KR20080032962A - Cathod for fuel cell, membrane-electrode assembly for fuel cell comprising same, and fuel cell system comprising same - Google Patents

Abstract

A cathode for a fuel cell is provided to facilitate oxygen supply even when using air as an oxidant, thereby increasing the rate of an electrochemical reaction and improving the cost efficiency and quality of a fuel cell. A cathode for a fuel cell comprises: an electrode substrate(20); an oxygen supplying layer(100) formed on the electrode substrate; and a catalyst layer(40) formed on the oxygen supplying layer. The oxygen supplying layer comprises a metal oxide. The metal oxide is selected from the group consisting of ceria(CeO2), ceria doped with a dopant and a combination thereof.

Description

Cathode electrode for fuel cell, membrane-electrode assembly and fuel cell system for fuel cell comprising same {CATHOD FOR FUEL CELL, MEMBRANE-ELECTRODE ASSEMBLY FOR FUEL CELL COMPRISING SAME, AND FUEL CELL SYSTEM COMPRISING SAME}

1 is a cross-sectional view schematically showing a cathode electrode for a fuel cell according to an embodiment of the present invention.

2 is a cross-sectional view schematically showing a cathode electrode for a fuel cell according to another embodiment of the present invention.

3 is a cross-sectional view schematically showing the structure of a membrane-electrode assembly for a fuel cell of the present invention.

4 schematically shows the structure of a fuel cell system of the present invention;

[Industrial use]

The present invention relates to a cathode electrode for a fuel cell, a membrane-electrode assembly for a fuel cell and a fuel cell system including the same, and more particularly, a cathode electrode for a fuel cell that can increase the potential of the cathode electrode to increase the electrochemical reaction rate. It relates to a membrane-electrode assembly and a fuel cell system for a fuel cell comprising the same.

[Prior art]

A fuel cell is a power generation system that directly converts the chemical reaction energy of hydrogen and oxygen contained in hydrocarbon-based materials such as methanol, ethanol and natural gas into electrical energy.

This fuel cell is a clean energy source that can replace fossil energy, and has the advantage of generating a wide range of outputs by stacking unit cells, and having an energy density of 4-10 times that of a small lithium battery. It is attracting attention as a compact and mobile portable power source.

Representative examples of the fuel cell include a polymer electrolyte fuel cell (PEMFC) and a direct oxidation fuel cell (Direct Oxidation Fuel Cell). When methanol is used as a fuel in the direct oxidation fuel cell, it is called a direct methanol fuel cell (DMFC).

The polymer electrolyte fuel cell has an advantage of having a high energy density and a high output, but requires attention to handling hydrogen gas and reforms fuel for reforming methane, methanol, natural gas, etc. to produce hydrogen as fuel gas. There is a problem that requires additional equipment such as a device.

On the other hand, the direct oxidation fuel cell has a lower energy density than the polymer electrolyte fuel cell, but it is easy to handle the fuel and has a low operating temperature, so that it can be operated at room temperature, and in particular, it does not require a fuel reforming device.

In such fuel cell systems, the stack that substantially generates electricity comprises several unit cells consisting of a membrane-electrode assembly (MEA) and a separator (also called a bipolar plate). It has a structure laminated to several tens. The membrane-electrode assembly is called an anode electrode (also called "fuel electrode" or "oxidation electrode") and a cathode electrode (also called "air electrode" or "reduction electrode") with a polymer electrolyte membrane containing a hydrogen ion conductive polymer therebetween. ) Is located.

The principle of generating electricity in a fuel cell is that fuel is supplied to an anode electrode, which is a fuel electrode, adsorbed to a catalyst of the anode electrode, fuel is ionized by an oxidation reaction, and electrons are generated, and the generated electrons are oxidized according to an external circuit. Reaching the cathode, which is the pole, hydrogen ions pass through the polymer electrolyte membrane and are delivered to the cathode. An oxidant is supplied to the cathode, and the oxidant, hydrogen ions, and electrons react on the catalyst of the cathode to generate electricity while producing water.

It is an object of the present invention to provide a cathode electrode for a fuel cell which can improve the electrochemical reaction rate.

Another object of the present invention is to provide a membrane-electrode assembly for a fuel cell comprising the cathode electrode.

Still another object of the present invention is to provide a fuel cell system including the cathode electrode.

In order to achieve the above object, the present invention provides a cathode electrode for a fuel cell comprising an oxygen supply layer formed on the electrode substrate electrode substrate and a catalyst layer formed on the oxygen supply layer.

The present invention also provides a membrane-electrode assembly for a fuel cell comprising a polymer electrolyte membrane positioned opposite one another and positioned between the anode electrode and the cathode electrode and between the anode electrode and the cathode electrode.

The invention also includes at least one membrane-electrode assembly and a separator, at least one electricity generating unit for generating electricity through an oxidation reaction of the fuel and a reduction reaction of the oxidant, a fuel supply unit for supplying fuel to the electricity generating unit and It provides a fuel cell system including an oxidant supply unit for supplying an oxidant to the electricity generating unit.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a cathode electrode for a fuel cell. In general, in the cathode of the fuel cell, there is a problem that performance is reduced by about 50% or more when air is used as the oxidizing agent as compared with oxygen. Therefore, pure oxygen should be used as an oxidizing agent, but this requires the use of a separate oxygen fuel tank, which is problematic in terms of the volume of the system and also the price of pure oxygen is not economical and difficult to handle.

In the present invention, this problem can be solved by using an oxygen supply layer for the cathode electrode which can supply oxygen smoothly in the air.

The cathode electrode of this invention contains an electrode base material, the oxygen supply layer formed in this electrode base material, and the catalyst layer formed in this oxygen supply layer.

As shown in FIG. 1, the oxygen supply layer 100 may be formed of a single layer 22 including a conductive material and a metal oxide formed on the electrode substrate 20, and as shown in FIG. 2. It may be formed of a double layer of the conductive layer 32 formed of the metal oxide layer 34 and the metal oxide layer 34 formed on the conductive layer. The catalyst layer 40 is formed on the oxygen supply layer 100.

The metal oxide is preferably a metal oxide capable of transferring oxygen and selectively storing and releasing oxygen, and a preferred metal oxide is ceria (CeO ₂ ) and ceria doped with dopants and combinations thereof. . Ceria doped with the dopant is more preferred because of its excellent thermal stability. The dopants include gadolium (Gd), zirconium (Zr), samarium (Zm), yttrium (Y), strontium (Sr), lanthanum (La), calcium (Ca), oxides thereof and mixtures thereof. One selected from the group consisting of can be used. The doping amount of the dopant is suitably 30% by weight or less based on the weight of ceria, and preferably 0.001% to 30% by weight.

The content of the metal oxide in the cathode of the present invention is preferably 5 to 30% by weight, more preferably 8 to 15% by weight, based on the weight of the conductive material, regardless of whether the structure of the oxygen supply layer is a single layer or a double layer. If the content of the metal oxide is less than 5% by weight, the effect of the present invention is not seen, and if it exceeds 30% by weight, there is a problem that the electrical conductivity of the oxygen supply layer is poor, which is not preferable.

Since the oxygen supply layer including the metal oxide can store and release oxygen, even when an air oxidant is used, oxygen can be dispersed well on the platinum catalyst surface, thereby improving the oxygen partial pressure on the catalyst surface. In addition, this effect of the present invention is preferable because the metal oxide used in the present invention is not electrically conductive, it can be maximized to be used in the oxygen supply layer formed on the electrode substrate as compared to the use in the catalyst layer. In addition, since the oxygen supply layer also serves to assist the diffusion of the reactants and the smooth discharge of the product, it is possible to improve the battery characteristics, this effect is also not obtained when using a metal oxide in the catalyst layer.

Since the thickness of the oxygen supply layer in the present invention does not affect the effect of the invention, the thickness need not be particularly limited.

The conductive material may be carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotube, carbon nanowire, carbon nano-horn or carbon nano ring ) Can be used.

In addition, the oxygen supply layer may further include a binder. The binder may be polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride, alkoxy vinyl ether, polyvinyl alcohol, cellulose acetate or Copolymers thereof and the like can be preferably used.

The oxygen supply layer is formed by mixing a conductive material, a metal oxide, a binder, and a solvent, and applying the mixture to an electrode substrate. As the solvent, alcohols such as ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, water, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran, etc. may be preferably used. The coating process may be screen printing, spray coating, or coating using a doctor blade according to the viscosity of the composition, but is not limited thereto.

The electrode substrate plays a role of supporting the electrode and diffuses the fuel and the oxidant to the catalyst layer, thereby serving to easily access the fuel and the oxidant to the catalyst layer. The electrode substrate is a conductive substrate, and representative examples thereof include carbon paper, carbon cloth, carbon felt, or metal cloth (porous film or polymer fiber composed of metal cloth in a fibrous state). The metal film is formed on the surface of the cloth formed with)) may be used, but is not limited thereto.

In addition, it is preferable to use a water-repellent treatment with a fluorine-based resin as the electrode base material because it can prevent the reactant diffusion efficiency from being lowered by water generated when the fuel cell is driven. Examples of the fluorine-based resin include polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonyl fluoride alkoxy vinyl ether, and fluorinated ethylene propylene ( Fluorinated ethylene propylene), polychlorotrifluoroethylene or copolymers thereof can be used.

In the catalyst layer of the present invention, any catalyst that can be used as a catalyst may be used as a catalyst, and a platinum-based catalyst may be used as a catalyst. The platinum-based catalyst may be platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy or platinum-M alloy (M is Ga, Ti, V, Cr, Mn, Fe, Co, Ni, Transition metals selected from the group consisting of Cu, Zn, Sn, Mo, W, Rh and mixtures thereof). As described above, the anode electrode and the cathode electrode may use the same material, but in order to prevent the catalyst poisoning caused by CO generated during the anode electrode reaction in the direct oxidation fuel cell, a platinum-ruthenium alloy catalyst is used as the anode. It is more preferable as an electrode catalyst. Specific examples include Pt, Pt / Ru, Pt / W, Pt / Ni, Pt / Sn, Pt / Mo, Pt / Pd, Pt / Fe, Pt / Cr, Pt / Co, Pt / Ru / W, Pt / Ru / Mo, Pt / Ru / V, Pt / Fe / Co, Pt / Ru / Rh / Ni, Pt / Ru / Sn / W and mixtures thereof may be used.

In addition, such a metal catalyst may be used as the metal catalyst (black) itself, or may be supported on a carrier. As the carrier, carbonaceous materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotubes, carbon nanofibers, carbon nanowires, carbon nanoballs or activated carbon may be used, or alumina, silica, zirconia, Inorganic fine particles such as titania may be used, but carbon-based materials are generally used.

The catalyst layer may also further comprise a binder resin to improve adhesion of the catalyst layer and transfer of hydrogen ions.

It is preferable to use a polymer resin having hydrogen ion conductivity as the binder resin, more preferably a cation exchange group selected from the group consisting of sulfonic acid group, carboxylic acid group, phosphoric acid group, phosphonic acid group and derivatives thereof in the side chain. Any polymer resin which has can be used. Preferably, a fluorine polymer, a benzimidazole polymer, a polyimide polymer, a polyetherimide polymer, a polyphenylene sulfide polymer, a polysulfone polymer, a polyether sulfone polymer, a polyether ketone polymer, a polyether One or more hydrogen ion conductive polymers selected from ether ketone polymers or polyphenylquinoxaline polymers, more preferably poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), Copolymers of tetrafluoroethylene with fluorovinyl ethers containing sulfonic acid groups, defluorinated sulfided polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5,5'-bibenzimidazole One containing at least one hydrogen ion conductive polymer selected from (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole) or poly (2,5-benzimidazole) may be used.

The hydrogen ion conductive polymer may replace H with Na, K, Li, Cs or tetrabutylammonium in an ion exchange group at the side chain end. In case of replacing H by Na in the ion-exchange group of the side chain terminal, NaOH is substituted in the preparation of the catalyst composition, and tetrabutylammonium hydroxide is used in the case of using tetrabutylammonium, and K, Li or Cs is also substituted with appropriate compounds. It can be substituted using. Since this substitution method is well known in the art, detailed description thereof will be omitted.

The binder resin may be used in the form of a single substance or a mixture, and may also be optionally used with a nonconductive polymer for the purpose of further improving adhesion to the polymer electrolyte membrane. It is preferable to adjust the usage-amount so that it may be suitable for a purpose of use.

Examples of the nonconductive polymer include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoro alkylvinyl ether copolymer (PFA), and ethylene / tetrafluoro Ethylene / tetrafluoroethylene (ETFE), ethylenechlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, copolymer of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), dode At least one selected from the group consisting of silbenzenesulfonic acid and sorbitol is more preferred.

The membrane-electrode assembly of the present invention including the cathode electrode includes an anode electrode and a cathode electrode positioned to face each other, and includes a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode. The membrane-electrode assembly of the present invention is schematically shown in FIG. That is, the membrane-electrode assembly 50 of the present invention includes an anode electrode 52 and a cathode electrode 51 of the present invention positioned opposite each other, and between the anode electrode 52 and the cathode electrode 51. A polymer electrolyte membrane 55 is located. The cathode electrode 51 has the configuration shown in FIG. 1 or 2, but is briefly shown in this drawing.

The anode electrode includes an electrode substrate and a catalyst layer formed on the electrode substrate. Since the catalyst described in the anode electrode can be used as a catalyst in the catalyst layer of the cathode, a separate description will be omitted.

In addition, the catalyst layer may further include a binder resin in the same manner as the cathode electrode, and since the binder resin used is the same as the anode electrode, a description thereof will be omitted. In addition, since the electrode substrate is the same as the anode electrode, description thereof will be omitted.

The polymer electrolyte membrane is generally used as a polymer electrolyte membrane in a fuel cell, and any one made of a polymer resin having hydrogen ion conductivity may be used. Representative examples thereof include a polymer resin having a cation exchange group selected from the group consisting of sulfonic acid groups, carboxylic acid groups, phosphoric acid groups, phosphonic acid groups and derivatives thereof in the side chain.

Representative examples of the polymer resin include a fluorine polymer, a benzimidazole polymer, a polyimide polymer, a polyetherimide polymer, a polyphenylene sulfide polymer, a polysulfone polymer, a polyether sulfone polymer and a polyether ketone It may include at least one selected from a polymer, a polyether-etherketone-based polymer or a polyphenylquinoxaline-based polymer, more preferably poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), Copolymers of tetrafluoroethylene with fluorovinyl ethers containing sulfonic acid groups, defluorinated sulfided polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5,5'-bibenzimidazole or at least one selected from (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole) or poly (2,5-benzimidazole).

In the hydrogen ion conductive group of the hydrogen ion conductive polymer, H may be substituted with Na, K, Li, Cs or tetrabutylammonium. In the hydrogen ion conductive group of the hydrogen ion conductive polymer, NaOH is substituted when H is replaced with Na, and tetrabutylammonium hydroxide is used when the substituent is substituted with tetrabutylammonium. It can be substituted using. Since this substitution method is well known in the art, detailed description thereof will be omitted.

The fuel cell system including the membrane-electrode assembly of the present invention includes at least one electricity generator, a fuel supply and an oxidant supply. The fuel cell system of the present invention can be applied to both a polymer electrolyte fuel cell system and a direct oxidation fuel cell system.

The electricity generating unit includes at least one membrane-electrode assembly and a separator (also referred to as a bipolar plate) of the present invention, and serves to generate electricity through an oxidation reaction of a fuel and a reduction reaction of an oxidant.

The fuel supply unit serves to supply fuel to the electricity generator. In the present invention, the fuel may include hydrogen or hydrocarbon fuel in gas or liquid state. Representative examples of the hydrocarbon fuel include methanol, ethanol, propanol, butanol or natural gas.

The oxidant supply unit serves to supply an oxidant to the electricity generator, and may use oxygen or air as the oxidant. In the present invention, even when using air, the rate of electrochemical reaction does not decrease, that is, shows an improved rate of electrochemical reaction, and therefore, the effect of the present invention can be maximized when using air. Therefore, it is more preferable to use economical air as the oxidizing agent.

A schematic structure of the fuel cell system of the present invention is shown in FIG. 4, which will be described in more detail with reference to the following. Although the structure shown in FIG. 4 shows a system for supplying fuel and oxidant to an electric generator using a pump, the fuel cell system of the present invention is not limited to such a structure, and a fuel cell using a diffusion method without using a pump is shown. Of course, it can also be used for system architecture.

The fuel cell system 1 of the present invention includes at least one electricity generation unit 3 for generating electrical energy through an oxidation reaction of a fuel and a reduction reaction of an oxidant, a fuel supply unit 5 for supplying the fuel, And an oxidant supply unit 7 for supplying an oxidant to the electricity generation unit 3.

In addition, the fuel supply unit 5 for supplying the fuel may include a fuel tank 9 storing fuel and a fuel pump 11 connected to the fuel tank 9. The fuel pump 11 serves to discharge the fuel stored in the fuel tank 9 by a predetermined pumping force.

The oxidant supply unit 7 for supplying the oxidant to the electricity generating unit 3 includes at least one oxidant pump 13 for sucking the oxidant with a predetermined pumping force.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

(Example 1)

1M aqueous ammonia solution was added dropwise to a solution obtained by mixing an aqueous solution of cerium nitrate (Ce (NO ₃ ) ₃ ) at 0.1 M concentration with an aqueous solution of zirconium nitrate (Zr (NO ₃ ) ₄ ) at 0.1 M concentration at 80: 20% by weight. dropping) to maintain a pH of 4-5. The resulting mixed solution was stirred for 1 hour, the stirred solution was filtered and the resulting filtrate was washed and dried to wash and dry the co-precipitate obtained, and the dried product was calcined at 600 ° C. for 3 hours to produce zirconium-doped ceria (Ce _0.8 Zr _0.2 O ₂ ) was prepared. At this time, the doping amount of zirconium was 20% by weight based on the weight of ceria.

A carbon powder, a polytetrafluoroethylene binder, an isopropyl alcohol solvent, and ceria doped with zirconium prepared above were mixed to prepare a composition for forming an oxygen supply layer. In this case, the amount of ceria doped with zirconium was set to 15% by weight based on the weight of the carbon powder. The mixing ratio of the carbon powder, the binder, and the isopropyl alcohol solvent was 1: 0.2: 10. The composition for forming an oxygen supply layer was evenly applied on the carbon paper electrode substrate by screen printing.

In order to remove the isopropyl alcohol used as the solvent and add the polytetrafluoroethylene binder to the carbon powder, the carbon paper electrode substrate coated with the oxygen supply layer composition was heated at a temperature of 350 ° C. And heat treatment for 1 hour in a nitrogen atmosphere.

A cathode electrode was prepared by applying a cathode catalyst layer composition prepared by mixing 5 g of Pt black cathode catalyst and 10.0 g of 10 wt% Nafion / H ₂ O / 2-propanol binder to carbon paper on which the oxygen supply layer was formed. It was.

(Example 2)

The same method as in Example 1 was performed except that the amount of ceria doped with zirconium was changed to 5 wt% based on the weight of the carbon powder.

(Example 3)

Except that the amount of ceria doped with zirconium was changed to 30% by weight based on the weight of the carbon powder was carried out in the same manner as in Example 1.

(Example 4)

The same method as in Example 1 was carried out except that the amount of ceria doped with zirconium was changed to 8 wt% based on the weight of the carbon powder.

(Example 5)

Except that the amount of ceria doped with zirconium was changed to 10% by weight based on the weight of the carbon powder was carried out in the same manner as in Example 1.

(Example 6)

The same method as in Example 1 was carried out except that the amount of ceria doped with zirconium was changed to 20% by weight based on the weight of the carbon powder.

(Example 7)

Except that the amount of the ceria doped with zirconium was changed to 25% by weight based on the weight of the carbon powder was carried out in the same manner as in Example 1.

(Example 8)

Except for using ceria doped with zirconium, instead of ceria doped with zirconium, the same procedure as in Example 1 was carried out.

(Comparative Example 1)

Carbon powder, polytetrafluoroethylene binder and isopropyl alcohol were mixed at a weight ratio of 1: 0.2: 10 to prepare a composition for forming a microporous layer, and the composition for forming a microporous layer was formed on a carbon paper by screen printing. Apply evenly. In order to remove the isopropyl alcohol used as a solvent and add polytetrafluoroethylene as a binder between the carbon powders sufficiently and evenly, the carbon paper coated with the microporous layer-forming composition was applied at 350 ° C. in a nitrogen atmosphere. Heat treatment was performed for a time.

The catalyst layer composition used in Example 1 was apply | coated to the carbon paper in which the microporous layer was formed, and the cathode electrode was manufactured.

A fuel cell was manufactured using the cathode electrode and the Pt-Ru anode electrode prepared according to Example 1 and Comparative Example 1. While supplying methanol fuel and air oxidant to this fuel cell, the current density of the fuel cell was measured and the results are shown in Table 1 below.

Current density (mA / cm ² ) ＠ 0.6V Example 1 810 Comparative Example 1 690

As shown in Table 1, it can be seen that the fuel cell using the cathode electrode having the fine pore layer of Example 1 exhibits a very high current density even when air is used as the oxidant as compared to Comparative Example 1. In addition, as a result of measuring the current density of the fuel cell using the cathode electrode in which the microporous layers of Examples 2 to 8 were formed, it was found to exhibit a high current density similar to that of Example 1.

All simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Since the cathode electrode of the present invention includes an oxygen supply layer, even if air is used as the oxidant, the oxygen supply is smooth and the electrochemical reaction rate can be improved, thereby providing a fuel cell having economical and excellent performance.

Claims (12)

Electrode substrates; An oxygen supply layer formed on the electrode substrate; And Catalyst layer formed in the oxygen supply layer Cathode electrode for a fuel cell comprising a. The method of claim 1, And the oxygen supply layer comprises a metal oxide. The method of claim 2, Wherein the metal oxide is selected from the group consisting of ceria (CeO ₂ ), dopant-doped ceria and combinations thereof. The method of claim 2, The content of the metal oxide is 5 to 30% by weight based on the weight of the conductive material cathode electrode for fuel cells. The method of claim 4, wherein The content of the metal oxide is 8 to 15% by weight of the cathode electrode for a fuel cell based on the weight of the conductive material. The method of claim 1, And the oxygen supply layer comprises a conductive material. The method of claim 6, The conductive material may be carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotube, carbon nanowire, carbon nano-horn, carbon nano ring And a combination thereof and a cathode for a fuel cell. The method of claim 1, And the oxygen supply layer is a single layer comprising a conductive material and a metal oxide. The method of claim 1, The oxygen supply layer A conductive layer formed on the electrode substrate and including a conductive material; And A metal oxide layer formed on the conductive layer The cathode electrode for a fuel cell comprising a double layer. An anode electrode and a cathode electrode located opposite each other; And A polymer electrolyte membrane positioned between the anode electrode and the cathode electrode Including, The cathode is the electrode of any one of claims 1 to 9. Membrane-electrode assembly for fuel cell. And at least one membrane-electrode assembly and a separator comprising an anode electrode and a cathode electrode positioned opposite to each other, and a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode, wherein the membrane comprises an electrode reaction and a reduction reaction of the oxidant. At least one electricity generating unit for generating electricity through; A fuel supply unit supplying fuel to the electricity generation unit; And Oxidant supply unit for supplying an oxidant to the electricity generating unit A fuel cell system comprising: 10. The fuel cell system of claim 1, wherein the cathode is the electrode of any one of claims 1-9. The method of claim 11, And the oxidant is air.

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