JP5217129B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell, and more particularly, to a fuel cell capable of improving durability.

  A fuel cell includes a membrane electrode assembly (hereinafter referred to as “MEA (Membrane Electrode Assembly)”) including an electrolyte membrane and electrodes (cathode and anode) disposed on both sides of the electrolyte membrane. Electrical energy generated by the electrochemical reaction is taken out through separators disposed on both sides of the MEA. Among fuel cells, polymer electrolyte fuel cells (hereinafter referred to as “PEFC (Polymer Electrolyte Fuel Cell)”) used in household cogeneration systems and automobiles, etc., operate at low temperatures. Is possible. In addition, PEFC has attracted attention as an optimal power source for electric vehicles and portable power sources because of its high energy conversion efficiency, short start-up time, and compact and lightweight system.

  A unit cell of PEFC includes an electrolyte membrane, a cathode and an anode including at least a catalyst layer, and a separator, and a theoretical electromotive force thereof is 1.23V. However, since such a low electromotive force is not sufficient as a power source for an electric vehicle or the like, the stack is usually configured by arranging end plates and the like at both ends in the stacking direction of a cell stack in which unit cells are stacked in series. A fuel cell of the form is used.

  On the other hand, it is becoming clear that hydrogen peroxide is generated in the MEA of the unit cell during power generation of the fuel cell, and this hydrogen peroxide serves as a starting point to degrade the electrolyte component contained in the MEA. Since such deterioration contributes to a decrease in the durability of the fuel cell, it is desired to reduce the hydrogen peroxide in the MEA to suppress the deterioration and improve the durability of the fuel cell.

Techniques aimed at improving the durability of fuel cells have been disclosed so far. For example, Patent Document 1 discloses a technology related to a fuel cell including an MEA including a metal having hydrogen peroxide decomposition performance. According to the technology, it is possible to improve the durability of the fuel cell. It will be.
US Patent Application Publication No. 2004/0043283

  However, in the technique disclosed in Patent Document 1, the metal provided in the MEA is ionized, and the ions are externally generated by water generated during power generation of the fuel cell (hereinafter referred to as “generated water”). Is discharged. Therefore, it is difficult to maintain the hydrogen peroxide decomposition performance for a long period of time, and there is a problem that it is difficult to improve the durability of the fuel cell.

  Then, this invention makes it a subject to provide the fuel cell which can improve durability.

In order to solve the above problems, the present invention takes the following means. That is,
Invention, electrolyte membranes and comprising an MEA having an electrode layer disposed on both sides of the electrolyte membrane, the MEA, the metal element and / or the metal element having a hydrogen peroxide scavenging according to claim 1 together with a compound is provided comprising, a part of the compound containing a metal element and / or the metal element having a hydrogen peroxide decomposition performance is covered by the decomposable substance can be decomposed by the hydrogen peroxide, the metal element and / Or the compound containing the metal element and the substance to be decomposed are immobilized in an electrolyte component provided in the electrolyte membrane or the electrode layer, and the substance to be decomposed does not have hydrogen peroxide decomposition ability, and wherein the degradable material der Rukoto with hydrogen peroxide prior to the electrolyte components by the fuel cell, to solve the above problems.

  Here, “hydrogen peroxide decomposing performance” means a property capable of decomposing not only hydrogen peroxide but also OH radicals and OOH radicals that may be present with the hydrogen peroxide. In addition, the “metal element having hydrogen peroxide decomposition performance” means a metal element simple substance capable of eluting metal ions having hydrogen peroxide decomposition performance (hereinafter, sometimes simply referred to as “decomposition performance”), Specific examples of the metal ions include transition metal ions and rare earth metal ions. Specific examples of a metal element simple substance and / or a compound containing the metal element simple substance (hereinafter sometimes collectively referred to as “deterioration preventing agent”) that can generate these ions include Mn, Fe, Pt, Pd, Ni, Cr, Cu, Ce, Sc, Rb, Co, Ir, Ag, Au, Rh, Ti, Zr, Al, Hf, Ta, Nb, Os and the like and a compound containing the above elements ( For example, an oxide etc. can be mentioned. Furthermore, “decomposable by hydrogen peroxide” means that it can be decomposed by OH radicals or OOH radicals that can be generated from hydrogen peroxide during operation of the fuel cell, in addition to the case where hydrogen peroxide itself can be decomposed. It is a concept that includes cases. In addition, the “decomposable substance that can be decomposed by hydrogen peroxide” means a substance that can be decomposed by hydrogen peroxide before the electrolyte component provided in the electrolyte membrane or electrode layer. Specific examples include hydrocarbon materials such as polyethersulfone (PES), polyetheretherketone (PEEK), polyparabenzophenylene (PPBP), polyethylene (PE), polyethylene terephthalate (PET), and electrode layers. Carbon materials (for example, carbon black, ketjen black, silicon carbide, etc.) that can form a carrier on which a catalyst (for example, platinum or platinum alloy containing platinum and at least one transition metal) is supported, electrodes Examples thereof include a catalyst-carrying carbon material in which the catalyst contained in the layer is carried on the carbon material.

According to a second aspect of the present invention, in the fuel cell according to the first aspect, a plurality of forms of substances to be decomposed are provided.

  Here, “a plurality of forms of substances to be decomposed” means that the substances to be decomposed to be coated with the metal element and / or the compound containing the metal element are different in composition, structure, thickness, shape, or the like. It means that it consists of a plurality of forms of substances to be decomposed, and it means that the deterioration preventing agent is coated with these substances to be decomposed.

The invention according to claim 3 is the fuel cell according to claim 2 , wherein the metal element and / or the compound containing the metal element is covered with the substance to be decomposed according to the first embodiment. The time when the performance is exhibited is different from the time when the hydrogen peroxide decomposition performance of the metal element and / or the compound containing the metal element, which is coated with the substance to be decomposed according to the second embodiment, is exhibited. It is characterized by.

The invention according to claim 4 is the fuel cell according to claim 3 , wherein the constituent material of the substance to be decomposed according to the first form is different from the constituent material of the substance to be decomposed according to the second form. It is characterized by.

The invention according to claim 5 is the fuel cell according to claim 3 or 4 , wherein the thickness of the substance to be decomposed according to the first form is different from the thickness of the substance to be decomposed according to the second form. It is characterized by.

The invention according to claim 6 is the fuel cell according to any one of claims 1 to 5 , wherein the substance to be decomposed has proton conductivity.

The invention according to claim 7 is the fuel cell according to any one of claims 1 to 5 , wherein the substance to be decomposed is a carbon material and / or a catalyst-supporting carbon material.

  Here, the “carbon material” according to the present invention is a material that can constitute a carrier on which an electrode layer catalyst (for example, platinum or a platinum alloy containing platinum and at least one transition metal) is supported. Specific examples thereof include carbon black, ketjen black, silicon carbide and the like. Furthermore, the “catalyst-supported carbon material” according to the present invention means a catalyst in which the catalyst contained in the electrode layer is supported on the carbon material.

According to the invention described in claim 1, part of the deterioration inhibitor, the decomposition material (hereinafter, sometimes described as "protective material".) Is covered by. Therefore, by immobilizing the deterioration preventing agent in the MEA through the protective material, it becomes possible to suppress the outflow of the deterioration preventing agent to the outside of the MEA, and the degradation performance of the deterioration preventing agent over a long period of time. Can be expressed. In addition, since a part of the deterioration preventing agent is coated with the substance to be decomposed, when the fuel cell of this form is operated, the decomposition performance of the deterioration preventing agent not covered with the substance to be decomposed is exerted, It becomes possible to exert the decomposition performance of the deterioration inhibitor coated with the decomposition substance. Therefore, it becomes possible to provide the fuel cell which can improve durability effectively by setting it as this form.

According to the second aspect of the present invention, there is provided a fuel cell including a deterioration preventing agent that is not covered with a substance to be decomposed and a deterioration preventing agent that is covered with each of a plurality of forms of the decomposition object. It becomes possible. Therefore, it becomes possible to provide the fuel cell which can improve durability more effectively by setting it as this form.

According to the invention described in claim 3 , the deterioration preventing agent is coated with different forms of substances to be decomposed. Therefore, the degradation performance manifestation timing of the degradation inhibitor coated with the substance to be decomposed according to the first embodiment and the degradation performance manifestation timing of the degradation inhibitor coated with the substance to be degraded according to the second configuration are provided. It becomes possible to shift. In this way, if the timing of developing the decomposition performance is shifted, the decomposition performance can be expressed over a long period of time. Therefore, according to the third aspect of the invention, it becomes easy to improve the durability of the fuel cell.

According to the fourth aspect of the present invention, the deterioration preventing agent is respectively coated with a plurality of forms of substances to be decomposed made of different constituent materials. If the constituent materials are different, it will be possible to shift the timing of the degradation performance of the degradation inhibitor coated with each of the plural forms of substances to be decomposed. It can be expressed over a long period of time.

According to the fifth aspect of the present invention, the deterioration preventing agent is coated with the substances to be decomposed having different thicknesses. If the thickness of the substance to be decomposed is different, it is possible to shift the timing of the degradation performance of the degradation inhibitor, so that it is possible to provide a fuel cell that can improve durability even with such a configuration. .

According to the sixth aspect of the present invention, the substance to be decomposed having proton conductivity is provided. Here, when the substance to be decomposed is mixed into the MEA, the power generation performance may be reduced. However, according to the invention described in claim 6 , the substance to be decomposed has proton conducting performance. Therefore, it becomes possible to suppress the fall of electric power generation performance by setting it as this form.

According to the seventh aspect of the present invention, the deterioration preventing agent is coated with the carbon material and / or the catalyst-supporting carbon material. Therefore, it is possible to delay the time when the degradation performance of the deterioration preventing agent starts to be exhibited, and it is possible to develop the degradation performance of the degradation preventing agent over a long period of time. Therefore, it becomes possible to provide the fuel cell which can improve durability by setting it as this structure. Further, the carbon material and / or the catalyst-supporting carbon material does not hinder the progress of the electrochemical reaction. Therefore, the deterioration preventing agent coated with the carbon material and / or the catalyst-supporting carbon material can be contained in the electrode layer of the anode and / or the cathode, and durability is improved by the deterioration preventing agent contained in the electrode layer. It is possible to provide a fuel cell that can be improved.

  During the operation of the fuel cell, hydrogen peroxide is generated by a side reaction of the electrochemical reaction, and the electrolyte components contained in the electrolyte membrane, catalyst layer, etc. constituting the MEA by OH radicals, OOH radicals, etc. resulting from the hydrogen peroxide Deteriorates. As a technology that can be a countermeasure against such deterioration, a fuel cell technology in which a metal and / or metal oxide capable of eluting ions having hydrogen peroxide decomposition performance is provided in the MEA has been proposed. . However, water is generated during operation of the fuel cell, and part of the water is discharged outside the fuel cell. For this reason, in the above technique in which a metal capable of eluting ions (hereinafter sometimes referred to as a “degradation inhibitor”) is simply mixed, ions are easily discharged together with the generated water, and the decomposition performance is extended over a long period of time. It is difficult to express over. On the other hand, if the above-mentioned deterioration preventing agent is immobilized in the MEA for a long period of time, it is possible to develop the decomposition performance over a long period of time and provide a fuel cell that can improve the durability. It becomes possible to do.

  The present invention has been made from such a viewpoint, and the gist thereof is that at least a part of the deterioration preventing agent is coated with a protective material (hereinafter sometimes referred to as “coating material”), and the deterioration preventing agent. It is in providing the fuel cell which can improve durability by setting it as the form which is hard to discharge | emit outside. And it is set as the fuel cell which can improve durability further by making several forms of the protective material which should coat | cover a part of degradation inhibitor.

  The fuel cell of the present invention will be specifically described below with reference to the drawings. In the following description, the unit cell may be simply referred to as “cell” and the reaction gas flow path may be simply referred to as “flow path”.

1. First Embodiment FIG. 1 is a cross-sectional view schematically showing a part of a fuel cell of the present invention according to a first embodiment. FIG. 1A schematically shows a part of a unit cell according to the first embodiment, and the horizontal direction on the paper is the stacking direction of the electrode layers. On the other hand, FIG. 1B shows an enlarged part of the MEA provided in the unit cell according to the first embodiment. On the other hand, FIG. 2 is a schematic view showing a part of the MEA in an enlarged manner when the fuel cell according to the first embodiment is operated, and the straight arrow in the figure indicates the moving direction of the generated water diffusing in the MEA. Show. Hereinafter, the fuel cell of the present invention according to the first embodiment will be described with reference to FIGS. 1 and 2 as appropriate.

  As shown in FIG. 1A, a unit cell 100 according to the first embodiment includes an electrolyte membrane 11, and an anode catalyst layer 12a and a cathode catalyst layer 13a disposed on both sides of the electrolyte membrane 11. An anode diffusion layer 12b disposed outside the anode catalyst layer 12a, a cathode diffusion layer 13b disposed outside the cathode catalyst layer 13a, and separators 6a and 6b disposed outside the anode diffusion layer 12b. I have. The laminate 15 sandwiched between the separators 6a and 6b includes an anode 12 and a cathode 13 as electrode layers, the anode 12 includes an anode catalyst layer 12a and an anode diffusion layer 12b, and the cathode 13 includes a cathode catalyst layer 13a and a cathode diffusion. Each layer 13b is provided. In the anode catalyst layer 12a and the cathode catalyst layer 13a, for example, carbon particles (hereinafter referred to as “platinum-supported carbon”) on which noble metal fine particles (for example, platinum fine particles) functioning as a catalyst for electrochemical reaction are supported. )), The anode diffusion layer 12b and the cathode diffusion layer 13b are made of, for example, carbon paper made of carbon fiber. Further, the separators 6a and 6b disposed on the outer side of the laminated body 15 are formed with reactive gas flow paths 7a, 7a,..., 7b, 7b,. , 7a,... Are supplied with a hydrogen-containing substance (hereinafter referred to as “hydrogen”), while the reaction gas flow paths 7b, 7b,. Are provided, and cooling medium flow paths 8, 8,... Are formed on the opposite surfaces.

Here, the electrolyte membrane 11, the anode catalyst layer 12 a, and the cathode catalyst layer 13 a according to the first embodiment have electrolyte components (for example, fluorine-containing ion exchange resins represented by Nafion, etc. Nafion is manufactured by DuPont, USA). (Registered trademark, which may be simply referred to as “Nafion” in the following). The electrolyte membrane 11, the anode catalyst layer 12a, and the cathode catalyst layer 13a are both undegradable with a deterioration preventing agent (for example, Ce ⁴⁺ ) and a protective material in which the deterioration preventing agent is dispersed (FIG. 1A). And a protective material (hereinafter sometimes referred to as “corrosion resistant material”) in which a deterioration inhibitor is dispersed is immobilized in the electrolyte component.

  When the fuel cell according to the first embodiment is operated, a part of hydrogen supplied from the flow paths 7a, 7a,... May pass through the electrolyte membrane 11 and reach the cathode catalyst layer 13a. A part of the air supplied from 7b, 7b,... May pass through the electrolyte membrane 11 and reach the anode catalyst layer 12a. When oxygen contained in the air is reduced on platinum and / or carbon particles of platinum-supported carbon contained in the anode catalyst layer 12a and the cathode catalyst layer 13a in the potential environment in the fuel cell, the reaction is in progress. In some cases, hydrogen peroxide may be generated, and OH radicals, OOH radicals, and the like may be generated. These radicals contribute to the deterioration of the electrolyte component provided in the MEA 14, and when the deterioration proceeds, the voltage of the fuel cell decreases and the power generation performance decreases. For this reason, it is desirable to improve the durability of the fuel cell by decomposing hydrogen peroxide which contributes to the deterioration, thereby suppressing the deterioration of the electrolyte component. Therefore, in the fuel cell according to the first embodiment, hydrogen peroxide that can be generated in the anode catalyst layer 12a and the cathode catalyst layer 13a is obtained by providing the MEA 14 with a deterioration preventing agent and a corrosion-resistant material. It decomposes and suppresses deterioration of electrolyte components.

  FIG. 1B is a cross-sectional view showing a part of the MEA according to the first embodiment in which the deterioration preventing agent and the corrosion-resistant material are dispersed, and shows an enlarged part of the electrolyte membrane provided in the MEA. Yes. As shown in the drawing, the electrolyte membrane 11 according to the first embodiment includes an electrolyte component 50, and the electrolyte component 50 includes the deterioration preventing agents 20, 20,..., And the deterioration preventing agents 20, 20,. The corrosion-resistant materials 30a, 30a,... Having the protective material 25a covering the deterioration preventing agents 20, 20,. Therefore, the hydrogen peroxide that has diffused into the electrolyte membrane 11 can be decomposed by the deterioration inhibitors 20, 20,... (See FIG. 2A). However, as described above, since water is generated during operation of the fuel cell, the deterioration inhibitors 20, 20,... Are easily discharged to the outside together with the generated water. In this way, when all the deterioration preventing agents 20, 20,... Are discharged, only the corrosion resistant materials 30a, 30a,... Are dispersed in the electrolyte component 50 (see FIG. 2B). ). Here, the corrosion resistant materials 30a, 30a,... Are produced by dispersing the deterioration preventing agents 20, 20,... In the protective materials 25a, 25a,. Does not have performance. Therefore, even if hydrogen peroxide diffuses into the electrolyte membrane 11a shown in FIG. 2B, it is difficult to effectively decompose the hydrogen peroxide. Therefore, when the fuel cell according to the first embodiment is further continuously operated, the electrolyte membrane 11a is easily attacked by OH radicals or the like.

  The electrolyte membrane 11a according to the first embodiment includes corrosion resistant materials 30a, 30a,. In this embodiment, the protective materials 25a, 25a,... Provided in the corrosion resistant materials 30a, 30a,... Are decomposed by OH radicals or the like before the electrolyte component 50. Therefore, in the electrolyte membrane 11a shown in FIG. 2 (B), the protective materials 25a, 25a,... Are decomposed by OH radicals and the like, and the deterioration preventing agents 20, 20,. It is discharged into the electrolyte component 50 (see FIG. 2C). In this way, when the form changes to the electrolyte membrane 11b including the deterioration preventing agents 20, 20,..., Hydrogen peroxide, OH radicals, and the like are removed by the deterioration preventing agents 20, 20,. It becomes possible to disassemble. That is, according to the fuel cell according to the first embodiment, unlike the conventional case, since the corrosion-resistant material is provided, it becomes possible to develop the decomposition performance over a long period of time and improve the durability. A fuel cell can be obtained.

2. Second Embodiment FIG. 3 is a cross-sectional view schematically showing a part of the fuel cell of the present invention according to a second embodiment. FIG. 3A schematically shows part of the unit cell according to the second embodiment, and the horizontal direction on the paper is the stacking direction of the electrode layers. On the other hand, FIG. 3B shows an enlarged part of the MEA provided in the unit cell according to the second embodiment. On the other hand, FIG. 4 is a schematic view showing a part of the MEA in an enlarged manner when the fuel cell according to the second embodiment is operated, and the straight arrow in the figure indicates the moving direction of the generated water diffusing in the MEA. Show. 3 and FIG. 4, the same reference numerals as those used in FIG. 1 and FIG. 2 are given to the substances and members having the same structure as the fuel cell shown in FIG. 1 and FIG. . Hereinafter, the fuel cell according to the second embodiment of the present invention will be described with reference to FIGS. 3 and 4.

  As shown in FIG. 3A, a unit cell 200 according to the second embodiment includes an electrolyte membrane 21, and an anode catalyst layer 22a and a cathode catalyst layer 23a disposed on both sides of the electrolyte membrane 21. An anode diffusion layer 12b disposed outside the anode catalyst layer 22a, a cathode diffusion layer 13b disposed outside the cathode catalyst layer 23a, and separators 6a and 6b disposed outside the anode diffusion layer 12b. I have. The laminate 25 sandwiched between the separators 6a and 6b includes an anode 22 and a cathode 23 as electrode layers. The anode 22 has an anode catalyst layer 22a and an anode diffusion layer 12b, and the cathode 23 has a cathode catalyst layer 23a and a cathode diffusion. Each layer 13b is provided. The anode catalyst layer 22a and the cathode catalyst layer 23a are provided with, for example, platinum-supporting carbon.

  Here, the electrolyte membrane 21, the anode catalyst layer 22a, and the cathode catalyst layer 23a according to the second embodiment are provided with an electrolyte component such as Nafion. The electrolyte membrane 21, the anode catalyst layer 22a, and the cathode catalyst layer 23a are provided with a deterioration preventing agent and a protective material (not shown in FIG. 3A) in which the deterioration preventing agent is dispersed. A corrosion-resistant material is fixed in the electrolyte component.

  FIG. 3B is a cross-sectional view showing a part of the MEA according to the second embodiment in which the deterioration inhibitor and the corrosion-resistant material are dispersed, and shows an enlarged part of the electrolyte membrane provided in the MEA. Yes. As illustrated, the electrolyte membrane 21 according to the second embodiment includes an electrolyte component 50. The electrolyte component 50 includes the deterioration inhibitors 20, 20,..., Corrosion resistant materials 30a, 30a,. , 30b,... Are dispersed. Here, the corrosion resistant material 30a is produced by dispersing the deterioration preventing agents 20, 20,... Into the protective material 25a, while the corrosion resistant material 30b is dispersed with the deterioration preventing agents 20, 20,. Thus, the protective material 25a and the protective material 25b are made of different materials. Hereinafter, the description will be continued assuming that the protective material 25b is more easily decomposed by OH radicals or the like than the electrolyte component 50, and the protective material 25a is more easily decomposed by OH radicals or the like than the protective material 25b.

  Hydrogen peroxide is also generated during the operation of the fuel cell according to the second embodiment, and the hydrogen peroxide can diffuse into the electrolyte membrane 21. When hydrogen peroxide diffuses into the electrolyte membrane 21 according to the second embodiment, the hydrogen peroxide is converted into the deterioration preventing agents 20, 20,... Provided in the electrolyte membrane 21 (see FIG. 4A). Is decomposed. However, as described above, since water is generated during operation of the fuel cell, the deterioration inhibitors 20, 20,... Are eventually discharged to the outside together with the generated water. In this way, when all of the deterioration inhibitors 20, 20,... Are discharged, the corrosion resistant materials 30a, 30a,... And the corrosion resistant materials 30b, 30b,. (See FIG. 4B). Here, the protective materials 25a, 25a,... Provided in the corrosion resistant materials 30a, 30a,... And the protective materials 25b, 25b,... Provided in the corrosion resistant materials 30b, 30b,. Therefore, even if hydrogen peroxide diffuses into the electrolyte membrane 21a shown in FIG. 4B, it is difficult to effectively decompose the hydrogen peroxide. Therefore, when the fuel cell according to the second embodiment is further continuously operated, the electrolyte membrane 21a is easily attacked by OH radicals and the like.

  The electrolyte membrane 21a includes corrosion resistant materials 30a, 30a,..., And the protective materials 25a, 25a,... Provided in the corrosion resistant materials 30a, 30a,. Prior to 50, it is decomposed by OH radicals or the like. Therefore, in the electrolyte membrane 21a shown in FIG. 4B, the protective materials 25a, 25a,... Are decomposed by OH radicals, etc., and the deterioration preventing agents 20, 20,. It is discharged into the electrolyte component 50 (see FIG. 4C). In this way, when the form changes to the electrolyte membrane 21b including the deterioration preventing agents 20, 20,... And the corrosion resistant materials 30b, 30b,..., The deterioration preventing agents 20, 20,. As a result, hydrogen peroxide and OH radicals are decomposed. Here, since water is generated during operation of the fuel cell, the deterioration inhibitors 20, 20,... Provided in the electrolyte membrane 21b are eventually discharged to the outside together with the generated water (see FIG. 4D). . When the deterioration inhibitors 20, 20,... Are all discharged in this way, the corrosion resistant materials 30b, 30b,... Become the electrolyte membrane 21c dispersed in the electrolyte component 50 (see FIG. 4D). .

  Here, the protective materials 25b, 25b,... Provided in the corrosion resistant materials 30b, 30b,... Have no decomposition performance, and the protective materials 25b, 25b,. Decomposed by etc. Therefore, when hydrogen peroxide, OH radicals, etc. diffuse into the electrolyte membrane 21c shown in FIG. 4D, the protective materials 25b, 25b,... Are decomposed and provided in the corrosion resistant materials 30b, 30b,. The deterioration preventing agents 20, 20,... Are released into the electrolyte component 50 (see FIG. 4E). In this way, when the form changes to the electrolyte membrane 21d including the deterioration preventing agents 20, 20,..., Hydrogen peroxide, OH radicals, and the like are removed by the deterioration preventing agents 20, 20,. It becomes possible to disassemble. That is, according to the second embodiment, by shifting the timing at which the degradation performance of the deterioration preventing agents 20, 20,... Is expressed, the degradation performance can be expressed over a long period of time. The fuel cell can further improve the durability.

3. Third Embodiment FIG. 5 is a cross-sectional view schematically showing a part of a fuel cell of the present invention according to a third embodiment. FIG. 5A schematically shows a part of a unit cell according to the third embodiment, and the horizontal direction in the drawing is the stacking direction of the electrode layers. On the other hand, FIG. 5B shows an enlarged part of the MEA provided in the unit cell according to the third embodiment. On the other hand, FIG. 6 is a schematic view showing a part of the MEA in an enlarged manner during the operation of the fuel cell according to the third embodiment, and the straight arrow in the figure indicates the direction of movement of generated water that diffuses in the MEA. Is shown. 5 and FIG. 6, the same reference numerals as those used in FIG. 3 and FIG. 4 are attached to substances and members having the same configuration as the fuel cell shown in FIG. 3 and FIG. . Hereinafter, when a carbon material and / or a catalyst-carrying carbon material is used as the substance to be decomposed, the substance to be decomposed is referred to as a “coating material”. The fuel cell according to the third embodiment of the present invention will be described below with reference to FIGS. 3 to 6 as appropriate.

As shown in FIG. 5A, a unit cell 300 according to the third embodiment includes an electrolyte membrane 21, an anode catalyst layer 32a and a cathode disposed on one side and the other side of the electrolyte membrane 21, respectively. The MEA 34 including the catalyst layer 33a, the anode diffusion layer 12b disposed outside the anode catalyst layer 32a, the cathode diffusion layer 13b disposed outside the cathode catalyst layer 33a, and the outside thereof. Separators 6a and 6b. The laminate 35 sandwiched between the separators 6a and 6b includes an anode 32 and a cathode 33 as electrode layers. The anode 32 has an anode catalyst layer 32a and an anode diffusion layer 32b, and the cathode 33 has a cathode catalyst layer 33a and a cathode diffusion. Each of the layers 33b is provided. The anode catalyst layer 32a and the cathode catalyst layer 33a include, for example, a corrosion-resistant material including a coating material made of a carbon material and a deterioration preventing agent made of CeO ₂ or the like coated with the coating material, and platinum-supported carbon (see FIG. 5 (A) are not shown).

Here, the electrolyte membrane 21, the anode catalyst layer 32a, and the cathode catalyst layer 33a provided in the unit cell 300 according to the third embodiment are provided with an electrolyte component 50 such as Nafion (FIGS. 3 and 4). FIG. 5B and FIG. 6). The electrolyte membrane 21 includes a deterioration preventing agent (for example, Ce ⁴⁺ ) and a protective material (see FIGS. 3 and 4) in which the deterioration preventing agent is dispersed. The anode catalyst layer 32a and the cathode catalyst layer 33a have corrosion resistant materials 55, 55,... Configured by covering the surfaces of the deterioration preventing agents 52, 52,. Are provided with corrosion resistant materials 56, 56,..., And platinum-supporting carbons 51, 51,. (See FIG. 6A). Hereinafter, the covering material 54 constituting the corrosion resistant material 56 is more easily decomposed (oxidized) by OH radicals or the like than the electrolyte component 50, and the covering material 53 constituting the corrosion resistant material 55 is more than the covering material 54. Are also likely to be decomposed (oxidized) by OH radicals or the like. The description of the fuel cell of the present invention according to the third embodiment using the cathode catalyst layer 33a is continued below.

  Also during the operation of the fuel cell according to the third embodiment, hydrogen peroxide is generated in the cathode catalyst layer 33a and the like. When the hydrogen peroxide is generated in the cathode catalyst layer 33a and the potential rises to a state where the covering material 53 can be decomposed by the OH radicals or the like generated due to the hydrogen peroxide, The covering material 53 is disassembled. When the covering material 53 is thus decomposed, the deterioration preventing agents 52, 52,... Covered with the covering material 53 can come into contact with hydrogen peroxide present in the cathode catalyst layer 33a, and the cathode catalyst. In the layer 33a, platinum-supported carbon 51, 51,..., Deterioration inhibitors 52, 52,..., And corrosion-resistant materials 56, 56,. )reference). When the deterioration preventing agents 52, 52,... Come into contact with hydrogen peroxide, the deterioration preventing agents 52, 52,. While the hydrogen is decomposed and the decomposition performance of the deterioration inhibitors 52, 52,... Contained in the corrosion resistant materials 55, 55,... Is expressed, the potential increase of the cathode catalyst layer 33a is prevented. After that, when the deterioration preventing agents 52, 52,... Contained in the corrosion resistant materials 55, 55,... Are discharged out of the cell 300, the decomposition performance of the deterioration preventing agents 52, 52,. When it disappears, the potential of the cathode catalyst layer 33a rises to a potential state in which the coating material 54 can be decomposed by OH radicals or the like generated due to hydrogen peroxide generated in the cathode catalyst layer 33a or the like (FIG. 6). (See (C)). After that, the covering material 54 is decomposed by OH radicals or the like, and the deterioration preventing agents 52, 52,... Covered with the covering material 54 come into contact with hydrogen peroxide present in the cathode catalyst layer 33a. A state of obtaining is obtained (see FIG. 6D). When the deterioration preventing agents 52, 52,... Covered with the covering material 54 can come into contact with hydrogen peroxide, the hydrogen peroxide in the cathode catalyst layer 33a is decomposed by the deterioration preventing agents 52, 52,. In addition, while the decomposition performance of the deterioration inhibitors 52, 52,... Contained in the corrosion resistant materials 56, 56,... Is expressed, the potential increase of the cathode catalyst layer 33a is prevented. As described above, according to the third embodiment, the electrolyte component provided in the catalyst layer is OH by the covering materials 53, 54 covering the deterioration preventing agents 52, 52,... And the deterioration preventing agents 52, 52,. The time when it begins to be damaged by radicals can be delayed. Therefore, with this configuration, the fuel cell 300 can further improve durability.

  In the above description, the form in which the deterioration preventing agent coated with two kinds of protective materials / coating materials (substances to be decomposed) made of different constituent materials is described. However, the fuel cell of the present invention is limited to this form. It may be a form in which a plurality of forms of corrosion-resistant materials are provided, each being covered with three or more forms of protective material / covering material different from each other. As described above, if a plurality of forms of corrosion-resistant materials are provided, it is easy to shift the timing for expressing the degradation performance of the deterioration preventing agent, and it is possible to develop the degradation performance for a longer period of time. In addition, a fuel cell can be provided.

  In the above description, the same deterioration preventing agent is covered with different forms of protective material / covering material (the electrolyte membranes 11 and 21 contain only the deterioration preventing agent 20 and the cathode catalyst layer 33a has Although the embodiment in which only the deterioration preventing agent 52 is contained is described, the present invention is not limited to this embodiment, and the deterioration preventing agent coated on the protective material can be of a plurality of types.

  In the fuel cells according to the second embodiment and the third embodiment, the form of the form is not particularly limited as long as there are a plurality of forms of the protective material / covering material to be coated with the deterioration preventing agent. As specific examples of different forms, in addition to the above-described form in which the constituent material of the protective material is changed, the thickness of the protective material covering the deterioration preventing agent is changed, the structure of the material constituting the protective material is changed, and the protective material is used as a covering material The crystallinity of the carbon material can be changed. Furthermore, you may change the form of a protective material by ion-exchange-grouping a part of protective material. When some of the protective materials are ion-exchanged, specific examples of the ion-exchange groups include sulfonic acid groups, phosphonic acid groups, carboxylic acid groups, and hydroxyl groups. In this way, if a protective material that is ion-exchanged is provided, the protective material is hydrophilized, so that hydrogen peroxide is attached before the protective material that is not ion-exchanged. It becomes possible to make it decompose, and it becomes possible to shift the timing of degrading performance of the degradation inhibitor. On the other hand, when the protective material is made of a resin, specific examples of the method of changing the structure of the protective material include a method of changing the structure by forming a bridging portion only in some of the protective materials. .

  The deterioration preventing agent provided in the fuel cell of the present invention is not particularly limited as long as it is a substance having hydrogen peroxide decomposition performance or a substance capable of eluting metal ions having hydrogen peroxide decomposition performance. Specific examples of Mn, Fe, Pt, Pd, Ni, Cr, Cu, Ce, Sc, Rb, Co, Ir, Ag, Au, Rh, Ti, Zr, Al, Hf, Ta, Nb, Os, etc. And a compound (for example, oxide) containing these elements.

  Further, in the present invention, the protective material / coating material (substance to be decomposed) to be coated with the deterioration preventing agent is decomposed by hydrogen peroxide or the like before the electrolyte component provided in the MEA, and the protective material is There is no particular limitation as long as it can generate power even when dispersed in a fuel cell. However, from the viewpoint of preventing discharge by generated water, it is preferably insoluble or hardly soluble in water. Specific examples of the protective material according to the present invention include a hydrocarbon material, a carbon material (for example, carbon black, ketjen black, silicon carbide, etc.), and a catalyst (for example, platinum, Examples thereof include a catalyst-supporting carbon material in which platinum and a platinum alloy containing at least one transition metal are supported on the carbon material. Specific examples of the hydrocarbon material include PES, PEEK, PPBP, PE, and PET. In the case where a hydrocarbon-based material is used as a protective material from the viewpoint of suppressing the decrease in the electrochemical reaction efficiency in the catalyst layer, the deterioration inhibitor coated with the protective material is dispersed in the electrolyte membrane. Is preferred.

  On the other hand, in the said 3rd Embodiment, although carbon material was illustrated as a coating | covering material, when degrading inhibitor is arrange | positioned in a catalyst layer, the to-be-degraded substance which can coat | cover the said degradation preventing agent is not limited to carbon material, The PES, PEEK, PPBP, PE, PET, etc. can also be used. However, from the viewpoint of making it difficult to reduce the efficiency of the electrochemical reaction in the catalyst layer, the carbon material that can be used as the catalyst carrier contained in the catalyst layer and / or the catalyst-supported carbon material is coated. It is preferable to use it as a material.

  In addition, when a carbon material is used as a coating material for covering the surface of the deterioration preventing agent, the thickness of the carbon material covering the surface of the deterioration preventing agent is not particularly limited, but before the electrolyte membrane is damaged. From the viewpoint of making the deterioration preventing agent and hydrogen peroxide in contact with each other, the thickness is preferably 1 μm or less.

Furthermore, in this invention, the manufacturing method of a fuel cell provided with a degradation inhibitor and a corrosion-resistant material is not specifically limited. As a specific example of the production method, a corrosion-resistant material provided with a deterioration preventing agent coated with a protective material and a deterioration preventing agent not covered with the protective material are prepared and prepared in advance, and these are in a liquid state. Examples of the method of manufacturing a fuel cell including the MEA by preparing an MEA including the electrolyte component after dispersing the electrolyte component into an electrolyte component including a deterioration inhibitor and a corrosion-resistant material can be given. . Here, the method for producing the corrosion-resistant material is not particularly limited.
(I) A method in which a protective material is made into a solution by means such as heating or dissolving in a solvent, a deterioration preventing agent is dispersed in the solution-protected protective material, a film is formed by a cast method, and then pulverized. ,
(II) The protective material is made into a solution by means such as heating or dissolving in a solvent, and after the deterioration inhibitor is dispersed in the solution-protected protective material, a solvent that does not dissolve the protective material is added to cause precipitation. A method of making the precipitate obtained by drying,
Etc. Specific examples of the solvent in which the protective material does not dissolve include a nonpolar solvent for the protective material having polarity.

In addition, the production method of the corrosion-resistant material provided with the deterioration preventing agent coated on the ion-exchange-protected protective material is not particularly limited. For example, by the method (I) or (II) above The produced corrosion resistant material
(I) a method for producing a corrosion-resistant material including a protective material ion-exchanged by immersion in sulfuric acid, phosphoric acid, or the like;
(Ii) a method of producing a corrosion-resistant material including an ion-exchange-based protective material by immersing in water after irradiation with light such as ultraviolet rays,
Etc.

  In the present invention, when a corrosion-resistant material is dispersed in the electrolyte component, depending on the form of the corrosion-resistant material, the proton conduction performance of the electrolyte component may be reduced, and the power generation performance of the fuel cell may be reduced. Therefore, it is preferable that at least a part of the corrosion-resistant material is a corrosion-resistant material including a sulfonated protective material from the viewpoint of suppressing the power generation performance degradation of the fuel cell of the present invention. If the protective material of such a form is provided, the sulfonic acid group of the protective material can contribute to proton conduction, and thus it is possible to suppress the power generation performance deterioration.

  In the present invention, the mass of the deterioration inhibitor dispersed in the electrolyte component is not particularly limited as long as it is a mass capable of exhibiting the above durability improvement effect. However, from the viewpoint of expressing the durability improvement effect while suppressing the proton conductivity decrease, when the mass of the electrolyte component in which the degradation inhibitor is dispersed is 100 parts by mass, the mass of the degradation inhibitor to be dispersed is The amount is preferably 10 parts by mass or less. Furthermore, in the present invention, as long as at least a part of the deterioration preventing agent is coated with a protective material, the coating ratio is not particularly limited. Specific examples of the ratio include 10% to 90%. Preferably, it is 20% to 50%.

  On the other hand, in the present invention, a corrosion-resistant material in a form in which the deterioration preventing agent is coated with the catalyst-supporting carbon material is dispersed in the electrolyte component of the catalyst layer, and is disposed on the surface of the deterioration preventing agent among the catalysts included in the catalyst layer. When the catalyst activity of the catalyst A and the catalyst B is substantially the same, the catalyst that is not disposed on the surface of the degradation inhibitor is “catalyst B”. The catalyst B is preferably 5 parts by mass or less with respect to 100 parts by mass in total. In this way, it is possible to obtain the durability improvement effect of the present invention while suppressing a decrease in power generation performance due to a decrease in the number of catalysts per unit volume. However, the catalytic activity of the catalyst A and the catalyst B is different, the catalytic activity of the catalyst A is higher than that of the catalyst B, and the power generation performance of the fuel cell does not deteriorate even if the catalyst layer contains 5 parts by mass or more of the catalyst A The catalyst layer may contain 5 parts by mass or more of the catalyst A.

  In the above description, Nafion provided with a fluorine-containing ion exchange resin is exemplified as the electrolyte component provided in the fuel cell. However, the electrolyte component provided in the electrolyte membrane and the catalyst layer according to the present invention is limited to the above components. However, a hydrocarbon ion exchange resin may be provided. Even when the MEA is provided with a hydrocarbon-based electrolyte component, the above-described effects can be obtained if the degradation inhibitor is coated with a protective material that can be decomposed by hydrogen peroxide prior to the electrolyte component. A fuel cell can be provided.

  Further, in the above description, the form in which the electrolyte membrane is provided with the deterioration preventing agent is illustrated, but the present invention is not limited to the form, and only the anode catalyst layer or the cathode catalyst layer, or the anode catalyst. It is also possible to adopt a form in which the deterioration preventing agent is provided only in the layer and the cathode catalyst layer.

  Moreover, in the said description, although the degradation inhibitor and the corrosion-resistant material were described about the form with which only MEA is provided, this invention is not limited to the said form. In consideration of the power generation performance and durability of the fuel cell, the diffusion layer and the separator surface (for example, the reaction gas flow path surface, etc.) may be provided with a deterioration preventing agent and / or a corrosion resistant material. Is possible. As described above, if a member other than the MEA is provided with the deterioration preventing agent and the corrosion-resistant material, the durability of the fuel cell can be further improved.

Furthermore, the fuel cell of the present invention is not limited to the form including the anode diffusion layer and the cathode diffusion layer illustrated in the drawings (FIGS. 1, 3, and 5), but one diffusion layer or both The form which does not have a diffusion layer may be sufficient.
In the above description, a fuel cell including a separator having a form in which reaction gas supply passages are formed on the anode side and the cathode side has been described. However, the fuel cell according to the present invention is not limited to this form. For example, a flat type separator in which no reaction gas supply path is formed may be provided on the anode side and / or the cathode side. In the case of such a fuel cell, a layer (anode diffusion layer or anode electrode layer and / or cathode diffusion layer or cathode electrode layer) to be brought into contact with the flat type separator is formed by a plating method, a foaming method, or the like. The fuel cell may be formed of stainless steel, foamed metal such as titanium or nickel, or a porous body such as sintered metal, and the reaction gas is supplied to the layer.

1. Electrolyte membrane durability test 1.1. Preparation of electrolyte membrane
After ceria was dispersed in PES in a state dissolved in a solvent such as N-Methyl-2-pyrrolidone, a film was formed by a casting method, and this film was pulverized to produce a corrosion-resistant material. Next, the fuel cell electrolyte membrane according to Example 1 was manufactured by dispersing the corrosion-resistant material and ceria in Nafion dissolved in a solvent.

  On the other hand, some of the corrosion-resistant materials were sulfonated by immersing some of the corrosion-resistant materials in sulfuric acid and separating the corrosion-resistant material from the sulfuric acid. And the electrolyte membrane for fuel cells concerning Example 2 was produced by disperse | distributing ceria, a corrosion-resistant material, and the sulfonated corrosion-resistant material in Nafion which melt | dissolved in the solvent.

  On the other hand, an electrolyte membrane for a fuel cell according to Comparative Example 1 having the same configuration as that of the electrolyte membrane except that the corrosion resistant material and ceria were not provided was produced. Using the fuel cell electrolyte membranes according to Example 1, Example 2 and Comparative Example 1 (hereinafter simply referred to as “electrolyte membranes”), the following durability tests were performed.

1.2. Durability Test Example 1 and Example were carried out by repeating (10 times) the Fenton test in which the electrolyte membranes according to Example 1, Example 2, and Comparative Example 1 were immersed in Fenton reagent containing iron ions for 60 minutes. The durability of the electrolyte membrane according to Example 2 and the electrolyte membrane according to Comparative Example 1 were evaluated. The evaluation results are shown in FIG. In FIG. 7, the vertical axis represents the fluorine ion concentration (ppm) in the Fenton reagent, and the horizontal axis represents the number of Fenton tests. The alternate long and short dash line indicates the result of Example 1, the straight line indicates the result of Example 2, and the broken line indicates the result of Comparative Example 1. In this endurance test, each electrolyte membrane was immersed in an unused Fenton reagent (a new Fenton reagent in which the electrolyte membrane was not yet immersed) in each Fenton test.

  Here, when the electrolyte component of the electrolyte membrane deteriorates, fluorine ions are eluted in the Fenton reagent. Therefore, there is a correlation between the deterioration of the electrolyte component and the fluorine ion concentration. The lower the fluorine ion concentration, the less the deterioration of the electrolyte component and the higher the durability of the fuel cell. Suggests.

  From FIG. 7, in the test using the electrolyte membrane according to Comparative Example 1, fluorine ions having a concentration of 1 ppm or more (about 3.5 ppm) were detected in the fourth Fenton test, whereas the electrolyte according to Example 1 was detected. In the test using the membrane, fluorine ions having a concentration of 1 ppm or more (about 1.5 ppm) were detected in the eighth Fenton test. Furthermore, in the test using the electrolyte membrane according to Example 2, the detected fluorine ion concentration was less than 1 ppm even after 10 Fenton tests. In the Fenton test according to Example 1, the fluorine ion concentration after the 10th time was about 4 ppm, whereas in the Fenton test according to Comparative Example 1, the fluorine ion concentration was about 18 ppm.

  From the above results, according to the electrolyte membranes of the examples (Examples 1 and 2), the concentration of the eluted fluorine ions could be suppressed to one-fourth or less of the electrolyte membrane according to Comparative Example 1. Therefore, it was confirmed that the durability of the fuel cell can be improved by adopting the configuration of the example. Moreover, in the form (Example 2) provided with a plurality of forms of corrosion resistant materials, the fluorine ion concentration was reduced as compared with the form (Example 1) provided with a single form of corrosion resistant material. Therefore, it was confirmed that a fuel cell capable of improving durability more effectively can be provided by adopting a configuration including a plurality of forms of corrosion-resistant materials. That is, according to the present invention, it has been confirmed that a fuel cell capable of improving durability can be provided.

2. Fuel cell durability test 2.1. Cell Preparation A deterioration inhibitor (CeO ₂ ) was added to carbon black (Ketjen EC, manufactured by Ketjen Black International Co., Ltd.) dispersed with ultrasound to a median diameter of 0.2 μm, and a Nafion solution (USA) The mixture was prepared by adding and kneading a 20% solution manufactured by DuPont. Here, the Nafion solution (hereinafter referred to as “electrolyte”) serves as a binder for adsorbing carbon black on CeO ₂ , and the mass ratio of CeO ₂ , carbon black, and electrolyte is CeO ₂ : carbon black: Electrolyte = 1: 1: 1. An electrolyte membrane (Nafion 112, USA) was prepared by mixing the mixture with catalyst-carrying particles in which platinum alloy particles were supported on carbon black so that the mass ratio of CeO _{2 to} platinum alloy particles was 5%. A cathode catalyst layer was prepared by spray-drying with a spray drier on one side of DuPont. On the other hand, a mixture is prepared by kneading the catalyst-supporting particles in which platinum alloy particles are supported on carbon black and a Nafion solution, and the mixture is spray-dried to the other surface of the electrolyte membrane with a spray dryer. Thus, an anode catalyst layer was prepared, and an MEA was prepared.
Thereafter, the MEA produced in the above process is sandwiched between a pair of diffusion layers made of carbon paper and thermocompression bonded to produce a laminate, and the laminate is sandwiched between a pair of carbon separators. A cell according to Example 3 was produced.

On the other hand, catalyst-supported particles in which platinum alloy particles are supported on carbon black and a Nafion solution are kneaded to prepare a mixture, and the mixture is spray-dried on one side and the other side of the electrolyte membrane with a spray dryer. Thus, a cell according to Comparative Example 2 was produced by the same process as that of the cell according to Example 3, except that the anode catalyst layer and the cathode catalyst layer were produced. Further, a cell according to Comparative Example 3 was produced by the same process as that of the cell according to Example 3 except that carbon black was not adsorbed on CeO ₂ and the surface of the deterioration preventing agent was not covered with the substance to be decomposed. did.

2.2. ON-OFF endurance test The cell according to Example 3, the cell according to Comparative Example 2, and the cell according to Comparative Example 3 were each kept at 80 ° C. and humidified so that the relative humidity was 50%. A gas was supplied to the anode of each cell, and air at 80 ° C. humidified to a relative humidity of 50% was supplied to the cathode of each cell. And the current density at the time of energization shall be 0.5 [A / cm < ² >], and it repeats the energization over 0.5 minutes and the energization stop over 0.5 minutes, and is ON-OFF with respect to each said cell A durability test was performed. The results are shown in FIG. The vertical axis of FIG. 8 is the cross leak amount [MPa], and the horizontal axis is the endurance time [h]. The longer the time until the cross leak amount starts to increase, the more the damage to the electrolyte membrane is suppressed and the endurance is. Judged to have improved. In FIG. 8, the solid line shows the result of the cell according to Example 3, the broken line shows the result of the cell according to Comparative Example 2, and the alternate long and short dash line shows the result of the cell according to Comparative Example 3.

  From FIG. 8, the cell according to Example 3 to which the deterioration preventing agent was added and the cell according to Comparative Example 3 were compared with the cell according to Comparative Example 2 to which the deterioration preventing agent was not added until the cross leak amount began to increase. Was long. Furthermore, the cell according to Example 3 in which the degradation inhibitor was coated with the substance to be decomposed had a higher cross leak amount than the cell according to Comparative Example 3 in which the degradation inhibitor was not coated with the substance to be degraded. The time was long. Therefore, in this ON-OFF durability test, it is possible to improve the durability of the fuel cell by adding a deterioration preventing agent. The durability improving effect is obtained by coating the deterioration preventing agent with a substance to be decomposed. It was confirmed that it became more prominent.

It is sectional drawing which shows roughly a part of fuel cell of this invention concerning 1st Embodiment. It is the schematic which shows a part of MEA at the time of the fuel cell operation | movement concerning 1st Embodiment. It is sectional drawing which shows roughly a part of fuel cell of this invention concerning 2nd Embodiment. It is the schematic which shows a part of MEA at the time of the fuel cell operation | movement concerning 2nd Embodiment. It is sectional drawing which shows roughly a part of fuel cell of this invention concerning 3rd Embodiment. It is the schematic which shows a part of cathode catalyst layer at the time of the fuel cell operation | movement concerning 3rd Embodiment. It is a figure which shows the result of an electrolyte membrane durability test. It is a figure which shows the result of a fuel cell durability test.

Explanation of symbols

11, 21 Electrolyte membrane 12, 22, 32 Anode (electrode layer)
13, 23, 33 Cathode (electrode layer)
14, 24, 34 MEA
20 Degradation inhibitor 25a, 25b Protective material (substance to be decomposed)
30a, 30b Corrosion-resistant material 51 Platinum-supported carbon 52 Deterioration inhibitor 53, 54 Coating material (substance to be decomposed)
55, 56 Corrosion resistant material 100, 200, 300 Fuel cell

Claims (7)

Comprising an MEA having an electrolyte membrane and electrode layers disposed on both sides of the electrolyte membrane;
The MEA is provided with a metal element having hydrogen peroxide decomposition performance and / or a compound containing the metal element,
Part of the metal element and / or said compound containing said metallic element is covered by the decomposable substance can be decomposed by the hydrogen peroxide,
The metal element and / or the compound containing the metal element and the substance to be decomposed are immobilized in an electrolyte component provided in the electrolyte membrane or the electrode layer,
Wherein the decomposition material does not have a hydrogen peroxide scavenging and characterized degradable substances der Rukoto with hydrogen peroxide to the prior electrolyte components, fuel cells. The fuel cell according to claim 1, wherein the substance to be decomposed is provided in a plurality of forms. The time when hydrogen peroxide decomposition performance of the compound containing the metal element and / or the metal element covered with the substance to be decomposed according to the first embodiment is exhibited;
The time when the hydrogen peroxide decomposition performance of the metal element and / or the compound containing the metal element is covered with the substance to be decomposed according to the second embodiment is different, The fuel cell according to claim 2 . 4. The fuel cell according to claim 3 , wherein the constituent material of the substance to be decomposed according to the first embodiment is different from the constituent material of the substance to be decomposed according to the second embodiment. Wherein the thickness of the decomposition products according to the first embodiment, the second and the thickness of the decomposition products according to the invention, wherein the different fuel cell according to claim 3 or 4. Wherein the decomposition material, and having a proton-conducting performance, fuel cell according to any one of claims 1-5. Wherein the decomposition material, carbon materials, and / or, characterized in that it is a catalyst supporting carbon material, fuel cell according to any one of claims 1-5.

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