JP3411562B2 - Electrode structure and polymer electrolyte fuel cell comprising the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode structure having a polymer electrolyte membrane and a polymer electrolyte fuel cell having the electrode structure.

[0002]

2. Description of the Related Art While petroleum resources are depleted, environmental problems such as global warming due to consumption of fossil fuels are becoming more serious.
Fuel cells have attracted attention as a clean electric power source for electric motors that does not generate carbon dioxide, have been extensively developed, and have been partially put into practical use. When the fuel cell is mounted on an automobile or the like, a solid polymer fuel cell using a polymer electrolyte membrane is preferably used because a high voltage and a large current are easily obtained.

The solid polymer electrolyte fuel cell comprises an electrode structure having a structure in which an ion-permeable polymer electrolyte membrane is sandwiched between a pair of electrodes, and a perfluoroalkylene polymer is used as the polymer electrolyte membrane. Those obtained by imparting proton conductivity by sulfonation of a compound or the like are used. The perfluoroalkylene sulfonic acid polymer has both the proton conductivity and the chemical resistance as a fluororesin, and for example, Nafion (trade name) manufactured by DuPont is widely used.

In the electrode structure having the above-mentioned structure, conventionally, the electrode and the polymer electrolyte membrane are softened by a resin forming the polymer electrolyte membrane in a state where the polymer electrolyte membrane is arranged between a pair of electrodes. It is manufactured by hot pressing at a temperature above the point.

However, since the electrode structure using the perfluoroalkylene sulfonic acid polymer is expensive, there is a demand for an electrode structure which can be manufactured at low cost. At the same time, the electrode structure is also required to have high heat resistance to withstand operation at high temperatures in response to the demand for higher output of the fuel cell. Although various electrode structures using a polymer that can be manufactured at low cost have been proposed, no electrode structure having high power generation performance has been obtained even when exposed to high temperatures.

[0006]

The present invention provides an electrode structure for a polymer electrolyte fuel cell which can be manufactured at low cost and has high heat resistance, and a polymer electrolyte fuel cell having excellent power generation performance. The purpose is to do.

[0007]

In order to achieve the above object, the electrode structure of the present invention comprises a pair of electrodes and an electrolyte membrane sandwiched between the electrodes, and both electrodes and the electrolyte membrane are integrated. In the electrode structure bonded together, the electrolyte membrane is an aromatic compound unit having an electron-withdrawing group in the main chain,
A polymer electrolyte membrane composed of a sulfonated product of a polyarylene polymer composed of an aromatic compound unit having no electron-withdrawing group in the main chain, and on one surface of the polymer electrolyte membrane,
An electrode containing 0.5 mg / cm ² of a platinum catalyst was provided, the polymer electrolyte membrane was brought into contact with a sulfuric acid aqueous solution having a pH of 1 on the surface opposite to the electrode, and nitrogen gas was passed through the electrode. The voltage applied between the sulfuric acid aqueous solution and the electrode is-
When continuously changed from 0.1 to 0.7 V, the amount of charge per unit area represented by the value obtained by dividing the peak area on the adsorption side of protons by the area of the electrode structure is 0.09 to
It is characterized in that the polyarylene polymer is sulfonated so as to have a range of 0.18 C / cm ² .

Polymer electrolyte used in the electrode structure of the present invention
The membrane is composed of the polyarylic unit composed of the both aromatic compound units.
It is obtained by sulfonating a ren-based polymer. Previous
The sulfonation is equivalent to the unit area measured under the above conditions.
The amount of electric charge (hereinafter sometimes abbreviated as “Q value”)
0.09-0.18C / cm²To be in the range of
Structure of polyarylene polymer and the polyarylene
The polyarylene-based polymerization defined by the structure of the polymer
By adjusting the amount of sulfonic acid introduced into the body
The polymer structure does not decompose even at high temperatures.
Rufone is obtained. The polymer electrolyte membrane has an electrode structure.
Q value is 0.09C / cm ²Less than
Sulfonated products from the above polyarylene polymers
Then, the sulfone introduced into the polyarylene polymer
The amount of acid groups is too small to obtain the desired power generation performance. Well
Further, the polymer electrolyte membrane has a Q
Value is 0.18C / cm²The polyary that exceeds
In the case of a sulfonated product from a ren-based polymer,
The amount of sulfonic acid groups introduced into the polymer
Therefore, it tends to be water soluble, or it must not be.
Even now, the sulfonic acid group is prone to thermal decomposition,
There is a problem that the solution temperature decreases. That is, manufacturing
Polymer when exposed to high temperatures during normal or operational
Part of the structure is easily pyrolyzed, causing defects such as pinholes
Therefore, the desired power generation performance cannot be obtained.

In the polyarylene polymer, the aromatic compound unit having an electron-withdrawing group in the main chain is not subjected to sulfonation, and only the aromatic compound unit having no electron-withdrawing group in the main chain is used. Undergoes sulfonation. Therefore,
By adjusting the molar ratio of the both aromatic compound units in the above range, the amount itself of the sulfonic acid group that can be introduced into the polyarylene polymer is controlled, and the polyarylene polymer in the above range. The Q value can be easily achieved.

In the polyarylene polymer, by adjusting the molar ratio of the both aromatic compound units in the above range, the electrode structure has a Q value in the above range in the subsequent sulfonation. be able to. Also, the electrode structure has a Q value in the above range by adjusting the sulfonation conditions for the polyarylene polymer obtained by adjusting the molar ratio of both aromatic compound units in the above range. Can be one.

In the polyarylene polymer, the aromatic compound unit having an electron-withdrawing group in the main chain exceeds 70 mol% and the aromatic compound unit having no electron-withdrawing group in the main chain is 30 mol%. When the amount is less than the above, the amount of sulfonic acid groups that can be introduced is small, and the Q value of the electrode structure is 0.09C /
It cannot be more than cm ² . In the polyarylene polymer, the aromatic compound unit having an electron-withdrawing group in the main chain is less than 5 mol% and the aromatic compound unit having no electron-withdrawing group in the main chain is 95 mol%. When it exceeds, the amount of sulfonic acid groups that can be introduced becomes excessive, and it is difficult to set the Q value of the electrode structure to 0.18 C / cm ² or less.

Since the electrode structure of the present invention integrates the electrode with the polymer electrolyte membrane in which the polyarylene polymer is appropriately sulfonated as described above, it has excellent power generation performance. Obtainable.

The electron withdrawing group used in the aromatic compound unit having an electron withdrawing group in the main chain is --CO.
-, - CONH -, - ( CF 2) p - (p is an integer of 1 to _{10), - C (CF 3)} 2 -, - COO -, - SO
At least one divalent electron-withdrawing group selected from the group consisting of — and —SO ₂ — can be mentioned.

The sulfonated polyarylene polymer constituting the polymer electrolyte membrane is, for example, 7 to 35 mol% of an aromatic compound unit having a benzophenone-4,4'-diyl structure represented by the following formula (1). And a sulfonated product of a polyarylene-based polymer composed of 65 to 93 mol% of an aromatic compound unit having a 4'-phenoxy-benzophenone-2,5-diyl structure represented by the following formula (2).

[0015]

[Chemical 1]

[0016]

[Chemical 2]

In the aromatic compound unit having the benzophenone-4,4'-diyl structure, two benzene rings are bonded by an -CO- group which is an electron-withdrawing group, and the aromatic group is at the 4,4'-position. By being involved in the polymerization reaction of the group unit, the main chain has an electron-withdrawing group. In addition, the aromatic compound unit having the 4′-phenoxy-benzophenone-2,5-diyl structure is involved in the polymerization reaction of the aromatic unit at the 2,5-position of the benzophenone residue to form the main chain. The main chain does not have an electron-withdrawing group.

The sulfonated polyarylene polymer is used in the range of 1.5 to 3 in order to obtain the Q value in the above range when used as the polymer electrolyte membrane when it is used as the electrode structure. It preferably has an ion exchange capacity of 0 meq / g.

Further, in the sulfonated product of the polyarylene polymer which constitutes the polymer electrolyte membrane, an aromatic compound having an electron-withdrawing group in the main chain has at least one ether bond between the aromatic compounds. A sulfonated product of a polyarylene-based polymer composed of 3 to 40 mol% of the aromatic compound unit bonded by (1) and 60 to 97 mol% of the aromatic compound unit having no electron-withdrawing property may be used. As the sulfonated compound, for example, 3 to 40 mol% of an aromatic compound unit having a bis (benzoyl) diphenyl ether-4,4′-diyl structure represented by the following formula (3) and the above formula (2)
4'-phenoxy-benzophenone-2,5 represented by
An example is a sulfonated product of a polyarylene polymer composed of 60 to 97 mol% of an aromatic compound unit having a diyl structure.

[0020]

[Chemical 3]

In the aromatic unit having the bis (benzoyl) diphenylether-4,4'-diyl structure, as shown in the above formula (3), two benzophenones having an electron-withdrawing property are linked by an ether bond. It has a configuration.

The sulfonated polyarylene polymer is used in the range of 1.5 to 3 in order to obtain a Q value in the above range when used as the polymer electrolyte membrane when it is used as the electrode structure. It preferably has an ion exchange capacity of 0 meq / g.

The polymer electrolyte fuel cell of the present invention is characterized by including the electrode structure having the above-mentioned structure. As described above, the polymer electrolyte fuel cell has 0.09 to 0.18 C / c.
Excellent power generation performance can be obtained by using an electrode structure having a Q value in the range of m ^2.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is an explanatory sectional view showing the structure of an electrode structure used in the polymer electrolyte fuel cell of the present embodiment, and FIG. 2 is a device for measuring the amount of charge per unit area in the electrode structure shown in FIG. And FIG. 3 is a graph showing an example of measurement of the charge amount per unit area of the electrode by the device of FIG.

The polymer electrolyte fuel cell using the polymer electrolyte membrane of this embodiment has an electrode structure having the structure shown in FIG. In the electrode structure, a polymer electrolyte membrane 3 is sandwiched between an oxygen electrode 1 and a fuel electrode 2, and both the oxygen electrode 1 and the fuel electrode 2 are on a diffusion layer 4 and on the diffusion layer 4. The formed catalyst layer 5 and the polymer electrolyte membrane 3 on the catalyst layer 5 side.
Touches. The diffusion layer 4 is made of carbon paper 6
And the underlayer 7.

In the electrode structure, as the underlayer 7, for example, carbon black mixed with a predetermined weight ratio and polytetrafluoroethylene (PTFE) are evenly dispersed in an organic solvent such as ethylene glycol to prepare a carbon paper. It is formed by applying on one side of No. 6 and drying. In the carbon paper 6, the oxygen electrode 1 has an oxygen passage 1a through which an oxygen-containing gas such as air flows, and
Then, a fuel passage 2a through which a fuel gas such as hydrogen flows is provided on the underlayer 7 side. Further, the catalyst layer 5 is formed, for example, by applying a catalyst paste obtained by uniformly mixing catalyst particles in which carbon black is supported with platinum at a predetermined weight ratio with an ion conductive binder onto the underlayer 7 and drying. It

The polymer electrolyte membrane 3 is attached to the oxygen electrode 1,
The electrode structure is formed by hot pressing while sandwiched between the catalyst layers 5 of the fuel electrode 2.

Next, the structure of the polymer electrolyte membrane 3 in the electrode structure will be described.

The polymer electrolyte membrane 3 in the electrode structure of this embodiment has an aromatic compound unit (hereinafter abbreviated as “unit A”) having an electron-withdrawing group in the main chain and an electron-withdrawing property in the main chain. Aromatic compound unit having no group (hereinafter referred to as "unit B")
Abbreviated)) is used.

Here, examples of the unit A constituting the sulfonated polyarylene polymer include aromatic units represented by the following general formula (4).

[0031]

[Chemical 4]

As -X- in the general formula (4), for example,
-CO-, -CONH-,-(CF ₂)_p-, -C (CF
₃)₂-, -COO-, -SO- and -SO₂− Karana
At least one divalent electron-withdrawing group selected from the group
Can be mentioned. Where-(CF₂)_p-Group p
Is an integer of 1 to 10, preferably an integer of 2 to 8.
The electron-withdrawing group is a Hammett device.
When the substituent constant is m-position of the phenyl group, 0.06 or more, p
In the case of the position, it means a group having a value of 0.01 or more.

R ^{1 to} R ⁸ in the general formula (4) are any of a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group, a sulfonic acid group and an allyl group. Examples of the halogen atom include a fluorine atom,
Examples of the alkyl group include a methyl group and an ethyl group, examples of the halogenated alkyl group include a trifluoromethyl group and a pentafluoroethyl group, and examples of the allyl group include a propenyl group. it can. Further, examples of the aryl group include a phenyl group and a pentafluorophenyl group.

Further, the unit A may have various bonding modes including the unit A, for example, -unit A-O-unit A.
A plurality of units A may be bonded to each other through at least one ether bond, such as-,-unit A-O-unit A-O-unit A-. By introducing an ether bond, the flexibility of the obtained polymer can be improved.

The unit B constituting the sulfonated polyarylene polymer is, for example, at least one of aromatic units represented by the following general formulas (5) to (7).
You can list the seeds.

[0036]

[Chemical 5]

[0037]

[Chemical 6]

[0038]

[Chemical 7]

Here, R ^{9 to} R ¹⁶ are the same or different,
It is a monovalent organic group containing a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an aryl group or a functional group that does not inhibit the polymerization reaction for forming polyarylene.

Examples of the halogen atom include a fluorine atom, chlorine atom, bromine atom and iodine atom, examples of the alkyl group include a methyl group and ethyl group, and examples of the halogenated alkyl group include: Examples thereof include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, and the like. An allyl group includes a propenyl group, and an aryl group includes a phenyl group and pentafluoro group. Examples thereof include a phenyl group, and examples of the aryl group include a phenyl group and a pentafluorophenyl group.

Examples of the monovalent organic group containing a functional group which does not inhibit the polymerization reaction for forming polyarylene include, for example,
Examples thereof include aryloxy, aryloxo, arylthiocarbonyl, aryloxycarbonyl, arylthio, arylsulfone and the like. The organic group is
It may be a monovalent organic group containing two or more functional groups,
For example, aryloxyaryloxo, aryloxyarylsulfone, arylthioaryloxo and the like can be mentioned. Furthermore, in the organic group, the aryl group can be replaced with an alkyl group, an alkylaryl group, an arylalkyl group, or the like.

In the sulfonated polyarylene polymer, the amount of the unit A is 5 to 70 mol%, preferably 7 to 60 mol%, and the amount of the unit B is 30 to 95 mol%, preferably 40 to 93 mol%. %. When the amount of the unit A is more than 70 mol% and the amount of the unit B is less than 30 mol%, the amount of the sulfonic acid group introduced into the polyarylene polymer is small and the amount of the sulfonated product is high. The Q value of the electrode structure using the molecular electrolyte membrane cannot be 0.09 C / cm ² or more. Further, the amount of the unit A is 5 mol%
If the amount of the unit B exceeds 95 mol%, the amount of sulfonic acid groups introduced into the polyarylene polymer becomes excessive, and an electrode using a polymer electrolyte membrane made of such a sulfonated compound is obtained. The Q value of the structure cannot be 0.18 C / cm ² or less.

The sulfonated polyarylene polymer is a monomer (hereinafter, referred to as "monomer A") corresponding to the repeating structural unit (unit A) represented by the general formula (4).
And a monomer corresponding to at least one repeating structural unit (unit B) selected from the group of the general formulas (5) to (7) (hereinafter abbreviated as “monomer B”).
And can be synthesized by copolymerizing in the presence of a catalyst system containing a transition metal compound in a solvent and then sulfonation using a sulfonating agent.

Examples of the monomer A include aromatic compounds represented by the following general formula (4) '.

[0045]

[Chemical 8]

Here, X and R in the general formula (4) '
^{1 to} R ⁸ are the same as in the general formula (4). Also, R ~
R 'are the same or different, is a halogen atom or a group represented by -OSO ₂ Z-, excluding a fluorine atom. Z
Represents an alkyl group, a halogenated alkyl group or an aryl group.

Examples of the halogen atom include chlorine atom, bromine atom and iodine atom, examples of the alkyl group include methyl group and ethyl group, and examples of the halogenated alkyl group include trifluoromethyl group. Examples of the aryl group include a phenyl group,
Examples thereof include p-tolyl group and the like.

Specific examples of the monomer A represented by the general formula (4) 'include 4,4'-dichlorobenzophenone,
2,4'-dichlorobenzophenone, 3,3'-dichlorobenzophenone, 4,4'-dibromobenzophenone, 2,4'-dibromobenzophenone, 3,3'-dibromobenzophenone, 3,3'-dichlorobenzophenone, 4, 4'-diiodobenzophenone, 2,4'-
Diiodobenzophenone, 3,3′-diiodobenzophenone, bis (4-trifluoromethylsulfonyloxyphenyl) ketone, bis (3-trifluoromethylsulfonyloxyphenyl) ketone, 4,4′-dichlorobenzanilide, 3,3'-dichlorobenzanilide,
3,4'-dichlorobenzanilide, 4,4'-dibromobenzanilide, 3,3'-dibromobenzanilide, 3,4'-dibromobenzanilide, 4,4'-diiodobenzanilide, 3,3 ' -Diiodobenzanilide, 3,4'-diiodobenzanilide, bis (chlorophenyl) difluoromethane, bis (chlorophenyl) tetrafluoroethane, bis (chlorophenyl) hexafluoropropane, bis (chlorophenyl) octafluorobutane, bis (chlorophenyl) ) Decafluoropentane, bis (chlorophenyl) dodecafluorohexane, bis (chlorophenyl) tetradecafluoroheptane, bis (chlorophenyl) hexadecafluorooctane, bis (chlorophenyl) octadecafluorononane, bis (chlorophenyl) ei Cosafluorodecane,
Bis (bromophenyl) difluoromethane, bis (bromophenyl) tetrafluoroethane, bis (bromophenyl) hexafluoropropane, bis (bromophenyl) octafluorobutane, bis (bromophenyl) decafluoropentane, bis (bromophenyl) dodeca Fluorohexane, bis (bromophenyl) tetradecafluoroheptane, bis (bromophenyl) hexadecafluorooctane, bis (bromophenyl) octadecafluorononane, bis (bromophenyl) eicosafluorodecane, bis (iodophenyl) difluoromethane ,
Bis (iodophenyl) tetrafluoroethane, bis (iodophenyl) hexafluoropropane, bis (iodophenyl) octafluorobutane, bis (iodophenyl) decafluoropentane, bis (iodophenyl) dodecafluorohexane, bis (iodophenyl)
Tetradecafluoroheptane, bis (iodophenyl)
Hexadecafluorooctane, bis (iodophenyl)
Octadecafluorononane, bis (iodophenyl) eicosafluorodecane, 2,2-bis (4-chlorophenyl) hexafluoropropane, 2,2-bis (3-chlorophenyl) hexafluoropropane, 2,2-bis (4 -Bromophenyl) hexafluoropropane, 2,
2-bis (3-bromophenyl) hexafluoropropane, 2,2-bis (4-iodophenyl) hexafluoropropane, 2,2-bis (3-iodophenyl) hexafluoropropane, bis (4-trifluoromethyl) Sulfonyloxyphenyl) hexafluoropropane, bis (3-trifluoromethylsulfonyloxyphenyl) hexafluoropropane, 4-chlorobenzoic acid-4
-Chlorophenyl, 4-chlorobenzoic acid-3-chlorophenyl, 3-chlorobenzoic acid-3-chlorophenyl, 3
-Chlorobenzoic acid-4-chlorophenyl, 4-bromobenzoic acid-4-bromophenyl, 4-bromobenzoic acid-3
-Bromophenyl, 3-bromobenzoic acid-3-bromophenyl, 3-bromobenzoic acid-4-bromophenyl, bis (4-chlorophenyl) sulfoxide, bis (3-chlorophenyl) sulfoxide, bis (4-bromophenyl) sulfoxide , Bis (3-bromophenyl) sulfoxide, bis (4-iodophenyl) sulfoxide, bis (3-iodophenyl) sulfoxide, bis (4-trifluoromethylsulfonyloxyphenyl) sulfoxide, bis (3-trifluoromethylsulfate Phenyloxyphenyl) sulfoxide, bis (4-chlorophenyl)
Sulfone, bis (3-chlorophenyl) sulfone, bis (4-bromophenyl) sulfone, bis (3-bromophenyl) sulfone, bis (4-iodophenyl) sulfone, bis (3-iodophenyl) sulfone, bis (4-
Examples thereof include trifluoromethylsulfonyloxyphenyl) sulfone and bis (3-trifluoromethylsulfonyloxyphenyl) sulfone.

Further, as a specific example of the monomer A in the case of forming the structure of -unit A-O-unit A-, 4,4'-bis (4-chlorobenzoyl) diphenyl ether, 4,4'-bis (4-chlorobenzoyl) diphenyl ether,
4'-bis (3-chlorobenzoyl) diphenyl ether, 4,4'-bis (4-bromobenzoyl) diphenyl ether, 4,4'-bis (3-bromobenzoyl)
Diphenyl ether, 4,4'-bis (4-iodobenzoyl) diphenyl ether, 4,4'-bis (3-iodobenzoyl) diphenyl ether, 4,4'-bis (4-trifluoromethylsulfonyloxyphenyl)
Diphenyl ether, 4,4'-bis (3-trifluoromethylsulfonyloxyphenyl) diphenyl ether, 4,4'-bis (4-methylsulfonyloxyphenyl) diphenyl ether, 4,4'-bis (3-methylsulfonyl) Roxyphenyl) diphenyl ether,
4,4′-bis (4-chlorobenzoylamino) diphenyl ether, 3,4′-bis (4-chlorobenzoylamino) diphenyl ether, 4,4′-bis (3-chlorobenzoylamino) diphenyl ether, 3,4 ′
-Bis (3-chlorobenzoylamino) diphenyl ether, 4,4'-bis (4-bromobenzoylamino)
Diphenyl ether, 3,4′-bis (4-bromobenzoylamino) diphenyl ether, 4,4′-bis (3-bromobenzoylamino) diphenyl ether,
3,4'-bis (3-bromobenzoylamino) diphenyl ether, 4,4'-bis (4-iodobenzoylamino) diphenyl ether, 3,4'-bis (4-iodobenzoylamino) diphenyl ether, 4,4 '
-Bis (3-iodobenzoylamino) diphenyl ether, 3,4'-bis (3-iodobenzoylamino)
Diphenyl ether, 4,4'-bis (4-trifluoromethylsulfonyloxyphenyl) diphenyl ether, 3,4'-bis (4-trifluoromethylsulfonyloxyphenyl) diphenyl ether, 4,4'-bis (3-tri Fluoromethylsulfonyloxyphenyl) diphenyl ether, 3,4′-bis (3-trifluoromethylsulfonyloxyphenyl) diphenyl ether, 4,4′-bis (4-methylsulfonyloxyphenyl) diphenyl ether, 3,4′- Bis (4-
Methylsulfonyloxyphenyl) diphenyl ether, 4,4′-bis (3-methylsulfonyloxyphenyl) diphenyl ether, 3,4′-bis (3-methylsulfonyloxyphenyl) diphenyl ether,
4,4'-bis (4-chlorophenylsulfonyl) diphenyl ether, 3,4'-bis (4-chlorophenylsulfonyl) diphenyl ether, 4,4'-bis (3
-Chlorophenylsulfonyl) diphenyl ether,
3,4'-bis (3-chlorophenylsulfonyl) diphenyl ether, 4,4'-bis (4-bromophenylsulfonyl) diphenyl ether, 3,4'-bis (4
-Bromophenylsulfonyl) diphenyl ether,
4,4'-bis (3-bromophenylsulfonyl) diphenyl ether, 3,4'-bis (3-bromophenylsulfonyl) diphenyl ether, 4,4'-bis (4
-Iodophenylsulfonyl) diphenyl ether,
3,4'-bis (4-iodophenylsulfonyl) diphenyl ether, 4,4'-bis (3-iodophenylsulfonyl) diphenyl ether, 3,4'-bis (3
-Iodophenylsulfonyl) diphenyl ether,
4,4'-bis (4-trifluoromethylsulfonyloxyphenylsulfonyl) diphenyl ether, 3,
4'-bis (4-trifluoromethylsulfonyloxyphenylsulfonyl) diphenyl ether, 4,4'-
Bis (3-trifluoromethylsulfonyloxyphenylsulfonyl) diphenyl ether, 3,4'-bis (3-trifluoromethylsulfonyloxyphenylsulfonyl) diphenyl ether, 4,4'-bis (4-
Methylsulfonyloxyphenylsulfonyl) diphenyl ether, 3,4′-bis (4-methylsulfonyloxyphenylsulfonyl) diphenyl ether, 4,
4'-bis (3-methylsulfonyloxyphenylsulfonyl) diphenyl ether, 3,4'-bis (3-methylsulfonyloxyphenylsulfonyl) diphenyl ether, 4,4'-bis (4-chlorophenyl) diphenylether dicarboxylate, 3,4'-bis (4-chlorophenyl) diphenyl ether dicarboxylate, 4,4'-bis (3-chlorophenyl) diphenyl ether dicarboxylate, 3,4'-bis (3-chlorophenyl) diphenyl ether dicarboxylate, 4, 4'-bis (4-bromophenyl) diphenyl ether dicarboxylate, 3,4'-bis (4-bromophenyl) diphenyl ether dicarboxylate, 4,4'-bis (3-bromophenyl) diphenyl ether dicarboxylate, , 4'-bis (3-bromophenyl) diphenyl ether dicarboxylate, 4,4'-bis (4-iodophenyl) diphenyl ether dicarboxylate, 3,4'-bis (4-iodophenyl) diphenyl ether dicarboxylate, 4,4'-bis (3-iodophenyl) diphenyl ether dicarboxylate, 3,4'-bis (3-iodophenyl) diphenyl ether dicarboxylate, 4,4'-bis (4-trifluoromethylsulfonyloxyphenyl) ) Diphenyl ether dicarboxylate, 3,4'-bis (4-trifluoromethylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 4,4'-bis (3-trifluoromethylsulfonyloxyphenyl) diphenyl ether dicarboxylate, Three , 4'-bis (3-trifluoromethylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 4,4'-bis (4-oromethylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 3,4'-bis (4 -Oromethylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 4,4'-bis (3-methylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 3,
4'-bis (3-methylsulfonyloxyphenyl) diphenyl ether dicarboxylate, 4,4'-bis
[(4-chlorophenyl) -1,1,1,3,3,3-
Hexafluoropropyl] diphenyl ether, 3,
4'-bis [(4-chlorophenyl) -1,1,1,
3,3,3-hexafluoropropyl] diphenyl ether, 4,4'-bis [(3-chlorophenyl) -1,
1,1,3,3,3-hexafluoropropyl] diphenyl ether, 3,4′-bis [(3-chlorophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4 '-Bis [(4-bromophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 3,4'-bis [(4-
Bromophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4′-bis
[(3-Bromophenyl) -1,1,1,3,3,3-
Hexafluoropropyl] diphenyl ether, 3,
4'-bis [(3-bromophenyl) -1,1,1,
3,3,3-hexafluoropropyl] diphenyl ether, 4,4'-bis [(4-iodophenyl) -1,
1,1,3,3,3-hexafluoropropyl] diphenyl ether, 3,4′-bis [(4-iodophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4, 4'-bis [(3-iodophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 3,4'-bis [(3-
Iodophenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4′-bis
[(4-Trifluoromethylsulfonyloxyphenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 3,4′-bis [(4-trifluoromethylsulfonyloxyphenyl)- 1, 1,
1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4′-bis [(3-trifluoromethylsulfonyloxyphenyl) -1,1,1,3,3,3
-Hexafluoropropyl] diphenyl ether, 3,
4'-bis [(3-trifluoromethylsulfonyloxyphenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4'-bis [(4
-Methylsulfonyloxyphenyl) -1,1,1,
3,3,3-Hexafluoropropyl] diphenyl ether, 3,4'-bis [(4-methylsulfonyloxyphenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4 '-Bis [(3-
Methylsulfonyloxyphenyl) -1,1,1,3
3,3-hexafluoropropyl] diphenyl ether, 3,4'-bis [(3-methylsulfonyloxyphenyl) -1,1,1,3,3,3-hexafluoropropyl] diphenyl ether, 4,4'- Bis [(4-
Chlorophenyl) tetrafluoroethyl] diphenyl ether, 4,4′-bis [(3-chlorophenyl) tetrafluoroethyl] diphenyl ether, 4,4′-bis [(4-chlorophenyl) hexafluoropropyl]
Diphenyl ether, 4,4'-bis [(3-chlorophenyl) hexafluoropropyl] diphenyl ether, 4,4'-bis [(4-chlorophenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(3-chlorophenyl) Octafluorobutyl] diphenyl ether, 4,4′-bis [(4-chlorophenyl) decafluoropentyl] diphenyl ether, 4,
4'-bis [(3-chlorophenyl) decafluoropentyl] diphenyl ether, 4,4'-bis [(4-butylphenyl) tetrafluoroethyl] diphenyl ether, 4,4'-bis [(3-butylphenyl) tetrafluoro Ethyl] diphenyl ether, 4,4′-bis [(4-butylphenyl) hexafluoropropyl] diphenyl ether, 4,4′-bis [(3-butylphenyl) hexafluoropropyl] diphenyl ether,
4,4'-bis [(4-butylphenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(3
-Butylphenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(4-butylphenyl) decafluoropentyl] diphenyl ether, 4,4'-
Bis [(3-butylphenyl) decafluoropentyl]
Diphenyl ether, 4,4′-bis [(4-iodophenyl) tetrafluoroethyl] diphenyl ether,
4,4'-bis [(3-iodophenyl) tetrafluoroethyl] diphenyl ether, 4,4'-bis [(4
-Iodophenyl) hexafluoropropyl] diphenyl ether, 4,4'-bis [(3-iodophenyl)
Hexafluoropropyl] diphenyl ether, 4,
4'-bis [(4-iodophenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(3-iodophenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(4-iodophenyl) deca Fluoropentyl] diphenyl ether, 4,4'-bis [(3-iodophenyl) decafluoropentyl] diphenyl ether, 4,4'-bis [(4-trifluoromethylsulfonyloxyphenyl) tetrafluoroethyl] diphenyl ether, 4, 4'-bis [(3-trifluoromethylsulfonyloxyphenyl) tetrafluoroethyl] diphenyl ether, 4,4'-bis [(4-trifluoromethylsulfonyloxyphenyl) hexafluoropropyl] diphenyl ether,
4,4′-bis [(3-trifluoromethylsulfonyloxyphenyl) hexafluoropropyl] diphenyl ether, 4,4′-bis [(4-trifluoromethylsulfonyloxyphenyl) octafluorobutyl] diphenyl ether, 4, 4'-bis [(3-trifluoromethylsulfonyloxyphenyl) octafluorobutyl] diphenyl ether, 4,4'-bis [(4-trifluoromethylsulfonyloxyphenyl) decafluoropentyl] diphenyl ether, 4,4 ' -Bis [(3-trifluoromethylsulfonyloxyphenyl) decafluoropentyl] diphenyl ether, 4,
4'-bis [(4-methylsulfonyloxyphenyl)
Tetrafluoroethyl] diphenyl ether, 4,4 '
-Bis [(3-methylsulfonyloxyphenyl) tetrafluoroethyl] diphenyl ether, 4,4'-bis [(4-methylsulfonyloxyphenyl) hexafluoropropyl] diphenyl ether, 4,4'-bis [(3- Methylsulfonyloxyphenyl) hexafluoropropyl] diphenyl ether, 4,4′-bis [(4-methylsulfonyloxyphenyl) octafluorobutyl] diphenyl ether, 4,4′-bis [(3-methylsulfonyloxyphenyl) Octafluorobutyl] diphenyl ether, 4,4′-bis [(4-methylsulfonyloxyphenyl) decafluoropentyl] diphenyl ether, 4,4′-bis [(3-methylsulfonyloxyphenyl) decafluoropentyl] diphenyl ether, etc. To name It is possible.

Examples of the monomer B include aromatic compounds represented by the following general formulas (5) 'to (7)'.

[0051]

[Chemical 9]

[0052]

[Chemical 10]

[0053]

[Chemical 11]

Here, X in the general formulas (5) 'to (7)'
And R ^{9 to} R ¹⁶ are the same as in the general formulas (5) to (7), and R to R ′ are the same as in the general formula (4) ′.

Specific examples of the monomer B represented by the general formula (5) 'include m-dichlorobenzene, m-dibromobenzene, m-diiodobenzene, m-dimethylsulfonyloxybenzene and 2,4-dichlorotoluene. , 2,
4-dibromotoluene, 2,4-diiodotoluene,
3,5-dichlorotoluene, 3,5-dibromotoluene, 3,5-diiodotoluene, 2,6-dichlorotoluene, 2,6-dibromotoluene, 2,6-diiodotoluene, 3,5-dimethylsulfur Phenyloxytoluene,
2,6-dimethylsulfonyloxytoluene, 2,4-
Dichlorobenzotrifluoride, 2,4-dibromobenzotrifluoride, 2,4-diiodobenzotrifluoride, 3,5-dichlorobenzotrifluoride, 3,5-dibromobenzotrifluoride, 3,5
-Diiodobenzotrifluoride, 1,3-dibromo-2,4,5,6-tetrafluorobenzene and the like can be mentioned.

Specific examples of the monomer B represented by the general formula (6) 'include 4'-phenoxy-2,4-dichlorobenzophenone, 2,5-dichloro-4'-phenoxybenzophenone and p-dichlorobenzene. , P-dibromobenzene, p-diiodobenzene, p-dimethylsulfonyloxybenzene, 2,5-dichlorotoluene, 2,5-dibromotoluene, 2,5-diiodotoluene, 2,5-dimethylsulfonyloxy benzene,
2,5-dichloro-p-xylene, 2,5-dibromo-
p-xylene, 2,5-diiodo-p-xylene, 2,
5-dichlorobenzotrifluoride, 2,5-dibromobenzotrifluoride, 2,5-diiodobenzotrifluoride, 1,4-dichloro-2,3,5,6-
Tetrafluorobenzene, 1,4-dibromo-2,3
5,6-Tetrafluorobenzene, 1,4-diiodo-
2,3,5,6-tetrafluorobenzene etc. can be mentioned.

Specific examples of the monomer B represented by the general formula (7) 'include 4,4'-dibromobiphenyl, 4,4'-diiodobiphenyl, 4,4'-dimethylsulfonoxybiphenyl, 4,4'-dimethylsulfonyloxy-3,3'-dipropenylbiphenyl,
4,4'-Dimethylsulfonyloxy-3,3'-dimethylbiphenyl, 4,4'-dimethylsulfonyloxy-3,3'-difluorobiphenyl, 4,4'-dimethylsulfonyloxy-3,3 ' , 5,5'-tetrafluorobiphenyl, 4,4'-dibromooctafluorobiphenyl and the like can be mentioned.

Among the monomers B represented by the above general formulas (5) ′ to (7) ′, 4′-phenoxy-2,5 is excellent because it has excellent solubility in the solvent and can have a high molecular weight. -Dichlorobenzophenone, 4'-phenoxy-2,4-dichlorobenzophenone, 4'-phenoxyphenyl-2,5-dichlorobenzoate, 4'-phenoxyphenyl-2,4-dichlorobenzoate and other dichlorobenzoic acid derivatives are preferable, In particular, 4'-phenoxy-2,5-dichlorobenzophenone is most preferred because a polymer electrolyte having excellent mechanical strength such as creep resistance is obtained when it is copolymerized with the monomer A represented by the general formula (4) '. preferable.

At least one kind of the monomer A represented by the general formula (4) 'and the general formulas (5)' to (7) '
The copolymerization ratio with at least one monomer B selected from the group of aromatic compounds represented by
And the same as the ratio. That is, the amount of the monomer A used is 5 to 60 mol%, preferably 7 to 50 mol%, and the amount of the monomer B used is 40 to 95 wt%, preferably 50.
~ 93% by weight. However, when the unit A is bonded by an ether bond, the ratio of the unit A-O-the unit A- is 3 to 4.
It is 0 mol%, preferably 5-35 mol%.

When the monomer B represented by the general formula (5) 'is used, the proportion thereof is preferably 50 mol% or less, more preferably 30 mol% based on the total amount of the monomers A and B. When the content is within the following range, the monomers A and B as a whole have excellent solubility in the solvent, and a high molecular weight is possible.

When the monomer B represented by the general formula (6) 'is used, the proportion thereof is preferably 10 mol% or more, more preferably 20 mol% with respect to the total amount of the monomers A and B. Within the above range, the monomers A and B as a whole have excellent solubility in the solvent, and a high molecular weight is possible.

When the monomer B represented by the general formula (7) 'is used, the proportion thereof is preferably 50 mol% or less, more preferably 30 mol%, based on the total amount of the monomers A and B. When the content is within the following range, the monomers A and B as a whole have excellent solubility in the solvent, and a high molecular weight is possible.

The catalyst used in producing the polyarylene polymer by copolymerization of the monomers A and B is a catalyst system containing a transition metal salt, a transition metal salt, a ligand and a reducing agent. And are essential ingredients. The catalyst system may use, in place of the transition metal compound and the ligand, a transition metal or a salt thereof in which a ligand is coordinated in advance, and in order to further increase the polymerization rate, a predetermined ""Salt" may be added.

Examples of the transition metal salt include nickel compounds such as nickel chloride, nickel bromide, nickel iodide and nickel acetylacetonate, palladium compounds such as palladium chloride, palladium bromide and palladium iodide, and iron chloride. Examples thereof include iron compounds such as iron bromide and iron iodide, and cobalt compounds such as cobalt chloride, cobalt bromide and cobalt iodide.

Examples of the ligand include triphenylphosphine, 2,2'-bipyridine, 1,5-cyclooctadiene, 1,3-bis (diphenylphosphino) propane and the like.

Examples of the reducing agent include iron,
Examples thereof include zinc, manganese, aluminum, magnesium, sodium and calcium. These reducing agents can be further activated and used by bringing them into contact with an acid such as an organic acid.

Examples of the transition metal having a ligand coordinated in advance or a salt thereof include, for example, nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis (triphenyl). Phosphine), nickel nitrate bis (triphenylphosphine), nickel chloride (2,2 ′ bipyridine), nickel bromide (2,2 ′ bipyridine), nickel iodide (2,
2'bipyridine), nickel nitrate (2,2 'bipyridine), bis (1,5-cyclooctadiene) nickel,
Examples thereof include tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphosphite) nickel and tetrakis (triphenylphosphine) palladium.

The salts added to the catalyst system to increase the polymerization rate include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide and sodium sulfate, potassium fluoride, potassium chloride, Examples thereof include potassium compounds such as potassium bromide, potassium iodide and potassium sulfate, and ammonium such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and tetraethylammonium sulfate.

The amount of the transition metal salt, the transition metal to which a ligand is coordinated in advance or the salt thereof in the catalyst system is determined by the amounts of the monomers A and B represented by the general formulas (4) 'to (7)'.
In general, 0.0001 to 10 moles per 1 mole of
It is preferably 0.01 to 0.5 mol. 0.0001
If it is less than 10 mol, the polymerization reaction will not proceed sufficiently, and if it exceeds 10 mol, the molecular weight of the obtained polyarylene polymer may not be sufficiently large.

In the catalyst system, the amount of the ligand with respect to the transition metal or salt thereof is usually 0.1 to 100 mol, preferably 1 to 10 mol, based on 1 mol of the transition metal or salt thereof. is there. If it is less than 0.1 mol, the catalytic activity will be insufficient, and if it exceeds 100 mol, the molecular weight of the obtained polyarylene polymer may not be sufficiently high.

The amount of the reducing agent in the catalyst system is usually 0.1 to 100 moles, preferably 1 to 100 moles of the monomers A and B represented by the general formulas (4) 'to (7)'. It is 1 to 10 mol. If it is less than 0.1 mol, the polymerization will not proceed sufficiently, and if it exceeds 100 mol, purification of the obtained polyarylene polymer may be difficult.

When the salt for increasing the polymerization rate is added to the catalyst system, the amount of the salt added is 1 mol in total of the monomers A and B represented by the general formulas (4) 'to (7)'. On the other hand, it is usually 0.001 to 100 mol, preferably 0.01 to 1 mol. If it is less than 0.001 mol, the effect of increasing the polymerization rate is insufficient, and if it exceeds 100 mol, purification of the obtained polyarylene polymer may be difficult.

As the polymerization solvent, for example, tetrahydrofuran, cyclohexanone, dimethyl sulfoxide,
Examples thereof include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone and γ-butyrolactam.
It is preferable to use the polymerization catalyst after drying it sufficiently. The above-mentioned general formula (4) ′ in the polymerization catalyst
The total concentration of the monomers A and B represented by (7) ′ is
Usually, it is 1 to 90% by weight, preferably 5 to 40% by weight. The polymerization temperature is usually 0 to 200 ° C., preferably 50.
To 80 ° C., and the polymerization time is usually 0.5 to 100 hours, preferably 1 to 40 hours.

The molecular weight of the polyarylene polymer is
Polystyrene-equivalent weight average molecular weight of 1,000 to 1,
, 000,000, preferably 1,500 to 200,000
It is 0.

The structure of the polyarylene polymer is, for example, 1230 to 1250 cm of infrared absorption spectrum.
^-1 C-O-C absorption, 1640 to 1660 cm ^-1 C =
O absorption, etc., or nuclear magnetic resonance spectrum (1H-
This can be confirmed by the peak of the aromatic proton at 6.8 to 8.0 ppm of (NMR).

Here, for example, using the monomer A represented by the general formula (4) ′ and the monomer B represented by the general formula (6) ′, the compounds represented by the general formula (4) and the general formula (6) are used. The reaction formula for obtaining a polymer composed of repeating structural units (however, having no sulfonic acid group) is
It can be expressed by the following equation (8).

[0077]

[Chemical 12]

Next, the polyarylene polymer is treated with sulfuric acid anhydride, fuming sulfuric acid, in the absence of a solvent or in the presence of a solvent.
A sulfonated product can be obtained by reacting with a sulfonating agent such as chlorosulfonic acid, sulfuric acid, or sodium hydrogen sulfite under known conditions. Examples of the solvent used for the sulfonation include hydrocarbon solvents such as n-hexane, tetrahydrofuran, ether solvents such as dioxane, aprotic polar solvents such as dimethylacetamide, dimethylformamide and dimethylsulfoxide,
Tetrachloroethane, dichloroethane, chloroform,
Examples thereof include halogenated hydrocarbons such as methylene chloride.

The reaction temperature for the sulfonation is not particularly limited, but is usually -50 to 200 ° C, preferably -10 to 1
It is 00 ° C. The reaction time for the sulfonation is usually 0.5 to 1000 hours, preferably 1 to 200 hours.

The amount of sulfonic acid group in the sulfonated polyarylene polymer obtained by the sulfonation is usually 0.0 with respect to 1 unit of the unit B constituting the polymer.
It is 5 to 2, preferably 0.3 to 1.5. 0.0
If the number is less than 5, the proton conductivity of the obtained polyarylene polymer sulfonate will be insufficient, and if the number is more than 2, the hydrophilicity will be improved to become a water-soluble polymer. Even if it does not reach, the hot water durability will decrease.

In the sulfonated polyarylene polymer, the unit A is benzophenone-4,4'-.
An aromatic compound unit having a diyl structure, wherein the unit B is 4 '
A phenoxy-benzophenone-2,5-diyl-structured aromatic compound unit is most suitable for the polymer electrolyte membrane of a polymer electrolyte fuel cell. In this case, it is preferable that the proportion of the unit A is 7 to 35 mol%, the proportion of the unit B is 65 to 93 mol%, and the proportion of the unit A is 8 to
Optimally, the proportion of 30 mol% and the unit B is 70 to 92 mol%. Further, the sulfonated polyarylene polymer preferably has an ion exchange capacity of 1.5 to 3.0 meq / g.

The structure of the sulfonated polyarylene polymer is 1030 to 1045 in the infrared absorption spectrum.
cm ^-1, S = O absorption at 1160~1190cm ^-1, 11
C-O-C absorption at 30 to 1250 cm ^-1 , 1640 to ¹
It can be confirmed by C═O absorption at 660 cm ⁻¹ or by the peak of aromatic proton at 6.8 to 8.0 ppm in the nuclear magnetic resonance spectrum (1H-NMR).

The polymer electrolyte membrane is produced, for example, by dissolving the sulfonated polyarylene polymer in an organic solvent to form a uniform solution, casting the resulting uniform solution in a flat mold and drying. can do. Examples of the organic solvent include dimethyl sulfoxide,
Aprotic polar solvents such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone can be mentioned. In addition to the casting method, the polymer electrolyte membrane can be manufactured by melt molding or the like.

Next, examples and comparative examples will be shown.

[0085]

Examples 1 to 4 and Comparative Examples 1 and 2 First, a monomer A corresponding to an aromatic compound unit having an electron-withdrawing group in the main chain.
And 4,5-dichloro-4-phenoxybenzophenone as a monomer B corresponding to the aromatic compound unit having no electron-withdrawing group in the main chain, Prepared in a molar ratio, sodium iodide, bistriphenylphosphine nickel dichloride, triphenylphosphine, along with a catalyst system consisting of zinc, using N- methylpyrrolidone as a solvent, a reflux pipe and a three-way cock in a three-necked flask nitrogen substituted,
Polymerization was carried out by heating in a 70 ° C. oil bath under a nitrogen atmosphere. In the catalyst system, the monomer A of each composition,
The ratio of B to the total is 13 mol% of sodium iodide, 3 mol% of bistriphenylphosphine nickel dichloride, 40 mol% of triphenylphosphine, and 2 mol of zinc.
It is 40 mol%.

After 20 hours from the start of the reaction, the polymerization reaction solution was diluted with N-methylpyrrolidone, and then the polymerization reaction solution was poured into a 1:10 hydrochloric acid / methanol solution to precipitate a polymer. After washing the polymer, filtration and vacuum drying,
A white powder was obtained. The weight average molecular weight of this polymer is 1
It was 60,000.

Concentrated sulfuric acid was added to the polymer obtained by the above polymerization reaction, and the mixture was stirred at room temperature for several hours to several tens of hours to carry out a sulfonation reaction. After the reaction, the reaction solution was poured into a large amount of pure water to precipitate the sulfonated polymer. The polymer was continuously washed with water until the pH reached 7, and the sulfonated polymer was recovered after filtration and vacuum dried at 90 ° C. to obtain a first polymer electrolyte. This polyelectrolyte has a (4′-phenoxybenzophenone-2,5-diyl) (benzophenone-4,4′-diyl) copolymerization represented by the following formula (9) by infrared absorption spectrum and nuclear magnetic resonance spectrum. It was confirmed to be a combined sulfonate.

The ion exchange capacity of the sulfonated (4'-phenoxybenzophenone-2,5-diyl) (benzophenone-4,4'-diyl) copolymer thus obtained depends on the reaction time of the sulfonation reaction, .5-3.0 me
It was dispersed in the range of q / g.

[0089]

[Chemical 13]

Next, a plurality of (4'-phenoxybenzophenone-2,5) having different ion exchange capacities are provided.
-Diyl) (benzophenone-4,4'-diyl) copolymer sulfonate and N-methylpyrrolidone
The mixture was uniformly mixed in a weight ratio of 2: 2 to prepare a plurality of (4′-phenoxybenzophenone-2,5-diyl) (benzophenone-4,4′-diyl) copolymer sulfonated solutions. Next, a plurality of polymer electrolyte membranes 3 were produced by a casting method in which each of the plurality of solutions was cast into a flat mold and dried. Each of the polymer electrolyte membranes 3 had a dry film thickness of 50 μm.

Next, as shown in FIG. 1, the plurality of polymer electrolyte membranes 3 were sandwiched between an oxygen electrode 1 and a fuel electrode 2, respectively, and the conditions were 80 to 180 ° C., 5 MPa, and 2 minutes each time. The electrode structure was manufactured by performing hot pressing several times.

Here, the oxygen electrode 1 and the fuel electrode 2 were manufactured as follows. First, carbon black and polytetrafluoroethylene (PTFE) particles are mixed at a weight ratio of carbon black: PTFE = 4: 6, and a slurry prepared by uniformly dispersing in ethylene glycol is applied to one side of carbon paper 6 and dried. To form the underlayer 7, and the diffusion layer 4 including the carbon paper 6 and the underlayer 7
Was manufactured.

Next, the catalyst particles obtained by supporting platinum particles on carbon black (furnace black) at a weight ratio of 1: 1 were added to the above-mentioned (4'-phenoxybenzophenone-2,5).
-Diyl) (benzophenone-4,4'-diyl) copolymer sulfonate solution (ion exchange capacity 2.2 meq /
g) as an ion conductive binder, and dispersed uniformly in a weight ratio of catalyst particles: ion conductive binder = 8: 5,
A catalyst paste was prepared. In addition, in the present example, the (4′-phenoxybenzophenone-2,5-diyl) (benzophenone-4,
A 4'-diyl) copolymer sulfonated solution was used, but a commercially available perfluoroalkylene sulfonic acid polymer compound (for example, Nafion (trade name) manufactured by DuPont)
You may use the solution of.

Next, the catalyst paste was screen-printed on the underlayer 7 of the diffusion layer 4 so that the amount of platinum was 0.5 mg / cm ² , dried at 60 ° C. for 10 minutes, and 120 ° C.
Was dried under reduced pressure to obtain an air electrode 1 and a fuel electrode 2.

Next, with respect to a plurality of electrode structures manufactured by using the polymer electrolyte membrane 3, the charge amount (Q value) per area of the electrode structures was measured as follows.

The Q value is measured using the apparatus shown in FIG.
In the apparatus shown in FIG. 2, the polymer electrolyte membrane 3 is provided with an electrode 11 having the same structure as the oxygen electrode 1 and the fuel electrode 2 shown in FIG. The polymer electrolyte membrane 3 of the electrode 11 is brought into contact with the sulfuric acid aqueous solution 13 of pH 1 housed in 12. The apparatus of FIG. 2 includes a reference electrode 14 and a reference electrode 15 immersed in a sulfuric acid aqueous solution 13, and the reference electrode 14, the reference electrode 15, and the diffusion layer 4 of the electrode 11 are connected to a potentio stud 16. Further, the electrode 11 is provided with a gas passage 11a corresponding to the oxygen passage 1a of the oxygen electrode 1 or the fuel passage 2a of the fuel electrode 2 shown in FIG. 1, so that the electrode 11 can come into contact with the nitrogen gas flowing through the gas passage 11a. It is configured.

In the apparatus of FIG. 2, the potentio stud 16
When a voltage is applied between the diffusion layer 4 and the sulfuric acid aqueous solution 13 by
Protons in the sulfuric acid aqueous solution 13 permeate the polymer electrolyte membrane 3 and reach the electrode 11 to exchange electrons. That is, when the protons come into contact with the platinum surface in the catalyst layer 7, electrons are transferred from the platinum to the protons. When a reverse voltage is applied, electrons are transferred from the adsorbed hydrogen atoms to platinum and diffuse as protons into the sulfuric acid aqueous solution. In the device of FIG. 2, the amount of platinum in the catalyst layer 7 in the electrode 11 is 0.5 m.
It is set to g / cm ² .

Therefore, the peak area on the adsorption side of protons (shown as a shaded area in FIG. 3) when the voltage is continuously changed from −0.1 V to 0.7 V is used as the charge amount, and the charge amount is determined by the electrode. The Q value was obtained by dividing by the area of 11. Here, the Q value represents a charge amount (C / cm ² ) per unit area of the electrode 11.

Next, the Q values measured as described above were 0.05 C / cm ² (Comparative Example 1) and 0.09 C / c.
m ² (Example 1), 0.12 C / cm ² (Example 2),
0.14 C / cm ² (Example 3), 0.18 C / cm
² (Example 4) and 0.20 C / cm ² (Comparative Example 2), the six electrode structures were measured for the power generation potential and the defective rate as follows, and the performances were compared.

(1) Measurement of Electric Power Generation Potential Each of the electrode structures is a single cell, and air is circulated to the oxygen electrode 1 and pure hydrogen is circulated to the fuel electrode 2 to generate electric power.
The cell potential at a current density of 0.2 A / cm ² was measured. Power generation conditions are 100 kPa for both poles, 50% utilization,
The relative humidity was 50% and the temperature was 85 ° C.

(2) Measurement of defective rate When a single cell was used as the electrode structure and helium gas was introduced into one electrode at a pressure of 0.5 kPa, a part of the polymer structure of the polyarylene polymer was thermally decomposed. However, when a defect such as a pinhole is generated, the helium gas leaks to the other electrode through the defect. Therefore, the amount of helium gas leaking to the other electrode was measured, and those having a volume of 0.1 ml / cm ² · min or more were determined to be defective. The presence or absence of the defect was inspected for 100 electrode structures, and the defect rate (%) was calculated by the following formula.

Defect rate (%) = (number of defectives / total number) × 100 However, in the measurement of the defective rate, after checking the heat resistance, the electrode structure was kept under a temperature condition of 120 ° C. for 3 hours. The measurement was performed.

Table 1 shows the measurement results of each electrode structure.

[0104]

[Table 1]

From Table 1, the Q value is 0.09 to 0.18 C /
electrode structures of Examples 1 to 4 in the range of cm ^2, as compared to Comparative Example 1 of the Q value is less than 0.09C / cm ^2, it is clear that high power potential. Also, the Q value is 0.18
The electrode structure of Comparative Example 2 exceeding C / cm ² apparently has a higher power generation potential than the electrode structures of Examples 1 to 4, but the defective rate is higher than that of the electrode structures of Examples 1 to 4. Is extremely high, and it is clear that thermal decomposition occurs in the polymer structure of the polymer electrolyte membrane.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing one structural example of an electrode structure used in a polymer electrolyte fuel cell of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of an apparatus for measuring a charge amount per unit area of an electrode structure.

FIG. 3 is a graph showing an example of measurement of the amount of charge per unit area of an electrode by the device of FIG.

[Explanation of symbols]

1, 2 ... Electrodes, 3 ... Polymer electrolyte membranes.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Soma 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Nobuhiro Saito 1-4-1 Chuo, Wako-shi, Saitama Stock Company Honda R & D Co., Ltd. (72) Inventor Kohei Goto 2-11-24 Tsukiji, Chuo-ku, Tokyo JEars Co., Ltd. (72) Inventor Fusumi Masaka 2-11-24 Tsukiji, Chuo-ku, Tokyo Je-Yes (56) Reference JP 10-21943 (JP, A) JP 2001-250567 (JP, A) JP 11-67224 (JP, A) Special table 10-507574 (JP, A) Special table 2000-509187 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 8/00-8/24 H01B 1/06

Claims (10)

(57) [Claims] 1. An electrode structure comprising a pair of electrodes and an electrolyte membrane sandwiched between the electrodes, wherein the electrodes and the electrolyte membrane are integrally bonded, wherein the electrolyte membrane has an electron-withdrawing main chain. A polymer electrolyte membrane comprising a sulfonated product of a polyarylene polymer comprising an aromatic compound unit having a polymerizable group and an aromatic compound unit having no electron-withdrawing group in the main chain. An electrode containing a platinum catalyst of 0.5 mg / cm ² was provided on one surface of the one surface, the polymer electrolyte membrane was brought into contact with a sulfuric acid aqueous solution having a pH of 1 on the surface opposite to the electrode, and nitrogen gas was applied to the electrode. When the voltage applied between the aqueous solution of sulfuric acid and the electrode was continuously changed to −0.1 to 0.7 V in a flowing state, the peak area on the adsorption side of the proton was determined as the peak area of the electrode structure. Electricity per unit area expressed by the value divided by the area An electrode structure characterized in that the polyarylene polymer is sulfonated so that the load is in the range of 0.09 to 0.18 C / cm ² . 2. The electrolyte membrane comprises aromatic compound units having an electron-withdrawing group in the main chain of 5 to 70 mol% and aromatic compound units having no electron-withdrawing group in the main chain of 30 to 95 mol%. The electrode structure according to claim 1, which is made of a sulfonated product of a polyarylene-based polymer consisting of 3. The electron withdrawing group is --CO-- or --CON.
_{H -, - (CF 2)} p - (p is an integer of 1 to 10),
_{-C (CF 3) 2 -,} - COO -, - SO -, - SO 2 -
3. At least one divalent electron-withdrawing group selected from the group consisting of:
The electrode structure described. 4. The sulfonated product of the polyarylene polymer constituting the polymer electrolyte membrane is a sulfonated product excluding those having a perfluoroalkylene structure in a part of a substituent or a main chain. The electrode structure according to any one of claims 1 to 3. 5. The sulfonated product of the polyarylene polymer that constitutes the polymer electrolyte membrane is benzophenone-4,
Aromatic compound unit of 4'-diyl structure 7 to 35 mol%
5. A sulfonated product of a polyarylene polymer, which comprises 65 to 93 mol% of an aromatic compound unit having a 4'-phenoxy-benzophenone-2,5-diyl structure. The electrode structure according to claim 1. 6. The electrode structure according to claim 5, wherein the sulfonated product of the polyarylene polymer has an ion exchange capacity of 1.5 to 3.0 meq / g. 7. The sulfonated polyarylene polymer constituting the polymer electrolyte membrane comprises an aromatic compound having an electron-withdrawing group in the main chain, and at least one ether bond between the aromatic compounds. Aromatic compound unit 3 bound by
7. A sulfonated product of a polyarylene polymer, which comprises ˜60 mol% and an aromatic compound unit having no electron-withdrawing property of 40-97 mol%. The electrode structure according to item 1. 8. The sulfonated product of the polyarylene-based polymer constituting the polymer electrolyte membrane is a bis (benzoyl) diphenyl ether-4,4′-diyl structure aromatic compound unit 3 to 40 mol% and 4 ′. -Phenoxy-benzophenone-2,5-diyl structure aromatic compound unit 60-
8. The electrode structure according to claim 7, which is a sulfonated product of a polyarylene polymer composed of 97 mol%. 9. The electrode structure according to claim 8, wherein the sulfonated product of the polyarylene polymer has an ion exchange capacity of 1.5 to 3.0 meq / g. 10. A polymer electrolyte fuel cell comprising an electrode structure in which a pair of electrodes and an electrolyte membrane sandwiched by both electrodes are integrally bonded, wherein the electrolyte membrane has an electron-withdrawing group in its main chain. Aromatic compound units having 5 to 70 mol% and aromatic compound units having no electron-withdrawing group in the main chain 30 to 9
A polymer electrolyte membrane made of a sulfonated product of a polyarylene-based polymer composed of 5 mol%, wherein an electrode containing 0.5 mg / cm ² of a platinum catalyst is provided on one surface of the polymer electrolyte membrane. Place the polymer electrolyte membrane on the surface opposite to the electrode.
When the voltage applied between the sulfuric acid aqueous solution and the electrode is continuously changed to −0.1 to 0.7 V while the nitrogen gas is passed through the electrode while being brought into contact with the H1 sulfuric acid aqueous solution. In order that the amount of charge per unit area represented by a value obtained by dividing the peak area on the adsorption side of protons by the area of the electrode structure is in the range of 0.09 to 0.18 C / cm ² ,
A polymer electrolyte fuel cell, characterized in that the polyarylene polymer is sulfonated.