KR100953617B1 - Electrode for fuel cell, membrane-electrode assembly for fuel cell comprising same, and fuel cell system comprising same - Google Patents

Abstract

The present invention relates to a fuel cell electrode and a fuel cell membrane-electrode assembly including the same, wherein the electrode includes an electrode substrate and a catalyst layer formed on the electrode substrate and including an active catalyst and a heteropolyacid additive supported on an inorganic carrier. .

Since the electrode for fuel cells of the present invention includes an additive having high electron and hydrogen ion conductivity, it can exhibit high power and is economical because this additive also serves to replace an expensive catalyst.

Fuel Cell, Heteropoly Acid, Additive, Output

Description

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

The present invention relates to a fuel cell electrode, a fuel cell membrane-electrode assembly including the same, and a fuel cell system including the same, and more particularly, to display a high output and economical fuel cell electrode, including a fuel cell membrane including the same. An electrode assembly and a fuel cell system comprising the same.

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.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode for fuel cells which can improve the output and is economical.

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

Yet another object of the present invention is to provide a fuel cell system comprising the membrane-electrode assembly.

In order to achieve the above object, the present invention provides an electrode for a fuel cell comprising an electrode substrate and a catalyst layer formed on the electrode substrate and comprising a heteropolyacid additive supported on an active catalyst and an inorganic carrier.

The additive has an average particle diameter of 1 nm to 100 μm.

The inorganic carrier may be selected from the group consisting of SiO ₂ , zeolite, alumina or combinations thereof.

The heteropolyacid is [PMo ₁₂ O ₄₀ ] ^3- , [PW ₁₂ O ₄₀ ] ^3- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeW ₁₂ O ₄₀ ] ^4- , [P ₂ W ₁₈ O ₆₂ ] ^6- , [SiW ₁₂ O ₄₀ ] ^4- , [PMo ₁₁ O ₃₉ ] ^7- , [P ₂ Mo ₅ O ₂₃ ] ^6- , [H ₂ W ₁₂ O ₄₀ ] ^6- and [PW ₁₁ O ₃₉ ] ^7- It may include at least one compound containing an anion selected from the group.

The heteropolyacid may include at least one compound including H ⁺ cation.

The supported amount of the heteropolyacid may be 0.01 to 10% by weight, preferably 0.1 to 5% by weight based on the weight of the carrier.

The invention also includes an anode electrode and a cathode electrode positioned opposite each other and a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode, wherein at least one of the anode electrode and the cathode electrode is an electrode having the above configuration. Provide an electrode assembly.

The invention also provides a fuel cell system comprising at least one electricity generator, a fuel supply and an oxidant supply. The electricity generating unit includes a membrane-electrode assembly including the electrode of the present invention and includes a separator. In addition, the electricity generating 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.

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

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an electrode for a fuel cell, and recently, research as a high active electrode catalyst has been actively conducted.

Among them, heteropoly acid such as H ₃ PW ₁₂ O ₄₀ is a solid catalyst, and has been recognized as a platinum-based alternative high activity catalyst because of its high electron and hydrogen ion conductivity. However, there are limitations in the practical use because it dissolves well in a polar aqueous solution such as water, methanol and ethanol, and a large amount of catalyst does not react and easily desorbs from the carrier.

In the present invention, the heteropoly acid was supported on the inorganic carrier and then used as an additive in the electrode to improve the output.

The electrode of the present invention includes an electrode substrate and a catalyst layer formed on the electrode substrate and comprising an active catalyst and an additive. The additive includes a heteropoly acid supported on an inorganic carrier. When the heteropoly acid is not supported on the inorganic carrier, the heteropoly acid is dissolved in a fuel that is a reactant, that is, a hydrocarbon fuel or, optionally, a mixture with water, so that the output is not maintained.

It is preferable that the said additive has an average particle diameter of 1 nm-100 micrometers, and it is more preferable to have an average particle diameter of 50-100 nm. When the average particle diameter of the additive is included in the above range, the size is almost similar to that of the catalyst, so that it may be uniformly mixed, so that other effects on the use of the additive may be uniformly obtained.

The inorganic carrier is preferably selected from the group consisting of SiO ₂ , zeolite and alumina. In the case of using such a carrier, the heteropoly acid can be more stably supported, and as a result, the effect of using the heteropoly acid can be maximized.

The heteropolyacid is [PMo ₁₂ O ₄₀ ] ^3- , [PW ₁₂ O ₄₀ ] ^3- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeW ₁₂ O ₄₀ ] ^4- , [P ₂ W ₁₈ O ₆₂ ] ^6- , [SiW ₁₂ O ₄₀ ] ^4- , [PMo ₁₁ O ₃₉ ] ^7- , [P ₂ Mo ₅ O ₂₃ ] ^6- , [H ₂ W ₁₂ O ₄₀ ] ^6- and [PW ₁₁ O ₃₉ ] ^7- It is preferable to include at least one compound containing an anion selected from the group. As the cation of the heteropolyacid, H ⁺ is preferable. Such heteropolyacids are highly electron and hydrogen ion conductive materials.

The supported amount of the heteropolyacid is preferably 0.01 to 10% by weight based on the weight of the carrier, and if the supported amount is less than 0.01% by weight, the effect is too small and problematic. It is not preferable because it may be.

The additive may be obtained by dissolving the heteropolyacid in a solvent and then mixing with a nano-sized inorganic carrier. In this case, any solvent having polar polarity such as H ₂ O, ethanol, methanol, isopropyl alcohol, and the like may be used.

In the present invention, the content of the additive is preferably 0.1 to 5% by weight based on the total weight of the catalyst layer. When the content of the additive is less than 0.1% by weight, other effects on the use of the additive are insignificant, and when the content of the additive is more than 5% by weight, the thickness of the catalyst layer increases as a result of the increase in the content of the additive, which is not preferable because the output is lowered.

The active catalyst may participate in the reaction of a fuel cell, and any one that can be used as a catalyst may be used, and a 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 and Ru). 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 fluoropolymer, 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) can 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 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.

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 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 electrode of the present invention may be formed by mixing the additive with an active catalyst and then mixing the obtained mixture with a binder to prepare a catalyst composition, or by mixing the additive with a binder first, then mixing the obtained mixture with an active catalyst The catalyst composition may also be prepared and formed. Since the process of forming the electrode using the catalyst composition is well known in the art, detailed description thereof will be omitted. The mixing process may be carried out in a separate solvent, and since the binder is generally sold in a form present in the solvent, it may not be necessary to use a separate solvent. When using a solvent, alcohols such as ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, water, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone tetrahydrofuran, etc. are preferably used. Can be. 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 of the present invention having the above configuration can be used for either or both of the anode electrode and the cathode electrode. When the electrode of the present invention is used for the anode electrode, the fuel oxidation ability can be improved, and when used for the cathode electrode, the hydrogen ion conductivity can be improved, and as a result, the oxidant reduction reaction is improved to obtain a high output membrane-electrode assembly. Can be. In addition, inexpensive heteropolyacids can also serve as catalysts compared to conventional platinum catalysts, and the amount of catalyst used can be reduced by the amount of heteropolyacids, which is economical.

The membrane-electrode assembly for a fuel cell of the present invention including the electrode as at least one of an anode electrode and a cathode electrode includes a polymer electrolyte membrane positioned between an anode electrode and a cathode electrode positioned to face each other.

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 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), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones, aryl ketones, poly (2,2'-m-phenylene)- And at least one selected from 5,5'-bibenzimidazole [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 of the present invention including the membrane-electrode assembly also includes at least one electricity generator, a fuel supply and an oxidant supply.

The electricity generating portion includes a membrane-electrode assembly and a separator (also called bipolar plate). The membrane-electrode assembly includes a polymer electrolyte membrane and cathode and anode electrodes existing on both sides of the polymer electrolyte membrane. 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 hydrogen or hydrocarbon fuel in gas or liquid state. 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. 1, which will be described in more detail with reference to the following. Although the structure shown in FIG. 1 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, 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)

After dissolving H ₃ PW ₁₂ O ₄₀ in a water solvent, it was supported on an SiO ₂ (specific surface area: 150 m ² / g) carrier having an average particle diameter of 100 nm to prepare an H ₃ PW ₁₂ O ₄₀ additive supported on an SiO ₂ carrier. It was. At this time, the loading amount of the H ₃ PW ₁₂ O ₄₀ was 0.01% by weight based on the weight of SiO ₂ .

5% of the prepared additives and 95% by weight of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst were mixed. A catalyst composition for the anode electrode was prepared by mixing 88% by weight of the obtained mixture and 12% by weight of 5% by weight Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder.

88 wt% Pt black (Johnson Matthey, HiSpec 100) cathode catalyst and 12 wt% Nafion / H ₂ O / 2-propanol (concentration: 5 wt%, Solution Technology Inc.) binder were mixed to form a catalyst composition for the cathode electrode. Prepared.

The anode electrode catalyst composition and the cathode electrode catalyst composition were coated on carbon paper to prepare an anode electrode and a cathode electrode, respectively.

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

The fuel cell membrane-electrode assembly is inserted between two gaskets, and then inserted into two separators having a predetermined gas flow channel and a cooling channel and pressed between copper end plates to manufacture a unit cell. It was.

(Example 2)

Except for changing the amount of H ₃ PW ₁₂ O ₄₀ to 1% by weight relative to the weight of SiO ₂ it was performed in the same manner as in Example 1.

(Example 3)

The loading of H ₃ PW ₁₂ O ₄₀ was carried out in the same manner as in Example 1 except for changing the loading amount to 2 wt% based on the weight of SiO ₂ .

(Example 4)

The loading of H ₃ PW ₁₂ O ₄₀ was carried out in the same manner as in Example 1 except for changing the loading amount to 6 wt% based on the weight of SiO ₂ .

(Example 5)

The loading was carried out in the same manner as in Example 1 except that the loading amount of H ₃ PW ₁₂ O ₄₀ was changed to 10 wt% based on the weight of SiO ₂ .

(Reference Example 1)

Except for changing the amount of H ₃ PW ₁₂ O ₄₀ to 0.001% by weight relative to the weight of SiO ₂ it was performed in the same manner as in Example 1.

(Reference Example 2)

Except for changing the amount of H ₃ PW ₁₂ O ₄₀ to 11% by weight relative to the weight of SiO ₂ it was performed in the same manner as in Example 1.

 (Example 1)

After dissolving H ₃ PW ₁₂ O ₄₀ in a water solvent, it was supported on an SiO ₂ carrier having a size of 50 nm to prepare an H ₃ PW ₁₂ O ₄₀ additive supported on an SiO ₂ carrier. At this time, the loading amount of the H ₃ PW ₁₂ O ₄₀ was 2% by weight based on the weight of SiO ₂ , the average particle diameter of the additive was 50nm.

5% of the prepared additives and 95% by weight of Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst were mixed, and 88% by weight of this mixture and 5% by weight of Nafion / H ₂ O / 2-propanol (Solution Technology Inc .) 12 wt% of the binder was mixed to prepare a catalyst composition for the anode electrode.

A catalyst composition for the cathode electrode was prepared by mixing 88 wt% Pt black (Johnson Matthey, HiSpec 100) cathode catalyst and 12 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder.

The anode electrode catalyst composition and the cathode electrode catalyst composition were coated on carbon paper to prepare an anode electrode and a cathode electrode, respectively.

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

The fuel cell membrane-electrode assembly is inserted between two gaskets, and then inserted into two separators having a predetermined gas flow channel and a cooling channel and pressed between copper end plates to manufacture a unit cell. It was.

 (Example 2)

5 wt% of the additive prepared in Example 1 and 95 wt% of Pt black (Johnson Matthey, HiSpec 6000) anode catalyst were mixed, and 88 wt% of the mixture and 5 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) was prepared in the same manner as in Example 1, except that 12 wt% of the binder was mixed to prepare a cathode electrode catalyst composition.

(Comparative Example 1)

Pt-Ru Black (Johnson Matthey, HiSpec 6000) 88% by weight of anode catalyst and 5% by weight of Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder was mixed to prepare a catalyst composition for the anode electrode It was.

A catalyst composition for the cathode electrode was prepared by mixing 88 wt% Pt black (Johnson Matthey, HiSpec 100) cathode catalyst and 12 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder.

The anode electrode catalyst composition and the cathode electrode catalyst composition were coated on carbon paper to prepare an anode electrode and a cathode electrode, respectively.

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

The fuel cell membrane-electrode assembly is inserted between two gaskets, and then inserted into two separators having a predetermined gas flow channel and a cooling channel and pressed between copper end plates to manufacture a unit cell. It was.

0.35V, 0.4V and 0.45V output densities of the fuel cells prepared according to Examples 1 to 5, Reference Examples 1 to 2, and Comparative Example 1 were measured at 70 ° C., and the results are shown in Table 1 below.

Loading amount of H ₃ PW ₁₂ O ₄₀ (relative to the weight of SiO ₂ ), wt% 70 ℃, mW / cm ² 0.45V 0.4 V 0.35V Reference Example 1 0.001 85 112 128 Example 1 0.01 85 113 132 Example 2 One 90 125 145 Example 3 2 95 128 154 Example 4 6 98 135 165 Example 5 10 86 115 145 Reference Example 2 11 82 110 131 Comparative Example 1 0 85 112 131

As shown in Table 1, in Examples 1 to 5 in which the H ₃ PW ₁₂ O ₄₀ additive was impregnated in an amount of 0.01 to 10 wt% based on the SiO ₂ carrier, and used in the electrode, It can be seen that the output density is excellent compared to. It can also be seen that when the additives are used in too small amounts (0.001% by weight, Reference Example 1) and in excessive amounts (11% by weight, Reference Example 2), output densities similar to or lower than those of Comparative Example 1 without additives were obtained. have.

(Example 6)

0.1% by weight of the H ₃ PW ₁₂ O ₄₀ additive carried on the carrier in an amount of 2% by weight based on the weight of the SiO ₂ carrier prepared in Example 3, 99.9% by weight of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst The same process as in Example 1 except that the mixture was prepared by mixing with.

(Example 7)

1 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 99 wt% of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst to prepare a mixture as in Example 6 above.

(Example 8)

2 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 99 wt% of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst to prepare a mixture as in Example 6 above.

(Example 9)

3 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 97 wt% of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst to prepare a mixture as in Example 6 above.

(Reference Example 3)

Example 3 was carried out in the same manner as in Example 6, except that 0.01 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 99.99 wt% of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst to prepare a mixture.

(Reference Example 4)

6 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 94 wt% of the Pt-Ru black (Johnson Matthey, HiSpec 6000) anode catalyst to prepare a mixture as in Example 6 above.

0.35V, 0.4V and 0.45V output densities of the fuel cells prepared according to Examples 6 to 9 and Reference Examples 3 to 4 were measured at 70 ° C., and the results are shown in Table 2 below. In addition, the results of Example 3 and Comparative Example 1 are also shown in Table 2 below.

Additive usage, weight percent 70 ℃, mW / cm ² 0.45V 0.4 V 0.35V Reference Example 3 0.01 85 112 131 Example 6 0.1 86 114 132 Example 7 One 88 121 148 Example 8 2 90 123 150 Example 9 3 93 123 152 Example 3 5 95 126 154 Reference Example 4 6 81 128 120 Comparative Example 1 0 85 112 131

As shown in Table 2, in Examples 3, 6 to 9 using the H ₃ PW ₁₂ O ₄₀ additive in an amount of 0.1 to 5% by weight with a Pt anode catalyst in Comparative Example 1 without an additive It can be seen that the output density is excellent compared to. In addition, when the additive is used in a small amount (0.01% by weight, Reference Example 3) and too much (6% by weight, Reference Example 4) relative to the anode catalyst, a power density similar to or lower than that of Comparative Example 1 without using the additive is obtained. It can be seen that.

(Example 10)

0.1 wt% of H ₃ PW ₁₂ O ₄₀ additive supported on the carrier and 99.9 wt% of Pt black (Johnson Matthey, HiSpec 6000) cathode catalyst were mixed in an amount of 2 wt% based on the weight of SiO ₂ carrier prepared in Example 3. It was. A cathode electrode was prepared by using a mixture of 88 wt% of the obtained mixture and 12 wt% of 5 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder to prepare a catalyst composition for the cathode electrode.

Pt-Ru Black (Johnson Matthey, HiSpec 6000) 88% by weight of anode catalyst and 5% by weight of Nafion / H ₂ O / 2-propanol (Solution Technology Inc.) binder was mixed to prepare a catalyst composition for the anode electrode It was.

The anode electrode was prepared by applying the anode catalyst catalyst composition to carbon paper.

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

The fuel cell membrane-electrode assembly is inserted between two gaskets, and then inserted into two separators having a predetermined gas flow channel and a cooling channel and pressed between copper end plates to manufacture a unit cell. It was.

(Example 11)

2 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 98 wt% of the Pt black (Johnson Matthey, HiSpec 6000) cathode catalyst, and was prepared in the same manner as in Example 10, except that the mixture was prepared.

(Example 12)

5 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 95 wt% of the Pt black (Johnson Matthey, HiSpec 6000) cathode catalyst, and was prepared in the same manner as in Example 10, except that the mixture was prepared.

(Reference Example 5)

The same procedure as in Example 10 was conducted except that a mixture was prepared by mixing 0.01 wt% of H ₃ PW ₁₂ O ₄₀ additive with 99.99 wt% of Pt black (Johnson Matthey, HiSpec 6000) cathode catalyst.

(Reference Example 6)

6 wt% of the H ₃ PW ₁₂ O ₄₀ additive was mixed with 94 wt% of the Pt black (Johnson Matthey, HiSpec 6000) cathode catalyst, and was prepared in the same manner as in Example 10, except that the mixture was prepared.

0.35V, 0.4V and 0.45V output densities of the fuel cells prepared according to Examples 10 to 12 and Reference Examples 5 to 6 were measured at 70 ° C., and the results are shown in Table 3 below. In addition, the results of Comparative Example 1 are also shown in Table 3 below.

Additive usage, weight percent 70 ℃, mW / cm ² 0.45V 0.4 V 0.35V Reference Example 5 0.01 85 112 131 Example 10 0.1 87 114 133 Example 11 2 96 130 150 Example 12 5 89 118 134 Reference Example 6 6 86 118 134 Comparative Example 1 0 85 112 131

As shown in Table 3, in the case of Examples 10 to 12 where the H ₃ PW ₁₂ O ₄₀ additive was mixed with the Pt cathode catalyst in an amount of 0.1 to 5% by weight, compared to Comparative Example 1 without using the additive It can be seen that the output density is excellent. In addition, when the additive is used in a small amount (0.01% by weight, Reference Example 5) and too much (6% by weight, Reference Example 6) relative to the cathode catalyst, a power density similar to or lower than that of Comparative Example 1 without using the additive is obtained. It can be seen that.

As a result of measuring the output characteristics of the batteries of Examples 1 to 2 and Comparative Example 1, it was found that Examples 1 to 2 showed a very high output compared to Comparative Example 1. The electrode for a fuel cell of the present invention is a high electron And additives having hydrogen ion conductivity, which can exhibit high power and are also economical because these additives also serve to replace expensive catalysts.

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 schematically showing the structure of a fuel cell system of the present invention.

Claims (21)

Electrode substrates; And A catalyst layer formed on the electrode substrate and comprising a heteropolyacid additive supported on an active catalyst and an inorganic carrier, The content of the additive is a fuel cell electrode of 0.1 to 5% by weight based on the total weight of the catalyst layer. The method of claim 1, The additive is a fuel cell electrode having an average particle diameter of 1nm to 100㎛. The method of claim 1, The inorganic carrier is a fuel cell electrode is selected from the group consisting of SiO ₂ , zeolite and alumina. The method of claim 1, The heteropolyacid is [PMo ₁₂ O ₄₀ ] ^3- , [PW ₁₂ O ₄₀ ] ^3- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeW ₁₂ O ₄₀ ] ^4- , [P ₂ W ₁₈ O ₆₂ ] ^6- , [SiW ₁₂ O ₄₀ ] ^4- , [PMo ₁₁ O ₃₉ ] ^7- , [P ₂ Mo ₅ O ₂₃ ] ^6- , [H ₂ W ₁₂ O ₄₀ ] ^6- and [PW ₁₁ O ₃₉ ] ^7- A fuel cell electrode comprising at least one compound containing an anion selected from the group. The method of claim 1, The heteropolyacid is a fuel cell electrode comprising at least one compound containing a H ⁺ cation. The method of claim 1, The supported amount of the heteropolyacid is a fuel cell electrode of 0.01 to 10% by weight based on the weight of the carrier. The method of claim 1, The content of the additive is a fuel cell electrode of 2 to 5% by weight based on the total weight of the catalyst 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; At least one of the anode electrode and the cathode electrode Electrode substrates; And A catalyst layer formed on the electrode substrate and comprising a heteropolyacid additive supported on an active catalyst and an inorganic carrier, The amount of the additive is 0.1 to 5% by weight based on the total weight of the catalyst layer electrode assembly for a fuel cell. The method of claim 8, The additive is a membrane-electrode assembly for a fuel cell having an average particle diameter of 1nm to 100㎛. The method of claim 8, Wherein the inorganic carrier is selected from the group consisting of SiO ₂ , zeolite and alumina. The method of claim 8, The heteropolyacid is [PMo ₁₂ O ₄₀ ] ^3- , [PW ₁₂ O ₄₀ ] ^3- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeW ₁₂ O ₄₀ ] ^4- , [P ₂ W ₁₈ O ₆₂ ] ^6- , [SiW ₁₂ O ₄₀ ] ^4- , [PMo ₁₁ O ₃₉ ] ^7- , [P ₂ Mo ₅ O ₂₃ ] ^6- , [H ₂ W ₁₂ O ₄₀ ] ^6- and [PW ₁₁ O ₃₉ ] ^7- Membrane-electrode assembly for a fuel cell comprising at least one compound containing an anion selected from the group. The method of claim 8, Wherein said heteropolyacid comprises at least one compound comprising H ⁺ cation. The method of claim 8, The support amount of the heteropolyacid is 0.01 to 10% by weight based on the weight of the carrier membrane-electrode assembly for a fuel cell. The method of claim 8, The amount of the additive is 2 to 5% by weight relative to the total weight of the catalyst layer for a fuel cell membrane electrode assembly. An electricity generator including at least one membrane-electrode assembly and a separator including an anode electrode and a cathode electrode positioned to face each other and a polymer electrolyte membrane positioned between the anode electrode and the cathode electrode; 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: At least one of the anode electrode and the cathode electrode is an electrode substrate; And A catalyst layer formed on the electrode substrate and comprising a heteropolyacid additive supported on an active catalyst and an inorganic carrier, The amount of the additive is 0.1 to 5% by weight based on the total weight of the catalyst layer fuel cell system. The method of claim 15, The additive is a fuel cell system having an average particle diameter of 1nm to 100㎛. The method of claim 15, The inorganic carrier is selected from the group consisting of SiO ₂ , zeolite and alumina. The method of claim 15, The heteropolyacid is [PMo ₁₂ O ₄₀ ] ^3- , [PW ₁₂ O ₄₀ ] ^3- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeW ₁₂ O ₄₀ ] ^4- , [P ₂ W ₁₈ O ₆₂ ] ^6- , [SiW ₁₂ O ₄₀ ] ^4- , [PMo ₁₁ O ₃₉ ] ^7- , [P ₂ Mo ₅ O ₂₃ ] ^6- , [H ₂ W ₁₂ O ₄₀ ] ^6- and [PW ₁₁ O ₃₉ ] ^7- A fuel cell system comprising at least one compound comprising an anion selected from the group. The method of claim 15, Wherein said heteropolyacid comprises at least a compound comprising an H ⁺ cation. The method of claim 15, The supported amount of the heteropoly acid is 0.01 to 10% by weight based on the weight of the carrier. The method of claim 15, The amount of the additive is 2 to 5% by weight based on the total weight of the catalyst layer fuel cell system.

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