode efficiently supplies ions supplied from the ion conductive membrane to the catalyst.

  The ion exchange resin for the catalyst layer used in the present invention is preferably a polymer having a proton exchange group in order to improve proton conductivity in the catalyst layer. Proton exchange groups contained in such polymers include sulfonic acid groups, carboxylic acid groups, and phosphoric acid groups, but are not particularly limited. Further, such a polymer having a proton exchange group is also selected without any particular limitation, but a polymer having a proton exchange group composed of a fluoroalkyl ether side chain and a fluoroalkyl main chain, a sulfonic acid group A polyarylene copolymer having the same is preferably used. In addition, a polyarylene polymer having a sulfonic acid group constituting the aromatic ion exchange resin membrane described above may be used as an ion exchange resin, and a polymer containing a fluorine atom having a proton exchange group, or ethylene Or other polymers obtained from styrene or the like, copolymers or blends thereof.

As such an ion exchange resin electrolyte, a known one can be used without particular limitation, and for example, Nafion (DuPont, registered trademark), a polyarylene copolymer having a sulfonic acid group, or the like can be used without any particular limitation.
Although the specific aspect of the polyarylene-type copolymer which has a sulfonic acid group which can be used for this invention is not specifically limited, A preferable aspect is mentioned later.

(3) Catalyst layer composition In the present invention, the proportion of the catalyst in the catalyst layer (in the case of carbon black carrying a catalyst) is 25% by mass to 85% by mass, preferably 40% by mass. It is 70% by mass, and the use ratio of the ion exchange resin electrolyte is 10% by mass to 60% by mass, preferably 15% by mass to 50% by mass, and does not have an ion exchange group used as necessary. The use ratio of the resin is 0% by mass to 40% by mass, preferably 0% by mass to 20% by mass, and the use ratio of the carbon fiber used as necessary is 0% by mass to 40% by weight. It is 0 mass%, Preferably it is 0 mass%-30 mass%, and the usage-amount of the dispersing agent used as needed is 0 mass%-10 mass% by weight ratio, Preferably it is 0 mass%-5 mass%. .

(4) Catalyst paste composition The catalyst paste is prepared by dissolving or dispersing each component in the usage ratio shown in the section of the catalyst layer in an organic solvent. The organic solvent used in the catalyst paste is not particularly limited, but it is more preferable to use water in combination with these organic solvents.

(5) Preparation of catalyst paste composition The catalyst paste composition can be prepared, for example, by mixing the above components and kneading them by a conventionally known method. The order of mixing the components is not particularly limited. For example, all the 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 the dispersant is added as necessary. It is preferable to add and to stir for a certain time. Moreover, you may adjust the quantity of an organic solvent as needed, and may adjust the viscosity of a composition.

(6) Formation of catalyst layer The catalyst layer of the membrane electrode assembly according to the present invention can be formed by directly applying the electrode paste composition onto an ion exchange resin membrane and drying it.

Examples of the electrode paste composition coating method include brush coating, brush coating, bar coater coating, knife coater coating, doctor blade method, screen printing, and spray coating.
Removal of the solvent of the coating film formed on the substrate is performed by drying at a temperature of 30 ° C. to 200 ° C., preferably 40 ° C. to 180 ° C., for a time of 1 minute to 250 minutes, preferably 5 minutes to 120 minutes. be able to.

Catalyst layer formed on the substrate, if the cathode side to which an oxidant is supplied, that the noble metal catalyst content in the catalyst layer is 0.1mg / cm ² ~6.0mg / cm ² preferably, more preferably from ^{0.3mg / cm 2 ~2.0mg / cm 2} . If the anode side of the fuel is supplied, the noble metal catalyst amount included in the catalyst layer is preferably from ^{0.1mg / cm 2 ~4.0mg / cm 2} , more preferably 0.2 mg / cm ² ~ 1.0 mg / cm ² .

  If the amount of the noble metal catalyst contained in the catalyst layer is less than the above range, the protonation reaction amount of hydrogen, which is a fuel, on both the cathode side and the anode side decreases, and the power generation performance decreases. If the amount of the noble metal catalyst contained in the catalyst layer is more than the above range, the amount of the noble metal catalyst that is not used in the reaction will increase. Air (oxygen) permeability and drainage may be reduced, and power generation performance may be reduced.

Manufacturing Method of Membrane Electrode Assembly The membrane-electrode assembly of the present invention is not particularly limited to the manufacturing method as long as each constituent material is laminated in the above order.

For example, a method in which a polymer electrolyte membrane is prepared in advance, electrode layers are formed on both surfaces of the membrane, the electrode layer is sandwiched between diffusion layers, and press processing is performed.
Alternatively, after the polymer electrolyte membrane is formed on the surface of the substrate, the substrate may be removed after the electrode layer and the polymer electrolyte membrane are joined.

[Fuel cell]
The fuel cell according to the present invention includes at least one electricity generation unit including at least one membrane-electrode assembly and separators located on both sides thereof; a fuel supply unit that supplies fuel to the electricity generation unit; and an oxidant. A fuel cell including an oxidant supply unit that supplies the electricity generation unit, wherein the membrane-electrode assembly is as described above.

  As the separator used in the battery of the present invention, those used in ordinary fuel cells can be used. Specifically, carbon type or metal type can be used.

  Moreover, as a member which comprises a fuel cell, it is possible to use a well-known thing without a restriction | limiting in particular. The battery of the present invention can be used as a single cell or as a stack in which a plurality of single cells are connected in series. As a stacking method, a known method can be used. Specifically, planar stacking in which single cells are arranged in a plane and bipolar stacking in which single cells are stacked via separators each having a fuel or oxidant flow path formed on the back surface of the separator can be used. .

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. Table 1 shows the evaluation results of the examples and comparative examples.

1. Ion exchange capacity A polymer electrolyte membrane and a membrane composed of polymer electrolyte components constituting each electrode catalyst layer are prepared, and a predetermined amount is weighed and phenolphthalein dissolved in a tetrahydrofuran (THF) / water mixed solvent is used as an indicator. Titration was performed using a standard solution of NaOH, and the ion exchange capacity was determined from the neutralization point.

2. Molecular weight The molecular weight of the polyarylene copolymer having no sulfonic acid group was determined by GPC using polystyrene (THF) as a solvent and the molecular weight in terms of polystyrene. As for the molecular weight of the polyarylene copolymer having a sulfonic acid group, the molecular weight in terms of polystyrene was determined by GPC using N-methyl-2-pyrrolidone (NMP) to which lithium bromide and phosphoric acid were added as an eluent.

3. Synthesis of Polyarylene Copolymer Having Sulfonic Acid Group A synthesis example of a polyarylene copolymer having a sulfonic acid group preferably used as a sulfonic acid group-containing aromatic polymer according to the present invention will be described. The present invention is not particularly limited to the following synthesis examples, but when these polyarylene copolymers having a sulfonic acid group are used as a polymer electrolyte membrane, a fuel cell exhibiting good power generation characteristics is obtained. be able to.

4). Specific surface area The specific surface area of the manganese-containing oxide was measured by the BET method (JIS R 1626; measurement method of specific surface area by gas adsorption BET method of fine ceramic powder).

5). Hydrogen peroxide exposure test Three polymer electrolyte membranes of 2 cm x 3 cm were exposed to 5% hydrogen peroxide water vapor at 85 ° C for 24 hours. The molecular weight of the polymer electrolyte membrane before and after exposure was measured, and the molecular weight retention rate (%) after exposure was determined by the following formula. If the molecular weight retention is high, hydrogen peroxide and radical resistance are considered to be high.
(Molecular weight after exposure) / (Molecular weight before exposure) x 100 (%)

6). Hot water elution test The polymer electrolyte membrane was immersed in hot water at 125 ° C. for 24 hours, and an oxide-derived metal in the immersion water was measured by ICP-Mass to confirm the presence or absence of elution.

7). TEM observation Whether or not the polymer electrolyte membrane has a microphase separation structure is determined by cutting out an ultrathin section of the membrane, staining the section with lead nitrate, and then an HF-100FA transmission electron microscope manufactured by Hitachi, Ltd. (Hereinafter referred to as TEM).

8). Initial output voltage The temperature was maintained at 90 ° C., hydrogen and air were supplied at atmospheric pressure to the anode and cathode at a humidity of 50% RH, and the voltage between terminals at a current density of 1.0 A / cm ² was measured.

9. Power Generation Durability Evaluation After measuring the initial output voltage, the fuel cell temperature was kept at 120 ° C., and durability evaluation was performed under the condition of humidity 40% RH. Hydrogen and air were supplied at atmospheric pressure, and the time until the voltage between the terminals became 0.3 V or less when the current density was maintained at 0.1 A / cm ² was measured.

[Synthesis Example 1]
(1) Synthesis of structural unit having aromatic structure Into a 1 L three-necked flask equipped with a stirrer, thermometer, Dean-Stark tube, nitrogen introduction tube, and cooling tube, 48.8 g (284 mmol) of 2,6-dichlorobenzonitrile 2,2-bis (4-hydroxyphenyl) -1,1,1,3,3,3-hexafluoropropane (89.5 g, 266 mmol) and potassium carbonate (47.8 g, 346 mmol) were weighed. After nitrogen substitution, 346 mL of sulfolane and 173 mL of toluene were added and stirred. The reaction solution was heated to reflux at 150 ° C. in an oil bath. Water produced by the reaction was trapped in a Dean-Stark tube. After 3 hours, when almost no water was observed, toluene was removed from the Dean-Stark tube out of the system. The reaction temperature was gradually raised to 200 ° C. and stirring was continued for 3 hours. Then, 9.2 g (53 mmol) of 2,6-dichlorobenzonitrile was added, and the reaction was further continued for 5 hours.

The reaction solution was allowed to cool, and diluted with 100 mL of toluene. Inorganic salts insoluble in the reaction solution were filtered, and the filtrate was poured into 2 L of methanol to precipitate the product. The precipitated product was filtered and dried, then dissolved in 250 mL of tetrahydrofuran, and poured into 2 L of methanol for reprecipitation. The precipitated white powder was filtered and dried to obtain 109 g of the desired product. The number average molecular weight (Mn) measured by GPC was 9,500.
It was confirmed that the obtained compound was an oligomer represented by the formula (I).

（２）スルホン酸基を有するポリアリーレン系共重合体の合成
攪拌機、温度計、窒素導入管をとりつけた１Ｌの三口フラスコに、３−（２，５−ジクロロベンゾイル）ベンゼンスルホン酸ネオペンチル１３５．２ｇ（３３７ｍｍｏｌ）、（１）で得られたＭｎ９，５００の芳香族構造を有する構造単位４８．７ｇ（５．１ｍｍｏｌ）、ビス（トリフェニルホスフィン）ニッケルジクロリド６．７１ｇ（１０．３ｍｍｏｌ）、ヨウ化ナトリウム１．５４ｇ（１０．３ｍｍｏｌ）、トリフェニルホスフィン３５．９ｇ（１３７ｍｍｏｌ）、亜鉛５３．７ｇ（８２１ｍｍｏｌ）をはかりとり、乾燥窒素置換した。ここにＮ，Ｎ−ジメチルアセトアミド（ＤＭＡｃ）４３０ｍＬを加え、反応温度を８０℃に保持しながら３時間攪拌を続けた後、ＤＭＡｃ７３０ｍＬを加えて希釈し、不溶物を濾過した。

(2) Synthesis of polyarylene copolymer having a sulfonic acid group 135.2 g of neopentyl 3- (2,5-dichlorobenzoyl) benzenesulfonate was added to a 1 L three-necked flask equipped with a stirrer, a thermometer and a nitrogen introducing tube. (337 mmol), 48.7 g (5.1 mmol) of the structural unit having an aromatic structure of Mn 9,500 obtained in (1), 6.71 g (10.3 mmol) of bis (triphenylphosphine) nickel dichloride, iodide 1.54 g (10.3 mmol) of sodium, 35.9 g (137 mmol) of triphenylphosphine, and 53.7 g (821 mmol) of zinc were 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 polymer having a sulfonic acid group represented by the formula (II). The ion exchange capacity of this polymer was 2.3 meq / g.

［実施例１］
［電解質膜の調製］
攪拌子を入れた５０ｍｌのスクリュー管に、合成例１で得られたスルホン酸基を有するポリアリーレン系共重合体（ＩＩ）を４．５ｇ、Ｎ―メチル−２−ピロリドン２５．５ｇをとり、室温で４時間攪拌した。この溶液にＭｎＯ₂含量９０ｗｔ％、比表面積４２ｍ²／ｇのＭｎＯ₂粉末（和光純薬製）０．０４６ｇを添加し、攪拌機で１５００ｒｐｍ、４時間攪拌し、透明な溶液を得た。その溶液をペットフィルム上にドクターブレードを用いてキャストし、恒温槽を用いて、６０℃で１時間、１４０℃で１時間乾燥し、溶媒を留去した。乾燥後、ペットフィルムから剥がし、厚さ５０μｍの高分子電解質膜を得た。

[Example 1]
[Preparation of electrolyte membrane]
In a 50 ml screw tube containing a stirrer, 4.5 g of polyarylene copolymer (II) having a sulfonic acid group obtained in Synthesis Example 1 and 25.5 g of N-methyl-2-pyrrolidone are taken, Stir at room temperature for 4 hours. To this solution, 0.046 g of MnO ₂ powder (manufactured by Wako Pure Chemical Industries, Ltd.) having a MnO ₂ content of 90 wt% and a specific surface area of 42 m ² / g was added and stirred with a stirrer at 1500 rpm for 4 hours to obtain a transparent solution. The solution was cast on a pet film using a doctor blade, dried using a thermostatic bath at 60 ° C. for 1 hour and 140 ° C. for 1 hour, and the solvent was distilled off. After drying, it was peeled off from the pet film to obtain a polymer electrolyte membrane having a thickness of 50 μm.

[Preparation of electrode paste]
Put 50 g of zirconia balls having a diameter of 5 mm (“YTZ ball” manufactured by Nikkato Co., Ltd.) into a 50 mL plastic bottle, 1.51 g of platinum-supported carbon particles (Pt: 46% by mass, “TEC10E50E” manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.), distillation 0.88 g of water, 12.47 g of n-propyl alcohol and 4.59 g of a 20 wt% solution of Nafion (trade name, manufactured by DuPont) were added and stirred for 60 minutes with a paint shaker to obtain an electrode paste.

[Manufacture of electrodes]
The electrode paste is applied with a doctor blade on one side of the electrolyte membrane prepared in each Example / Comparative Example using a mask having an opening of 5 cm × 5 cm, and 5 cm is applied on the surface where the electrode paste is not applied. The electrode paste was applied with a doctor blade using a mask having an opening of × 5 cm. After drying this at 120 ° C. for 60 minutes, the amount of catalyst applied to each electrode catalyst layer was 0.50 mg / cm ² .

[Production of gas diffusion layer]
(1) Production of porous substrate Carbon paper (trade name: TGPH-060, manufactured by Toray Industries, Inc.) as a porous substrate is cut into a size of 5 cm x 5 cm, and this is 30 mL of 1.2 mass% polytetra After being immersed in the fluoroethylene resin fine particle dispersion aqueous solution for 5 minutes, it was dried in a drying furnace at 75 ° C. for 15 minutes. This substrate was baked in an electric furnace at 370 ° C. for 1 hour to produce a water repellent coated porous substrate for anode and cathode.

(2) Formation of water repellent coated porous substrate with microporous layer 2.4 g of carbon particles (trade name: Vulcan XC-72, manufactured by Cabot Corporation), 6.2 g of 60 mass% polytetrafluoroethylene resin fine particle dispersed aqueous solution , 104.9 g of distilled water, and 10.3 g of a dispersant (trade name: TRITONX-100, manufactured by Sigma-Aldrich) are mixed, and this mixture is mixed with planetary ball mill (trade name: P-5, manufactured by Fritsch) until uniform. ) Was used to prepare a paste for forming a microporous layer for an anode. After applying this paste uniformly using an applicator so that the weight of the microporous layer is 1.0 mg / cm ² , the paste is dried in a drying oven at 75 ° C. for 30 minutes to provide a water repellent coating with a microporous layer. A porous substrate was prepared.

[Fabrication of fuel cell]
The electrolyte membrane having the electrode catalyst layer formed on both sides is sandwiched between two gas diffusion layers and hot press molded under a pressure of 60 kg / cm ² and a temperature of 160 ° C. for 20 minutes to produce a membrane-electrode assembly. did. The obtained electrode-membrane assembly was sandwiched between two titanium current collectors, and a heater was placed on the outside thereof to produce a fuel cell for evaluation having an effective area of 25 cm ² .

[Example 2]
An electrolyte membrane was produced in the same manner as in Example 1 except that the stirring conditions were changed to 20000 rpm and 60 seconds.

[Example 3]
In a 50 ml screw tube containing a stirrer, 4.5 g of the polyarylene copolymer (II) having a sulfonic acid group obtained in Synthesis Example 1 and 25.5 g of N-methyl-2-pyrrolidone are taken, Stir at room temperature for 4 hours. To this solution, 0.092 g of MnO ₂ powder (manufactured by Wako Pure Chemical Industries, Ltd.) having a MnO ₂ content of 90 wt% and a specific surface area of 42 m ² / g was added and stirred with a stirrer at 10,000 rpm for 120 seconds to obtain a transparent solution. The solution was cast on a pet film using a doctor blade, dried using a thermostatic bath at 60 ° C. for 1 hour and 140 ° C. for 1 hour, and the solvent was distilled off. After drying, it was peeled off from the pet film to obtain a polymer electrolyte membrane having a thickness of 50 μm.

[Example 4]
In a 50 ml screw tube containing a stirrer, 4.5 g of the polyarylene copolymer (II) having a sulfonic acid group obtained in Synthesis Example 1 and 25.5 g of N-methyl-2-pyrrolidone are taken, Stir at room temperature for 4 hours. To this solution, 0.138 g of MnO ₂ powder having a MnO ² content of 90 wt% and a specific surface area of 42 m ² / g was added and stirred with a stirrer at 10,000 rpm for 120 seconds to obtain a transparent solution. The solution was cast on a pet film using a doctor blade, dried using a thermostatic bath at 60 ° C. for 1 hour and 140 ° C. for 1 hour, and the solvent was distilled off. After drying, it was peeled off from the pet film to obtain a polymer electrolyte membrane having a thickness of 50 μm.

[Example 5]
It was produced in the same manner as in Example 1 except that MnO ₂ was changed to Mn ₂ O ₃ (manufactured by high purity chemical).
[Example 6]
It was produced in the same manner as in Example 1 except that MnO ₂ was changed to Bi ₂ Mn ₄ O ₁₀ .

[Comparative Example 1]
It was produced in the same manner as in Example 1 except that MnO ₂ was not added.
[Comparative Example 2]
50 g of the polymer of Synthesis Example 1 and 5 g of manganese dioxide having a specific surface area of about 60 m ² / g were added to a plastic bottle, stirred for 20 minutes with a disperser, and uniformly dispersed.

[Comparative Example 3]
The well-crushed polyether ether ketone was dissolved in concentrated sulfuric acid and stirred under a nitrogen atmosphere to obtain a polyether ether ketone having a sulfonic acid group. Recovery was performed by re-precipitation in excess water. The ion exchange capacity of this polymer was 2.2 meq / g. It was produced in the same manner as in Comparative Example 1 except that this polymer was used.

[Comparative Example 4]
It was prepared in the same manner as in Example 1 except that the polymer of Synthesis Example 1 was changed to a polyether ether ketone having a sulfonic acid group.

  The polymer electrolyte membrane thus obtained was subjected to a hydrogen peroxide exposure test (molecular weight retention rate (%), hot water elution test, initial output voltage measurement, power generation durability test (voltage holding time (h)). Furthermore, the domain observation was performed by TEM photographs.

  The results are also shown in Table 1.

Claims (8)

A polymer electrolyte membrane comprising (A) a polyarylene copolymer having a sulfonic acid group and (B) a manganese-containing oxide having a specific surface area measured by the BET method of 55 m ² / g or less.   2. The polymer according to claim 1, wherein the (B) manganese-containing oxide is at least one of a manganese oxide or a complex oxide containing Mn and at least one element of Ni, Bi, and Ce. Electrolyte membrane. (B) the manganese-containing oxide is at least one of MnO _2, Mn ₂ O _3, complex oxides containing Mn and Bi, the composite oxide containing Mn and Ni, polymer of claim 2 Electrolyte membrane. (A) The polyarylene-based copolymer having a sulfonic acid group includes a structural unit represented by the following general formula (3) and a structural unit represented by the following general formula (4). Item 4. The polymer electrolyte membrane according to any one of Items 1 to 3.

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. p represents an integer of 1 to 12, m represents an integer of 0 to 10, n represents an integer of 0 to 10, and k represents 1 Represents an integer of ~ 4.)

(In the formula, A and D are independently a direct bond, or —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) ₁ — (l is an integer of 1 to 10). in _{a), - (CH 2) l} - (l is an integer of 1 to 10), - CR - a _'2 (R' is an aliphatic hydrocarbon group, aromatic hydrocarbon group or a halogenated hydrocarbon group ), At least one structure selected from the group consisting of cyclohexylidene group, fluorenylidene group, —O—, and —S—, B is an oxygen atom or a sulfur atom, and R ^{1 to} R ¹⁶ May be the same or different from each other, and are selected from the group consisting of a hydrogen atom, a fluorine atom, an alkyl group, a halogenated alkyl group in which some or all are halogenated, an allyl group, an aryl group, a nitro group, and a nitrile group At least one atom or group selected, s, t Represents an integer of 0 to 4, r represents 0 or an integer of 1 or more.) (A) The polyarylene copolymer having a sulfonic acid group includes a structure represented by the following general formula (1), The polymer electrolyte membrane according to claim 4.

[In the formula (1), Y represents —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _i — (i represents an integer of 1 to 10). Or —C (CF ₃ ) ₂ —, Z is independently a direct bond, — (CH ₂ ) _j — (j represents an integer of 1 to 10), —C (CH ₃ ) ₂ —, — O— or —S— is represented, and Ar represents —SO ₃ H, —O (CH ₂ ) _p SO ₃ H or —O (CF ₂ ) _p SO ₃ H (p represents an integer of 1 to 12). The aromatic group which has a substituent represented by this is shown, m shows the integer of 0-10, n shows the integer of 0-10, k shows the integer of 1-4.
A and D are each independently a direct bond, —CO—, —SO ₂ —, —SO—, —CONH—, —COO—, — (CF ₂ ) _i — (i represents an integer of 1 to 10. ), — (CH ₂ ) _j — (j represents an integer of 1 to 10), —CR ′ ₂ — (R ′ represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group or a halogenated hydrocarbon group. ), Cyclohexylidene group, fluorenylidene group, —O— or —S—, B is independently an oxygen atom or sulfur atom, and R ^{1 to} R ¹⁶ are each independently hydrogen atom, fluorine atom, alkyl Group, a halogenated alkyl group, allyl group, aryl group, nitro group or nitrile group partially or wholly halogenated, s and t each represent an integer of 0 to 4, and r is 0 or 1 or more Indicates an integer. ]
Z is a direct bond or, -O -, - represents at least one structure selected from the group consisting of S-, Y _{is, -CO -, - SO 2 -} , - SO -, - CONH -, - COO —, — (CF ₂ ) ₁ — (wherein 1 is an integer of 1 to 10), —C (CF ₃ ) ₂ —, at least one structure selected from the group consisting of — and R ²⁰ is a nitrogen-containing complex A ring group is shown. q represents an integer of 1 to 5, and p represents an integer of 0 to 4.
x, y, z represents a molar ratio when x + y + z = 100 mol%. ] (A) A step of dissolving or dispersing a polyarylene copolymer having a sulfonic acid group in an organic solvent, and (B) adding a manganese-containing oxide having a specific surface area measured by the BET method of 55 m ² / g or less. And (B) a step of dispersing the manganese-containing oxide by high-speed stirring at a rotational speed of 5000 times / minute or more, and a method for producing a polymer electrolyte membrane.   An electrode-membrane assembly comprising the polymer electrolyte membrane according to any one of claims 1 to 5.   A polymer electrolyte fuel cell comprising the electrode-membrane assembly according to claim 7.