JP2010003571A - Polymer electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte for a fuel cell with excellent protonic conductivity and handleability useful as electrolyte for a fuel cell as a constituent material for a solid polymer fuel cell and a direct-methanol fuel cell. <P>SOLUTION: The electrolyte for a fuel cell is structured of a polymeric copolymer having a hydrophilic site with a sulfonic acid group as a side chain and a repetition unit not showing protonic conductivity as a main chain. A ratio (mol%) of the repetition unit not showing protonic conductivity is within a range of 0 to 20 to a repetition unit 1 showing protonic conductivity, and a weight-average molecular weight is within a range of 10,000 to 200,000. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrolyte for a fuel cell or a method for producing the same, a polymer electrolyte fuel cell using them, and a constituent material thereof.

  Polymer electrolytes containing proton conductive substituents are used as raw materials for electrochemical devices such as fuel cells, humidity sensors, gas sensors, and electrochromic display devices. Among these, fuel cells are expected as one of the pillars of new energy technology. Solid polymer fuel cells that use polymer electrolytes with proton-conducting substituents can be operated at low temperatures and can be reduced in size, weight, mobile vehicles such as automobiles, household cogeneration systems, and civilian use. Application to small portable devices is under consideration. In particular, direct methanol fuel cells that use methanol directly as fuel have a simple structure, ease of fuel supply and maintenance, and / or characteristics such as high energy density. As such, it is expected to be applied to small portable devices for private use such as mobile phones and notebook computers. A gas diffusion electrode of a polymer electrolyte fuel cell diffuses a fuel and an oxidant to an anode catalyst layer to which a fuel (methanol, hydrogen, etc.) is supplied, a cathode catalyst layer to which an oxidant (oxygen, air, etc.) is supplied The material for forming the catalyst layer includes a fuel cell catalyst, a polymer electrolyte, and the like.

  As a polymer electrolyte conventionally used, perfluorocarbon sulfonic acid resins represented by Nafion (registered trademark) have been widely studied. Perfluorocarbon sulfonic acid resin has high proton conductivity and is said to be excellent in chemical stability such as acid resistance and oxidation resistance. However, since Nafion (registered trademark) is a fluorine-based polymer electrolyte, the raw material used is high, and it is very expensive because it undergoes a complicated manufacturing process. Further, since the resin is soluble in methanol and easily swells in methanol and water, it is not suitable as an electrolyte material for a direct methanol fuel cell (hereinafter referred to as DMFC) that is always exposed to a methanol atmosphere. It was.

  From such a viewpoint, a polymer electrolyte replacing Nafion (registered trademark) has been studied and proposed. For example, in Non-Patent Document 1, poly (2,6-diphenyl-1,4-phenylene oxide) (hereinafter referred to as PPPO) having a structure containing many phenyl groups easily sulfonated in the molecule and having high-temperature stability. The ion exchange capacity (hereinafter abbreviated as IEC) obtained by sulfonation treatment of 0.7 to 2.8 meq. / G polymer electrolyte (sulfonated poly (2,6-diphenyl-1,4-phenylene oxide) (hereinafter abbreviated as S-PPPO)). However, in this document, S-PPPO has an IEC of 2.6 meq. It has been shown that it dissolves in water at / g or more and cannot be used as an electrolyte membrane for fuel cells.

  In Patent Document 1, poly (2,6-diphenyl-1,4-phenylene oxide) cast film is sulfonated with chlorosulfonic acid in a mixed solvent system, and S-PPPO is used as an electrolyte. It is exemplified that it was effective in suppressing the amount of permeation. However, proton conductivity is not sufficient, and in order to obtain conductivity higher than this, it is necessary to increase the amount of sulfonic acid groups introduced, but this is difficult for the same reason as in Non-Patent Document 1.

  Patent Document 2 discloses a polyelectrolyte having a sulfonated poly (2,6-diphenyl-1,4-phenylene oxide) and an unsulfonated polyethersulfone as a block copolymer in the main chain. Compared with a polymer electrolyte into which a sulfonic acid group is introduced, the proton conductivity is equivalent or higher, the water absorption rate is relatively low, and the water resistance is considered excellent. However, since a sulfonic acid group is contained in the main chain, there is a concern that strength is reduced due to water content.

  Patent Document 3 aims to improve durability, hot water resistance or proton conduction efficiency, which is insufficient with a conventional polyarylene polymer electrolyte, and regularly introduces sulfonic acid groups into the side chain to contact the catalyst. An improved electrolyte has been disclosed. However, the side chains are only introduced randomly and their effects are limited.

Patent Document 4 discloses a polymer having a super strong acid group in the side chain and an aromatic main chain, but an expensive perfluoro-based reagent is used, and there is a problem in practical use from the viewpoint of cost. There is.
New Materials For Fuel Cell And Modern Battery Systems II 794-800 JP 2004-273286 A JP 2001-250567 A JP 2005-82757 A Japanese Patent Laid-Open No. 2004-2596

  The present invention has been made in view of the above problems, and provides a polymer electrolyte useful as a binder for a solid polymer fuel cell, a direct methanol fuel cell polymer electrolyte membrane, and a catalyst layer. It is to be. In other words, it is an inexpensive hydrocarbon-based material with a variety of chemical structures, has a high ion exchange capacity site that is advantageous for conductivity, especially in low moisture conditions, and has high proton conductivity. It is to provide a molecular electrolyte, a polymer electrolyte membrane using the molecular electrolyte, and a catalyst layer binder that suppresses swelling due to water.

  As a result of intensive studies to solve the above problems, the inventors of the present invention are at least a polymer compound represented by the following formula (1), and have an ion exchange capacity of 3.0 meq. / G to 6.5 meq. The electrolyte membrane for a fuel cell obtained from a polymer electrolyte characterized by containing an electrolyte portion of / g shows excellent proton conductivity and low swellability, and the above-mentioned polymer is obtained from a raw material that is easily available at low cost. The inventors have found that the electrolyte can be easily produced, and have completed the present invention. The present invention has been completed based on such new findings and includes the following inventions.

(In the formula, Ar represents an aromatic ring having 6 to 30 carbon atoms. G represents an electrolyte moiety. B represents a direct bond or —O—Ar′—, —CO—Ar′—, —SO ₂ —Ar′—). (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms, in which part or all of the hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are a plurality of aromatic rings, these may be directly bonded, Divalent —O—, —CO—, and —SO ₂ —, which may be the same or different from each other. W may be the same or different from each other, and W is a direct bond or a linking group selected from —O—, —CO—, and —SO ₂ —, and when there are a plurality thereof, they may be the same or different. Y may be a direct bond or —O—, —CO—, —SO ₂ —, —O—A. r′—O— (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms in which a part or all of hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are plural aromatic rings, these are directly bonded. Or may be linked by divalent —O—, —CO—, —SO ₂ —, which may be the same or different.) When there are a plurality, they may be the same or different from each other, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom or a halogen atom, and when there are a plurality, they may be the same as each other A, b, c and d each represent an integer of 1 to 4, s represents an integer of 1 to 10, q represents an integer of 1 to 50, and m and n are 1 to 100. Represents an integer.)
That is, the present invention is a polymer compound represented by the following formula (1), and has an ion exchange capacity of 3.0 meq. / G to 6.5 meq. The present invention relates to a fuel cell electrolyte or a method for producing the same.

(In the formula, Ar represents an aromatic ring having 6 to 30 carbon atoms. G represents an electrolyte moiety. B represents a direct bond or —O—Ar′—, —O—Ar′—, —CO—Ar′—, —SO ₂ —Ar ′ — (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms, in which part or all of the hydrogen atoms are substituted by fluorine atoms, or an unsubstituted aromatic ring. Or a divalent —O—, —CO— or —SO ₂ — group, which may be the same or different. Yes, when present in plural, they may be the same or different from each other W is a direct bond or a linking group selected from —O—, —CO—, —SO ₂ —, and when present in plural, Y may be the same as or different from each other, Y may be a direct bond or —O—, —CO—, —S. _{2 -, -. O-Ar'} -O- (Ar ' some or all hydrogen atoms are substituted by fluorine atoms, or an aromatic ring is more representative of the unsubstituted aromatic ring having 6 to 30 carbon atoms In this case, they may be directly bonded or may be linked by divalent —O—, —CO— or —SO ₂ —, which may be the same or different. In the case where a plurality of linking groups are present, they may be the same or different from each other, and R ¹ , R ² , R ³ and R ⁴ are each independently a hydrogen atom or a halogen atom, They may be the same or different from each other, a, b, c, and d represent an integer of 1 to 4, s represents an integer of 1 to 10, q represents an integer of 1 to 50, m and n represents an integer of 1 to 100.)
In the present invention, the electrolyte moiety described in the above formula (1) is sulfonated at 3.0 meq. / G to 6.5 meq. The present invention relates to a polymer electrolyte characterized by having an ion exchange capacity of / g or a method for producing the same.

(In the formula, A is a linking group selected from —O—, —S—, and —NH—, and when there are a plurality thereof, they may be the same or different. R ⁵ is independently a hydrogen atom, When there are a plurality of aryl groups, substituted aryl groups, and aryloxy groups having 6 to 30 carbon atoms, they may be the same or different from each other, o represents an integer of 1 to 4, and l represents 1 to 50 Represents an integer.)
The present invention is also characterized in that the main chain of the polymer represented by the above formula (1) is obtained by polymerizing a site represented by the following formula (3) and a site represented by the following formula (4). The present invention relates to a polymer electrolyte or a method for producing the same.

(In the formula, Ar, G, B, W, Y, R ¹ , R ² , R ³ , R ⁴ and b, c, s, q are the same as described above. A ′ and d ′ are 1-5. Represents an integer.)

(W, Y, m in the formula are the same as above.)
In addition, the present invention provides the polymer electrolyte obtained by reacting the site represented by the following formula (5) with the site represented by the following formula (6), or a method for producing the same. About.

(In the formula, Ar, G, B, Y and s are the same as described above.)

(Wherein W, R ¹ and R ² are the same as described above. A ′ and b ′ represent an integer of 1 to 5)
In the polymer electrolyte of the present invention, the above formula (5) is obtained by reacting the site represented by the following formula (7) with the electrolyte precursor site represented by the above formula (2). It is characterized by.

(In the formula, Ar, B, Y and s are the same as described above.)
Further, the present invention provides a polymer electrolyte according to the above formula (1), either a site represented by the above formula (2) or a site obtained by reacting a site represented by the above formula (2) with Ar ′, The present invention relates to a polymer electrolyte obtained by reacting a site represented by the following formula (8) and then sulfonating or a method for producing the same.

(In the formula, Ar, W, Y, R ¹ , R ² , R ³ , R ⁴ and a, b, c, d, s, and q are the same as above. B ′ is a hydroxyl group, —O—Ar ′. —, —O—Ar ′, —CO—Ar′— (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms in which part or all of the hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are a plurality of these, they may be directly bonded or may be linked by divalent —O—, —CO— or —SO ₂ —, and these may be the same or different. And when there are a plurality of linking groups, they may be the same as or different from each other.)
In the present invention, the deprotection product after the deprotection or deprotection after the above formula (8) has polymerized the site represented by the above formula (6) and the site represented by the following formula (9): , Ar ′, and a polymer electrolyte, or a method for producing the same.

(In the formula, Ar, Y and s are the same as described above. R represents a hydroxyl-protecting group.)
In the present invention, the above formula (2) has a structure represented by the following formula (10), and after introducing a sulfonic acid group, the ion exchange capacity is 3.0 meq. / G to 6.5 meq. The present invention relates to a polymer electrolyte or a method for producing the same.

(In the formula, A and l are the same as defined above, and R ⁶ is each independently a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a substituted aryl group, or an aryloxy group. Or r may be different, and r represents an integer of 1 to 3.)
The present invention also relates to a polymer electrolyte, wherein the formula (10) has a structure represented by the following formula (11) or a method for producing the same.

(In the formula, l is the same as described above.)
Further, the present invention has an ion exchange capacity of 4.0 meq. In which a sulfonic acid group is introduced at the site represented by the above formula (11). /G-5.0 meq. The present invention relates to a polymer electrolyte having an electrolyte portion of / g or a method for producing the same.

  The present invention also relates to a polymer electrolyte, which is an aromatic polymer containing a polyethersulfone structure in the main chain, or a method for producing the same.

  The polymer electrolyte composite of the present invention contains at least one polymer electrolyte and a polymer compound having no sulfonic acid group.

  The polymer electrolyte membrane of the present invention contains the polymer electrolyte.

  The catalyst layer for a fuel cell of the present invention contains the polymer electrolyte.

  The membrane electrode assembly of the present invention includes any one of the polymer electrolyte, the polymer electrolyte membrane, and the fuel cell catalyst layer.

  The solid polymer fuel cell of the present invention includes any of the polymer electrolyte, the polymer electrolyte membrane, the fuel cell catalyst layer, and the membrane electrode assembly.

  The direct methanol fuel cell of the present invention includes any of the polymer electrolyte, the polymer electrolyte membrane, the fuel cell catalyst layer, and the membrane electrode assembly.

  According to the present invention, the polymer compound represented by the following formula (1) has an ion exchange capacity of 3.0 meq. / G to 6.5 meq. By using a polymer electrolyte containing an electrolyte portion of / g as an electrolyte membrane for fuel cells, it is an inexpensive hydrocarbon-based material having a variety of chemical structures, and in particular, conductivity in a low moisture state It is possible to provide a polymer electrolyte having a high ion exchange capacity site advantageous to the above and having excellent proton conductivity.

(In the formula, Ar represents an aromatic ring having 6 to 30 carbon atoms. G represents an electrolyte moiety. B represents a direct bond or —O—Ar′—, —O—Ar′—Ar′—, —CO—Ar). A connecting group selected from '-, -SO ₂ -Ar'- (Ar' represents an aromatic ring in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an unsubstituted aromatic ring); When present, they may be the same as or different from each other, W is a direct bond or a linking group selected from —O—, —CO—, and —SO ₂ —, Y may be a direct bond or —O—, —CO—, —SO ₂ —, —O—Ar′—O—, —O—Ar′—Ar′—O— (Ar 'Represents an aromatic ring in which some or all of the hydrogen atoms are substituted with fluorine atoms, or an unsubstituted aromatic ring. R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom or a halogen atom, and when there are a plurality of linking groups, They may be the same or different from each other, a, b, c, and d represent an integer of 1 to 4, s represents an integer of 1 to 10, q represents an integer of 1 to 50, m and n represents an integer of 1 to 100.)
In addition, by using this polymer electrolyte as a polymer electrolyte membrane and catalyst layer binder, it is an inexpensive hydrocarbon-based material with a variety of chemical structures, and its conductivity, especially in low moisture conditions, A polymer electrolyte membrane and a catalyst layer binder having an advantageous high ion exchange capacity site and excellent proton conductivity can be obtained. Furthermore, by combining with a polymer compound that does not have a sulfonic acid group and introducing a cross-linked structure, high performance such as mechanical strength, suppression of swelling, and long-term durability is achieved in accordance with the excellent properties of the original polymer electrolyte. A polymer electrolyte membrane and a catalyst layer binder can be obtained.

An embodiment of the present invention will be described as follows. It should be noted that the present invention is not limited to the following description.
(1. Polymer electrolyte of the present invention)
The polymer electrolyte of the present invention is at least a polymer compound represented by the following formula (1), and has an ion exchange capacity of 3.0 meq. / G to 6.5 meq. As long as it has an electrolyte part of / g, the specific components such as other components, forms and production conditions are not particularly limited. With such a configuration, excellent proton conductivity is exhibited. These are preferably processed into a membrane shape and used as an electrolyte membrane of a polymer electrolyte fuel cell or a direct methanol fuel cell, since excellent power generation characteristics can be exhibited. In addition, a fuel cell catalyst layer is formed in combination with a fuel cell catalyst and used as an anode or cathode catalyst layer of a polymer electrolyte fuel cell or a direct methanol fuel cell. This is preferable.

(In the formula, Ar represents an aromatic ring having 6 to 30 carbon atoms, G represents an electrolyte moiety, and B represents a direct bond or —O—Ar′—, —CO—Ar′—, —SO ₂ —Ar′—). (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms, in which part or all of the hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are a plurality of aromatic rings, these may be directly bonded, Divalent —O—, —CO—, and —SO ₂ —, which may be the same or different from each other. W may be the same or different from each other, and W is a direct bond or a linking group selected from —O—, —CO—, and —SO ₂ —, and when there are a plurality thereof, they may be the same or different. Y may be a direct bond or —O—, —CO—, —SO ₂ —, —O—A. r′—O— (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms in which a part or all of hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are plural aromatic rings, these are directly bonded. Or may be linked by divalent —O—, —CO—, —SO ₂ —, which may be the same or different.) When there are a plurality, they may be the same or different from each other, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom or a halogen atom, and when there are a plurality, they may be the same as each other A, b, c and d each represent an integer of 1 to 4, s represents an integer of 1 to 10, q represents an integer of 1 to 50, and m and n are 1 to 100. Represents an integer.)
The polymer electrolyte of the present invention will be described in more detail. In the above formula (1), Ar represents an aromatic ring having 6 to 30 carbon atoms, examples of the main aromatic ring include benzene, naphthalene, and biphenyl, and examples of the heterocyclic aromatic ring include pyridine and benzimidazole. it can.

  In the above formula (1), G represents an electrolyte site and is represented by the following formula (2).

In the formula, A is a linking group selected from —O—, —S—, and —NH—, and when there are a plurality of them, they may be the same or different. R ⁵ is independently a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a substituted aryl group, or an aryloxy group, and when there are a plurality of R ^{5 s} , they may be the same or different. Specifically, a phenyl group, a naphthyl group, a 4-phenylphenyl group, a 4-phenoxyphenyl group and the like can be listed, and a hydrogen atom and a phenyl group are preferable from the standpoint of availability of monomers. l represents an integer of 1 to 50, preferably 1 to 20. If it is greater than 20, swelling with water or methanol may increase. o represents an integer of 1 to 3.

In the above formula (1), B is a direct bond or a linking group selected from —O—Ar′—, —CO—Ar′—, and —SO ₂ —Ar′—. And divalent aromatic groups selected from (12a) to (12c).

(R ^{7 to} R ¹¹ are each independently a hydrogen atom or a halogen atom, and when a plurality of R ^{7 to} R ¹¹ are present, they may be the same or different. E, f, g, h, and i are integers of 1 to 4). And when present in plural, they may be the same or different from each other, and V is a direct bond or a linking group selected from —O—, —CO—, and —SO ₂ —. (It may be the same or different. T represents an integer of 0 to 5.)
In the above formula (1), W is a direct bond or a divalent linking group, and specifically includes —O—, —CO—, —SO ₂ —, and the like. , 4′-dihydroxydiphenylsulfone and 4,4′-dichlorodiphenylsulfone can be synthesized by polycondensation. When the main chain copolymer is a block, the weight average molecular weight of the block made of polyethersulfone is preferably 250 to 50000, more preferably 250 to 20000. If it is larger than 50000, the solubility may be lowered and the handling property may be deteriorated.

In the above formula (1), Y is a direct bond or a divalent linking group, and specific examples include —O—, —CO—, —SO ₂ —, —O—Ar′—O—, and the like. Ar ′ includes a divalent aromatic group selected from the above formulas (12a) to (12c). When there are a plurality of these, they may be the same or different.

In the above formula (1), R ¹ , R ² , R ³ and R ⁴ each independently represent a hydrogen atom or a halogen atom, and as the halogen atom, a fluorine atom is preferable because of its high reactivity, and there are a plurality of them. In this case, they may be the same as or different from each other. a, b, c, and d represent the number of substituents on the aromatic ring and are in the range of 1-4. s represents an integer of 1 to 10 and is a balance with the length of l, but is preferably in the range of 1 to 5. q represents an integer of 1 to 50, preferably 1 to 30. m and n represent an integer of 1 to 100.

The above formula (3) in the polymer electrolyte of the present invention will be described in more detail. In the above formula (3), Ar, G, B, W, Y, R ¹ , R ² , R ³ , R ⁴ and b, c, s, q are the same as described above. a ′ and d ′ each represent an integer of 1 to 5.
(2. Method for producing polymer electrolyte of the present invention)
Next, an example is given and demonstrated about the manufacturing method which concerns on the polymer electrolyte of this invention. In addition, the manufacturing method of the polymer electrolyte of this invention is not limited to the following.
(2-1. Production Method of General Formula (2))
The electrolyte site of the present invention is a general method of polymerization (“New Polymer Experimental 3 Polymer Synthesis / Reaction (2) Condensation Polymer Synthesis” p. 350-359, (1996) Kyoritsu Shuppan Co., Ltd.) Company) etc. can be applied. For example, in the case of poly (2,6-diphenyl-1,4-phenylene oxide), oxidative polymerization in which 2,6-diphenylphenol is carried out in the presence of a catalyst and oxygen, or after halogenating a monomer, the basic conditions in the presence of the catalyst It can be produced by the Ullmann reaction carried out in step 1 or polymerization utilizing a phase transfer catalyst.
(2-2. Method for producing polymer electrolyte of general formula (1))
Next, the manufacturing method of the polymer electrolyte of this invention is demonstrated. There is no particular limitation on the method of chemically bonding two or more precursors to increase the molecular weight, and the method can be appropriately determined depending on the reactivity of the monomer to be polymerized. For the details of the polymerization method, a general method (“Synthesis and Reaction of Polymer (2)” p.249-255, (1991) Kyoritsu Shuppan Co., Ltd.) can be applied. In order to increase the molecular weight, there are a method in which two or more monomers are mixed and polymerized, a method in which a second monomer or polymer is added after polymerizing a single monomer, and the like. By using or combining these methods, a block copolymer, a random copolymer, an alternating copolymer, a multiblock copolymer, a graft copolymer, or the like can be produced. In addition, when the monomer has a functional group capable of causing a side reaction, the side reaction is performed using a known method (“Protective Groups in Organic Synthesis (THIRD EDITION)” p. 17-148, (1999) WILEY-INTERSCIENCE). It is possible to obtain a polymer having a functional group by polymerizing after protecting the functional group that can occur, and deprotecting the obtained polymer. For example, using a monomer in which the hydroxyl group is protected by an alkoxy group or a siloxy group And a method of deprotecting the protecting group under suitable conditions after polymerization.

  In order to obtain the polymer electrolyte represented by the above formula (1), a compound in which halogen remains at the terminal represented by the above formula (3) and a compound in which a hydroxyl group remains at the terminal represented by the above formula (4) And a method of condensing in the presence of an alkali. Moreover, in order to obtain the polymer electrolyte represented by the above formula (8), a compound in which halogen remains at the terminal represented by the above formula (6) and a hydroxyl group remaining at the terminal represented by the above formula (9). And a method of condensing the obtained compound in the presence of an alkali. In addition, when compounds having hydroxyl groups remaining at the ends are bonded to each other, they may be condensed in the same condensation reaction by adding halogen compounds at both ends such as perfluorobenzene, perfluorobiphenyl, and 4,4′-dichlorodiphenylsulfone. On the other hand, in the case where compounds having halogen remaining at the ends are bonded to each other, they can be condensed by the same condensation reaction by adding a dihydroxy compound such as 4,4′-hydroxydiphenylsulfone. Examples of the alkali include sodium hydroxide, potassium hydroxide, potassium carbonate, metallic sodium, metallic potassium, metallic lithium, sodium hydride, potassium hydride, lithium hydride, triethylamine, pyridine and the like. The condensation reaction can be performed in a molten state without using a solvent, but it is preferably performed in a suitable solvent. Examples of the solvent include aromatic hydrocarbon solvents, halogen solvents, ether solvents, ketone solvents, amide solvents, sulfone solvents, sulfoxide solvents, and the like. Among them, N, N-dimethylacetamide, N, A mixed system of an amide solvent such as N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone and a halogen solvent such as dichlorobenzene or trichlorobenzene is preferable. Moreover, these may be used independently or may use 2 or more types together. What is necessary is just to set the reaction temperature of a polymerization reaction process suitably according to a polymerization reaction. Specifically, it may be set to 20 ° C. to 250 ° C. of the optimum use range, and more preferably 40 ° C. to 200 ° C. If the temperature is lower than this range, the reaction is slow, and if the temperature is high, the main chain may be broken.

  When the above formula (8) is a polyethersulfone, the production method is not particularly limited, and examples thereof include a method in which a dihalogenated diphenylsulfone and a diol are reacted in the presence of an alkali. Examples of the dihalogenated diphenyl sulfone include 4,4′-difluorodiphenyl sulfone, 4,4′-dichlorodiphenyl sulfone, 2,2′-difluorodiphenyl sulfone, 2,2′-dichlorodiphenyl sulfone, and the like. Some or all of the atoms may be substituted with fluorine atoms, or a mixture of two or more. Examples of the diol include hydroquinone, methoxyhydroquinone, 4,4′-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl, 2,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenyl ether, and bis (4-hydroxyphenyl). Sulfides and the like can be enumerated, and these may have some or all of the hydrogen atoms substituted with fluorine atoms, may have other substituents, or may be a mixture of two or more.

When B of the compound represented by the formula (7) is —O—Ar ′, for example, an aromatic hydroxyl group and Ar ′ may be reacted under alkaline conditions. In the case of —CO—Ar′— and —SO ₂ —Ar′—, for example, one may be a carboxylic acid halide or a sulfonic acid halide, and the other one may be a hydrogen atom. Examples of the carboxylic acid halide include carboxylic acid chloride and carboxylic acid fluoride, and examples of the sulfonic acid halide include sulfonic acid chloride and sulfonic acid fluoride. For example, aluminum chloride, iron chloride, antimony chloride, titanium chloride, bismuth chloride and the like can be listed as the Lewis acid. Although this reaction can be performed in a molten state without using a solvent, it is preferably performed in an appropriate solvent. Examples of the solvent include aliphatic hydrocarbon solvents, halogen solvents, and the like. Among them, halogen solvents such as dichloromethane, chlorobenzene, and dichlorobenzene are preferable from the viewpoint of solubility. What is necessary is just to set reaction temperature suitably according to a compound. Specifically, it may be set to −50 ° C. to 250 ° C. of the optimum use range, and more preferably −20 ° C. to 200 ° C. If the temperature is lower than this range, the reaction may be slow, and if the temperature is high, side reactions may occur.

  As a method for synthesizing the compound represented by the above formula (5), for example, an electrolyte precursor site having a site capable of nucleophilic reaction such as a hydroxyl group represented by the above formula (2) and B represented by the above formula (7) A compound having a leaving group such as a halogen atom at the site may be reacted in the presence of an alkali. Examples of the alkali include sodium hydroxide, potassium hydroxide, potassium carbonate, metallic sodium, metallic potassium, metallic lithium, and sodium hydride. , Potassium hydride, lithium hydride, triethylamine, pyridine and the like. The reaction can be performed in a molten state without using a solvent, but it is preferably performed in an appropriate solvent. Examples of the solvent include aromatic hydrocarbon solvents, halogen solvents, ether solvents, ketone solvents, amide solvents, sulfone solvents, sulfoxide solvents, and the like. Among them, N, N-dimethylacetamide, N, A mixed system of an amide solvent such as N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone and a halogen solvent such as dichlorobenzene or trichlorobenzene is preferable. Moreover, these may be used independently or may use 2 or more types together. What is necessary is just to set reaction temperature suitably. Specifically, it may be set to the optimum use range of 20 ° C to 250 ° C, more preferably 40 ° C to 200 ° C. If the temperature is lower than this range, the reaction may be slow, and if the temperature is high, side reactions may occur.

  As a synthesis method of the compound represented by the above formula (3), for example, a compound having a site capable of nucleophilic reaction such as a hydroxyl group represented by the above formula (5) and halogen at both ends represented by the above formula (6). The compound having a halogen may be reacted in the presence of an alkali. Examples of the compound having halogen at both ends include perfluorobenzene, perfluorobiphenyl, and 4,4′-difluorodiphenylsulfone. Examples of the alkali include sodium hydroxide, potassium hydroxide, potassium carbonate, metallic sodium, metallic potassium, metallic lithium, sodium hydride, potassium hydride, lithium hydride, triethylamine, pyridine and the like. The reaction can be performed in a molten state without using a solvent, but it is preferably performed in an appropriate solvent. Examples of the solvent include aromatic hydrocarbon solvents, halogen solvents, ether solvents, ketone solvents, amide solvents, sulfone solvents, sulfoxide solvents, and the like. Among them, N, N-dimethylacetamide, N, A mixed system of an amide solvent such as N-dimethylformamide, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone and a halogen solvent such as dichlorobenzene or trichlorobenzene is preferable. Moreover, these may be used independently or may use 2 or more types together. What is necessary is just to set reaction temperature suitably. Specifically, it may be set to the optimum use range of 20 ° C to 250 ° C, more preferably 40 ° C to 200 ° C. If the temperature is lower than this range, the reaction may be slow, and if the temperature is high, side reactions may occur.

  Examples of the sulfonating agent in the sulfonation step for obtaining the polymer electrolyte include sulfuric acid, chlorosulfonic acid, fuming sulfuric acid and the like. Among them, chlorosulfonic acid is preferable because it has an appropriate reactivity. The solvent in the sulfonation step is not particularly limited as long as it does not inhibit the reaction, and ether solvents, hydrocarbon solvents, aromatic hydrocarbon solvents, halogen solvents and the like can be listed, and among them, methylene chloride and Halogen solvents such as 1,2-dichloroethane are preferred. These may be used alone or in combination of two or more. What is necessary is just to set the reaction temperature of a sulfonation process suitably according to reaction, Specifically, what is necessary is just to set to -80 to 200 degreeC which is the optimal use range of a sulfonating agent, More preferably, it is -50 to 120 degreeC. ° C, more preferably -20 ° C to 80 ° C. If the temperature is lower than this range, the reaction is slow, and if the temperature is high, a rapid reaction occurs and the intended sulfonation does not proceed to 100%.

The electrolyte site of the present invention has an IEC of 3.0 meq. / G to 6.5 meq. / G. If it is lower than this, the effect of the present invention may not be obtained, and if it is higher than this, sulfonation may be difficult.
(3. Fuel cell electrolyte membrane of the present invention)
The fuel cell electrolyte membrane of the present invention is obtained by processing the above-described fuel cell electrolyte into a membrane shape (film shape). The film thickness may be appropriately set in consideration of mechanical strength, handling properties, fuel and oxidant blocking properties, and membrane resistance. Specifically, 5 to 200 μm is preferable, and 20 to 100 μm is more preferable. If it is thinner than this range, the membrane resistance will be small, but the mechanical strength may be insufficient, the handleability may be impaired, and the permeation amount of fuel and oxidant may be excessive. On the other hand, if it is thicker than this range, the membrane resistance may be high and the desired performance as an electrolyte membrane may not be exhibited.

As a film forming method, a known method used in a polymer film or an electrolyte membrane can be applied. Specifically, a solution casting method can be used in the case of solvent solubility, and a melt extrusion method or a hot pressing process can be used in the case of thermoplasticity, but is not limited thereto. In addition, the fuel cell electrolyte of the present invention can be combined with other binder resin or electrolyte and processed into a form in which it is dispersed in other matrix components as it is.
(4. Catalyst layer for fuel cell of the present invention)
The catalyst layer for a fuel cell of the present invention is composed of the above-described electrolyte for a fuel cell, a catalyst for a fuel cell, and, if necessary, a water repellent and a binder resin. The fuel cell catalyst used in the present invention may be literally a fuel cell catalyst conventionally known to those skilled in the art, and includes a conductive catalyst carrier and a catalytically active substance supported by the conductive catalyst carrier. Any other specific configuration is not particularly limited. Specifically, a catalyst active for the electrode reaction of the fuel cell is used. On the anode side, a catalyst having the ability to oxidize fuel (such as methanol or hydrogen) is used. Specific examples of the conductive catalyst support include carbon supports having a high surface area such as carbon black, ketjen black, activated carbon, carbon nanohorn, and carbon nanotube. The catalyst support ability, electronic conductivity, and electrochemical stability can be exemplified. Therefore, these materials are preferable. Specific examples of the catalytically active substance include platinum, cobalt, ruthenium, and the like, and these may be used alone or as an alloy containing at least one of them, or any mixture. In particular, considering the oxidizing ability of the fuel, the reducing ability of the oxidizing agent, and durability, platinum or an alloy containing platinum is preferable. If necessary, these may be composed of three or more components using iron, tin, rare earth elements or the like for stabilization and long life.

  The fuel cell catalyst layer of the present invention is prepared by applying a catalyst ink containing the fuel cell electrolyte of the present invention, the fuel cell catalyst, and a solvent onto a support and removing the solvent. The solvent can be used without any limitation as long as it can dissolve the fuel cell electrolyte and does not poison the fuel cell catalyst. The catalyst ink may contain additives such as a non-electrolyte binder, a water repellent, a dispersant, a thickener, and a pore-forming agent as necessary. In addition, those additives conventionally known to those skilled in the art can be used, and other specific configurations are not particularly limited.

  The catalyst ink prepared by the above composition and method can be applied by the following coating method depending on the viscosity and the type of substrate. The method for applying the catalyst ink onto the substrate may be any method known to those skilled in the art, and the other specific configuration is not particularly limited. For example, methods using a knife coater, a bar coater, a spray, a dip coater, a spin coater, a roll coater, a die coater, a curtain coater, screen printing, and the like can be enumerated, but are not limited thereto.

In the present invention, when a polymer film is used as the substrate, a fuel cell catalyst layer transfer sheet can be produced, and when a conductive porous sheet is used, a fuel cell gas diffusion electrode can be produced.
(5. Membrane electrode assembly of the present invention)
The membrane electrode assembly of the present invention includes any one of the above-described fuel cell electrolyte, fuel cell electrolyte membrane, and fuel cell catalyst layer. That is, the fuel cell electrolyte, the fuel cell electrolyte membrane, and the fuel cell catalyst layer of the present invention are used in at least one of the electrolyte membrane, anode catalyst layer, and cathode catalyst layer, which are constituents of the membrane electrode assembly. Other specific configurations are not particularly limited. Therefore, in the membrane electrode assembly of the present invention, as the electrolyte membrane, in addition to the fuel cell electrolyte membrane of the present invention, for example, perfluorocarbon sulfonic acid-based polymer electrolyte membranes such as Nafion and Asahi Glass manufactured by DuPont ( Flemion manufactured by Asahi Kasei Co., Ltd., Aciplex manufactured by Asahi Kasei Corporation, Gore Select manufactured by Gore, etc. may be used. As the non-fluorine polymer electrolyte membrane, those conventionally known to those skilled in the art can be used. For example, as a polymer electrolyte membrane suitable for a membrane electrode assembly for direct methanol fuel cells, a pore filling membrane in which a nonelectrolytic porous support is filled with a polymer electrolyte or a polymer electrolyte and a nonelectrolyte are combined. It is preferable to use a composite electrolyte membrane or the like.

  In the production of the fuel cell membrane / electrode assembly of the present invention, the conditions of the heat-pressure welding may literally be those conventionally known to those skilled in the art, and the other specific configurations are not particularly limited. The optimum conditions need to be set as appropriate according to the type of polymer electrolyte contained in each of the electrolyte membrane, the anode side catalyst layer, and the cathode side catalyst layer. Generally, the temperature of the heating and pressure welding is equal to or lower than the thermal deterioration or thermal decomposition temperature of the polymer electrolyte contained in the polymer electrolyte membrane or the catalyst layer, and the polymer electrolyte contained in the polymer electrolyte membrane or the catalyst layer. It is preferable to carry out the reaction at a temperature above the glass transition point or softening point of the polymer electrolyte, or at a temperature above the glass transition point or softening point of the polymer electrolyte contained in the polymer electrolyte membrane or the catalyst layer. In addition, the pressurizing condition of the heat pressure contact is generally in the range of 0.1 MPa or more and 20 MPa or less, and the polymer electrolyte membrane and the catalyst layer are in sufficient contact with each other, and there is no deterioration in characteristics due to significant deformation of the material used. preferable.

  In the membrane / electrode assembly of the present invention, the catalyst layer obtained by the production method of the present invention is disposed on both surfaces of the polymer electrolyte membrane, the polymer electrolyte membrane and the catalyst layer are joined, and then the polymer film is bonded. By peeling off, a three-layer membrane electrode assembly (three-layer MEA: Membrane Electrode Assembly, CCM: Catalytic Coating Membrane) composed of a polymer electrolyte membrane, an anode-side catalyst layer, and a cathode-side catalyst layer can be produced.

  In addition, when a gas diffusion electrode for a fuel cell obtained by the production method of the present invention is used instead of the catalyst layer, a five-layer membrane electrode assembly in which a diffusion layer is formed outside the three-layer membrane electrode assembly (5-layer MEA) can be manufactured.

Furthermore, at least a layer made of a water repellent conductive material composed of conductive carbon particles and a water repellent agent is provided between the diffusion layer and the catalyst layer as needed, and the electrolyte at the periphery of the diffusion layer It is added that a seven-layer membrane electrode assembly formed by arranging a pair of gaskets on the membrane is also within the scope of the present invention.
(6. Polymer electrolyte fuel cell and direct methanol fuel cell of the present invention)
The polymer electrolyte fuel cell and the direct methanol fuel cell of the present invention are configured such that the membrane electrode assembly described above is inserted between a pair of separators in which flow paths for feeding fuel and oxidant are formed, and the like. It is obtained. The separator is not particularly limited, and for example, a conductive material such as carbon graphite or stainless steel can be used. In particular, when a metal material such as stainless steel is used, it is preferable to perform a corrosion resistance treatment. Instead of these separators, members having fuel and oxidant supply paths may be substituted.

  When supplying hydrogen or hydrogen-rich gas as a fuel to the anode, it is classified into a solid polymer fuel cell, and when supplying methanol and its aqueous solution, it is classified directly into a methanol fuel cell. In either case, the oxidizing agent for the cathode is not particularly limited, but oxygen or air can be used. The oxidant supplied to the cathode may be humidified with water, but the use of a non-humidified oxidant is preferable because the cathode flooding phenomenon can be suppressed.

  It should be noted that the polymer electrolyte fuel cells according to the present embodiment can be used alone or in a stacked manner to form a stack, or a fuel cell system incorporating them.

  Hereinafter, examples will be shown, and the embodiment of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail. Further, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and the present invention is also applied to the embodiments obtained by appropriately combining the disclosed technical means. It is included in the technical scope of the invention.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples, In the range which does not change the summary, it can change suitably.
(Reference Example 1)
Under a nitrogen atmosphere, a solution of 16.6 g (120 mmol) of dimethoxyhydroquinone in CH ₂ Cl ₂ (100 ml) was cooled to an internal temperature of −15 ° C. To this, 17.4 g (130.8 mmol) of aluminum chloride and 15.6 ml (132 mmol) of 4-fluorobenzoyl chloride were sequentially added, and the mixture was stirred at the same temperature for 19 hours. After confirming the completion of the reaction by TLC, the reaction was stopped by pouring into water (500 ml). After extraction with CH ₂ Cl ₂ , the organic phase was washed with 10 wt% NaOH aqueous solution (300 ml), extracted again with CH ₂ Cl ₂ , washed with water, and the aqueous layer was removed. The organic layer was dried over magnesium sulfate and concentrated under reduced pressure to obtain 30.6 g of 2,4-dimethoxy-4′-fluorobenzophenone as a slightly yellow oil.
(Reference Example 2)
In a nitrogen atmosphere, 16.5 g (n = 12) of poly (2,6-diphenyl-1,4-phenylene oxide), 1.45 g (5.5 mmol) of 2,4-dimethoxy-4′-fluorobenzophenone and potassium carbonate A mixed solution of N, N-dimethylacetamide (35 ml) and o-dichlorobenzene (20 ml) containing 1.1 g (7.7 mmol) was stirred for 24 hours under oil bath heating conditions at 180 ° C. After confirming the completion of the reaction by TLC, it was poured into methanol (500 ml) to precipitate. The solid was collected by filtration and dried in vacuo at 60 ° C. and used as it was in the next reaction.
(Reference Example 3)
Under a nitrogen atmosphere, a CH ₂ Cl ₂ (40 ml) solution containing 2,4-dimethoxy-4′-poly (2,6-diphenylphenoxy) benzophenone (5.5 mmol) was cooled to an internal temperature of −15 ° C. To this, 13 ml of a 1M CH ₂ Cl ₂ solution of BBr ₃ was added dropwise, followed by stirring at room temperature for 22 hours. After confirming the completion of the reaction by TLC, the reaction was stopped by pouring into water (200 ml). After extraction with ethyl acetate, the extract was washed with a saturated aqueous sodium chloride solution (100 ml), dried over magnesium sulfate, and concentrated under reduced pressure. This was purified by silica gel column chromatography to obtain 2,4-dihydroxy-4′-poly (2,6-diphenyl-1,4-phenyleneoxy) benzophenone (n = 12) as yellow crystals. 8 g was obtained (hereinafter referred to as G-12).
(Reference Example 4)
Under a nitrogen atmosphere, 2,4-dihydroxy-4′-poly (2,6-diphenyl-1,4-phenyleneoxy) benzophenone (n = 12) 2.8 g (0.89 mmol) and potassium carbonate 172 mg (1.25 mmol) ), A mixed solution of NMP (20 ml) and cyclohexane (5 ml) was stirred for 2 hours under heating at 150 ° C., and then the system was cooled to 50 ° C. To this, 892 mg (2.7 mmol) of perfluorobiphenyl was added, followed by stirring for 2 hours under a heating condition of 110 ° C. After confirming the completion of the reaction by TLC, the mixed solution was poured into a mixed solvent of methanol (300 ml) and water (100 ml) to precipitate the target product as a solid. The solid was collected by filtration and dried in vacuo at 60 ° C. to obtain 3.1 g of the target compound as an almost white solid (hereinafter referred to as G-12F).
Example 1
In a nitrogen atmosphere, a mixed solution of NMP (4.5 ml) and toluene (1.5 ml) containing 1.5 g of terminal OH oligomer PES and 76 mg of potassium carbonate was stirred for 2 hours under 160 ° C. oil bath heating conditions. After removing water and toluene azeotropically from the system, the temperature of the oil bath was lowered to 80 ° C. 1.5g of G-12F was added thereto, and polymerization was carried out under a heating condition of 120 ° C for 4 hours. The resulting polymer was dropped into 300 ml of methanol, and then the polymer was collected by filtration (number average molecular weight 25000, hereinafter referred to as GP-12F).

1 g of the copolymer obtained above was dissolved in CH ₂ Cl ₂ (15 ml), chlorosulfonic acid (0.5 ml) was added dropwise, and the mixture was stirred at room temperature for 14 hours. The solid was separated by filtration, immersed in ion-exchanged water, stirred and filtered repeatedly and washed until the washing water became neutral. The solid was filtered off and vacuum dried at 100 ° C. for 24 hours to obtain a yellow solid (1 g) as a polymer electrolyte.

After this was dissolved in NMP, the solution was cast on a glass plate, air-dried at 55 ° C. for 15 hours, and then further vacuum-dried at 105 ° C. for 18 hours. The ion exchange capacity of this membrane was 1.8 meq / g.
(Example 2)
A polymer was obtained in the same manner as in Example 1 except that G-9F was used as a polymer precursor (number average molecular weight 35000, hereinafter referred to as GP-9F). After sulfonation, a membrane was formed. The ion exchange capacity was 1.7 meq / g.
(Example 3)
A polymer was obtained in the same manner as in Example 1 except that G-9 was used as the polymer precursor (number average molecular weight 61000, hereinafter referred to as GP-9). After sulfonation, a membrane was formed. The ion exchange capacity was 1.7 meq / g.
Example 4
A polymer was obtained in the same manner as in Example 1 except that G-8 was used as the polymer precursor (number average molecular weight 33,000, hereinafter referred to as GP-8). After sulfonation, a membrane was formed. The ion exchange capacity was 1.6 meq / g.
(Reference Example 5)
1,3-dimethyl containing 2 g (8 mmol) of 4,4′-dihydroxydiphenylsulfone, 3.05 g (12 mmol) of 4,4′-difluorodiphenylsulfone and 2.32 g (16.8 mmol) of potassium carbonate under a nitrogen atmosphere A mixed solution of -2-imidazolidinone (9 ml) and toluene (3 ml) was stirred for 1 hour under oil bath heating conditions at 150 ° C., and water and toluene were removed azeotropically from the system. Polymerization was carried out by raising the temperature to 180 ° C. After 4 hours, the system was returned to room temperature, a solution of 0.56 g (4 mmol) of methoxyhydroquinone in toluene (3 ml) was added, and the mixture was stirred under oil bath heating conditions at 160 ° C. for 2 hours.

The resulting polymer was dropped into 300 ml of water, neutralized by adding an acid, and the polymer was collected by filtration. The polymer was stirred and washed with hot water, and then the polymer was again collected by filtration and vacuum dried at 60 ° C. The obtained polymer was dissolved in DMSO (20 ml) and then added dropwise to methanol (400 ml) to precipitate again. The polymer was collected by filtration and vacuum dried at 80 ° C. to obtain 5.3 g of a copolymer (number average molecular weight 27000).
(Reference Example 6)
Under a nitrogen atmosphere, a CH ₂ Cl ₂ (100 ml) solution containing 5 g of the methoxy-protected copolymer was cooled to an internal temperature of −15 ° C. To this, 15 ml of a 1MCH ₂ Cl ₂ solution of BBr ₃ was added dropwise, followed by stirring at room temperature for 30 hours. Thereafter, the reaction was stopped by pouring into water (200 ml). The resulting solid was collected by filtration, washed with MeOH, and vacuum dried at 60 ° C. to obtain 5 g of the desired deprotected copolymer as an almost white solid.
(Reference Example 7)
N, N-dimethylacetamide (20 ml) and cyclohexane containing 3 g (n = 5) poly (2,6-diphenyl-1,4-phenylene oxide) and 0.46 g (3.3 mmol) potassium carbonate under a nitrogen atmosphere The mixed solution (5 ml) was stirred for 1 hour under oil bath heating conditions at 150 ° C., and cyclohexane was distilled off. After returning the system to room temperature, 2.4 g (7.2 mmol) of perfluorobiphenyl was added, followed by stirring for 4 hours under heating at 110 ° C. After confirming the completion of the reaction by TLC, it was poured into methanol (500 ml) to precipitate. The solid was collected by filtration and dried in vacuo at 60 ° C. and used as it was in the next reaction.
(Example 5)
In a nitrogen atmosphere, a mixed solution of NMP (9 ml) and toluene (3 ml) containing 1 g of the above deprotected copolymer and 152 mg of potassium carbonate was stirred for 1 hour under 180 ° C. oil bath heating conditions. Distilled off. After returning the system to room temperature, 1.36 g of PPPO (n = 5) whose end was previously capped with perfluorobiphenyl was added, and the mixture was stirred for 3 hours under heating at 110 ° C. After dropping the reaction solution into 300 ml of methanol, the polymer was collected by filtration, washed with acetone, and then vacuum-dried at 60 ° C. to obtain 2.0 g of a copolymer (number average molecular weight 33,000, hereinafter referred to as GP-F5). .

After sulfonation, a membrane was formed. The ion exchange capacity was 1.4 meq / g.
(Comparative Example 1)
In a nitrogen atmosphere, a three-necked flask containing 1.46 g (14 mmol) of styrene monomer, 0.97 g (6 mmol) of 4-acetoxystyrene and 10 mg of azobisisobutyronitrile was stirred and polymerized under a 90 ° C. oil bath heating condition. Went. After stirring for 1 hour and 30 minutes, the resulting polymer was dissolved in 20 ml of THF, dropped into 50 ml of methanol, precipitated as a white solid, collected by filtration, and then vacuum dried at room temperature to obtain 2.1 g (weight) of the copolymer. Average molecular weight 88,000).
6 ml of a 1 mol / l methanol solution of sodium methoxide was added to the styrene-acetoxystyrene copolymer obtained above, and after deprotection under heating conditions at 60 ° C., a solution of 0.73 g of propane sultone in 1 ml of methanol was added. The solution was added dropwise and stirred at the same temperature for 1 hour. After returning the system to room temperature, the sodium salt of alkylstyrene sulfonic acid produced as a white solid was collected by filtration. A 10% aqueous HCl solution was added thereto, and the mixture was stirred for 8 hours under heating at 70 ° C., then the target product was collected by filtration, washed several times with water, and then dried in vacuo to obtain 2.0 g of a white solid. After this was dissolved in DMSO, the solution was cast on a glass plate, dried by ventilation at 70 ° C. for 6 hours, and further vacuum dried at 50 ° C. for 2 hours to form a film.
The ion exchange capacity of this membrane was 1.7 meq / g.

<Molecular weight measurement method>
As for the molecular weight of the polymer, the weight average molecular weight in terms of polystyrene was determined by GPC. NMP containing 20 mol% lithium bromide was used as a solvent.

<Measurement method of ion exchange capacity>
The target electrolyte (about 100 mg: sufficiently dried) was immersed in 20 mL of a saturated aqueous sodium chloride solution at 25 ° C., and subjected to an ion exchange reaction in a water bath at 60 ° C. for 3 hours. After cooling to 25 ° C., the membrane was thoroughly washed with ion exchanged water, and all of the saturated aqueous sodium chloride solution and the washing water were collected. To this recovered solution, a phenolphthalein solution was added as an indicator, and neutralization titration was performed with a 0.01N sodium hydroxide aqueous solution to calculate the ion exchange capacity. The results are shown in Table 1.

<Measurement method of proton conductivity>
A polymer electrolyte membrane (about 10 mm × 40 mm) stored in ion-exchanged water was taken out, and water on the surface of the polymer electrolyte membrane was wiped off with a filter paper. A polymer electrolyte membrane was placed in a two-electrode non-sealed PTFE cell, and a platinum electrode was placed on the membrane surface (on the same side) so that the distance between the electrodes was 30 mm. The membrane resistance at 23 ° C. was measured by an alternating current impedance method (frequency: 42 Hz to 5 MHz, applied voltage: 0.2 V, Hioki LCR meter 3531Z HITESTER), and proton conductivity was calculated. The results are shown in Table 1.

<Measurement method of swelling degree>
The electrolyte was placed in a thermo-hygrostat whose temperature was adjusted to 23 ° C. and dried for 30 minutes under humidity control of relative humidity 98%, 80%, 60% and 50%, respectively. The thickness was measured. The dry film was immersed in a sufficient amount of ion-exchanged water and swollen by holding it for 2 hours or longer as a swollen film, and the film thickness was measured. The degree of swelling was calculated from the film pressure of each of the dry film and the swollen film and the following formula.
Swelling degree (%) = film thickness during swelling / film thickness during drying × 100
Table 1 shows data of various properties of the copolymers obtained in Example 1, Example 2 and Example 3.

From the comparison between Example 2 and Example 3 and Comparative Example 1, the fuel cell electrolyte membrane prepared from the fuel cell electrolyte of the present invention had a membrane swelling ratio despite the same ion exchange capacity as that of the comparative example. Was kept low, suggesting excellent handling properties, indicating the effectiveness of the present invention.

  The electrolyte for fuel cell of the present invention has various industrial applicability represented by solid polymer fuel cell and direct methanol fuel cell.

Claims (17)

It is a polymer compound represented by the following formula (1), and has an ion exchange capacity of 3.0 meq. / G to 6.5 meq. / G of electrolyte sites, or a method for producing the polymer electrolyte.
(In the formula, Ar represents an aromatic ring having 6 to 30 carbon atoms. G represents an electrolyte moiety. B represents a direct bond or —O—Ar′—, —CO—Ar′—, —SO ₂ —Ar ′. -(Ar 'represents a hydrogen atom in which some or all of the hydrogen atoms are substituted with fluorine atoms or an unsubstituted aromatic ring having 6 to 30 carbon atoms. When there are a plurality of aromatic rings, they may be directly bonded. A divalent —O—, —CO—, and —SO ₂ —, which may be the same or different. W may be the same or different from each other, W is a direct bond or a linking group selected from —O—, —CO—, and —SO ₂ —, Y may be a direct bond or —O—, —CO—, —SO ₂ —, —O—. Ar′—O— (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms in which a part or all of hydrogen atoms are substituted by fluorine atoms or unsubstituted. When there are a plurality of aromatic rings, they are directly bonded. Or may be linked by divalent —O—, —CO—, —SO ₂ —, which may be the same or different.) When there are a plurality, they may be the same or different from each other, R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom or a halogen atom, and when there are a plurality, they may be the same as each other A, b, c and d each represent an integer of 1 to 4, s represents an integer of 1 to 10, q represents an integer of 1 to 50, and m and n are 1 to 100. Represents an integer.) The electrolyte site described in the above formula (1) sulfonates the site represented by the following formula (2) to 3.0 meq. / G to 6.5 meq. The polymer electrolyte according to claim 1 or a method for producing the same according to claim 1, wherein the ion exchange capacity is / g.
(In the formula, A is a linking group selected from —O—, —S—, and —NH—, and when there are a plurality thereof, they may be the same or different. R ⁵ is independently a hydrogen atom, When there are a plurality of aryl groups, substituted aryl groups, and aryloxy groups having 6 to 30 carbon atoms, they may be the same or different from each other, o represents an integer of 1 to 4, and l represents 1 to 50 Represents an integer.) The main chain of the polymer represented by the formula (1) is obtained by polymerizing a site represented by the following formula (3) and a site represented by the following formula (4). Or a method for producing the polymer electrolyte.
(In the formula, Ar, G, B, W, Y, R ¹ , R ² , R ³ , R ⁴ and b, c, s, q are the same as described above. A ′ and d ′ are 1-5. Represents an integer.)
(W, Y, m in the formula are the same as above.) The said Formula (3) is obtained by making the site | part shown by following formula (5), and the site | part shown by following formula (6) react, The high in any one of Claims 1-3 characterized by the above-mentioned. Molecular electrolyte or method for producing the same.
(In the formula, Ar, G, B, Y and s are the same as described above.)
(Wherein W, R ¹ and R ² are the same as described above. A ′ and b ′ represent an integer of 1 to 5) The above formula (5) is obtained by reacting the site represented by the following formula (7) with the electrolyte precursor site represented by the above formula (2). The polyelectrolyte as described, or its manufacturing method.
(In the formula, Ar, B, Y and s are the same as described above.) The polymer electrolyte described in the above formula (1) is either the site represented by the above formula (2) or the one obtained by reacting the site represented by the above formula (2) with Ar ′, and the following formula (8) 2. The polymer electrolyte according to claim 1, or a method for producing the polymer electrolyte, wherein the polymer electrolyte is obtained by reacting a site represented by the formula (1) and then sulfonating the site.
(In the formula, Ar, W, Y, R ¹ , R ² , R ³ , R ⁴ and a, b, c, d, s, and q are the same as above. B ′ is a hydroxyl group, —O—Ar ′. —, —CO—Ar′—, —SO ₂ —Ar′— (Ar ′ represents an aromatic ring having 6 to 30 carbon atoms, in which part or all of the hydrogen atoms are substituted with fluorine atoms, or unsubstituted. When there are a plurality of aromatic rings, they may be directly bonded or may be connected by divalent —O—, —CO— or —SO ₂ —, which may be the same or different. And when there are a plurality of linking groups, they may be the same as or different from each other.) After the above formula (8) is polymerized with the site represented by the above formula (6) and the site represented by the following formula (9), the deprotection is deprotected, or after deprotection, Ar ′ (Ar 'Represents a hydrogen atom in which some or all of the hydrogen atoms are substituted with fluorine atoms or an unsubstituted aromatic ring having 6 to 30 carbon atoms. When there are a plurality of aromatic rings, they are divalent even if they are directly bonded. of -O -, - CO -, - SO 2 - may be linked with, claim 1, which are characterized in that which was reacted with may) be different even for the same. Or the polymer electrolyte of Claim 6, or its manufacturing method.
(In the formula, Ar, Y and s are the same as described above. R represents a hydroxyl-protecting group.) The above formula (2) has a structure represented by the following formula (10), and after introducing a sulfonic acid group, the ion exchange capacity is 3.0 meq. / G to 6.5 meq. The polymer electrolyte according to any one of claims 1 to 7, or a method for producing the same.
(In the formula, A and l are the same as defined above, and R ⁶ is each independently a hydrogen atom, an aryl group having 6 to 30 carbon atoms, a substituted aryl group, or an aryloxy group. Or r may be different, and r represents an integer of 1 to 3.) The said Formula (10) consists of a structure shown by following formula (11), The polymer copolymer or polymer electrolyte in any one of Claims 1-8, or its manufacturing method.
(In the formula, l is the same as described above.)   The ion exchange capacity is 4.0 meq., In which a sulfonic acid group is introduced at the site represented by the above formula (11). /G-5.0 meq. The polymer electrolyte according to any one of claims 1 to 9, or a method for producing the polymer electrolyte, having an electrolyte portion of / g.   The polymer electrolyte according to any one of claims 1 to 10, or a production method thereof, wherein the main chain is an aromatic polymer containing a polyethersulfone structure.   A polymer electrolyte composite comprising at least one polymer electrolyte according to any one of claims 1 to 11 and comprising a polymer compound having no sulfonic acid group.   The electrolyte membrane for fuel cells containing the polymer electrolyte in any one of Claims 1-12.   A fuel cell catalyst layer comprising the polymer electrolyte according to claim 1.   A membrane electrode assembly comprising any of the polymer electrolyte according to any one of claims 1 to 12, the electrolyte membrane for a fuel cell according to claim 13, and the catalyst layer for a fuel cell according to claim 14.   The polymer electrolyte according to any one of claims 1 to 12, the electrolyte membrane for a fuel cell according to claim 13, the catalyst layer for a fuel cell according to claim 14, and the membrane electrode assembly according to claim 15. A solid polymer fuel cell.     The polymer electrolyte according to any one of claims 1 to 12, the electrolyte membrane for a fuel cell according to claim 13, the catalyst layer for a fuel cell according to claim 14, and the membrane electrode assembly according to claim 15. A direct methanol fuel cell.