KR20090023904A - Membrane-electrode assembly for fuel cell and fuel cell system comprising same - Google Patents

Abstract

A membrane-electrode assembly for a fuel cell is provided to prevent a crossover phenomenon of fuel and improve efficiency of a catalyst. A membrane-electrode assembly for a fuel cell comprises: a polymeric electrolyte membrane(20); an anode/cathode electrode(26) located on both sides of the polymeric electrolyte membrane; and a fuel crossover constraining layer located between the polymeric electrolyte membrane and the anode/cathode electrode, having a carbon nanotube(22) and a metal rod(24). An axis(a) of the carbon nanotube and a surface of the polymeric electrolyte membrane are not parallel with each other.

Description

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

The present invention relates to a fuel cell membrane-electrode assembly and a fuel cell system including the same, and more particularly, to a fuel cell membrane-electrode assembly and a fuel cell system including the same, which are excellent in efficiency and prevent fuel crossover. It is about.

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 fuel and has a low operating temperature, so that it can be operated at room temperature, in particular, it does not require a fuel reformer.

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 a “fuel electrode” or an “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, and the fuel is oxidized to generate hydrogen ions and electrons. Reaching the cathode electrode, hydrogen ions pass through the polymer electrolyte membrane and are delivered to the cathode electrode. 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 fuel cell membrane-electrode assembly capable of improving catalyst efficiency and preventing fuel crossover.

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

In order to achieve the above object, the present invention is a polymer electrolyte membrane; And a fuel crossover suppression layer positioned between an anode electrode and a cathode electrode positioned on both sides of the polymer electrolyte membrane, and between the polymer electrolyte membrane and the anode electrode and the cathode electrode, the fuel crossover suppression layer including a carbon nanotube and a metal rod. A membrane-electrode assembly for a fuel cell, wherein the axis of the carbon nanotubes and the surface of the polymer electrolyte membrane are provided so as not to be parallel to each other.

It is preferable that the angle of the axis of the carbon nanotube and the surface of the polymer electrolyte membrane is substantially substantially perpendicular, and more preferably 70 to 90 °.

The present invention also provides a fuel cell system including an electric generator, a fuel supply, and an oxidant supply including at least one of the membrane-electrode assembly and the separator. The electricity generation unit serves to generate electricity through the oxidation reaction of the fuel and the reduction reaction of the oxidant. The fuel supply unit serves to supply fuel to the electricity generation unit, and the oxidant supply unit serves to supply an oxidant to the electricity generation unit.

As described above, the membrane-electrode assembly for a fuel cell of the present invention can prevent crossover of fuel and can improve catalyst efficiency, thereby providing a fuel cell system having excellent performance.

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

The present invention relates to a membrane-electrode assembly for a fuel cell, wherein the membrane-electrode assembly includes a polymer electrolyte membrane and an anode electrode and a cathode electrode positioned on both sides of the polymer electrolyte membrane, wherein the polymer electrolyte membrane and the anode electrode and Located between the cathode electrodes and comprises a fuel crossover suppression layer comprising a carbon nanotube and a metal rod. In the present invention, the carbon nanotubes are preferably positioned such that the axes of the carbon nanotubes and the surface of the polymer electrolyte membrane are not parallel to each other, and are preferably substantially close to vertical, specifically, an angle of 70 to 90 °. More preferably. The axis of the carbon nanotubes and the surface of the polymer electrolyte membrane may be present at an angle of 70, 75, 80, 85 or 90 °. The orientation of the carbon nanotubes is more important in terms of catalyst efficiency as well as crossover aspects of hydrocarbon fuels. When the carbon nanotubes are present at an angle of less than 70 °, the surface area where the carbon nanotubes and the surface of the polymer electrolyte membrane are in contact with each other is reduced, which may decrease the catalyst efficiency, which is not preferable.

As such, the carbon nanotubes positioned not parallel to the surface of the polymer electrolyte membrane may provide an effect of suppressing fuel crossover. When the carbon nanotubes are positioned in parallel with the surface of the polymer electrolyte membrane, the metal rods formed thereon may be formed in a dense membrane form, which may function as a blocking membrane for suppressing fuel supply and dispersion. .

In this case, the metal rod is preferably located on the end surface of the carbon nanotubes located in the direction of the catalyst layer of the anode electrode or the cathode electrode. As such, the metal rod is positioned at the end surface of the carbon nanotubes positioned in the direction of the catalyst layer of the anode electrode or the cathode electrode, thereby making the topology of the metal into a brush type, thereby increasing the surface area as much as possible.

Since such a metal rod can also serve as a promoter, battery characteristics can be further improved. In addition, the metal rod may bring about an increase in the number of hydroxy groups according to the strong interaction with the surroundings to maximize the activity of the catalyst.

Preferably, the metal rod has a height of 100 to 500 nm. The height of the metal rods may range from 100, 150, 200, 250, 300, 350, 400, 450 and 500 nm. If the height of the metal rod is shorter than 100 nm, the effect of using the metal rod is almost insignificant, and if the height of the metal rod is larger than 500 nm, the metal rod is formed in the form of a metal film. It is not preferable because it can be suppressed completely.

The metal in the metal rod is preferably selected from the group consisting of Au, W, Pt, Mo, Cu, Pd, Ru, and combinations thereof, and more preferably selected from the group consisting of Au, W, and combinations thereof. Do.

The carbon nanotube and the metal rod formed on the surface of the polymer electrolyte membrane may serve as a barrier to prevent the fuel from crossover, that is, as a fuel crossover prevention layer. Accordingly, the membrane-electrode assembly of the present invention is reduced in the crossover of the fuel compared to the conventional membrane-electrode assembly.

Since the length of the carbon nanotubes is not a factor influencing the effects of the present invention, the length is not significant.

1 shows a representative example of a membrane-electrode assembly for a fuel cell of the present invention. As shown in FIG. 1, the carbon nanotubes are formed such that the angle (theta) of the axis a of the carbon nanotubes 22 and the surface of the polymer electrolyte membrane 20 is substantially about 90 ° in the polymer electrolyte membrane 20. (22) is located. Moreover, the metal rod 24 is located on this carbon nanotube 22, and the electrode 26 is located on this metal rod 24.

1 illustrates an example in which the axis a of the carbon nanotubes 22 and the surface angle α of the polymer electrolyte membrane 20 are about 90 °, but the present invention is not limited thereto. The shaft and the surface of the polymer electrolyte membrane may be all included in the rights of the present invention if they are not parallel to each other.

The cathode electrode and the anode electrode include an electrode substrate and a catalyst layer.

In the catalyst layer, any catalyst that can be used as a catalyst may be used as a catalyst in the reaction of the fuel cell, and a representative platinum-based catalyst may be used as a representative example. 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, At least one catalyst selected from the group consisting of Cu, Zn, Sn, Mo, W, Rh, Ru, and combinations thereof. 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 One or more selected from the group consisting of / Mo, Pt / Ru / V, Pt / Fe / Co, Pt / Ru / Rh / Ni, and Pt / Ru / Sn / W can 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 further include a binder resin for improving the adhesion of the catalyst layer and the 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 and fluorovinyl ethers containing sulfonic acid groups, sulfided polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5,5'-bibenzimidazoles or poly ( 2,5-benzimidazole) may be used that includes at least one hydrogen ion conductive polymer selected from.

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 with Na in the side chain terminal ion exchanger, NaOH is substituted for the preparation of the catalyst composition, and tetrabutylammonium hydroxide is substituted for tetrabutylammonium, and K, Li or Cs may be 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.

In addition, when forming the catalyst layer, a thickener may be further added to adjust the viscosity of the catalyst layer composition. As the thickener, polyethylene glycol may be representatively used, but is not limited thereto, and any agent capable of controlling the viscosity without adversely affecting the catalyst layer may be used. In this case, the amount of the thickener may be used in a small amount by adjusting within a range in which an appropriate viscosity of the catalyst layer composition can be obtained.

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 of (referred to as a metalized polymer fiber) 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 resin include polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polyperfluoroalkyl vinyl ether, polyperfluorosulfonylfluoride alkoxyvinyl ether, and fluorinated ethylene propylene ( Fluorinated ethylene propylene), polychlorotrifluoroethylene or copolymers thereof can be used.

In addition, a microporous layer may be further included to enhance the reactant diffusion effect in the electrode substrate. These microporous layers are generally conductive powders having a small particle diameter, such as carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotubes, carbon nanowires, and carbon nanohorns. -horn or carbon nano ring.

The microporous layer is prepared by coating a composition comprising a conductive powder, a binder resin and a solvent on the electrode substrate. The binder resin 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. 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 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 group, carboxylic acid group, phosphoric acid group, phosphonic acid group 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 one or more selected from polymers, polyether-etherketone-based polymers or polyphenylquinoxaline-based polymers, more preferably poly (perfluorosulfonic acid) (generally marketed as Nafion), poly (Perfluorocarboxylic acid), copolymer of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid group, sulfide polyether ketone, aryl ketone, poly (2,2'-m-phenylene) -5,5 And at least one selected from '-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 case of replacing H with Na in the side chain terminal ion exchanger, NaOH is substituted for the preparation of the catalyst composition, and tetrabutylammonium hydroxide is substituted for tetrabutylammonium, and K, Li or Cs may be 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.

In the present invention, a method of forming a carbon layer positioned between the polymer electrolyte membrane and the electrode includes a method of growing carbon nanotubes on the polymer electrolyte membrane or forming a slurry coating. In the case of performing the slurry coating, after the coating process is performed, an electric field or a magnetic field is applied to give a directivity or to have a directivity using a physical method. The method of forming the carbon nanotubes directionally, that is, the method of forming the carbon nanotubes so as not to be parallel to the surface of the polymer electrolyte membrane may be any method of placing the carbon nanotubes at any angle, An example is a method of attaching and detaching an adhesive tape or a roller to a carbon nanotube.

The membrane-electrode assembly of the present invention can be applied to both a polymer electrolyte fuel cell (PEMFC) and a direct oxidation fuel cell (PEMFC), but is more preferably applied to a direct oxidation fuel cell. Can be.

The fuel cell system of the present invention comprising the membrane-electrode assembly of the present invention includes at least one electricity generator, a fuel supply and an oxidant supply.

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

The fuel supply unit serves to supply fuel to the electricity generation unit, and the oxidant supply unit serves to supply an oxidant such as oxygen or air to the electricity generation unit.

In the present invention, the fuel may include a hydrogen or hydrocarbon fuel in gaseous or liquid state, and the hydrocarbon fuel is more preferable because the present invention is more suitable for the direct oxidation fuel cell. Representative examples of the hydrocarbon fuel include methanol, ethanol, propanol, butanol or natural gas.

A schematic structure of the fuel cell system of the present invention is shown in FIG. 2, which will be described in more detail with reference to the following. Although the structure shown in FIG. 2 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 generating 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.

The electricity generator 3 is composed of a membrane-electrode assembly 17 for oxidizing and reducing a fuel and an oxidant, and a separator 19 and 19 'for supplying fuel and an oxidant to both sides of the membrane-electrode assembly. At least one of these electricity generating units 3 constitutes a stack 15.

Hereinafter, 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)

A carbon nanotube, a Nafion solution, and isopropyl alcohol were mixed in a 30:10:60 weight ratio, and a small amount of polyethylene glycol (number average molecular weight 1000) was added to the mixed solution to adjust the viscosity to prepare a slurry. The prepared slurry was applied to a Nafion 115 (perfluorosulfonic acid) polymer electrolyte membrane to form a carbon nanotube layer. An adhesive tape was attached and detached to the carbon nanotube layer so that the angle of the axis of the carbon nanotube and the surface of the polymer electrolyte membrane was substantially about 90 °.

Subsequently, Au was deposited on the carbon nanotubes to form a metal rod having a height of about 300 nm to prepare a polymer electrolyte membrane having a fuel crossover suppression layer including the carbon nanotubes and the metal rods.

Using 88 wt% Pt-Ru black (Johnson Matthey) and Pt black (Johnson Matthey) catalyst and 12 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) at 5 wt% concentration as binder A catalyst composition for the anode electrode and a catalyst composition for the cathode electrode were prepared, respectively. The anode electrode was prepared by applying the anode catalyst composition to a carbon paper electrode substrate, and the cathode electrode composition was coated on a carbon paper electrode substrate to prepare a cathode. At this time, the catalyst loading in the anode electrode and the cathode electrode was 4mg / cm ² respectively.

A catalyst layer of the anode electrode and the cathode electrode and the fuel crossover suppression layer formed on the polymer electrolyte membrane were placed in contact with each other to prepare a membrane-electrode assembly in a conventional manner.

(Example 2)

The same process as in Example 1 was carried out except that Au was deposited on the carbon nanotubes to form a metal rod having a height of about 100 nm.

(Example 3)

The same process as in Example 1 was carried out except that Au was deposited on the carbon nanotubes to form a metal rod having a height of about 200 nm.

(Example 4)

The same process as in Example 1 was carried out except that Au was deposited on the carbon nanotubes to form a metal rod having a height of about 400 nm.

(Example 5)

The same process as in Example 1 was carried out except that Au was deposited on the carbon nanotubes to form a metal rod having a height of about 500 nm.

(Example 6)

The same process as in Example 1 was carried out except that a W metal rod was formed instead of Au.

(Comparative Example 1)

Using 88 wt% Pt-Ru black (Johnson Matthey) and Pt black (Johnson Matthey) catalyst and 12 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) at 5 wt% concentration as binder A catalyst composition for the anode electrode and a catalyst composition for the cathode electrode were prepared, respectively. The anode electrode was prepared by applying the catalyst composition for the anode electrode to a carbon paper electrode substrate, and the cathode electrode composition was prepared by applying the catalyst composition for the cathode electrode to the carbon paper electrode substrate. At this time, the catalyst loading in the anode electrode and the cathode electrode was 4mg / cm ² respectively.

A membrane-electrode assembly was prepared using the anode electrode, the cathode electrode, and the Nafion 115 (perfluorosulfonic acid) polymer electrolyte membrane, and a unit cell was prepared using the membrane-electrode assembly.

Methanol crossover (methanol transmittance) was measured for the polymer electrolyte membranes of Example 1 and Comparative Example 1. Methanol transmittance is 1M methanol at both ends after placing the polymer electrolyte membrane and the polymer electrolyte membrane of Comparative Example 1 in which the fuel crossover suppression layer prepared according to Example 1 was formed at the center of the two-compartment discharge cell. When the deionized water mixed liquid and deionized water were circulated respectively, the concentration of methanol that passed through the electrolyte membrane was measured by the change of refractive index.

In addition, 1M methanol was supplied to the unit cells prepared according to Example 1 and Comparative Example 1, and 0.4V output density (output characteristics) was measured at a temperature of 70 ° C., and the results are shown in Table 1 below. .

Example Comparative example Methanol permeability (cm ² / s at 60 ° C) 1.6 X 10 ^-5 3.6 X 10 ^-6 Power density (mW / cm ² ) 135 105

As shown in Table 1 above, the unit cell of Example 1 was found to have a lower methanol crossover rate and an excellent output density than the unit cell of Comparative Example 1.

In addition, as a result of measuring the methanol transmittance and output characteristics of Examples 2 to 6, similar to Example 1, the methanol transmittance was lower than that of Comparative Example 1, and the output density was excellent.

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.

1 is a view showing an example of a membrane-electrode assembly for a fuel cell of the present invention.

2 schematically illustrates the structure of a fuel cell system of the present invention;

Claims (14)

Polymer electrolyte membranes; Anode and cathode electrodes positioned on both sides of the polymer electrolyte membrane; And A membrane-electrode assembly for fuel cells, positioned between the polymer electrolyte membrane and an anode electrode and a cathode electrode, comprising a fuel crossover suppression layer comprising a carbon nanotube and a metal rod, The axis of the carbon nanotubes and the surface of the polymer electrolyte membrane are positioned not parallel to each other membrane-electrode assembly for a fuel cell. The method of claim 1, The angle of the axis of the carbon nanotubes and the surface of the polymer electrolyte membrane is 70 to 90 ° membrane-electrode assembly for a fuel cell. The method of claim 1, The metal rod is a membrane-electrode assembly for a fuel cell is located on the end surface of the carbon nanotubes located in the direction of the catalyst layer of the anode electrode or the cathode electrode. The method of claim 1, The metal rod is a membrane-electrode assembly for a fuel cell having a height of 100 to 500nm. The method of claim 1, The metal rod is selected from the group consisting of Au, W, Pt, Mo, Cu, Pd, Ru and combinations thereof. The method of claim 5, Wherein the metal rod is selected from the group consisting of Au, W and a combination thereof. A polymer electrolyte membrane An anode electrode and a cathode electrode located on both sides of the polymer electrolyte membrane and a fuel crossover suppression layer positioned between the polymer electrolyte membrane and the anode electrode and the cathode electrode, comprising a carbon nanotube and a metal rod (rod) And at least one membrane-electrode assembly and a separator, wherein the axis of the carbon nanotube and the surface of the polymer electrolyte membrane are not parallel to each other, and generate electricity through oxidation of a fuel and reduction of an oxidant. At least one electricity generating unit; A fuel supply unit supplying fuel to the electricity generation unit; And Oxidant supply unit for supplying an oxidant to the electricity generating unit Fuel cell system comprising a. The method of claim 7, wherein The angle of the axis of the carbon nanotubes and the surface of the polymer electrolyte membrane is 70 to 90 ° fuel cell system. The method of claim 7, wherein The fuel cell system is located on the end surface of the carbon nanotubes located in the direction of the catalyst layer of the anode electrode or the cathode electrode. The method of claim 7, wherein The metal rod has a height of 100-500 nm. The method of claim 7, wherein The metal rod is selected from the group consisting of Au, W, Pt, Mo, Cu, Pd, Ru, and combinations thereof. The method of claim 11, The metal rod is selected from the group consisting of Au, W, and combinations thereof. The method of claim 7, wherein The fuel cell system is a direct oxidation fuel cell system. The method of claim 7, wherein And the fuel is a hydrocarbon fuel.

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