JP2005146264A - Compound, ion-exchange body, proton conductor and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a proton conductor which has a high ionic conductivity and a low methanol cross-over and to provide a high-power fuel cell using this proton conductor. <P>SOLUTION: After a sulfonation reaction is carried out on at least one compound of formulas (III) and (IV), a sol-gel reaction is carried out, or after the sol-gel reaction, the sulfonation reaction is carried out to obtain a compound, [wherein in formulas (III) and (IV), R<SP>3</SP>and R<SP>5</SP>are each an alkyl group, an aryl group or a heterocyclic group; R<SP>4</SP>and R<SP>6</SP>are each a hydrogen atom, an alkyl group, an aryl group or a silyl group; m3 and m4 are each an integer of 1-3; L<SP>3</SP>and L<SP>4</SP>are each a single bond or a bivalent linking group; Ar<SP>3</SP>and Ar<SP>4</SP>are each an aryl, heteroaryl, arylene or heteroarylene group having at least one electron-donating group; s3, s41 and s42 are each an integer of 1-4; Y<SP>1</SP>is a polymerizable group which can form a carbon-carbon bond or a carbon-oxygen bond by polymerization.]. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a compound and an ion exchanger, a proton conductor, an electrode membrane composite containing the compound, and a fuel cell using the same.

Technical background

  In recent years, solid polymer fuel cells are expected to be put to practical use in household power sources, in-vehicle power sources, and the like as clean power generation devices that are friendly to the global environment. In these polymer electrolyte fuel cells, those using hydrogen and oxygen as fuels are the mainstream. Recently, a direct methanol fuel cell (DMFC) using methanol instead of hydrogen as a fuel has been proposed, and it is expected to be a high-capacity battery for portable devices that replaces the lithium secondary battery, and has been actively researched.

  The important functions of the electrolyte membrane (proton conductor) for polymer electrolyte fuel cells are to physically use the fuel (hydrogen, methanol aqueous solution, etc.) supplied to the positive electrode and the oxidant gas (oxygen, etc.) supplied to the negative electrode. Insulating the positive electrode, electrically insulating the positive electrode and the negative electrode, and transmitting protons generated on the positive electrode to the negative electrode. In order to satisfy these functions, a certain degree of mechanical strength and high proton conductivity are required.

  In general, a sulfonic acid group-containing perfluorocarbon polymer represented by Nafion (registered trademark) is used for the polymer electrolyte fuel cell electrolyte membrane. These electrolyte membranes have excellent ionic conductivity and relatively high mechanical strength, but have the following points to be improved. That is, in these electrolyte membranes, protons conduct through water in the cluster channels formed by the water and sulfonic acid groups contained in the membrane, so that the ionic conductivity depends greatly on the moisture content of the membrane due to the humidity of the battery usage environment. To do. The polymer electrolyte fuel cell is preferably operated in a temperature range of 100 to 150 ° C. from the viewpoint of reducing poisoning of the catalyst electrode by CO and increasing the activation of the catalyst electrode. However, in such an intermediate temperature range, the ionic conductivity decreases with a decrease in the water content of the electrolyte membrane, so that expected battery characteristics cannot be obtained. Further, the softening point of the electrolyte membrane is around 120 ° C., and when operated in this temperature range, the mechanical strength of the electrolyte membrane is poor. On the other hand, when these electrolyte membranes are used in DMFC, these membranes, which are inherently water-containing, have low barrier properties against fuel methanol, so that methanol supplied to the positive electrode permeates the electrolyte membrane and reaches the negative electrode. Resulting in. This causes a so-called methanol crossover phenomenon, in which the battery output decreases, which is one of the important issues to be solved for commercialization of DMFC.

  Increasing momentum to develop proton conductors to replace Nafion®, several promising electrolyte materials have been proposed. For example, as a measure for facilitating film formation while taking advantage of the properties of inorganic materials, nanocomposite materials combined with polymer materials have been proposed. For example, a method for producing a proton conductor by combining a polymer compound having a sulfonic acid group in the side chain with a silicon oxide and a protonic acid is disclosed (Patent Documents 1 to 3). In addition, organic-inorganic nano-hybrid proton conductors that are produced by a sol-gel reaction in the presence of a protonic acid using an organosilicon compound as a precursor have been proposed (Patent Documents 4 to 5 and Non-Patent Documents 1 to 1). 3). These organic-inorganic composites and hybrid proton conductors are composed of silicic acid and protonic acid, which is composed of an inorganic component that is a proton conducting site and an organic component that imparts flexibility to the material, but the proton conductivity of the membrane. If the inorganic component is increased to increase the mechanical strength of the membrane, the mechanical strength of the membrane decreases, and if the organic component is increased to increase flexibility, the proton conductivity decreases. Therefore, it is difficult to obtain a material that satisfies the two characteristics. is there. Moreover, there is no sufficient description regarding methanol permeability, which is an important characteristic for DMFC applications.

JP-A-10-69817 Japanese Patent Laid-Open No. 11-203936 JP 2001-307752 A Japanese Patent No. 3103888 German patent DE 10061920A1 "Electrochimica Acta", 1998, 43, 10-11, p.1301 "Industrial Materials", Nikkan Kogyo Shimbun, 2002, 50, p.39 "Solid State Ionics", 2001, No. 145, p.127

  An object of the present invention is to provide a proton conductor having low methanol permeability suitable for DMFC and a fuel cell using the proton conductor.

  As a result of diligent research in view of the above object, the present inventor has found that a sol-gel reaction precursor composed of an organosilicon compound and a sol-gel reaction precursor obtained by sulfonating an aryl group having an electron donating group (preferably a hydroxyl group). The silicon-oxygen matrix part in which the organic molecular chain and the proton-donating group that becomes the proton conduction path are combined is phase-separated in nano size, and the organic molecular chain is preferably oriented horizontally with respect to the film surface. By doing so, it was found that an organic-inorganic nanohybrid material in which the proton conduction path was formed in a direction crossing the membrane surface, and that the resulting membrane was flexible and had high mechanical strength, and reached the present invention. In particular, a sulfone obtained by sulfonation of an organosilicon compound represented by any one or more of general formulas (VII) and / or (VIII) and a compound represented by general formulas (III) and / or (IV) The organic-inorganic hybrid proton conductor obtained by a sol-gel reaction in which a solution containing an acid compound is combined has a strong tendency. These proton conductors were found to form an aggregate of organic molecular chains by polarization microscope observation. In this case, a silicon-oxygen network to which a proton donating group serving as a proton conduction path is bound is inevitably formed in a direction perpendicular to the orientation direction of the organic molecular assembly. Therefore, a proton conduction path across the membrane can be constructed by controlling the orientation direction of the organic molecular chain in the horizontal direction with respect to the membrane surface.

  The object of the present invention can be achieved by the following constitution.

（一般式（III）および（IV）中、Ｒ³およびＲ⁵はアルキル基、アリール基またはヘテロ環基を表し、Ｒ⁴およびＲ⁶は水素原子、アルキル基、アリール基またはシリル基を表し、ｍ３およびｍ４はそれぞれ１〜３の整数を表す。Ｌ³およびＬ⁴は単結合または２価の連結基を表す。Ａｒ³およびＡｒ⁴は、少なくとも１つの電子供与性基を有するアリール基もしくはヘテロアリール基、又はアリーレン基もしくはヘテロアリーレン基を表す。ｓ３、ｓ４１、およびｓ４２は１〜４の整数を表す。Ｙ¹は重合により炭素−炭素結合または炭素−酸素結合を形成しうる重合性基を表す。） (1) A method of subjecting at least one of the compounds represented by the following general formulas (III) and (IV) to a sulfonation reaction followed by a sol-gel reaction, or a sol-gel reaction followed by a sulfonation reaction The compound obtained by the method of giving.

(In the general formulas (III) and (IV), R ³ and R ⁵ represent an alkyl group, an aryl group or a heterocyclic group, R ⁴ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group or a silyl group, m3 and m4 each represent an integer of 1 to ^3. L ³ and L ⁴ each represent a single bond or a divalent linking group, Ar ³ and Ar ⁴ represent an aryl group or hetero group having at least one electron-donating group. Represents an aryl group, an arylene group or a heteroarylene group, s3, s41, and s42 represent an integer of 1 to 4. Y ¹ represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization. Represents.)

 (2) The compound according to (1), wherein the electron donating group is a hydroxyl group.

 (3) The compound according to (1) or (2), which is obtained by a method of further adding at least one organosilicon compound having a mesogen-containing group in the sol-gel reaction.

（一般式（VII）および（VIII）中、Ａ³およびＡ⁴はそれぞれメソゲンを含む有機原子団を表し、Ｒ⁹およびＲ¹¹はそれぞれアルキル基、アリール基またはヘテロ環基を表し、Ｒ¹⁰およびＲ¹²はそれぞれ水素原子、アルキル基、アリール基またはシリル基を表し、Ｙ²は重合により炭素−炭素結合または炭素−酸素結合を形成しうる重合性基を表し、ｍ７およびｍ８はそれぞれ１〜３の整数を表し、ｓ７１およびｓ８はそれぞれ１〜８の整数を表し、ｓ７２は１〜４の整数を表す。） (4) The compound according to the above (3), wherein the organosilicon compound having a group containing a mesogen is at least one of the compounds represented by the following general formulas (VII) and (VIII).

(In the general formula (VII) and (VIII), A ³ and A ⁴ each represents an organic atomic group containing a mesogen, respectively R ⁹ and R ¹¹ are an alkyl group, an aryl group or a heterocyclic group, R ¹⁰ and R ¹² represents a hydrogen atom, an alkyl group, an aryl group or a silyl group, Y ² represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization, and m7 and m8 are each 1 to 3 S71 and s8 each represent an integer of 1 to 8, and s72 represents an integer of 1 to 4.)

 (5) An ion exchanger comprising the compound according to any one of (1) to (4) above.

 (6) A proton conductor having the compound according to any one of (1) to (4) above.

(7) The proton conductor according to (6), which is in the form of a membrane.
(8) An electrode membrane assembly having the proton conductor according to (6) or (7) between an anode and a cathode.

 (8-2) A fuel cell having the electrode membrane assembly according to (7).

(9) The proton conductor according to the above (6) or (7), which comprises a step of subjecting a compound represented by the following general formula (III) and / or (IV) to a sol-gel reaction followed by a sulfonation reaction Production method.

（一般式（III）および（IV）中、Ｒ³およびＲ⁵はアルキル基、アリール基またはヘテロ環基を表し、Ｒ⁴およびＲ⁶は水素原子、アルキル基、アリール基またはシリル基を表し、ｍ３およびｍ４はそれぞれ１〜３の整数を表す。Ｌ³およびＬ⁴は単結合または２価の連結基を表す。Ａｒ³およびＡｒ⁴は、少なくとも１つの水酸基を有するアリール基を表す。ｓ３、ｓ４１、およびｓ４２は１〜４の整数を表す。Ｙ¹は重合により炭素−炭素結合または炭素−酸素結合を形成しうる重合性基を表す。）

(In the general formulas (III) and (IV), R ³ and R ⁵ represent an alkyl group, an aryl group or a heterocyclic group, R ⁴ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group or a silyl group, m3 and m4 each represent an integer of 1 to ^3. L ³ and L ⁴ each represent a single bond or a divalent linking group, Ar ³ and Ar ⁴ each represent an aryl group having at least one hydroxyl group, s3, s41 and s42 represent an integer of 1 to 4. Y ¹ represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization.

(10) The proton conductor according to (6) or (7) above, comprising a step of sulfonating a compound represented by the following general formula (III) and / or (IV) and then subjecting it to a sol-gel reaction. Production method.

（一般式（III）および（IV）中、Ｒ³およびＲ⁵はアルキル基、アリール基またはヘテロ環基を表し、Ｒ⁴およびＲ⁶は水素原子、アルキル基、アリール基またはシリル基を表し、ｍ３およびｍ４はそれぞれ１〜３の整数を表す。Ｌ³およびＬ⁴は単結合または２価の連結基を表す。Ａｒ³およびＡｒ⁴は、少なくとも１つの水酸基を有するアリール基を表す。ｓ３、ｓ４１、およびｓ４２は１〜４の整数を表す。Ｙ¹は重合により炭素−炭素結合または炭素−酸素結合を形成しうる重合性基を表す。ｍ３またはｍ４が２以上のときＲ⁴またはＲ⁶はそれぞれ同一でも異なってもよい。）

(In the general formulas (III) and (IV), R ³ and R ⁵ represent an alkyl group, an aryl group or a heterocyclic group, R ⁴ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group or a silyl group, m3 and m4 each represent an integer of 1 to ^3. L ³ and L ⁴ each represent a single bond or a divalent linking group, Ar ³ and Ar ⁴ each represent an aryl group having at least one hydroxyl group, s3, s41 and s42 represent an integer of 1 to 4. Y ¹ represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization, and R ⁴ or R ⁶ when m3 or m4 is 2 or more. May be the same or different.)

(11) The method for producing a proton conductor as described in (6) above, wherein in any one of the above (9) or (10), sulfonation is performed with an SO ₃ or SO ₃ organic complex.
(12) The method for producing a proton conductor as described in (11) above, wherein the sulfonation reaction temperature is from −50 ° C. to 150 ° C.

  In the proton conductor of the present invention, the sulfo group is covalently bonded to the silicon-oxygen three-dimensional cross-linked matrix, the ion conductivity at room temperature is high, the resistance to methanol aqueous solution is high, and the methanol crossover is reduced. Therefore, when used in a direct methanol fuel cell, it is possible to obtain a higher output than a conventional proton conductor. In addition, when an aggregate formed by aligning at least part of the organic molecular chain is formed, the rate of voltage decrease because the ionic conductivity is higher and the resistance to methanol aqueous solution is high and the methanol crossover is further reduced. Becomes smaller.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

[1] Organosilicon compound and sulfonic acid group-containing precursor The proton conductor of the present invention has a structure in which an electron donating group, preferably an aryl group containing a hydroxyl group and a sulfo group are covalently bonded to a silicon oxygen three-dimensional crosslinked matrix. . The proton conductor can be formed by a sol-gel reaction using the organosilicon compounds represented by the general formulas (III) and (IV) as precursors, respectively. The precursor for forming these will be described in detail below.

[1-1] Organosilicon compound precursor The proton conductor of the present invention is formed by a sol-gel reaction using the organosilicon compound represented by the general formula (III) and / or (IV) as a precursor. be able to.

In the organosilicon compound represented by the general formula (III) and / or (IV), R ³ and R ⁵ represent an alkyl group, an aryl group or a heterocyclic group, and R ⁴ and R ⁶ represent a hydrogen atom or an alkyl group. Represents an aryl group or a silyl group. Preferable examples of the alkyl group represented by R ^{3 to} R ⁶ include a linear, branched or cyclic alkyl group (for example, an alkyl group having 1 to 20 carbon atoms, preferably a methyl group, an ethyl group, an isopropyl group, n-butyl group, 2-ethylhexyl group, n-decyl group, cyclopropyl group, cyclohexyl group, cyclododecyl group and the like), and preferred examples of the aryl group represented by R ^{3 to} R ⁶ include Examples thereof include 6-20 substituted or unsubstituted phenyl groups, naphthyl groups, etc. Preferred examples of the heterocyclic groups represented by R ³ and R ⁵ include substituted or unsubstituted hetero 6-membered rings (pyridyl, Morpholino groups, etc.), substituted or unsubstituted hetero 5-membered rings (furyl, thiophene groups, etc.) and the like. In addition, preferable examples of the silyl group represented by R ⁴ and R ⁶ include a silyl group (trimethylsilyl group, triethylsilyl group, triethylsilyl group) substituted with three alkyl groups selected from alkyl groups having 1 to 10 carbon atoms. An isopropylsilyl group), or a polysiloxane group (-(Me ₂ SiO) _n H (n = 10 to 100) or the like). Further, m3 and m4 are preferably the case where m3 and m4 are 2 or 3, more preferably 3. In addition, when m3, 3-m3, m4, or 3-m4 is 2 or more, the respective parentheses may be the same or different.

L ³ and L ^{4 each} represents a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group, an alkenylene group, an arylene group, —O—, —S—, —CO—, —NR′— (R ′ is a hydrogen atom or an alkyl group), —SO ₂ —. And a divalent linking group formed by combining two or more of these. Among the above linking groups, a single bond, an alkylene group or a combination of an alkylene group and —O— or a combination of an alkylene group, —CO— and —O— is preferable, and the alkylene group has 2 to 6 carbon atoms. Are preferred. The single bond refers to the case where Si and Ar ³ or Ar ⁴ are directly bonded.

Ar ³ represents an aryl group or heteroaryl group (hereinafter referred to as a (hetero) aryl group) substituted with at least one electron donating group. The electron donating group is preferably a substituent having a Hammett σp value of −0.15 or less as described in Chemical Review Vol. 91, No. 2 (1991), pages 165 to 195. For example, a methyl group (-0.17), a methoxy group (-0.27), a hydroxyl group (-0.37), a dimethylamino group (-0.83), etc. are mentioned. Particularly preferred is a hydroxyl group. When the number of electron donating groups is 1, the position at which the electron donating group is substituted is ortho, meta, para to (R ⁴ O) m3-Si (R ³ ) 3-m3-L ^3- . Any position may be sufficient, Preferably it is an ortho position or a para position, More preferably, it is an ortho position. When the number of electron donating groups is 2 or more, any position may be substituted. The (hetero) aryl group may further have a substituent other than the electron donating group. In this case, the position to be replaced may be any position. Further, the (hetero) aryl group may be condensed, and in this case, it is preferably bicyclic. Ar3 is preferably a (hetero) aryl group having 6 to 24 carbon atoms as an aryl group substituted with at least one electron donating group, such as a hydroxyphenyl group, a hydroxynaphthyl group, a hydroxybiphenyl group, or a methoxyfuryl group. A methoxythienyl group, a hydroxypyridyl group, and the like.

Ar ⁴ represents an arylene group or heteroarylene group (hereinafter referred to as a (hetero) arylene group) substituted with at least one electron donating group. The electron donating group has the same meaning as that which can be substituted with Ar ³ , and the preferred range is also the same. The position at which the electron donating group is substituted is (R ⁶ O) _m4 -Si (R ⁵ ) _3-m4 -L ⁴ _- when Ar ⁴ is a 6-membered ring and the number of electron donating groups is 1, or The position may be any of ortho, meta, and para with respect to Y ^1- , preferably ortho or para, and more preferably ortho. When the number of electron donating groups is 2 or more, any position may be substituted. When Ar ⁴ is a 5-membered ring, it may be in any position with respect to (R ⁶ O) _m4 -Si (R ⁵ ) _3-m4 -L ⁴ -or Y ^1- , and preferably On carbon is preferred. The (hetero) arylene group may further have a substituent other than the electron donating group. In this case, the position to be replaced may be any position. Further, the (hetero) arylene group may be condensed, and in this case, it is preferably bicyclic. Ar ⁴ is preferably an arylene group substituted with at least one electron-donating group, preferably a (hetero) arylene group having 6 to 24 carbon atoms, such as hydroxyphenylene group, hydroxynaphthylene group, hydroxybiphenylene group, methoxy For example, a flangyl group, a methoxythiophene diyl group, and a hydroxypyridine diyl group. Preferred groups include the following groups.

1． Alkyl group The alkyl group may have a substituent, more preferably an alkyl group having 1 to 24 carbon atoms, still more preferably 1 to 10 carbon atoms, and may be linear or branched. May be. For example, methyl group, ethyl group, propyl group, butyl group, i-propyl group, i-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, tert-octyl group, decyl group, dodecyl group, tetradecyl group 2-hexyldecyl group, hexadecyl group, octadecyl group, cyclohexylmethyl group, octylcyclohexyl group and the like.

2. Aryl group The aryl group may have a substituent or may be condensed, and more preferably an aryl group having 6 to 24 carbon atoms, such as a phenyl group, a 4-methylphenyl group, and a 3-cyanophenyl group. , 2-chlorophenyl group, 2-naphthyl group and the like.

3. Heterocyclic Group The heterocyclic group may have a substituent or may be condensed. In the case of a nitrogen-containing heterocyclic group, the nitrogen in the ring may be quaternized. More preferably, it is a C2-C24 heterocyclic group, for example, 4-pyridyl group, 2-pyridyl group, 1-octylpyridinium-4-yl group, 2-pyrimidyl group, 2-imidazolyl group, 2-thiazolyl group. Etc.

4). More preferably an alkoxy group having 1 to 24 carbon atoms, such as a methoxy group, an ethoxy group, a butoxy group, an octyloxy group, a methoxyethoxy group, a methoxypenta (ethyloxy) group, an acryloyloxyethoxy group, or a pentafluoropropoxy group Etc.

5). An acyloxy group is more preferably an acyloxy group having 1 to 24 carbon atoms, such as an acetyloxy group and a benzoyloxy group.

6． An alkoxycarbonyl group is more preferably an alkoxycarbonyl group having 2 to 24 carbon atoms, such as a methoxycarbonyl group or an ethoxycarbonyl group.

7). Carbamoyloxy group (for example, N, N-dimethylcarbamoyloxy group, N, N-diethylcarbamoyloxy group, morpholinocarbonyloxy group, N, N-di-n-octylaminocarbonyloxy group, Nn-octylcarbamoyloxy group) Group),
Alkoxycarbonyloxy group (eg, methoxycarbonyloxy group, ethoxycarbonyloxy group, tert-butoxycarbonyloxy group, n-octylcarbonyloxy group)

8). Aryloxycarbonyloxy group (for example, phenoxycarbonyloxy group, p-methoxyphenoxycarbonyloxy group, pn-hexadecyloxyphenoxycarbonyloxy group,
An amino group (for example, amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group),
Acylamino group (for example, formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group, 3,4,5-tri-n-octyloxyphenylcarbonylamino group)

9. Aminocarbonylamino group (for example, carbamoylamino group, N, N-dimethylaminocarbonylamino group, N, N-diethylaminocarbonylamino group, morpholinocarbonylamino group)

10. Alkoxycarbonylamino group (for example, methoxycarbonylamino group, ethoxycarbonylamino group, tert-butoxycarbonylamino group, n-octadecyloxycarbonylamino group, N-methyl-methoxycarbonylamino group),

11. Aryloxycarbonylamino group (for example, phenoxycarbonylamino group, p-chlorophenoxycarbonylamino group, mn-octyloxyphenoxycarbonylamino group),

12 Sulfamoylamino group (for example, sulfamoylamino group, N, N-dimethylaminosulfonylamino group, Nn-octylaminosulfonylamino group),

13. Alkyl and arylsulfonylamino groups (for example, methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group)

14 Sulfamoyl group (for example, N-ethylsulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group) N- (N′-phenylcarbamoyl) sulfamoyl group),

15. Alkyl and arylsulfinyl groups (eg, methylsulfinyl group, ethylsulfinyl group, phenylsulfinyl group, p-methylphenylsulfinyl group),

16. Alkyl and arylsulfonyl groups (eg, methylsulfonyl group, ethylsulfonyl group, phenylsulfonyl group, p-methylphenylsulfonyl group),

17. An acyl group (for example, acetyl group, pivaloyl group, 2-chloroacetyl group, stearoyl group, benzoyl group, pn-octyloxyphenylcarbonyl group),
An aryloxycarbonyl group (for example, phenoxycarbonyl group, o-chlorophenoxycarbonyl group, m-nitrophenoxycarbonyl group, p-tert-butylphenoxycarbonyl group),

18. A carbamoyl group (for example, carbamoyl group, N-methylcarbamoyl group, N, N-dimethylcarbamoyl group, N, N-di-n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group),

19. Silyl group (preferably a silyl group having 3 to 30 carbon atoms, for example, trimethylsilyl group, tert-butyldimethylsilyl group, phenyldimethylsilyl, trimethoxysilyl, triethoxysilyl, dimethoxymethylsilyl, diethoxymethylsilyl, triacetoxysilyl ),

20. A cyano group,
21. A fluoro group,
22. Mercapto group,
23. Hydroxyl group

  s3, s41 and s42 are integers of 1 to 4, preferably 1 to 3. In addition, when s3, s41, and s42 are two or more, each parenthesis may be the same or different.

Y ¹ is a polymerizable group capable of forming a polymer by forming a carbon-carbon or carbon-oxygen bond. For example, acryloyl group, methacryloyl group, vinyl group, ethynyl group, alkylene oxide group (ethylene oxide group, trimethylene oxide) Group) and the like. Of these, acryloyl group, methacryloyl group, ethylene oxide group, trimethylene oxide group and the like are preferable. Particularly preferred are an ethylene oxide group and a trimethylene oxide group.

Y ¹ is bonded to Ar ⁴ by a single bond or via a substituent on Ar ⁴ .

  Specific examples of the organosilicon compound are listed below, but are not limited thereto.

[1-2] Introduction of sulfo group In the proton conductor of the present invention, sulfone is added to the organosilicon compound represented by the general formula (III) or (IV) either before or after the sol-gel reaction described later or after film formation. It is preferable to introduce a sulfo group by acting an agent. In the sulfonating agent, a sulfo group is introduced by reacting directly with or on the substituent of Ar ³ or Ar ⁴ (hetero) aryl group in general formula (III) or (IV).

As the sulfonating agent, for example, the sulfonating agent described in “3rd edition, New Experimental Chemistry Course Vol. 14, Synthesis and Reaction of Organic Compounds” (edited by Chemical Society of Japan) can be used. Preferably, sulfuric acid, chlorosulfonic acid, fuming sulfuric acid, amido sulfuric acid, sulfur trioxide, sulfur trioxide complex _{(e.g., SO 3 -DMF, SO 3 -THF} , SO 3 - , such as pyridine - dioxane, SO ₃₎ include . Particularly preferred is a sulfur trioxide complex.
As the solvent used in the sulfonation reaction, the solvent described in the solvent used in the sol-gel reaction described later is preferably used. The total amount of the solvent is preferably 0.1 to 100 g, more preferably 1 to 10 g, relative to 1 g of the precursor compound. The reaction temperature is related to the reaction rate and can be selected depending on the reactivity of the precursor and the type and amount of the selected sulfating agent. Preferably it is -20 degreeC-150 degreeC, More preferably, it is 0 degreeC-120 degreeC, More preferably, it is 20 degreeC-100 degreeC. The amount of the sulfonating agent used is preferably 1 to 10 times, more preferably 2 to 5 times the total number of moles of the compound of the general formula (III) and the compound of the general formula (IV). In order to suppress decomposition of the sulfonating agent, the sulfonation reaction is preferably performed under conditions close to anhydrous conditions by dehydrating the solvent and the like.

[1-3] Mesogen-containing organosilicon compound In the present invention, in the sol-gel reaction, it is preferable to further add at least one silicon compound having a mesogen-containing group, and the silicon compound having a mesogen-containing group is represented by the general formula ( VII) and at least one compound represented by formula (VII) are preferred.

In the organosilicon compound containing mesogens represented by the general formulas (VII) and (VIII), R ⁹ and R ¹¹ represent an alkyl group, an aryl group or a heterocyclic group, and R ¹⁰ and R ¹² represent a hydrogen atom, an alkyl group Represents an aryl group or a silyl group. Preferable examples of the alkyl group represented by R ^{9 to} R ¹² include a linear, branched or cyclic alkyl group (for example, an alkyl group having 1 to 20 carbon atoms, such as a methyl group, an ethyl group, an isopropyl group, n -Butyl group, 2-ethylhexyl group, n-decyl group, cyclopropyl group, cyclohexyl group, cyclododecyl group, etc.). Preferred examples of the aryl group represented by R ^{9 to} R ¹² include 6 carbon atoms. -20 substituted or unsubstituted phenyl groups, naphthyl groups and the like. Preferred examples of the heterocyclic group represented by R ⁹ and R ¹¹ include substituted or unsubstituted hetero 6-membered rings (pyridyl, morpholino). Group), a substituted or unsubstituted hetero 5-membered ring (furyl, thiophene group, etc.) and the like. In addition, preferable examples of the silyl group represented by R ¹⁰ and R ¹² include a silyl group (trimethylsilyl group, triethylsilyl group, trimethylsilyl group substituted with three alkyl groups selected from alkyl groups having 1 to 10 carbon atoms). An isopropylsilyl group), or a polysiloxane group (-(Me ₂ SiO) _n H (n = 10 to 100) or the like). m7 and m8 are preferably when m7 and / or m8 is 2 or 3, and more preferably when m7 and / or m8 is 3. In addition, when m7, m8, 3-m7, 3-m8, s71, s72 or s8 is 2 or more, the respective parentheses may be the same or different.
s71 is an integer of 1 to 8, preferably 1 to 4, and more preferably 1 to 2. s72 is an integer of 1 to 4, preferably 1 to 2, and more preferably 1. s8 is an integer of 1 to 8, preferably 1 to 4, and more preferably 1 to 2.

A ³ and A ⁴ are organic groups containing mesogens, and preferable examples of mesogenic groups are described in “Flussige Kristalle in Tabellen II” by Dietrich Demus and Horst Zaschke, 1984, p.7-18. The thing that is. Among these, those represented by the following general formula (IX) are preferable.

In general formula (IX), Q ¹¹ and Q ¹² represent a divalent linking group or a single bond. Examples of the divalent linking group include —CH═CH—, —CH═N—, —N═N—, —N (O) ═N—, —COO—, —COS—, —CONH—, —COCH _2. —, —CH ₂ CH ₂ —, —OCH ₂ —, —CH ₂ NH—, —CH ₂ —, —CO—, —O—, —S—, —NH—, — (CH ₂ ) ₁ to ₃ — , —CH═CH—COO—, —CH═CH—CO—, — (C≡C) ₁ to ₃ —, combinations thereof, and the like are preferable, —CH ₂ —, —CO—, —O—, —CH = CH-, -CH = N-, -N = N-, combinations thereof, and the like are more preferable. These divalent linking groups may be groups in which a hydrogen atom is substituted with another substituent. Q ¹¹ and Q ¹² are alkenylene group, an alkylene group, one or more -O- and one or more _{- (CH 2) 1 ~ 3} - a combination or a single bond of preferably, - [- O- (CH ₂ ) _m11 ] _m10- (m11 is an integer of 1 to 24, preferably 2 to 16, more preferably 3 to 11. m10 is an integer of 1 to 3, preferably 1 to 2, and more preferably 1. When m10 is 2 or more, each parenthesis may be the same or different.) Is more preferable.

Y ¹¹ represents a divalent 4- to 7-membered ring substituent or a condensed ring substituent composed of them, and m9 represents an integer of 1 to 3. Y ¹¹ is preferably a 6-membered aromatic group, a 4- to 6-membered saturated or unsaturated aliphatic group, a 5- or 6-membered heterocyclic group, or a condensed ring thereof. Preferable specific examples of Y ¹¹ include substituents represented by (Y-1) to (Y-30) shown below, and combinations thereof. Among these substituents, (Y-1), (Y-2), (Y-18), (Y-19), (Y-21), (Y-22) and (Y-29) are more preferable. More preferably (Y-1), (Y-2), (Y-21) and (Y-29).

  The organosilicon compound containing a mesogenic group preferably contains at least one alkyl group or alkylene group having 5 or more carbon atoms together with a mesogen in order to enhance molecular orientation. 5-24 are preferable and, as for carbon number of this alkylene group, 6-16 are more preferable. The alkyl group or alkylene group contained in the organosilicon compound may have a substituent. Preferable substituents include alkyl groups, aryl groups, heterocyclic groups, alkoxy groups, acyloxy groups, cyano groups, fluoro groups, alkoxycarbonyl groups, and the like shown for the above-described substituents.

Y ² is a polymerizable group capable of forming a carbon-carbon or carbon-oxygen bond to form a polymer. For example, acryloyl group, methacryloyl group, vinyl group, ethynyl group, alkylene oxide group (ethylene oxide group, trimethylene oxide) Group) and the like. Of these, acryloyl group, methacryloyl group, ethylene oxide group, trimethylene oxide group and the like are preferable.

In the general formulas (VII) and (VIII), the silyl group (—Si (OR ¹⁰ ) _m7 (R ⁹ ) _3-m7 or —Si (OR ¹² ) _m8 (R ¹¹ ) _3-m8 ) is an organic atomic group A single bond to a mesogen group, an alkylene group or an alkenylene group constituting A ³ or A ⁴ , or a bond via a linking group. The linking group is preferably an alkylene group having 1 to 15 carbon atoms or a combination of these alkylene groups and mesogenic linking groups Q ¹¹ and Q ¹² . The silyl group is preferably bonded to the alkylene group.

Although the specific example of a mesogen containing organosilicon compound is given to the following, it is not limited to these.

[2] Proton Conductor Production Method [2-1] Sol-Gel Method In the present invention, a solid is obtained by hydrolysis, condensation, drying, or (in some cases firing) a metal alkoxide, which is generally called a sol-gel method. Use the method. For example, the methods described in Patent Documents 1 to 3, Patent Document 8 and Non-Patent Document 3 can be used. In general, an acid catalyst is used for the condensation. However, in the present invention, the precursor itself described in [1-2] itself becomes an acid catalyst, and thus it is not necessary to add an acid separately.

  A typical method for producing the proton conductor of the present invention is to dissolve a compound represented by the general formula (III) or (IV) in a solvent (for example, DMF, THF, dioxane, methylene chloride, diethyl ether, etc.) React with sulfonating agent. After completion of the sulfonation reaction, it is mixed with the mesogen-containing organosilicon compound described in [1-3] dissolved in an arbitrary solvent, and hydrolysis and polycondensation of alkoxysilyl groups (hereinafter referred to as “sol-gel reaction”). Make it progress. Alternatively, the compound represented by the general formula (III) or (IV) and the mesogen-containing organosilicon compound described in [1-3] are dissolved in an arbitrary solvent, a sulfonating agent is added, and a sulfo group is introduced. The sol-gel reaction is allowed to proceed. In these reactions, heating may be performed as necessary. The viscosity of the reaction mixture (sol) gradually increases, and the solvent is distilled off and dried to obtain a solid (gel). A film-like solid can be obtained by pouring the sol into a desired container or applying it at a stage where fluidity exists, and then evaporating and drying the solvent. In order to make the generated silica network more dense, it is possible to further heat after drying if necessary. Further, the compound represented by the general formula (III) or (IV) and the mesogen-containing organosilicon compound described in [1-3] are dissolved in an arbitrary solvent, and the product obtained after the sol-gel reaction is dissolved with a sulfonating agent. A membrane may be prepared by introducing a sulfo group by treatment.

  The solvent used in the sol-gel reaction is not particularly limited as long as it dissolves the precursor organosilicon compound, but is preferably a carbonate compound (ethylene carbonate, propylene carbonate, etc.), a heterocyclic compound (3-methyl-2). -Oxazolidinone, N-methylpyrrolidone, etc.), cyclic ethers (dioxane, tetrahydrofuran, etc.), chain ethers (diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene glycol dialkyl ether, polypropylene glycol dialkyl ether, etc.), Alcohols (methanol, ethanol, isopropanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol mono Alkyl ether, polypropylene glycol monoalkyl ether, etc.), polyhydric alcohols (ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, glycerin, etc.), nitrile compounds (acetonitrile, glutaronitrile, methoxyacetonitrile, propionitrile, benzonitrile) Etc.), esters (carboxylic acid esters, phosphoric acid esters, phosphonic acid esters, etc.), aprotic polar substances (dimethyl sulfoxide, sulfolane, dimethylformamide, dimethylacetamide, etc.), nonpolar solvents (toluene, xylene, etc.), chlorine-based A solvent (methylene chloride, ethylene chloride, etc.), water or the like can be used. Of these, alcohols such as ethanol, isopropanol and fluorine-substituted alcohol, nitrile compounds such as acetonitrile, glutaronitrile, methoxyacetonitrile, propionitrile and benzonitrile, and cyclic ethers such as dioxane and tetrahydrofuran are particularly preferable. These may be used alone or in combination of two or more. For the purpose of controlling the drying rate, a solvent having a boiling point of 100 ° C. or higher such as N-methylpyrrolidone, dimethylacetamide, sulfolane, dioxane and the like may be added to the solvent. The total amount of the solvent is preferably 0.1 to 100 g, more preferably 1 to 10 g, relative to 1 g of the precursor compound.

An acid catalyst may be used for the purpose of accelerating the progress of the sol-gel reaction. The acid catalyst is preferably an inorganic or organic proton acid. Examples of inorganic protonic acids include hydrochloric acid, sulfuric acid, phosphoric acids (H ₃ PO ₄ , H ₃ PO ₃ , H ₄ P ₂ O ₇ , H ₅ P ₃ O ₁₀ , metaphosphoric acid, hexafluorophosphoric acid, etc.), boric acid, nitric acid Perchloric acid, tetrafluoroboric acid, hexafluoroarsenic acid, hydrobromic acid, solid acids (tungstophosphoric acid, tungsten peroxo complex, etc.), and the like. Examples of organic protonic acids include phosphoric acid esters (for example, phosphoric acid esters having 1 to 30 carbon atoms, phosphoric acid methyl ester, phosphoric acid propyl ester, phosphoric acid dodecyl ester, phosphoric acid phenyl ester, phosphoric acid dimethyl ester, Phosphorous acid dododecyl ester, etc.), phosphorous acid esters (for example, phosphorous acid esters having 1 to 30 carbon atoms, phosphorous acid methyl ester, phosphorous acid dodecyl ester, phosphorous acid diethyl ester, phosphorous acid Diisopropyl, phosphorous acid dododecyl ester, etc.), sulfonic acids (for example, sulfonic acids having 1 to 15 carbon atoms, such as benzenesulfonic acid, toluenesulfonic acid, hexafluorobenzenesulfonic acid, trifluoromethanesulfonic acid, dodecylsulfonic acid, etc.) Carboxylic acids (for example, carboxylic acids having 1 to 15 carbon atoms) Acetic acid, trifluoroacetic acid, benzoic acid, substituted benzoic acid, etc.), imides (bis (trifluoromethanesulfonyl) imidic acid, trifluoromethanesulfonyl trifluoroacetamide, etc.), phosphonic acids (for example, phosphones having 1 to 30 carbon atoms) Perfluorocarbon sulfonic acid polymers represented by low molecular weight compounds such as methylphosphonic acid, ethylphosphonic acid, phenylphosphonic acid, diphenylphosphonic acid, 1,5-naphthalene bisphosphonic acid, etc., or Nafion (registered trademark), Poly (meth) acrylates having a phosphate group in the side chain (for example, those described in JP-A-2001-114844), sulfonated polyether ether ketones (for example, those described in JP-A-6-93111) Sulfonated polyethersulfone For example, it has proton acid sites such as sulfonated products of heat-resistant aromatic polymers such as those described in JP-A-10-45913) and sulfonated polysulfone (for example, described in JP-A-9-245818). A high molecular compound is mentioned. Two or more of these may be used in combination.

  The reaction temperature of the sol-gel reaction is related to the reaction rate and can be selected depending on the reactivity of the precursor and the type and amount of the selected acid. Preferably it is -20 degreeC-150 degreeC, More preferably, it is 0 degreeC-80 degreeC, More preferably, it is 20 degreeC-60 degreeC.

[2-2] Polymerization by polymerizable group Y When the polymerizable groups Y ¹ and Y ² are carbon-carbon unsaturated bonds such as (meth) acryloyl group, vinyl group, ethynyl group, etc., Takayuki Otsu and Masami Kinoshita Co-authored, “Experimental Methods for Polymer Synthesis”, Chemical Doujin and Takatsu Otsu, “Lecture Polymerization Reaction Theory 1 Radical Polymerization (I)”, Radical Polymerization, a general polymer synthesis method described in Chemical Dojin Can be used.

  As the radical polymerization method, a thermal polymerization method using a thermal polymerization initiator and a photopolymerization method using a photopolymerization initiator can be used. Preferred examples of the thermal polymerization initiator include 2,2'-azobis (isobutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl 2,2'-azobis (2-methyl). Azo initiators such as propionate) and peroxide initiators such as benzoyl peroxide. Preferred examples of the photopolymerization initiator include α-carbonyl compounds (US Pat. Nos. 2,367,661 and 2,367,670). ), Acyloin ether (US Pat. No. 2,244,828), α-hydrocarbon-substituted aromatic acyloin compound (US Pat. No. 2,722,512), polynuclear quinone compound (US Pat. Nos. 3,046,127 and 2,951,758) Description), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549) 3676), acridine and phenazine compounds (JP-A-60-105667 and US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,221,970).

  The polymerization initiator may be added to the reaction solution before the sol-gel reaction of [2-1] or may be added after the sol-gel reaction and immediately before the reaction solution is applied. The addition amount of the polymerization initiator is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass, based on the total amount of monomers.

When the polymerizable group represented by Y ¹ and Y ² is an alkylene oxide group such as an ethylene oxide group or a trimethylene oxide group, the polymerization catalyst is a proton acid (the proton acid mentioned in [2-1] above) or a Lewis acid. (Preferably boron trifluoride (including ether complex), zinc chloride, aluminum chloride, etc.) can be preferably used. When a sol-gel reaction proton acid is used as the proton acid, it is not particularly necessary to add it for the polymerization of the polymerizable groups Y ¹ and Y ² . When adding a polymerization catalyst, it is preferable to add to a reaction liquid just before apply | coating. Usually, the polymerization proceeds in the film by heating or light irradiation after coating. As a result, the molecular orientation is fixed and the strength of the film is improved.

[2-3] Combined use with other silicon compounds In order to improve the film characteristics of the material, two or more kinds of precursors described in the above [1-1] to [1-3] may be mixed as necessary. May be used. For example, m3 or m4 in the precursor represented by the general formula (III) or (IV) is a mixture of 3 and 2, respectively, or m7 in the precursor represented by the general formula (VII) or (VIII) Alternatively, a more flexible film can be formed by mixing compounds having m8 of 3 and 2, respectively, or combining them. You may add another silicon compound to these precursors further. Examples of the other silicon compounds include organic silicon compounds represented by the following general formula (X) or polymers having these as monomers.

In the general formula (X), R ¹³ represents a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, R ¹⁴ represents a hydrogen atom, an alkyl group, an aryl group or a silyl group, and m12 is 0-4. It represents an integer, when m12 or 4-m12 is 2 or more, R ¹³ or R ¹⁴ may be the same or different. Further, they may be linked to each other by a substituent of R ¹³ or R ¹³ to form a multimer.

M12 in the general formula (X) is preferably 0 or 1, and R ¹⁴ is preferably an alkyl group. Further, examples of preferable compounds when m12 is 0 include tetramethoxysilane (TMOS), tetraethoxysilane (TEOS) and the like, and examples of preferable compounds when m12 is 1 or 2 include the following compounds. Can be mentioned.

一般式(X)で表される化合物を併用する場合、前駆体の有機ケイ素化合物に対して１〜５０モル％の範囲で用いるのが好ましく、１〜２０モル％の範囲で用いるのがより好ましい。

When the compound represented by the general formula (X) is used in combination, it is preferably used in the range of 1 to 50 mol%, more preferably in the range of 1 to 20 mol% with respect to the organosilicon compound of the precursor. .

[2-4] Film-forming method In the present invention, the support for applying the sol-gel reaction mixture is not particularly limited, but preferred examples include a glass substrate, a metal substrate, a polymer film, a reflector and the like. Can do. Examples of the polymer film include cellulose-based polymer films such as TAC (triacetyl cellulose), ester-based polymer films such as PET (polyethylene terephthalate) and PEN (polyethylene naphthalate), PTFE (polytrifluoroethylene), and the like. Fluoropolymer film, polyimide film and the like. The coating method may be a known method, for example, curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, print coating method, etc. it can.

[2-5] Addition of polymer compound The proton conductor of the present invention contains various polymer compounds for the purpose of (1) increasing the mechanical strength of the membrane and (2) increasing the acid concentration in the membrane. You may make it contain. (1) For the purpose of increasing mechanical strength, a polymer compound having a molecular weight of about 10,000 to 1,000,000 and having good compatibility with the proton conductor of the present invention is suitable. For example, perfluorinated polymer, polystyrene, polyethylene glycol, polyoxetane, poly (meth) acrylate, polyether ketone, polyether sulfone, poly and the like, and copolymers thereof are preferable, and the content is 1 to 30% by mass. The range of is preferable. (2) For the purpose of increasing the acid concentration, perfluorocarbon sulfonic acid polymer represented by Nafion, poly (meth) acrylate having a phosphate group in the side chain, sulfonated polyetheretherketone, sulfonated polyethersulfone, sulfone Polymer compounds having a ptronic acid moiety such as sulfonated products of heat-resistant aromatic polymers such as sulfonated polysulfone and sulfonated polybenzimidazole are preferred, and the content is preferably in the range of 1 to 30% by mass.

  The sol-gel reaction using the organosilicon compound precursor proceeds after applying the sol-gel reaction mixture, while the organic sites of the organosilicon compound are oriented. Various techniques can be employed to promote the orientation of the sol-gel composition. For example, the above-described support or the like can be subjected to an orientation treatment in advance. Various general methods can be adopted as the alignment treatment, but preferably a method for performing alignment treatment such as rubbing by providing a liquid crystal alignment layer such as various polyimide alignment films and polyvinyl alcohol alignment films on a support, etc. A method of applying a magnetic field or an electric field to the sol-gel composition on the support, a method of heating, or the like can be used.

  The orientation state of the organic-inorganic hybrid proton conductor can be confirmed by observing optical anisotropy with a polarizing microscope. The observation direction may be arbitrary, but it can be said that there is anisotropy if there is a portion where the light and darkness are switched by rotating the sample under crossed Nicols. The orientation state is not particularly limited as long as it exhibits anisotropy. When a texture that can be recognized as a liquid crystal phase is observed, the phase can be specified, and may be a lyotropic liquid crystal phase or a thermotropic liquid crystal phase. In the case of a lyotropic liquid crystal phase, the alignment state is preferably a hexagonal phase, a cubic phase, a lamellar phase, a sponge phase, or a micelle phase, and particularly preferably exhibits a lamellar phase or a sponge phase at room temperature. The thermotropic liquid crystal phase is preferably a nematic phase, a smectic phase, a crystal phase, a columnar phase and a cholesteric phase, and particularly preferably exhibits a smectic phase or a crystal phase at room temperature. An orientation state in which the orientation in these phases is maintained in a solid state is also preferable. The anisotropy here means a state where the direction vector of the molecule is not isotropic.

  10-500 micrometers is preferable and, as for the thickness of the organic-inorganic hybrid type proton conductor obtained by peeling from a support body, 25-100 micrometers is especially preferable.

[2-6] Filling the pore membrane The proton conductor of the present invention can be impregnated into the pores of the porous substrate to form a membrane. The sol-gel reaction solution of the present invention is applied on a substrate having pores and impregnated, or the substrate is immersed in the sol-gel reaction solution, and a proton conductor is filled in the pores to form a membrane. May be. Preferable examples of the substrate having pores include porous polypropylene, porous polytetrafluoroethylene, porous cross-linked heat-resistant polyethylene, and porous polyimide.

[2-7] Addition of catalytic metal to proton conductor An active metal catalyst that promotes the oxidation-reduction reaction between the anode fuel and the cathode fuel may be added to the proton conductor of the present invention. Thereby, the fuel which has penetrated into the proton conductor is consumed in the proton conductor without reaching the other electrode, and crossover can be prevented. The active metal species used is not limited as long as it functions as an electrode catalyst, but platinum or an alloy based on platinum is suitable.

[3] Fuel Cell [3-1] Configuration of Battery A fuel cell using the organic-inorganic hybrid proton conductor of the present invention will be described. FIG. 1 shows the structure of a fuel cell electrode membrane assembly (hereinafter referred to as “MEA”; hereinafter referred to as “Membraue and Electrode Assembly”) 10. The MEA 10 includes a proton conductor 11 and an anode electrode 12 and a cathode electrode 13 that face each other with the proton conductor 11 interposed therebetween.

The anode electrode 12 and the cathode electrode 13 are composed of porous conductive sheets (for example, carbon paper) 12a and 13a and catalyst layers 12b and 13b. The catalyst layers 12b and 13b are made of a dispersion in which carbon particles (for example, ketjen black, acetylene black, carbon nanotubes, etc.) carrying a catalyst metal such as platinum particles are dispersed in a proton conductor (eg, Nafion, etc.). In order to bring the catalyst layers 12b and 13b into close contact with the proton conductor 11, the porous conductive sheets 12a and 13a coated with the catalyst layers 12b and 13b are applied to the proton exchange membrane 11 by a hot press method (preferably 120 to 130). Pressure bonding at ² ° C. and 2 to 100 kg / cm ² ), or after applying the catalyst layers 12b and 13b coated on a suitable support to the proton conductor 11 while being transferred, the porous conductive sheet 12a, The method of sandwiching with 13a is generally used.

  FIG. 2 shows an example of a single fuel cell. The fuel cell includes an MEA 10, a pair of separators 21 and 22 that sandwich the MEA 10, and a current collector 17 and a packing 14 made of a stainless steel net attached to the separators 21 and 22. An anode pole side opening 15 is provided in the anode pole side separator 21, and a cathode pole side opening 16 is provided in the cathode pole side separator 22. Gas fuel such as hydrogen and alcohols (such as methanol) or liquid fuel such as an alcohol aqueous solution is supplied from the anode electrode side opening 15, and oxidant gas such as oxygen gas and air is supplied from the cathode electrode side opening 16. Is supplied.

[3-2] Catalyst Material A catalyst in which active metal particles such as platinum are supported on a carbon material is used for the anode electrode and the cathode electrode. The particle size of the active metal that is usually used is in the range of 2 to 10 nm. The smaller the particle size, the greater the surface area per unit mass and the greater the activity, which is advantageous. It is said that the limit is about 2 nm.

  The active polarization in the hydrogen-oxygen fuel cell is larger in the cathode electrode (air electrode) than in the anode electrode (hydrogen electrode). This is because the cathode electrode reaction (oxygen reduction) is slower than the anode electrode. For the purpose of improving the activity of the oxygen electrode, various platinum-based binary metals such as Pt—Cr, Pt—Ni, Pt—Co, Pt—Cu, and Pt—Fe can be used. In a direct methanol fuel cell using an aqueous methanol solution as an anode fuel, it is important to suppress catalyst poisoning due to CO that occurs during the oxidation process of methanol. For this purpose, platinum-based binary metals such as Pt—Ru, Pt—Fe, Pt—Ni, Pt—Co, Pt—Mo, Pt—Ru—Mo, Pt—Ru—W, Pt—Ru—Co Platinum-based ternary metals such as Pt—Ru—Fe, Pt—Ru—Ni, Pt—Ru—Cu, Pt—Ru—Sn, and Pt—Ru—Au can be used.

  As the carbon material for supporting the active metal, acetylene black, Vulcan XC-72, ketjen black, carbon nanohorn (CNH), and carbon nanotube (CNT) are preferably used.

[3-3] Structure and material of catalyst layer The function of the catalyst layer provides (1) transport of fuel to active metal, and (2) oxidation (anode) and reduction (cathode) reaction fields of the fuel. (3) transferring electrons generated by oxidation-reduction to the current collector, and (4) transporting protons generated by the reaction to the proton conductor. For (1), the catalyst layer needs to be porous so that liquid and gaseous fuel can permeate deeply. (2) is the active metal catalyst described in [3-2], and (3) is the same as the carbon material described in [3-2]. In order to fulfill the function (4), a proton conductor is mixed in the catalyst layer.

  The proton conductor of the catalyst layer is not limited as long as it is a solid having a proton donating group, but a polymer compound having an acid residue used for the proton conductor (for example, perfluorocarbon sulfonic acid represented by Nafion, Side chain phosphate group poly (meth) acrylate, sulfonated polyetheretherketone, sulfonated polybenzimidazole and other heat-resistant aromatic polymers), acid-fixed organic-inorganic hybrid proton conductor (For example, the proton conductors described in Patent Documents 1 to 8 and Non-Patent Documents 1 to 3) are preferably used. A proton conductor obtained by sol-gel reaction of a precursor used for the proton conductor of the present invention may be used for the catalyst layer. In this case, since it is the same kind of material as the proton conductor, the adhesion between the proton conductor and the catalyst layer is advantageously increased.

The amount of active metal used is suitably in the range of 0.03 to 10 mg / cm ² from the viewpoint of battery output and economy. The amount of the carbon material supporting the active metal is suitably 1 to 10 times the mass of the active metal. The amount of the proton conductor is suitably 0.1 to 0.7 times the mass of the active metal-carrying carbon.

[3-4] Porous conductive sheet (electrode substrate)
It is also called an electrode base material, a diffusion layer, or a backing material, and plays a role of collecting current and preventing water accumulation and gas diffusion from deteriorating. Usually, carbon paper or carbon cloth is used, and PTFE treatment for water repellency can also be used.

[3-5] Preparation of MEA (Electrode Membrane Complex) The following four methods are preferable for the preparation of MEA.
Proton conductor coating method: Cathode paste (ink) based on active metal-supported carbon, putron conductive material, and solvent is applied directly on both sides of the proton conductor, and a porous conductive sheet is (thermally) pressed into five layers. An MEA having a configuration is manufactured.
Porous conductive sheet coating method: A catalyst paste is applied to the surface of a porous conductive sheet to form a catalyst layer, and then pressure-bonded to a proton conductor to produce a 5-layer MEA.
Decal method: After applying a catalyst paste on PTFE to form a catalyst layer, only the catalyst layer is transferred to the proton conductor to form a three-layer MEA, and a porous conductive sheet is pressure-bonded to form a five-layer structure. An MEA is produced.
Post-catalyst loading method: After coating and forming an ink in which a platinum-unsupported carbon material is mixed with a proton conductor on a proton conductor, a porous conductive sheet or PTFE, the film is impregnated with platinum ions, A catalyst layer is formed by reducing and precipitating in the membrane. After forming the catalyst layer, the MEA is produced by the above methods (1) to (3).

[3-6] Fuel and supply method As fuel for a fuel cell using a solid polymer membrane, anode fuel may be hydrogen, alcohols (methanol, isopropanol, ethylene glycol, etc.), ethers (dimethyl ether). , Dimethoxymethane, trimethoxymethane, etc.), formic acid, borohydride complexes, ascorbic acid and the like. Examples of the cathode fuel include oxygen (including oxygen in the atmosphere) and hydrogen peroxide.

In the direct methanol fuel cell, a methanol aqueous solution having a methanol concentration of 3 to 64% by mass is used as the anode fuel. According to the anode reaction formula (CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e), 1 mol of water is required for 1 mol of methanol, and the methanol concentration at this time corresponds to 64% by mass. The higher the methanol concentration, there is an advantage that the mass and volume of the battery including the fuel tank with the same energy capacity can be reduced. However, the higher the methanol concentration, the more the so-called crossover phenomenon, in which methanol permeates the proton conductor and reacts with oxygen on the cathode side to lower the voltage, and the output decreases. The optimal concentration is determined by the nature. The cathode reaction formula of the direct methanol fuel cell is (3 / 2O ₂ + 6H ⁺ + 6e → H ₂ O), and oxygen (usually oxygen in the air) is used as the fuel.

  The methods for supplying the anode fuel and the cathode fuel to the respective catalyst layers include (1) a method of forced circulation using an auxiliary device such as a pump (active type), and (2) a method not using an auxiliary device. There are two types (for example, a passive type in the case of liquid due to capillary action or natural fall, and in the case of gas, the catalyst layer is exposed and supplied to the atmosphere), and these can be combined with the anode and cathode. is there. The former has advantages such as the ability to use high-concentration methanol as a fuel by circulating the water produced at the cathode, and the ability to increase the output by supplying air, but the fuel supply system reduces the size. There is a difficult drawback. The latter is advantageous in that it can be miniaturized, but has the disadvantage that the fuel supply tends to be rate-limiting and it is difficult to produce a high output.

[3-7] Cell Stacking Since the single cell voltage of a fuel cell is generally 1 V or less, single cells are stacked in series according to the required voltage of the load. As the stacking method, “planar stacking” in which the single cells are arranged on a plane and “bipolar stacking” in which the single cells are stacked via separators having fuel flow paths formed on both sides are used. The former is suitable for a small fuel cell because the cathode electrode (air electrode) comes out on the surface, so that air can be easily taken in and can be made thin. In addition to this, a method of applying MEMS technology, performing fine processing on a silicon wafer, and stacking has been proposed.

[4] Applications of fuel cells Fuel cells are considered to be used in various applications such as automobiles, households, and portable devices. In particular, direct methanol fuel cells can be reduced in size and weight. Taking advantage of the fact that it is unnecessary, it is expected to be used as an energy source for various portable devices and portable devices. For example, mobile devices that can be preferably applied include mobile phones, mobile notebook computers, electronic still cameras, PDAs, video cameras, portable game machines, mobile servers, wearable personal computers, and mobile displays. Examples of portable devices that can be preferably applied include portable generators, outdoor lighting devices, flashlights, and electric (assist) bicycles. Moreover, it can be preferably used as a power source for industrial or household robots or other toys. Furthermore, it is also useful as a power source for charging secondary batteries mounted on these devices.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1-1
1. Proton conductor fabrication
(1) Preparation of proton conductor (E-1-1) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich Co., Ltd.) (0 .15 g) was added and allowed to react at room temperature for 12 hours. Thereafter, V-2 (38 mg) and water (0.05 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a 120 μm thick film was obtained.

(2) Preparation of proton conductor (E-1-2) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-5 (73 mg) and water (0.11 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 110 μm was obtained.

(3) Preparation of proton conductor (E-1-3) A solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved was added to a SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-8 (86 mg) and water (0.11 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 110 μm was obtained.

(4) Preparation of proton conductor (E-1-4) A solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved was added to a SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-13 (79 mg), TEOS (50 mg) and water (0.16 ml) were added, and the mixture was heated with stirring at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 130 μm was obtained.

(5) Production of proton conductor (E-1-5) To a solution of DMF (0.5 ml) in which A-9 (0.1 g) was dissolved, SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.13 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-13 (68 mg) and water (0.09 ml) were added, and the mixture was heated with stirring at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a 120 μm thick film was obtained.

(6) Preparation of proton conductor (E-1-6) To a solution of DMF (0.5 ml) in which A-11 (0.1 g) was dissolved, SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.18 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-13 (92 mg) and water (0.13 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 110 μm was obtained.

(7) Preparation of proton conductor (E-1-7) To a solution of DMF (0.5 ml) in which A-16 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich Co., Ltd.) ( 0.11 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-14 (67 mg) and water (0.08 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a 120 μm thick film was obtained.

(8) Preparation of proton conductor (E-1-8) To a solution of DMF (1 ml) in which A-1 (0.1 g) and A-16 (0.13 g) were dissolved, an SO ₃ -DMF complex ( Aldrich (manufactured)) (0.31 g) was added and reacted at room temperature for 12 hours. Thereafter, water (0.11 ml) was added, and the mixture was heated with stirring at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 130 μm was obtained.

(9) Preparation of proton conductor (E-1-9) A-1 (0.1 g), V-13 (79 mg), and TEOS (50 mg) were dissolved in ethanol, and 2% hydrochloric acid water 50 μl at 25 ° C. Was added and stirred for 20 minutes. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 72 hours. The polyimide film was immersed in DMF (0.5 ml) in which SO3-DMF complex (Aldrich (manufactured)) (0.15 g) was dissolved, and then the coated material was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 130 μm was obtained.

(10) Preparation of proton conductor (E-1-10) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, SO ₃ -DMF complex (Aldrich (manufactured)) (0 .15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, V-13 (79 mg) and water (0.10 ml) were added, and the mixture was heated and stirred at 50 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 130 μm was obtained.

(11) Preparation of proton conductor (R-1-1) V-13 (800 mg) and TEOS (200 mg) were dissolved in ethanol, and 50 μl of 2% aqueous hydrochloric acid was added at 25 ° C. and stirred for 20 minutes. . To this solution was added an isopropanol phosphate solution (phosphoric acid (H ₃ PO ₄ , 500 mg) / isopropanol 1 ml), and the mixture was stirred at 25 ° C. for 30 minutes, and then applied onto a Teflon sheet using an applicator. After standing at room temperature for 2 hours, it was heated at 50 ° C. for 2 hours, and further heated at 80 ° C. for 3 hours. Thereafter, it was peeled off from the Teflon sheet to obtain a comparative transparent sheet-like solid (R-1-1) having a thickness of 85 μm.
(12) Preparation of proton conductor (R-1-2) SO ₃ (80 mg) was dissolved in 0.2 ml of methylene chloride in a solution of triethoxyphenylsilane (0.24 g) in methylene chloride (0.5 ml). The solution was added dropwise. After reacting at room temperature for 5 hours, the solvent was distilled off. To the obtained residue, an ethanol solution of V-13 (0.24 g) and water were added, and the mixture was stirred at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and allowed to stand for 24 hours. The solidified coated material was peeled off from the polyimide film, washed with water and dried to obtain a film having a thickness of 130 μm.

(13) Preparation of proton conductor (R-1-3) 3-Mercaptopropyltrimethoxysilane (0.19 g) and diethoxydimethylsilane (0.15 g) were dissolved in ethanol (0.5 ml) to obtain 2% Hydrochloric acid water (50 μl) was added and stirred at 50 ° C. for 3 hours. The solvent was distilled off to obtain 0.15 g of viscous oil. This oil was dissolved in methylene chloride and cooled in an ice bath. m-Chloroperbenzoic acid (0.67 g) was gradually added, and when the addition was completed, the mixture was warmed to room temperature and further stirred for 2 hours. A solid precipitated from the reaction solution, and a film could not be formed.

(14) Preparation of proton conductor (R-1-4) The following compounds were synthesized based on the references described in “Solid State Ionics”, 2001, No. 145, p.127. However, it did not become a film.

Example 1-2
(1) Preparation of proton conductor (E-2-1) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich (manufactured)) (0 .15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-13 (207 mg) and water (0.11 ml) were added, and the mixture was heated with stirring at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 120 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was composed of a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(2) Preparation of proton conductor (E-2-2) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) and S-13 (207 mg) were dissolved, an SO ₃ -DMF complex (Aldrich) (Made)) (0.15 g) was added and allowed to react at room temperature for 12 hours. Thereafter, water (0.11 ml) was added, and the mixture was heated and stirred at 60 ° C. for 3 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 120 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was composed of a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(3) Preparation of proton conductor (E-2-3) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich (manufactured)) (0 .15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-21 (235 mg) and water (0.15 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 110 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. Thus, it was found that the film was constituted by a collection of aggregates in which the mesogenic portions of S-21 were accumulated in a certain direction.

(4) Preparation of proton conductor (E-2-4) To a solution of DMF (0.5 ml) in which A-9 (0.1 g) was dissolved, SO ₃ -DMF complex (Aldrich (manufactured)) (0 .15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-13 (177 mg) and water (0.09 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 110 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was composed of a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(5) Preparation of proton conductor (E-2-5) To a solution of DMF (0.5 ml) in which A-11 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich (manufactured)) (0 .18 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-13 (240 mg) and water (0.16 ml) were added, and the mixture was heated and stirred at 50 ° C. for 3 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 130 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was constituted by a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(6) Preparation of proton conductor (E-2-6) To a solution of DMF (0.5 ml) in which A-16 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.22 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-13 (150 mg) and water (0.10 ml) were added, and the mixture was heated with stirring at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 120 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was constituted by a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(7) Preparation of proton conductor (E-2-7) A-1 (0.1 g) and S-13 (207 mg) were dissolved in ethanol, and 50 μl of 2% hydrochloric acid water was added at 25 ° C. for 20 minutes. Stir. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 72 hours. The polyimide film was immersed in DMF (0.5 ml) in which SO ₃ -DMF complex (Aldrich (manufactured)) (0.15 g) was dissolved, and then the coated material was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 130 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was constituted by a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(8) Preparation of proton conductor (E-2-8) To a solution of DMF (0.5 ml) in which A-1 (0.1 g) was dissolved, an SO ₃ -DMF complex (Aldrich (manufactured)) ( 0.15 g) was added and allowed to react for 12 hours at room temperature. Thereafter, S-25 (200 mg) and water (0.11 ml) were added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a white film having a thickness of 120 μm was obtained. A membrane was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was composed of a collection of aggregates in which the mesogenic portions of S-25 were accumulated in a certain direction.

(9) Preparation of proton conductor (E-2-9) SO ₃ -DMF complex (Aldrich) (0.053 g), A-1 (0.0347 g) and S-30 (0.15 g) were converted to DMF ( 0.75 ml) and stirred at 25 ° C. for 7 hours (this solution is referred to as SOL-1). After adding water (0.06 ml) to SOL-1, it was cast on a Teflon sheet and left at 70 ° C. for 4 hours. The solidified coating was peeled off from the Teflon sheet and washed with water. After drying, a white film having a thickness of 150 μm was obtained. Fine domains with optical anisotropy were observed with a polarizing microscope, and it was found that the film was constituted by a collection of aggregates in which mesogenic portions of S-30 were accumulated in a certain direction.
(10) Preparation of proton conductor (E-2-10)
To a solution of DMF (0.5 ml) in which A-1 (0.1 g) and S-13 (0.207 g) were dissolved, an SO ₃ -DMF complex (Aldrich) (0.15 g) was added and the mixture was heated at 80 ° C. The reaction was performed for 4 hours. Thereafter, water (0.11 ml) was added, and the mixture was stirred with heating at 60 ° C. for 4 hours. The mixture was cast on a polyimide membrane (Upilex-75S, Ube Industries, Ltd.) and left for 24 hours. The solidified coating was peeled off from the polyimide film and washed with water. After drying, a film having a thickness of 125 μm was obtained. Fine domains with optical anisotropy were confirmed by a polarizing microscope. As a result, it was found that the film was composed of a collection of aggregates in which the mesogenic portions of S-13 were accumulated in a certain direction.

(11) Preparation of proton conductor (R-2-1) V-13 (800 mg) and TEOS (200 mg) were dissolved in ethanol, 50 μl of 2% hydrochloric acid water was added at 25 ° C., and the mixture was stirred for 20 minutes. To this solution, an isopropanol phosphate solution (phosphoric acid (H ₃ PO ₄ , 500 mg) / isopropanol 1 ml) was added and stirred at 25 ° C. for 30 minutes, and then applied onto a Teflon sheet using an applicator. After standing at room temperature for 2 hours, it was heated at 50 ° C. for 2 hours, and further heated at 80 ° C. for 3 hours. Thereafter, it was peeled off from the Teflon sheet to obtain a comparative transparent sheet-like solid (R-2-1) having a thickness of 85 μm.

2. Resistance to methanol aqueous solution Proton conductors obtained (E-1-1-1 to E-1-10, E-2-1 to E-2-10), and proton conductors for comparison (R-1-1-1) Samples obtained by punching R-1-2, R-2-1) and Nafion 117 (manufactured by DuPont) into a circle having a diameter of 13 mm were each immersed in 5 ml of a 10% by mass methanol aqueous solution for 48 hours. The proton conductors of the present invention (E-1-1 to E-1-10, E-2-1 to E-2-10) show almost no swelling and change in shape and strength before immersion. I couldn't. On the other hand, the comparative samples R-1-1 and R-1-2 were cracked. In R-1-1, 85% by mass of phosphoric acid was eluted in the methanol aqueous solution. In Nafion 117, swelling of about 70% by mass was observed, and a change in the shape of the film was also observed. From the above, it has been found that the proton conductor of the present invention has sufficient resistance to a methanol aqueous solution of fuel used in a direct methanol fuel cell.

3. Measurement of methanol permeability The obtained proton conductors (E-1-1, E-1-3, E-1-4, E-1-6, E-1-8, E-1-10, E- 2-1 to E-2-10), and a proton conductor (R-1-1, R-2-1) for comparison and a sample obtained by punching Nafion 117 into a circle having a diameter of 13 mm were formed into a circular hole (diameter 5 mm) was reinforced with vacant teplon tape. The stainless steel cell shown in FIG. 3 is provided with the reinforcing membrane, a methanol aqueous solution is injected into the upper part, hydrogen gas is allowed to flow from the lower gas inlet at a constant flow rate, and the amount of methanol that permeates the membrane is connected to the lower detector. Measured by chromatography. The results are shown in Tables 1 and 2. Here, each numerical value of methanol concentration shows a relative value when the detected amount of Nafion 117 is 1.

(result)
From Table 1, it can be seen that the methanol permeability of the proton conductor of the present invention is 1/5 or less that of Nafion 117. Furthermore, it can be seen from Table 2 that the methanol permeability of the proton conductor including an organic molecular chain including a mesogenic group is 1/10 or less of that of Nafion 117.

4). Proton conductors (E-1-1-1 to E-1-10, E-2-1 to E-2-10) of the present invention obtained in Measurement 1 of ion conduction, and proton conductors for comparison (R -1-1 to R-1-2, R-2-1) and Nafion 117 are punched into a circle with a diameter of 13 mm, sandwiched between two stainless steel plates, and ionized at 25 ° C. and 95% relative humidity by the AC impedance method. Conductivity was measured. The results are shown in Tables 3 and 4.

(result)
Although the proton conductor of the present invention does not reach Nafion 117, compared to the hybrid membranes (R-1-1-1 to R-1-2, R-2-1) that do not show the optical anisotropy of the comparative example, It turns out that high ionic conductivity is shown.

Example 3
(1) Preparation of catalyst film (1-1) Preparation of catalyst film A 2 g of platinum-supported carbon (50 mass% of platinum is supported on Vulcan XC72) and 15 g of Nafion solution (5% alcohol aqueous solution) are mixed with an ultrasonic disperser. Dispersed for 30 minutes. The average particle size of the dispersion was about 500 nm. The obtained dispersion was coated on carbon paper (thickness 350 μm), dried, and then punched out into a circle having a diameter of 9 mm to prepare a catalyst film A.

(1-2) Production of catalyst membrane B Example 1-2 (9) on 300 mg of platinum / ruthenium-supported carbon (20% by mass of platinum and 20% by mass of ruthenium supported on ketjen black) moistened with 0.3 ml of water After adding SOL-1 (0.8 ml) prepared in (1), the mixture was dispersed with an ultrasonic disperser for 10 minutes. The obtained paste was applied onto carbon paper (thickness 350 μm), dried, and then punched out into a circle having a diameter of 9 mm to produce a catalyst film B.

(1-3) Preparation of catalyst film C A catalyst film C was prepared in the same manner except that the platinum / ruthenium-supported carbon in (1-2) was changed to the platinum-supported carbon used in (1-1).

(2) Production of MEA Proton conductors produced in Example 1 (E-1-3, E-1-4, E-1-6, E-1-7, E-1-8, E-2- 1, E-2-4, E-2-6, E-2-8, E-2-9) and Nafion 117 on both sides of the catalyst membrane A obtained above, and the coated surface is in contact with the proton conductor The films were laminated together and thermocompression bonded at 80 ° C., 3 Mpa for 2 minutes to prepare MEA-1-1 to 1-5, MEA-2-1 to 2-5, and MEA6. Further, the catalyst membrane B is bonded to one side of the proton conductor (E-2-9) and Nafion 117, and the catalyst membrane C is bonded to the other side, and thermocompression bonded at 80 ° C., 1 MPa for 1 minute, and MEA-2- 7 and MEA-2-8 were produced.

(3) Fuel Cell Characteristics The MEA obtained in (2) was set in the fuel cell shown in FIG. 2, and a 46 mass% methanol aqueous solution was injected into the anode side opening 15. MEA-2-7 and MEA-2-8 were set so that the catalyst film B was on the anode side and the catalyst film C was on the cathode side. At this time, the cathode side opening 16 is open to the atmosphere. A constant current of 5 mA / cm ² was applied between the anode electrode 12 and the cathode electrode 13 with a galvanostat, and the cell voltage at this time was measured. The results are shown in Tables 5 and 6.

(result)
The initial voltage of battery C 6 produced by MEA-6 using a Nafion membrane was high, but the voltage decreased over time. This voltage drop with time is due to a so-called methanol crossover phenomenon in which the methanol of fuel supplied to the anode electrode leaks to the cathode electrode through the Nafion membrane. On the other hand, the batteries 1-1 to 1-5 and 2-1 to 2-5 of the battery C produced by the MEA-1-1 to 5 and MEA-2-1 to 5 using the proton conductor of the present invention are voltage Is stable and can be maintained at a higher voltage. Furthermore, it was found that the battery C-2-7 using the same kind of proton conductor and proton conductor in the catalyst membrane was particularly excellent.

It is a schematic sectional drawing which shows the structure of the catalyst electrode joining film | membrane using the proton conductor of this invention. It is a schematic sectional drawing which shows an example of the structure of the fuel cell of this invention. The schematic of the cell made from stainless steel employ | adopted for the measurement of methanol permeability | transmittance of this invention is shown.

Explanation of symbols

10 ... Fuel cell electrode membrane composite (MEA)
DESCRIPTION OF SYMBOLS 11 ... Proton conductor 12 ... Anode electrode 12a ... Anode electrode porous conductive sheet 12b ... Anode electrode catalyst layer 13 ... Cathode electrode 13a ... Cathode electrode porous conductive sheet 13b ... Cathode electrode catalyst layer 14 ... packing 15 ... anode electrode side opening 16 ... cathode electrode side opening 17 ... current collectors 21 and 22 ... separator 31 · · · proton conductor 32 Teflon tape reinforcing material 33 Methanol aqueous solution injection part 34 Carrier gas inlet 35 Detection port (connected to gas chromatography)
36 ・ ・ ・ Rubber packing

Claims (9)

A method of subjecting at least one of the compounds represented by the following general formulas (III) and (IV) to a sulfonation reaction followed by a sol-gel reaction, or a method of subjecting a sol-gel reaction to a sulfonation reaction A compound obtained by

(In the general formulas (III) and (IV), R ³ and R ⁵ represent an alkyl group, an aryl group or a heterocyclic group, R ⁴ and R ⁶ represent a hydrogen atom, an alkyl group, an aryl group or a silyl group, m3 and m4 each represent an integer of 1 to ^3. L ³ and L ⁴ each represent a single bond or a divalent linking group, Ar ³ and Ar ⁴ represent an aryl group or hetero group having at least one electron-donating group. Represents an aryl group, an arylene group or a heteroarylene group, s3, s41, and s42 represent an integer of 1 to 4. Y ¹ represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization. Represents.)  The compound according to claim 1, wherein the electron donating group is a hydroxyl group.  The compound according to claim 1 or 2, which is obtained by a method of further adding at least one organosilicon compound having a mesogen-containing group in the sol-gel reaction. The compound according to claim 3, wherein the organosilicon compound having a group containing a mesogen is at least one of compounds represented by the following general formulas (VII) and (VIII).

(In the general formula (VII) and (VIII), A ³ and A ⁴ each represents an organic atomic group containing a mesogen, respectively R ⁹ and R ¹¹ are an alkyl group, an aryl group or a heterocyclic group, R ¹⁰ and R ¹² represents a hydrogen atom, an alkyl group, an aryl group or a silyl group, Y ² represents a polymerizable group capable of forming a carbon-carbon bond or a carbon-oxygen bond by polymerization, and m7 and m8 are each 1 to 3 S71 and s8 each represent an integer of 1 to 8, and s72 represents an integer of 1 to 4.)  The ion exchanger which has a compound of any one of Claims 1-4.  The proton conductor which has a compound of any one of Claims 1-4.  The proton conductor according to claim 6, which is in the form of a membrane.  The electrode membrane assembly which has a proton conductor of Claim 6 or 7 between the anode and the cathode.  A fuel cell comprising the electrode membrane assembly according to claim 7.

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