Solid polymer electrolyte fuel cell

Abstract

To improve the durability of a fuel cell.SOLUTION: A fuel cell 100 includes a membrane electrode assembly 115 in which electrodes are bonded to both sides of an electrolyte membrane 107, and a cerium complex containing a carrier and cerium, and the mass ratio of the carrier content to the cerium content in the cerium complex is 15 or more and 100 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polymer electrolyte fuel cell.

Background Art

[0002] In a polymer electrolyte fuel cell, the electrolyte membrane deteriorates over time due to the generation of hydrogen peroxide and radicals by side reactions. As a technique for suppressing such membrane deterioration, there is a method of using cerium ions as a radical quencher.

[0003] For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2019-50207) describes a method for producing a membrane electrode assembly for a polymer electrolyte fuel cell in which at least one of a cathode and an anode catalyst layer is formed using a liquid composition containing a liquid medium, a fluorine-containing polymer having a sulfonic acid group and a ring structure, and a specific amount of trivalent or tetravalent cerium ions with respect to the sulfonic acid group having the fluorine polymer (Claims 1, 9), and it is said that a cerium salt can be used to obtain cerium ions (Paragraph 0178). According to the production method described in the same document, it is said that a membrane electrode assembly having a catalyst layer excellent in resistance to hydrogen peroxide or peroxide radicals, having a higher output voltage, and capable of maintaining a high output voltage over a long period can be produced (Paragraph 0017).

[0004] In addition, Patent Document 2 (Japanese Patent Application Laid-Open No. 2012-79621) describes, as a technique aimed at providing a fuel cell with improved long-term durability by immobilizing a peroxide decomposition catalyst on a carrier (paragraph 0015), a membrane electrode assembly including a polymer electrolyte membrane, electrode layers disposed on both sides of the electrolyte membrane, and a gas diffusion layer disposed on the side opposite to the electrolyte membrane of the electrode layer, a gas sealant disposed around the membrane electrode assembly, and a fuel cell composed of separators sandwiching these, and describes a fuel cell including a peroxide decomposition catalyst immobilized on a carrier (Claim 1). More specifically, it is described that cerium-supported zirconium phosphate in which a specific amount of cerium is immobilized on zirconium phosphate having a specific structure is prepared and blended into a solid electrolyte membrane (Examples 1 to 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When using cerium ions derived from a cerium compound as in Patent Document 1, there was room for improvement in that the movement of cerium ions occurred during power generation of the fuel cell and the effect of the quencher decreased. In addition, in Patent Document 2, a cerium compound is immobilized on a carrier. When the present inventors studied such a technique, it was revealed that although a large amount of cerium was blended with the carrier and a large amount of cerium was used, there was still room for improvement in the durability of the fuel cell.

[0007] The present invention provides a technique for improving the durability of a fuel cell.

Means for Solving the Problems

[0008] According to the present invention, the following polymer electrolyte fuel cells and membrane electrode assemblies are provided. [1] A membrane electrode assembly in which electrodes are joined to both sides of an electrolyte membrane, A cerium composite containing a carrier and cerium, and A polymer electrolyte fuel cell, wherein a mass ratio of the content of the carrier to the content of the cerium in the cerium composite is 15 or more and 100 or less. [2] The polymer electrolyte fuel cell according to [1], wherein the cerium composite is provided on at least one of the electrodes. [3] The polymer electrolyte fuel cell according to [2], wherein a cerium content per unit area of the electrode is 2.0 μg / cm 2 or more and 10 μg / cm 2 or less. [4] The polymer electrolyte fuel cell according to any one of [1] to [3], wherein the carrier is zirconium phosphate. [5] The polymer electrolyte fuel cell according to any one of [1] to [3], wherein the carrier is at least one selected from the group consisting of zirconium phosphonate and an inclusion compound. [6] An electrode having a catalyst layer and a diffusion layer containing a catalyst and a polymer electrolyte, An electrolyte membrane, A cerium composite containing a carrier and cerium, and A membrane electrode assembly for a polymer electrolyte fuel cell, wherein a mass ratio of the content of the carrier to the content of the cerium in the cerium composite is 15 or more and 100 or less. [7] The membrane electrode assembly according to [6], wherein the cerium composite is provided on at least one of the electrodes. [8] The membrane electrode assembly according to [7], wherein a cerium content per unit area of the electrode is 2.0 μg / cm 2 or more and 10 μg / cm 2 or less. [9] The membrane electrode assembly according to any one of [6] to [8], wherein the cerium complex is provided on the electrolyte membrane.

[10] The membrane electrode assembly according to any one of [6] to [9], wherein the carrier is zirconium phosphate.

[11] The membrane electrode assembly according to any one of [6] to [9], wherein the carrier is at least one selected from the group consisting of zirconium phosphonate and an inclusion compound.

[0009] In addition, any combination of these respective configurations, and those obtained by converting the expression of the present invention between methods, apparatuses, etc. are also effective as aspects of the present invention. For example, according to the present invention, A catalyst electrode for a polymer electrolyte fuel cell, A catalyst layer containing a catalyst and a polymer electrolyte, A diffusion layer, A cerium complex containing a carrier and cerium, And having, A catalyst electrode for a fuel cell can also be provided, wherein the mass ratio of the content of the carrier to the content of the cerium in the cerium complex is 15 or more and 100 or less.

[0010] Also, according to the present invention, a method for manufacturing a polymer electrolyte fuel cell including a step of forming a membrane electrode assembly using the catalyst electrode for a fuel cell in the present invention can be provided.

Effects of the Invention

[0011] According to the present invention, the durability of the fuel cell can be improved.

Brief Description of the Drawings

[0012]

Figure 1

Modes for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described based on specific examples. Each component can be used alone or in combination of two or more. In this specification, "~" indicating a numerical range represents "above" and "below", and includes both the upper limit value and the lower limit value.

[0014] (Polymer electrolyte fuel cell)

[0015] FIG. 1 is a cross-sectional view schematically showing the configuration of the fuel cell in this embodiment. The polymer electrolyte fuel cell (fuel cell 100) shown in FIG. 1 includes a membrane electrode assembly (MEA) 115 in which electrodes (catalyst electrodes: fuel electrode 105 and oxidant electrode 113) are joined to both surfaces of an electrolyte membrane 107, and a cerium composite (not shown) containing a carrier and cerium. And the mass ratio (carrier / cerium) of the content of the carrier to the content of cerium in the cerium composite is 15 or more and 100 or less.

[0016] In this embodiment, a cerium composite containing a carrier at a specific ratio with respect to cerium is provided in the fuel cell 100. Therefore, the fuel cell 100 is excellent in durability. More specifically, according to this embodiment, cerium ions (for example, Ce 3+ ) can be continuously and efficiently released, and the movement of cerium ions in the membrane electrode assembly 115 can be effectively suppressed. Therefore, radicals (for example, OH radicals) generated during the operation of the fuel cell 100 can be continuously and stably removed, so that the deterioration of the electrolyte membrane 107 can be suppressed and the fuel cell 100 can be used for a long time.

[0017] In Patent Document 2, since cerium is incorporated into the polymer electrolyte membrane, there is still room for improvement in terms of the complexity of the membrane manufacturing method and the limitation on the size and physical properties of the membrane. On the other hand, in the fuel cell 100, since the cerium complex can be added only to the electrodes, it is also excellent in the ease of manufacturing the membrane electrode assembly 115. For example, compared with the case where the cerium complex is previously contained in the electrolyte membrane 107, the preparation of the electrolyte membrane 107 is easy, the degree of freedom in selecting the material, thickness, physical properties, etc. of the electrolyte membrane 107 to be used is also excellent, and it is also effective in suppressing the decrease in proton conductivity due to ion exchange by cerium ions. That is, in the present embodiment, the cerium complex is specifically contained in the membrane electrode assembly 115 and is preferably provided on at least one of the electrodes. Moreover, although it is desirable that the cerium complex is contained in the electrodes, from the viewpoint of more stably improving the life of the fuel cell 100, the cerium complex may preferably be contained in at least one selected from the electrolyte membrane 107 and the diffusion layer described later.

[0018] The mass ratio (carrier / cerium) in the cerium complex is 15 or more, more preferably 20 or more, from the viewpoint of improving the durability of the fuel cell 100. Moreover, from the viewpoint of uniformly mixing the catalyst and the electrolyte, the mass ratio (carrier / cerium) is 100 or less, preferably 80 or less, more preferably 60 or less.

[0019] Here, the mass ratio (carrier / cerium) in the cerium complex can be specifically measured by inductively coupled plasma (ICP) analysis or X-ray fluorescence analysis.

[0020] Moreover, the cerium content per unit area of the electrode is, for example, 1.0 μg / cm 2 or more, preferably 2.0 μg / cm 2 or more, from the viewpoint of improving the durability of the fuel cell 100. Also, from the viewpoint of maintaining proton conductivity, the cerium content per unit area of the electrode is preferably 10 μg / cm 2 or less, more preferably 8 μg / cm 2 or less, and even more preferably 7 μg / cm 2 or less.

[0021] Specifically, the cerium content per unit area of the electrode is the average value of the area concentration of cerium in the thickness direction. Also, specifically, the cerium content per unit area of the electrode can be measured by ICP analysis or fluorescence X-ray analysis (XRF). Hereinafter, the configuration of the fuel cell 100 will be described in more detail.

[0022] The fuel cell 100 includes a fuel electrode (anode) 105, an electrolyte membrane 107, an oxidant electrode (air electrode, cathode) 113, and a membrane electrode assembly 115 having the above-described cerium complex. The fuel electrode 105 includes a catalyst layer 103 and a diffusion layer 101 in this order from the side of the electrolyte membrane 107. Also, the oxidant electrode 113 includes a catalyst layer 109 and a diffusion layer 111 in this order from the side of the electrolyte membrane 107. The catalyst layer of each electrode contains a catalyst and a polymer electrolyte. On the outside of the diffusion layer 101 of the fuel electrode 105 and the diffusion layer 111 of the oxidant electrode 113, a separator 117 and a separator 119 are respectively disposed, and these separators sandwich the membrane electrode assembly 115.

[0023] The cerium complex is preferably provided on at least one of the fuel electrode 105 and the oxidant electrode 113, and may be provided on both electrodes. From the viewpoint of more effectively removing radicals, it is more preferable that the fuel electrode 105 has the cerium complex. The cerium complex may be attached to the electrode or may be immobilized. From the viewpoint of further improving the durability of the fuel cell 100, the cerium complex is preferably immobilized on the electrode.

[0024] The cerium composite is preferably provided in at least a partial region within the plane of the electrode, and from the viewpoint of further improving the durability of the fuel cell 100, it is preferably provided throughout the plane. At this time, the cerium composite may be provided at any part of the electrode, and is included in at least one of, for example, the catalyst layer and the diffusion layer. Further, for example, the electrode may have a layer containing the cerium composite between the catalyst layer and the diffusion layer.

[0025] From the viewpoint of more stably removing radicals and improving the ease of manufacturing the electrode, the cerium composite is preferably included in the catalyst layer, more preferably uniformly included within the plane of the catalyst layer, and even more preferably uniformly included throughout the catalyst layer. For example, the cerium composite may be included on the surface of the catalyst layer, and from the viewpoint of more effectively removing radicals, it is preferably included on the surface of the catalyst layer on the side of the electrolyte membrane 107. Further, the cerium composite may be dispersed in the electrolyte membrane 107.

[0026] On the other hand, the cerium composite may be included in the diffusion layer, and is, for example, uniformly included within or throughout the plane of the diffusion layer. Thereby, the effect of improving the durability by cerium ions is likely to persist.

[0027] Also, from the viewpoint of more stably removing radicals, it is also preferable that the cerium composite is provided on the electrolyte membrane 107. At this time, the cerium composite is more preferably uniformly included within the plane of the electrolyte membrane 107, and even more preferably uniformly included throughout the electrolyte membrane 107. Next, the configuration of the cerium composite will be described.

[0028] (Cerium composite) The cerium composite contains a carrier and cerium. Specifically, cerium is supported as cerium ions or a cerium compound. The cerium compound is one or more compounds selected from the group consisting of, for example, cerium salts and cerium oxide, and is preferably a cerium salt. The cerium salt may be a hydrate. Specific examples of the cerium salt include inorganic salts such as cerium carbonate, cerium chloride, cerium phosphate, cerium nitrate, cerium sulfate, cerium diammonium nitrate, and cerium tetraammonium sulfate; and one or more selected from the group consisting of organic salts such as cerium acetate (for example, cerium(III) acetate monohydrate) and cerium oxalate. From the viewpoints of reducing catalyst poisoning and removing anions, the cerium salt is preferably an organic salt, and more preferably cerium acetate.

[0029] Specifically, the carrier has a structure capable of supporting a cerium compound, and preferably has a structure capable of gradually releasing cerium ions from the viewpoint of improving the durability of the fuel cell 100. From the same viewpoint, it is preferable that the carrier can include or encapsulate the cerium compound in its structure. From the viewpoint of improving the sustained release property of cerium ions, the carrier preferably has at least one structure selected from the group consisting of a three-dimensional network structure such as a porous structure and a two-dimensional layered structure.

[0030] Specific examples of the material of the carrier include inorganic compounds such as zirconium compounds; and inclusion compounds such as calixarenes and crown ethers. Examples of the zirconium compound include one or more compounds selected from the group consisting of zirconium phosphate, zirconium phosphonate, zirconium sulfate, zirconium sulfophenylphosphonate, and zirconia. The zirconium compound may be a hydrate.

[0031] As zirconium phosphate, those of each crystal structure can be used, and specific examples include α-Zr(HPO4)2·H2O, γ-Zr(HPO4)2·H2O, and HZr2(PO4)3. From the viewpoint of improving the durability of the fuel cell 100, zirconium phosphate preferably contains HZr2(PO4)3, and more preferably contains NASICON (Na Super Ionic Conductor) type HZr2(PO4)3.

[0032] Regarding zirconium phosphonate, those of each crystal structure can also be used. Specific examples of zirconium phosphonate include Zr(O3PR)2 and Zr(O3PRPO3). In the above formula, R is an alkyl group (having 1 to 10 carbon atoms), a phenyl group, a vinyl group, a phosphonic acid group, a carboxyl group, a hydroxyl group, a cyano group, an amino group, a sulfo group, or a halogen, or a substituent containing them. A plurality of Rs may be the same or different.

[0033] From the viewpoint of more stably improving the durability of the fuel cell 100, the carrier preferably contains at least one of zirconium phosphate and zirconium phosphonate, and more preferably contains one or more selected from the group consisting of layered zirconium phosphate, NASICON-like zirconium phosphate, and layered zirconium phosphonate. From the viewpoints of durability improvement and easy availability, the carrier is preferably zirconium phosphate. On the other hand, from the viewpoint of functionality such as imparting ionic properties, the carrier is preferably at least one selected from the group consisting of zirconium phosphonate and an inclusion compound.

[0034] From the viewpoint of efficiently incorporating the cerium composite in a wide area within the plane of the electrode, the shape of the carrier is preferably powder. There is no limitation on the shape of the powder. For example, spherical, plate-like such as scaly, needle-like, and lumps containing one or more of these can be mentioned. The shape of the powder can also be selected according to the crystal structure of the carrier.

[0035] From the viewpoint of making the average particle diameter of the powder excellent in the sustained release property of cerium ions, it is preferably 0.5 μm or more, more preferably 0.8 μm or more, and still more preferably 1.0 μm or more. Also, from the viewpoint of efficiently including the cerium complex in a wide area within the plane of the electrode, the average particle diameter of the powder is preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 3 μm or less.

[0036] Here, the average particle diameter of the powder of the carrier is measured by a scanning electron microscope. For example, when the particles are substantially spherical, the average particle diameter can be obtained by measuring the diameters of any 100 particles included in the electron microscope image and obtaining the average value. For particles other than spherical ones, for example, for any 100 particles included in the electron microscope image, the diameter obtained by dividing the sum of the longest diameter and the shortest diameter by 2 can be calculated, and the average value thereof can be taken as the average particle diameter.

[0037] In the fuel cell 100, for example, the following materials are used as the diffusion layer, catalyst, and solid electrolyte of each electrode. Commercially available products may be used as these materials. As the diffusion layer 101 and the diffusion layer 111, porous materials or the like are used, and carbon materials such as carbon paper and carbon nonwoven fabric are mentioned. For the catalyst layer 103 of the fuel electrode 105 and the catalyst layer 109 of the oxidant electrode 113, for example, carbon particles supporting a catalyst metal are used. The types of catalysts for each electrode may be the same or different. Examples of the types of catalyst metals include noble metals such as platinum, gold, silver, palladium, rhodium, iridium, ruthenium, and their alloys. Examples of the material of the solid electrolyte include ionomers such as fluorine-based ionomers such as Nafion (registered trademark, the same applies hereinafter) and hydrocarbon-based ionomers.

[0038] Examples of the material of the electrolyte membrane 107 include perfluorosulfonic acid polymers such as Nafion, Flemion (registered trademark), Aciplex (registered trademark), and Dow Membrane, and hydrocarbon-based electrolyte membranes. The material of the electrolyte membrane 107 may be the same as or different from the material of the solid electrolyte contained in the electrodes.

[0039] (Manufacturing method) Also, the fuel cell 100 is manufactured, for example, by the following method. A catalyst is supported on carbon particles by a predetermined method such as an impregnation method to obtain a catalyst (catalyst support) for each electrode. The obtained catalyst and the polymer electrolyte are dispersed in a solvent, applied to the diffusion layer of each electrode, and dried to form a catalyst layer, thereby obtaining an electrode (gas diffusion electrode) used as the fuel electrode 105 and the oxidant electrode 113.

[0040] In the manufacturing process of these electrodes, a cerium complex is disposed in a predetermined region of at least one of the electrodes. When the cerium complex is contained in the electrode, the method can be selected, for example, according to the site where the cerium complex is included. For example, when the cerium complex is contained in the catalyst layer, in the above-described catalyst layer formation process, the cerium complex is dispersed in the solvent together with the catalyst and the polymer electrolyte to obtain catalyst ink, which can be applied to the diffusion layer by spray coating or the like and dried. When the cerium complex is contained on the surface of the catalyst layer or at the interface between the catalyst layer and the electrolyte membrane, for example, after the above-described catalyst layer formation process, the solvent in which the cerium complex is dispersed can be applied to the surface of the catalyst layer or the electrolyte membrane and dried. At this time, the cerium complex may be provided in layers on the surface of the catalyst layer or may be scattered on the surface of the catalyst layer. When cerium is contained in the diffusion layer, for example, the diffusion layer can be immersed in a solvent in which the cerium complex is dispersed and dried to obtain a diffusion layer containing the cerium complex. Also, a solvent containing the cerium complex may be applied to the diffusion layer by spray coating or the like. Also, when a cerium complex is contained in the electrolyte membrane, for example, a mixed solution for a coating film containing a cerium complex and a polymer electrolyte may be prepared, applied onto a substrate, dried, and then peeled off from the substrate to obtain an electrolyte membrane with a predetermined thickness.

[0041] After preparing the fuel electrode 105, the oxidant electrode 113, and the electrolyte membrane 107, the fuel electrode 105, the electrolyte membrane 107, and the oxidant electrode 113 are arranged in this order and joined by thermocompression bonding or the like to obtain a membrane electrode assembly 115. Thereafter, separators for each electrode are arranged on both sides of the membrane electrode assembly 115, and the fuel cell 100 shown in FIG. 1 is obtained.

[0042] There is no limitation on the use of the fuel cell 100 obtained in this embodiment, and examples include in-vehicle use, railway use, ship use, aircraft use, and household (such as cogeneration) use. Also, there is no limitation on the types of fuel and oxidant supplied to the fuel cell 100. As the fuel, for example, gaseous fuels such as hydrogen; liquid fuels such as methanol can be used. Also, the oxidant can be, for example, air (oxygen).

[0043] The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can also be adopted.

Example

[0044] (Examples 1 to 3, Comparative Example 1) In this example, an MEA was fabricated and evaluated by the following method.

[0045] (Synthesis method of NZP / cerium complex) 11.7 g of NASICON-type zirconium phosphate (NZP) was added with 250 mL of an aqueous cerium acetate solution, and heated at an internal temperature of 80 °C for 65 hours. The mixed solution after reflux was filtered under reduced pressure, and the obtained precipitate was washed with 150 mL of water and filtered twice. The washed precipitate was dried under reduced pressure at 90 °C for 2 hours to obtain an NZP / cerium composite. The cerium concentration of the synthesized composite was measured by X-ray fluorescence analysis (XRF). Using nickel(II) chloride hexahydrate as a standard substance, the cerium concentration was determined by the internal standard method using the nickel element. The ZP / Ce ratio, that is, the mass ratio (carrier / cerium), was calculated by (100 - cerium concentration) / cerium concentration (where the unit of cerium concentration is mass %). By changing the concentration of cerium acetate, NZP / cerium composites with different ZP / Ce ratios were synthesized. Representative examples are shown in Table 1.

[0046] (Synthesis method of ZP / cerium composite) 700 mL of an aqueous cerium acetate solution was added to 10.5 g of layered zirconium phosphate (ZP), and heated at an internal temperature of 80 °C for 70 hours. The mixed solution after reflux was filtered under reduced pressure, and the obtained precipitate was washed with 150 mL of water and filtered three times. The washed precipitate was dried under reduced pressure at 90 °C for 2 hours to obtain a ZP / cerium composite. The cerium concentration of the composite synthesized by the above method was measured by X-ray fluorescence analysis (XRF). By changing the concentration of cerium acetate, ZP / cerium composites with different ZP / Ce ratios were synthesized. Representative examples are shown in Table 1.

[0047]

Table 1

[0048] (Fabrication method of gas diffusion electrode (GDE)) After mixing the Pt catalyst, 20% Nafion dispersion, water / 1-propanol mixed solvent and the above cerium composite, pulverization and mixing were carried out using an ultrasonic pulverizer. The prepared catalyst ink was applied to and dried on the gas diffusion layer using a spray gun to fabricate a GDE. The composition of the catalyst ink and the fabricated GDE are shown in Table 2.

[0049]

Table 2

[0050] (Method for manufacturing MEA, cell assembly, and conditioning) The types of zirconium phosphate of the cerium complex, ZP / Ce ratio, Pt content, and Ce content used in each example are shown in Table 3. The Pt content and Ce content were measured by the method described below. In a fuel cell evaluation cell with an electrode area of 5 cm 2 , a cell assembly was performed by laminating a cathode GDE, a Nafion 211 membrane, and an anode GDE. The hydrogen flow rate at the anode was 139 NmL / cm 2 , and the air flow rate at the cathode was 332 NmL / cm 2 . Conditioning was performed at 0.5 V for 20 hours under the conditions of a cell temperature of 80°C and a gas humidity of 100% RH for both hydrogen and air.

[0051] (Measurement of Pt content and Ce content) The prepared GDE was measured by XRF to determine the Pt content and Ce content per unit area. Quantitative analysis was performed using a calibration curve method.

[0052] (Evaluation) (Open Circuit Voltage (OCV) test) The OCV test was carried out under the conditions of a hydrogen flow rate of 139 NmL / cm at the anode 2 , an air flow rate of 332 NmL / cm at the cathode 2 , a cell temperature of 90°C, and a gas humidity of 30% RH for both hydrogen and air. The OCV at 500 h or the time when the OCV decreased to 0.7 V in each example is shown in Table 3. Based on these results, the durability was evaluated according to the following criteria.

[0053] (Evaluation criteria for durability) The evaluation criteria are shown below. A: The OCV after 500 hours is 0.7 V or higher. B: The OCV after 500 hours is less than 0.7V, or the OCV drops to 0.7V before 500 hours.

[0054]

Table 3

[0055] From Table 3, in Examples 1 to 3, since they have a cerium composite containing a carrier at a specific ratio with respect to cerium, a fuel cell with excellent durability could be obtained.

Explanation of Reference Signs

[0056] 100 Fuel cell 101 Diffusion layer 103 Catalyst layer 105 Fuel electrode 107 Electrolyte membrane 109 Catalyst layer 111 Diffusion layer 113 Oxidant electrode 115 Membrane electrode assembly 117 Separator 119 Separator

Claims

1. A membrane electrode assembly in which electrodes are joined to both sides of an electrolyte membrane, A cerium composite containing a carrier and cerium, Comprising, A polymer electrolyte fuel cell in which the mass ratio of the content of the carrier to the content of the cerium in the cerium composite is 15 or more and 100 or less.

2. The polymer electrolyte fuel cell according to claim 1, wherein the cerium composite is provided on at least one of the electrodes.

3. The cerium content per unit area of the electrode is 2.0 μg / cm 2 or more and 10 μg / cm 2 or less. The solid polymer electrolyte fuel cell according to claim 2.

4. The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the carrier is zirconium phosphate.

5. The polymer electrolyte fuel cell according to any one of claims 1 to 3, wherein the carrier is at least one selected from the group consisting of zirconium phosphonate and an inclusion compound.

6. An electrode having a catalyst layer containing a catalyst and a polymer electrolyte and a diffusion layer, An electrolyte membrane, A cerium composite containing a carrier and cerium, Having, A membrane electrode assembly for a polymer electrolyte fuel cell in which the mass ratio of the content of the carrier to the content of the cerium in the cerium composite is 15 or more and 100 or less.

7. The membrane electrode assembly according to claim 6, wherein the cerium composite is provided on at least one of the electrodes.

8. The cerium content per unit area of the electrode is 2.0 μg / cm 2 or more and 10 μg / cm 2 or less. The membrane electrode assembly according to claim 7.

9. The membrane electrode assembly according to claim 6, wherein the cerium composite is provided on the electrolyte membrane.

10. The membrane electrode assembly according to any one of claims 6 to 9, wherein the carrier is zirconium phosphate.

11. The membrane electrode assembly according to any one of claims 6 to 9, wherein the carrier is at least one selected from the group consisting of zirconium phosphonate and an inclusion compound.

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