JP2006092810A - Electrolyte material, electrolyte membrane, catalyst paste, membrane electrode assembly, and fuel cell - Google Patents

Abstract

Disclosed is an electrolyte material having excellent oxidation resistance and high performance.
SOLUTION: General formula: (XSiO _1.5 ) _n (1): {n is an integer of 6 or more; X is an alkyl group, a sulfo group, a phenyl group, a carboxy group, an alkoxy group, — (OC _m H _2m ) _p -OC _m H _{2m + 1} (m is a natural number, P is an integer of 0 or more) and a substituent in which a part of hydrogens of these substituents are replaced by an ion exchange group; And a polysiloxane compound having a structure represented by at least one molecule including one or more ion-exchange groups. The organic-inorganic hybrid compound having a silsesquioxane skeleton was found to exhibit high oxidation resistance, and the present invention was completed.
[Selection] Figure 1

Description

  The present invention relates to an electrolyte material and an electrolyte membrane, a catalyst paste, a membrane electrode assembly, and a fuel cell that employ the electrolyte material.

  An electrolyte material suitable for a fuel cell is a perfluoro-based electrolyte material. The perfluoro-based electrolyte material is represented by Nafion (trademark), and is a material generally employed in fuel cells, and is a material excellent in oxidation resistance. In the fuel cell, when protons produced at the anode reach the cathode through the electrolyte membrane during the electrode reaction process, they are oxidized by oxygen supplied to the cathode to produce water. The hydroxyl radicals may diffuse and decompose fuel cell components.

Further, due to the nature of the resin skeleton, a segment having a water repellent structure and a segment having a hydrophilic structure are mixed, and the water repellent layer and the hydrophilic layer have a phase separation structure. For this reason, the structure has a well-balanced function of water retention and gas diffusibility.
JP 2002-298855 A JP 2002-164055 A JP 2004-123794 A JP 2003-292608 A JP 2004-119242 A

  However, although perfluoro-based electrolyte material has high performance when applied to a fuel cell, it is a material synthesized through a complicated process and has a high fluorine content, so the cost is very high. It is an obstacle to the spread of batteries.

  This invention is made | formed in view of the said actual condition, and makes it the subject which should be solved to provide the electrolyte material which can exhibit high performance while being excellent in oxidation resistance. Another object to be solved is to provide an electrolyte membrane, a catalyst paste, a membrane electrode assembly, and a fuel cell that employ the electrolyte material.

In order to solve the above-mentioned problems, the present inventors have intensively studied and, as a result, completed the following invention. That is, the electrolyte material of the present invention has a general formula: (XSiO _1.5 ) _n (1): {n is an integer of 6 or more; X is an alkyl group, a sulfo group, a phenyl group, a carboxy group, an alkoxy group, — (OC _m H _2m ) _p -OC _m H _{2m + 1} (m is a natural number, P is an integer of 0 or more) and a substituent in which a part of hydrogens of these substituents are substituted with an ion exchange group; Can be selected independently from each other, and is characterized by containing a polysiloxane compound having a structure represented by at least one molecule including one or more ion-exchange groups. It is desirable that n is 8, X is a phenyl group or a sulfonated phenyl group, and the ion exchange capacity is less than 6.14 meq / g.

The other electrolyte material of the present invention that solves the above problems is represented by the general formula: (YSiO _1.5 ) _n (2): {n is an integer of 6 or more; Y is an alkyl group, a sulfo group, a phenyl group, a carboxy group , An alkoxy group, — (OC _m H _2m ) _p —OC _m H _{2m + 1} (m is a natural number, P is an integer of 0 or more) and a substituent in which a part of hydrogens of these substituents are substituted with ion exchange groups. A polysiloxane monomer having a structure represented by: Y can be independently selected from each other, and includes one or more ion-exchange groups and one or more polymerizable groups in the whole molecule} And a polymer material that can be synthesized by copolymerizing the polymerizable group included in the polysiloxane monomer and one or more additive monomers that are optionally added and have a polymerizable group that can be polymerized. It is characterized by containing. Here, the addition of the additional monomer is optional.

  As a result of searching for a material having high oxidation resistance, the present inventors focused on an organic-inorganic hybrid type compound having a silsesquioxane skeleton. It has been found that an organic-inorganic hybrid compound having a silsesquioxane skeleton exhibits high oxidation resistance. In the present specification, the “ion exchange group” is an acidic group and is a functional group that can exhibit ion exchange ability under the use conditions of the ion conductive material of the present invention. Particularly strongly acidic groups are preferred.

  And the electrolyte membrane of this invention which solves the said subject has the electrolyte material of this invention mentioned above, and the porous membrane which impregnates the electrolyte material, It is characterized by the above-mentioned. Sufficient mechanical strength is given by impregnating the above-mentioned electrolyte material in the porous membrane. The porous membrane is preferably composed of polyimide. Moreover, the catalyst paste of the present invention that solves the above-described problems includes the above-described electrolyte material of the present invention and a catalyst.

  Furthermore, the membrane electrode assembly of the present invention that solves the above problems includes an electrolyte membrane, a catalyst layer laminated on both sides of the electrolyte membrane, and a diffusion layer laminated on the opposite side of the catalyst layer to the electrolyte membrane. A membrane electrode assembly for a fuel cell, wherein the electrolyte membrane is the electrolyte membrane of the present invention described above and / or the catalyst layer is a layer formed from the catalyst paste of the present invention described above. It is characterized by. And the fuel cell of this invention which solves the said subject has this membrane electrode assembly of this invention, It is characterized by the above-mentioned.

  The electrolyte material and catalyst paste of the present invention can achieve both oxidation resistance and proton conductivity. The electrolyte membrane and membrane electrode assembly of the present invention can achieve both oxidation resistance and proton conductivity and can provide sufficient strength. The fuel cell of the present invention can achieve both high durability and performance.

(Electrolyte material)
(First embodiment)
The electrolyte material of this embodiment is characterized in that it contains a polysiloxane compound and other materials mixed as necessary.

The polysiloxane compound is a compound having a structure represented by the general formula (1). The polysiloxane compound represented by the general formula (1) is a compound in which n repeating units represented by (XSiO _1.5 ) are bonded. In other words, as an ideal chemical structure, of the four covalent bonds of a silicon atom, three are bonded to other silicon atoms through oxygen atoms, and the functional group represented by X is bonded to the remaining one. Depending on the bonding mode between silicon atoms, various structures can be adopted.

As a skeleton of the polysiloxane compound represented by the general formula (1), a random structure that does not show a clear regularity in the bond between silicon atoms, or a ladder structure that can be represented by a compound represented by the following general formula (3) And a fully condensed cage structure and an incompletely condensed cage structure which can be represented by the compound (T ³ ₈ ) represented by the general formula (4). Incompletely condensed cage structures include structures in which the bonds between some silicon atoms in the fully condensed cage structure are hydrolyzed (general formula (4): T ³ ₆ T ² ₂ ), and some silicon atoms are missing. The structure (general formula (5): T ³ ₄ T ² ₃ ) can be illustrated.

  Although it is considered that the incomplete condensation cage structure does not strictly apply to the polysiloxane compound represented by the general formula (1), such a structural defect is within the assumption. That is, in general formula (1), as described above, three of the four covalent bonds of each silicon atom are bonded to another silicon atom via an oxygen atom, and the remaining one is bonded to X. This is because the chemical structure represented by the general formula is often not valid as it is for the structure of the boundary portion such as the terminal portion of the polymer in general. This also applies to the polysiloxane monomer represented by the general formula (2) described later.

X is an alkyl group, a sulfo group, a phenyl group, a carboxy group, an alkoxy _{group, - (OC m H 2m)} p -OC m H 2m + 1 (m is a natural number, P is an integer of 0 or more) of as well as their substituent one Partial hydrogen is arbitrarily selected from substituents substituted with ion exchange groups. X can be selected independently from each other, and contains at least one ion exchange group in the whole molecule. Examples of the ion exchange group include a sulfo group, a carboxy group, and a phosphate group, and a strongly acidic sulfo group is particularly preferable. The amount of ion exchange groups introduced is preferably large from the viewpoint of improving proton conductivity, and is preferably small from the viewpoint of the stability (solubility in water, etc.) of the electrolyte material. For example, when the ion exchange group is a sulfo group, the average value of the introduction amount of the ion exchange group is preferably about 0.125 to 1.625 per silicon atom.

  Further, based on the ion exchange capacity, 0.8 meq / g or more and 6.2 meq / g or less is preferable. In particular, when n in the general formula (1) is 8, and X is a phenyl group or a sulfonated phenyl group, the ion exchange capacity is preferably less than 6.14 meq / g. As the upper limit of the ion exchange capacity when n in the general formula (1) is 8, and X is a phenyl group or a sulfonated phenyl group, it is further 5.5 meq / g or less, 5.0 meq / g or less, 4 A value such as 0.5 meq / g or less, 4.0 meq / g or less, 3.9 meq / g or less can be adopted as a preferable value. As the lower limit, a value such as 1.0 meq / g or more and more than 1.17 meq / g can be adopted as a preferable value. The combination of the upper limit value and the lower limit value is arbitrary.

Specific examples of polysiloxane compounds include C ₄₈ H ₄₀ O ₁₂ Si ₈ (compounds in which X in the general formulas (1) and (4) are all phenyl groups and n is 8), and X (phenyl group) And a compound obtained by sulfonation of a part thereof, or C ₇₂ H ₆₀ O ₁₈ Si ₁₂ (a compound in which X in the general formulas (1) and (4) is all a phenyl group and n is 12), And a compound obtained by sulfonating a part of). Both are polysiloxane compounds having a fully condensed cage structure.

The manufacturing method of the polysiloxane compound of General formula (1) is not specifically limited. For example, it can be synthesized by mixing a trifunctional silane (SiX (OH) ₃ ) having a corresponding X functional group and performing a dehydration reaction. A conventional method can be adopted for introducing the functional group of X into silane.

  Furthermore, in addition to the polysiloxane compound represented by the general formula (1), the electrolyte material of the present embodiment can contain other electrolyte materials as materials to be mixed as necessary. For example, perfluoro-based electrolyte materials (such as Nafion), hydrocarbon-based electrolyte materials (including those in which some hydrogen atoms are replaced by fluorine, eg, polystyrene having a sulfo group introduced), and other inorganic electrolytes Materials (heteropoly acids such as silicotungstic acid) and the like. These other electrolyte materials are preferably uniformly dispersed and mixed with the polysiloxane compound represented by the general formula (1).

(Second Embodiment)
The electrolyte material of the present embodiment is characterized by containing a polymer material and other materials mixed as necessary.

  The polymer material is obtained by copolymerizing a polysiloxane monomer and one or more additive monomers optionally added having a polymerizable group and a polymerizable group included in the polysiloxane monomer. It contains a polymeric material that can be synthesized by

The polysiloxane monomer is a compound having a structure represented by the general formula (2). The polysiloxane compound represented by the general formula (2) is a compound in which n repeating units represented by (YSiO _1.5 ) are bonded. This structure is substantially the same as the polysiloxane compound {(XSiO _1.5 ) _n } represented by the general formula (1) except that Y has a polymerizable group in at least one of them. Therefore, further explanation is omitted. As a result of forming a polymer, the stability to water can be improved regardless of the amount of ion exchange groups introduced into the polysiloxane skeleton portion in the general formula (2). In particular, the stability to water can be greatly improved by adopting a three-dimensional network structure or the like by selecting an additive monomer described later.

  Usual functional groups such as vinyl group, carboxy group, and OH group can be selected as the polymerizing group. When a vinyl group is employed, radical polymerization or the like can be performed, and carboxy or OH group can be polymerized by adding phosgene, diisocyanate, or the like. Two or more polysiloxane monomer units represented by the general formula (2) are introduced per carboxyl group or OH group. For example, the electrolyte material of this embodiment has a chemical structure represented by the general formula (7).

As described above, the additive monomer adjusts the stability of the electrolyte material of the present embodiment with respect to water, adjusts the hydrophobic-hydrophilic balance of the electrolyte material, and improves physical properties. Selected for purpose and added. The additive monomer is a compound in which a polymerizable group corresponding to the polymerizable group of the polysiloxane monomer is introduced. When the polysiloxane monomer has a vinyl group, vinyl monomers such as styrene and divinylbenzene can be exemplified. When the polymerizable group is an OH group or a carboxy group, glycol, divalent phenol, or dicarboxylic acid is used. Etc. The added monomer forms a polymer together with the polysiloxane monomer by random copolymerization or block copolymerization. For example, when the additive monomer (CH ₂ = CHZ) is included, the electrolyte material of this embodiment has a chemical structure represented by the general formula (8).

(Electrolyte membrane)
The electrolyte membrane of this embodiment has an electrolyte material and a porous membrane. Since the electrolyte material of the present embodiment described above can be employed as it is as the electrolyte material, further explanation is omitted here.

  The porous film is a thin film having a large number of pores communicating with the front and back surfaces of the film. The pores are impregnated with an electrolyte material. The porosity of the porous membrane is preferably high from the viewpoint of proton conductivity. Further, from the viewpoint of the strength of the film, it is preferable to limit it to a value below to some extent. For example, the porosity of the porous film is preferably about 20% to 90%, and more preferably about 40% to 70%.

  The porous membrane is preferably composed of a polymer material regardless of organic or inorganic. As the polymer material, a material having high chemical and physical stability under the environment in the fuel cell is desirable. For example, organic polymer materials such as engineering plastics (polyimide, fluororesin, etc.), polyolefins (polyethylene, polypropylene, etc.), carbon materials (carbon paper, porous carbon, etc.), ceramic materials (glass, alumina, etc.) may be adopted. it can. In particular, it is preferable to employ an organic polymer material (such as polyimide) having excellent film strength and high flexibility.

  As a method for forming holes in these materials, conventional methods can be employed. For example, a method of stretching a film without pores (polymer material, etc.), a method of forming a non-woven fabric or woven fabric after making it into a fiber (polymer material, carbon material, ceramic material, etc.), kneading fine powder that can be dissolved and removed, etc. Examples thereof include a method of forming a film after dispersion and dissolving and removing fine powder (polymer material, carbon material, ceramic material, etc.), a mechanical method, and the like.

  The electrolyte material is preferably a solid material. The solid electrolyte material is impregnated into the pores by permeating or press-fitting into the porous membrane in a state melted by heating or dissolved in a solvent, and then the liquid electrolyte material is cooled or dried. Thus, a stable film can be formed by returning to a solid state.

(Catalyst paste and membrane electrode assembly)
The catalyst paste of this embodiment has an electrolyte material and a catalyst. The catalyst paste preferably contains an appropriate solvent. A catalyst layer can be formed by applying this catalyst paste to an electrolyte membrane or a diffusion layer. Since the electrolyte material of the present embodiment described above can be employed as it is as the electrolyte material, further explanation is omitted here. The catalyst is generally used as a catalyst-supported powder in which a catalyst is supported on a supported powder. As the catalyst, platinum or a noble metal catalyst obtained by alloying platinum with another element (ruthenium, palladium, etc.) is used. Carbon powder or the like is used as the support powder. Platinum-supported carbon using carbon powder as the support powder and platinum as the catalyst is widely used. Platinum of the platinum-supporting carbon may be alloyed with other elements, or may be used by mixing with other elements. The catalyst itself may be used as a powder without using the supported powder.

  The membrane electrode assembly of this embodiment has an electrolyte membrane, a catalyst layer, and a diffusion layer. Here, the electrolyte membrane is a member that mainly exhibits proton conductivity in the film thickness direction, the catalyst layer is a member that catalyzes the oxidation-reduction reaction, and the diffusion layer is permeable to gases such as fuel gas and air and moisture. It is a member that has excellent properties and can also exhibit electrical and thermal conductivity. The diffusion layer is known to be composed of surface-treated carbon paper or the like. The catalyst layer can be formed by applying a catalyst paste on the surface of the electrolyte membrane and / or the diffusion layer. The membrane electrode assembly employs the electrolyte membrane of the present embodiment for the electrolyte membrane and / or a layer formed from the catalyst paste of the present embodiment for the catalyst layer.

(Fuel cell)
The fuel cell of this embodiment is a solid polymer electrolyte fuel cell. As the fuel cell of this embodiment, a fuel cell is used alone or a stack in which a plurality of layers are stacked is formed. The fuel cell has the membrane electrode assembly of the present embodiment described above, and the membrane electrode assembly is sandwiched between separators.

  The separator can be of a generally used material and form. A flow path through which the fuel gas or oxidant gas flows is formed in the separator, and a gas supply device is connected to the separator.

(Synthesis Examples 1-5)
C ₄₈ H ₄₀ O ₁₂ Si ₈ : (C ₆ H ₅ SiO _1.5 ) ₈ (octaphenyl POSS (poly oligomeric silsesquioxane), manufactured by Aldrich, product number 52,682-7) 7 g (Synthesis Examples 1, 2 4 and 5) or C ₇₂ H ₆₀ O ₁₈ Si ₁₂ : (C ₆ H ₅ SiO _1.5 ) ₁₂ (Dodecaphenyl POSS, manufactured by Aldrich, product number 54,420-5) 7 g (Synthesis Example 3) in 150 mL of 1,2-dichloroethane The dispersed and suspended solution was heated to 60 ° C. with stirring, and after adding an amount of chlorosulfonic acid shown in Table 1, the solution was heated at 60 ° C. for 2 hours.

  Thereafter, the precipitate formed by allowing to cool to room temperature is collected by filtration, washed with 1,2-dichloroethane and vacuum-dried, whereby the polysiloxane compound represented by the general formula (1) (X is phenyl ( Partially sulfonated); n was 8 in Synthesis Examples 1, 2, 3, and 5 and 12) in Synthesis Example 3. The product has ion exchange capacities of Synthesis Example 1: 3.88 meq / g, Synthesis Example 2: 2.11 meq / g, Synthesis Example 3:. The results were 75 meq / g, Synthesis Example 4: 6.14 meq / g, and Synthesis Example 5: 1.17 meq / g.

  The ion exchange capacity was measured by the following method. First, after replacing the ion exchange group with the H type for the test sample, 0.05 g of the evaluation sample was weighed with a precision balance in a 100 ml beaker and dissolved in 20 mL of ethanol.

  One drop of phenolphthalein as an indicator was dropped into the solution and titrated with a 0.05 mol / L sodium hydroxide aqueous solution. The end point of the titration was the time when the state of the dissolved solution turned red was held for several seconds. The ion exchange capacity was calculated from the titration of the aqueous sodium hydroxide solution using the following formula.

  (Ion exchange capacity) (meq / g) = (0.05 × Titration volume (ml)) / (Dry mass of dissolved test sample (g))

(Synthesis Example 6)
Under a nitrogen atmosphere, a solution of 0.2 g of benzoyl peroxide dissolved in 200 mL of styrene was added dropwise to 200 mL of xylene heated to 90 ° C. with stirring for 3 hours. After completion of dropping, the mixture was further maintained at 90 ° C. for 1 hour. Next, the solution is cooled to room temperature, this solution is dropped into a large amount of methanol, and the resulting precipitate is purified by filtration, dried at 110 ° C. for 3 hours, and dried powdery hydrocarbon polymer (styrene heavy polymer). Combined) was obtained.

  It was Mw115000 when the molecular weight of this styrene polymer was measured by GPC (gel permeation chromatography). A solution prepared by dissolving 150 g of this styrene polymer in 500 mL of 1,2-dichloroethane was dropwise added with 30 mL of chlorosulfonic acid while heating and stirring at 60 ° C., and further maintained at 60 ° C. for 1 hour. The chlorosulfonated styrene polymer obtained here was washed with 1,2-dichloroethane and ion exchange water, and then immersed in ion exchange water at room temperature for 1 hour to hydrogenate the sulfo group. Thereafter, a powdered sulfonated styrene polymer was obtained by vacuum freeze-drying. The ion exchange capacity was 3.92 meq / g.

(Manufacture of electrolyte membrane)
A solution obtained by dissolving the polysiloxane compounds of Synthesis Examples 1 to 6 in dimethylformamide at a concentration of 10% by mass was impregnated into a porous polyimide film having a film thickness of 40 μm and a porosity of 60%, and was heated and dried at 90 ° C. for 1 hour. The test sample of each test example which is an electrolyte membrane dried by vacuum-drying the membrane was obtained. Table 2 shows the film thickness after drying and the amount of electrolyte material impregnated. The film thickness was adjusted to about 50 μm in a dry state, and the impregnation amount was adjusted to about 100% by dry mass with respect to the porous polyimide film. The properties of the obtained electrolyte membrane are also shown in Table 2. Proton conductivity was measured by the AC impedance method.

(Evaluation of oxidation resistance)
About the electrolyte membrane of each test example, oxidation resistance was evaluated by the Fenton test. The Fenton test was carried out by maintaining an aqueous solution containing 2 ppm of Fe ²⁺ and 3% hydrogen peroxide at 60 ° C., and measuring the mass change when the electrolyte membrane was immersed therein. Here, the higher the oxidation resistance, the smaller the mass change in the Fenton test.

  The results are shown in FIG. As is clear from FIG. 1, it was found that the oxidation resistance of the electrolyte membrane was improved as the ion exchange capacity of the impregnated electrolyte material decreased. It is expected that this is due to the fact that ion exchange groups can be the starting point of radical attack, and that the increase in ion exchange capacity has led to an increase in water solubility, resulting in insufficient form stability. The

(Manufacture of catalyst paste)
20 g of platinum-supporting carbon containing platinum as a catalyst (platinum supporting amount 50 mass%) was added to 50 g of a 10 mass% solution of the electrolyte materials of Synthesis Examples 1 to 6 to form a slurry. Thereafter, 60 g of ion-exchanged water and 60 g of ethanol were added and mixed and dispersed until the particle size of the platinum-supporting carbon became 1.0 μm or less. Final mixing and dispersion were performed with a high-speed homogenizer to obtain catalyst pastes of the respective test examples.

(Manufacture of membrane electrode assembly)
The catalyst paste of each test example was coated on a water-repellent treated carbon paper (thickness 180 μm, porosity 65%) as a gas diffusion base material (diffusion layer) with a bar coater so that the amount of platinum supported was 1 mg / cm ^2. did. After coating, heating and drying were performed at 80 ° C. for 30 minutes to obtain an electrode film on which a catalyst layer was formed. The corresponding electrolyte membrane of each test example was sandwiched between two electrode membranes arranged so as to be in contact with each other on the catalyst layer side, and then joined by hot pressing at 170 ° C. and 8 MPa for 3 minutes. A joined body was obtained.

(Evaluation of battery performance)
The membrane electrode assembly of each test example was incorporated into a single cell for fuel cell evaluation and evaluated. Evaluation was made by measuring the change in output voltage when the current density was changed. The evaluation (operation) conditions of the single cell for fuel cell evaluation are electrode area 9 cm ² , cell internal temperature 75 ° C., supplied gas is pure hydrogen corresponding to 90% utilization on the anode side, and 40% utilization on the cathode side. The corresponding air. As the humidification amount for the gas, 0.2 mol of water was used in a molar ratio with respect to 1 mol of each gas.

  The results are shown in FIG. As is clear from FIG. 2, it was found that the battery performance was improved as the proton conductivity of the electrolyte membrane increased.

  Moreover, when the results of Test Examples 1 and 3 were compared, no significant difference was observed between them. Since there was no great difference in the above-mentioned oxidation resistance value, the fluctuation of the value of n in the general formula (1) has a great influence on the battery performance (output characteristics, oxidation resistance) at least about 8-12. I found that there was no.

It is the graph which showed the oxidation resistance of each test sample in an Example. It is the graph which showed the IV characteristic of the fuel cell using each test sample in an Example.

Claims (11)

General formula: (XSiO _1.5 ) _n (1)
{N is an integer of 6 or more; X is an alkyl group, a sulfo group, a phenyl group, a carboxy group, an alkoxy group, — (OC _m H _2m ) _p —OC _m H _{2m + 1} (m is a natural number, P is 0 or more An integer) as well as a substituent in which part of hydrogen of these substituents is optionally substituted with an ion exchange group; X can be selected independently of each other and contains at least one ion exchange group in the whole molecule }
An electrolyte material comprising a polysiloxane compound having a structure represented by:   The electrolyte material according to claim 1, wherein n is 8, X is a phenyl group or a sulfonated phenyl group, and an ion exchange capacity is less than 6.14 meq / g. General formula: (YSiO _1.5 ) _n (2)
{N is an integer of 6 or more; Y is an alkyl group, a sulfo group, a phenyl group, a carboxy group, an alkoxy group, — (OC _m H _2m ) _p —OC _m H _{2m + 1} (m is a natural number, P is 0 or more Integer) as well as those substituents in which part of the hydrogens are substituted with ion exchange groups; Y can be selected independently of each other, contains one or more ion exchange groups and contains one or more Contains polymerizable group throughout molecule}
A polysiloxane monomer having a structure represented by:
Contains a polymer material that can be synthesized by copolymerizing the polymerizable group provided in the polysiloxane monomer and one or more additive monomers that are optionally added and have a polymerizable group. An electrolyte material characterized by that.   The electrolyte material according to claim 1, wherein the polysiloxane skeleton of the compound represented by the general formula (1) or (2) has a fully condensed cage structure or an incompletely condensed cage structure.   The electrolyte material according to claim 1, wherein the ion exchange group is a sulfo group.   The electrolyte material according to claim 1, wherein the electrolyte material is dispersed and mixed with another type of electrolyte material. The electrolyte material according to any one of claims 1 to 6,
An electrolyte membrane comprising a porous membrane impregnated with the electrolyte material.   The electrolyte membrane according to claim 7, wherein the porous membrane is made of polyimide.   A catalyst paste comprising the electrolyte material according to claim 1 and a catalyst. A membrane electrode assembly for a fuel cell, comprising an electrolyte membrane, a catalyst layer laminated on both sides of the electrolyte membrane, and a diffusion layer laminated on the catalyst layer opposite to the electrolyte membrane,
The membrane electrode assembly, wherein the electrolyte membrane is the electrolyte membrane according to claim 7 and / or the catalyst layer is a layer formed from the catalyst paste according to claim 9.   A fuel cell comprising the membrane electrode assembly according to claim 10.

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