KR20080010575A - Method of preparing membrane-electrode assembly - Google Patents

Abstract

A method for preparing a membrane electrode assembly for a fuel cell, a membrane electrode assembly prepared by the method, and a fuel cell system containing the membrane electrode assembly are provided to minimize the damage of a catalyst layer during the manufacturing process and to improve the performance of a fuel cell by minimizing the interference resistance between a polymer electrolyte membrane and a catalyst layer. A method for preparing a membrane electrode assembly comprises the steps of (S1) forming a catalyst on the one side of an electrode substrate with an interval from the outer circumference of a first electrode substrate to the inside, thereby forming a first electrode; (S2) adhering a releasing film to the circumference of the first electrode substrate; (S3) coating a polymer electrolyte membrane composition on the first electrode substrate where a releasing film is adhered, thereby forming a polymer electrolyte membrane; (S4) removing the releasing film from the first electrode substrate; and (S5) forming a catalyst layer on a second electrode substrate, thereby forming a second electrode, and adhering the second electrode to the other side of the polymer electrolyte membrane.

Description

Manufacturing method of membrane-electrode assembly for fuel cell {METHOD OF PREPARING MEMBRANE-ELECTRODE ASSEMBLY}

1 is a process diagram schematically showing a method of manufacturing a membrane-electrode assembly for a fuel cell according to an embodiment of the present invention.

2 schematically illustrates a membrane-electrode assembly for a fuel cell according to another embodiment of the present invention.

3 is a view schematically showing the structure of a fuel cell system according to another embodiment of the present invention.

[Industrial use]

The present invention relates to a method for manufacturing a fuel cell membrane electrode assembly, and more particularly, to a method for manufacturing a fuel cell membrane electrode assembly capable of minimizing damage to a catalyst layer during a manufacturing process.

[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 the 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 method of manufacturing a membrane-electrode assembly for a fuel cell, in which the manufacturing process is simple and the damage of the catalyst layer can be minimized during manufacturing.

In order to achieve the above object, the present invention forms a catalyst layer on one surface of the electrode substrate at intervals inward from the outer edge of the first electrode substrate to form a first electrode, the release film on the edge of the first electrode substrate To form a polymer electrolyte membrane by applying the composition for forming a polymer electrolyte membrane on the first electrode substrate having the release film attached thereto, removing the release film from the first electrode substrate, and forming a catalyst layer on the second electrode substrate. By manufacturing a second electrode and then bonding the second electrode to the other surface of the polymer electrolyte membrane.

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

In a fuel cell, the membrane-electrode assembly is composed of a polymer electrolyte membrane and anode and cathode electrodes positioned on both sides of the polymer electrolyte membrane. In this membrane-electrode assembly, electricity is generated by oxidation and reduction reactions by fuel and oxidant. Let's do it. The reaction occurring in the membrane-electrode assembly may occur well when the interfacial adhesion between the polymer electrolyte membrane and the electrode is excellent, and the contact area with the electrode at the interface should be wide.

Typically, the membrane-electrode assembly is prepared by forming a catalyst layer on an electrode substrate and then bonding it to a polymer electrolyte membrane, or first forming a catalyst layer on a polymer electrolyte membrane and then bonding it to an electrode substrate.

However, these methods have a high risk of damaging the catalyst layer, and as a result, the resistance between the catalyst layer and the polymer electrolyte membrane in the prepared membrane-electrode assembly increases.

On the other hand, in the present invention, by forming a polymer electrolyte membrane using a doctor blade on the electrode substrate on which the catalyst layer is formed, the membrane-electrode assembly can be easily manufactured and the damage of the catalyst layer during the manufacturing process can be minimized. As a result, the manufactured membrane-electrode assembly can minimize the resistance on the polymer electrolyte membrane and the catalyst layer to improve the performance of the fuel cell.

1 is a process diagram briefly showing a method of manufacturing a membrane-electrode assembly according to an embodiment of the present invention.

Referring to FIG. 1, in the method of manufacturing a membrane-electrode assembly according to an embodiment of the present invention, a first electrode is formed by forming a catalyst layer on one surface of the electrode substrate at intervals inward from an outer edge of the first electrode substrate. Forming (S1), attaching a release film to the edge of the first electrode substrate (S2), and forming a polymer electrolyte membrane by applying a composition for forming a polymer electrolyte membrane on the first electrode substrate to which the release film is attached. (S3), removing the release film from the first electrode substrate (S4), forming a catalyst layer on the second electrode substrate to manufacture a second electrode, and then preparing the second electrode on the other side of the polymer electrolyte membrane. Bonding to one surface (S5).

More specifically, first, the first electrode substrate is prepared.

A conductive substrate may be used as the first electrode substrate, and a representative example thereof may be carbon paper, carbon cloth, carbon felt, or metal cloth (metal in a fiber state). Or a metal film formed on the surface of the cloth formed of a porous film or a polymer fiber composed of a cloth (referring to a metalized polymer fiber), and the like, but is not limited thereto.

In addition, the first electrode base material is water-repellent with a fluorine resin such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated ethylene propylene, polychlorotrifluoroethylene or fluoroethylene polymer. The treatment is more preferable because the gas diffusion efficiency can be prevented from being lowered by water generated when the fuel cell is driven.

In addition, a microporous layer may be formed on the electrode substrate to enhance the diffusion effect of the reactants on the electrode substrate.

The microporous layer is generally a conductive powder having a small particle diameter, for example, carbon powder, carbon black, acetylene black, activated carbon, carbon fiber, fullerene, carbon nanotube, carbon nanowire, carbon nano horn (carbon nano) -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. As the binder resin, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, cellulose acetate, and the like may be preferably used. The solvent may be ethanol, isopropyl alcohol, n-propyl alcohol, butyl alcohol, or the like. Alcohol, water, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone and the like can 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.

Subsequently, the first electrode is formed by forming a catalyst layer on one surface of the electrode substrate at intervals inward from the outer edge of the first electrode substrate (S1).

The catalyst layer formation may be performed by direct application or transfer coating.

When the catalyst layer is formed by the direct coating method, the composition for forming a catalyst layer containing the catalyst may be directly applied to the electrode substrate and then dried. At this time, the coating process is made of a screen printing method, a spray coating method, a coating method using a doctor blade, a gravure coating method, a dip coating method, a silk screen method, a painting method, and a slot die method according to the viscosity of the composition. It may be carried out by a method selected from the group, but is not limited thereto. More preferably, the screen printing method can be used.

The catalyst layer forming composition includes a catalyst and a solvent.

As the catalyst, any one that can be used as a catalyst may participate in the reaction of the fuel cell, and as a representative example, a platinum-based catalyst may be used. 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, and Rh). 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 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 catalyst may be used as the catalyst itself (black), or may be used on a carrier. As the carrier, carbon-based materials such as graphite, denka black, ketjen black, acetylene black, carbon nanotube, carbon nanofiber, carbon nanowire, carbon nanoball, or activated carbon may be used, and alumina, silica, zirconia, Or inorganic fine particles such as titania may be used, but carbon-based materials are generally used.

It is preferable to use the solvent which shows polarity as said solvent. Specifically water; Alcohol solvents such as methanol, ethanol and isopropyl alcohol; Amide solvents such as N, N-dimethylacetamide (DMAC), N-methyl pyrrolidone (NMP) and dimethylformamide (DMF); And sulfoxide solvents such as dimethyl sulfoxide and the like.

The catalyst layer forming composition may further include 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. Specifically, 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 A hydrogen ion conductive polymer selected from the group consisting of ether ketone polymers, polyphenylquinoxaline polymers, copolymers thereof and mixtures thereof, preferably poly (perfluorosulfonic acid), poly (purple) Fluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones, aryl ketones, poly (2,2'-m-phenylene) -5, 5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole), copolymers thereof and mixtures thereof Selected from military It may be a hydrogen ion conductive polymer.

When the catalyst layer is formed by the transfer coating method, the catalyst layer may be formed by applying the catalyst layer-forming composition to a release film and drying to form a catalyst layer, which is then transferred to an electrode substrate by hot rolling. The catalyst layer forming composition is the same as described above.

Examples of the release film include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) ethylene / tetrafluoro the ethylene (ethylene / Tetrafluoroethylene (ETFE)), such as the fluorine resin film, or polyimide (Kapton ^®, DuPont Co.), a polyester wherein the release film, it is possible to use a non-fluorine-based polymer film, such as (Mylar ^®, DuPont Co.) The coating step of the composition for forming a catalyst layer is as described above.

In the transfer coating process, the catalyst layer formed on the release film is placed on an electrode substrate, and then hot rolled to transfer the catalyst layer. The temperature at the time of hot rolling is 100-250 degreeC, More preferably, it is 100-200 degreeC. In addition, the pressure during hot rolling is preferably 700 to 2000 psi, more preferably 700 to 1500 psi. Within the above temperature and pressure range, the catalyst layer is smoothly transferred, and if it is out of the above range, the catalyst layer is not completely transferred or the catalyst layer has an excessively dense structure.

Thereafter, a release film is attached to an edge portion of the electrode substrate on which the catalyst layer is not formed with respect to the first electrode substrate on which the catalyst layer is formed (S2).

The release film is to match the height difference between the place where the catalyst layer is formed and the portion is not formed, it is preferable to use a film that can be easily peeled off.

The release film may be the same as the release film described above when forming the catalyst layer.

Subsequently, the polymer electrolyte membrane-forming composition is coated on the first electrode substrate to which the release film is attached (S3).

The polymer electrolyte membrane-forming composition may be prepared by dissolving a cation exchange resin in a solvent.

As the cation exchange resin, any of a cationic polymer resin having hydrogen ion conductivity can 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.

Specific 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 A hydrogen ion conductive polymer selected from the group consisting of a polymer, a polyether-etherketone-based polymer, a polyphenylquinoxaline-based polymer, a copolymer thereof and a mixture thereof can be used, and more preferably poly (perfluorosulfonic acid). ), Poly (perfluorocarboxylic acid), copolymer of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid group, defluorinated sulfide polyether ketone, aryl ketone, poly (2,2'-m-phenyl Ethylene) -5,5'-bibenzimidazole (poly (2,2 '-(m-phenylene) -5,5'-bibenzimidazole), poly (2,5-benzimidazole) copolymers thereof and these Mixture of It may be selected from selected from the group consisting of.

It is preferable to use the solvent which shows polarity as said solvent. Specifically water; Alcohol solvents such as methanol, ethanol and isopropyl alcohol; Amide solvents such as N, N-dimethylacetamide (DMAC), N-methyl pyrrolidone (NMP) and dimethylformamide (DMF); And sulfoxide solvents such as dimethyl sulfoxide and the like.

The polymer electrolyte membrane-forming composition may further include an inorganic additive to reduce fuel permeability of the polymer electrolyte membrane.

Examples of the inorganic additives include silica (fumed silica), trade names include Aerosil, Cab-O-sil, etc., alumina, mica, and zeolite (trade names SAPO-5, XSM-5, AIPO- 5, VPI-5, MCM-41, etc.), barium titanate, ceramic, inorganic silicate, zirconium hydrogen phosphate, α-Zr (O _a1 PCH _a2 OH) _a (O _b1 PC _b2 H _b4 SO _b5 H) _b · nH ₂ O (where, a1, a2, a, b1 , b2, b4, b5 and b are the same or independently represent an integer of 0 to 14 to each other, n is an integer of 0 to 50), ν-Zr ( PO _a1 ) (H _a2 PO _a3 ) _a (HO _b1 PC _b2 H _b3 SO _b4 H) _b nH ₂ O (where a1, a2, a3, a, b1, b2, b3, b4 and b are the same or Independently of each other, an integer from 0 to 14, n is an integer from 0 to 50), Zr (O _a1 PC _a2 H _a3 ) _a Y _b (where a1, a2, a3, a and b are the same or independently of each other) an integer of from 0 to _{14), Zr (O a1 PCH} a2 OH) a Y b · nH 2 O ( where, a1, a2, a and b are same or Are independently from 0 to 14, an integer to each other, n is an integer of 0 to 50), α-Zr (O a1 PC a2 H a3 SO a4 H) a · nH 2 O ( where, a1, a2, a3, a4 and a is the same or independently of each other is an integer from 0 to 14, n is an integer from 0 to 50), α-Zr (O _a1 POH) H ₂ O (where a1 is an integer from 0 to 14), (P ₂ O ₅ ) _a (ZrO ₂ ) _b (where a and b are the same or independently of each other an integer from 0 to 14) glass and P ₂ O ₅ -ZrO ₂ -SiO ₂ One or more mixtures selected from the group consisting of glass are preferred, with inorganic silicates being most preferred.

The prepared polymer electrolyte membrane-forming composition may have a viscosity of 800 to 1500 cps, more preferably 1000 to 1200 cps. If the viscosity of the composition is less than 800 cps, uniform dispersion and stability are inferior, and if it is more than 1500 cps, coating becomes uneven, which is not preferable.

Thereafter, the prepared polymer electrolyte membrane-forming composition may be uniformly mixed by mechanical mixing or ultrasonic mixing.

The composition for forming a polymer electrolyte membrane prepared as described above is coated on a first electrode substrate having a catalyst layer formed thereon and a release film attached to an edge portion outside the catalyst layer forming portion.

At this time, the coating process of the composition for forming the polymer electrolyte membrane is screen printing method, spray coating method, coating method using a doctor blade, gravure coating method, dip coating method, silk screen method, painting method, slot die ( slot die) method, and a combination thereof may be performed by a method selected from the group consisting of, but is not limited thereto. More preferably, the doctor blade method which can apply | coat a polymer electrolyte membrane to uniform thickness can be used.

Thereafter, the coated polymer electrolyte membrane-forming composition is dried to form a polymer electrolyte layer. In this way, the polymer electrolyte membrane-forming composition may be applied to form a polymer electrolyte membrane on the catalyst layer, thereby minimizing damage to the catalyst layer and simultaneously manufacturing a membrane-electrode assembly.

The release film is removed from the first electrode substrate (S4).

Subsequently, a second electrode manufactured by forming a catalyst layer on the second electrode substrate is bonded to the other surface of the polymer electrolyte membrane (S5) to prepare a membrane-electrode assembly (S6).

The method of forming the second electrode is the same as the method of forming the first electrode. In addition, the method of adhering the second electrode to the polymer electrolyte membrane may be carried out by a conventional method such as physically adhering.

The present invention also provides a membrane-electrode assembly manufactured by the above manufacturing method.

2 is a schematic cross-sectional view of a membrane-electrode assembly for a fuel cell of the present invention. Referring to FIG. 2, the membrane-electrode assembly 10 according to an embodiment of the present invention includes the polymer electrolyte membrane 50 and the fuel cell electrodes 20 and 20 disposed on both surfaces of the polymer electrolyte membrane 50, respectively. Include '). The electrode includes electrode substrates 40 and 40 'and catalyst layers 30 and 30' formed on the surface of the electrode substrate.

In the membrane-electrode assembly 10, the electrode 20 disposed on one surface of the polymer electrolyte membrane 50 is called an anode electrode (or a cathode electrode), and the electrode 20 ′ disposed on the other surface is called a cathode electrode ( Or anode electrode). The anode electrode 20 causes an oxidation reaction to generate hydrogen ions and electrons from the fuel delivered to the catalyst layer 30 through the electrode base 40, and the polymer electrolyte membrane 50 is hydrogen generated from the anode electrode 20. Ions are moved to the cathode electrode 20 ', and the cathode electrode 20' passes through the hydrogen ions supplied through the polymer electrolyte membrane 50 and the electrode base 40 'and is transferred to the catalyst layer 30'. Causes a reduction reaction to produce water.

The present invention also provides a fuel cell system comprising a membrane-electrode assembly.

The fuel cell system includes at least one electricity generating unit including the membrane-electrode assembly and the separator, and includes a fuel supply unit supplying fuel to the electricity generating unit and an oxidant supply unit supplying an oxidant to the electricity generating unit.

The electricity generating unit includes a membrane-electrode assembly, a separator (also called a bipolar plate), 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 generation unit, and the oxidant supply unit serves to supply an oxidant such as oxygen or air to the electricity generation unit. Fuels in the present invention include hydrogen or hydrocarbon fuels 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. 3, which will be described in more detail with reference to the following. Although the structure shown in FIG. 3 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 does not use a pump, but uses a fuel diffusion method. Of course, it can also be used in the battery system structure.

 The fuel cell system 100 of the present invention includes at least one electricity generation unit 115 for generating electrical energy through an oxidation reaction of a fuel and a reduction reaction of an oxidant, a fuel supply unit 120 for supplying the fuel, And an oxidant supply unit 130 for supplying an oxidant to the electricity generating unit 115.

In addition, the fuel supply unit 120 for supplying the fuel may include a fuel tank 122 storing fuel and a fuel pump 124 connected to the fuel tank 122. The fuel pump 124 serves to discharge the fuel stored in the fuel tank 122 by a predetermined pumping force.

The oxidant supply unit 130 supplying the oxidant to the electricity generating unit 115 includes at least one oxidant pump 132 that sucks the oxidant with a predetermined pumping force.

The electricity generator 115 includes a membrane-electrode assembly 112 for oxidizing and reducing a fuel and an oxidant, and a separator 114 and 114 'for supplying fuel and an oxidant to both sides of the membrane-electrode assembly. At least one electricity generating unit 115 gathers to form a stack 110.

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)

Pt black (Hispec ^® 1000, manufactured by Johnson Matthey) and Pt / Ru black (Hispec ^® 6000, manufactured by Johnson Matthey) in 10 grams of Nafion (Nafion ^® , 4.5 g of an aqueous dispersion was added dropwise, followed by mechanical stirring to prepare a composition for forming a catalyst layer. The catalyst layer forming composition was directly coated on one surface of the carbon paper electrode substrate by screen printing to prepare a cathode electrode and an anode electrode, respectively. At this time, the catalyst layer forming area is 5 X 5 cm ^{2 And the} catalyst loading amount is 3 mg / cm ² respectively.

In the electrode substrate on which the catalyst layer was formed, a release film of polytetrafluoroethylene having a height equal to the height of the catalyst layer was attached to an edge portion of the catalyst layer that is not formed.

Separately, a commercially available 5 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc., EW = 1,100) solution was stirred at room temperature and evaporated under reduced pressure, and then dimethylacetamide (10 wt%) DMAc) was added and mechanically stirred at 100 ° C. for 24 hours to prepare a composition for polymer electrolyte membrane formation.

The prepared polymer electrolyte membrane-forming composition was coated on the electrode substrate with the release film using a doctor blade and then dried to form a polymer electrolyte membrane. The release film attached to the edge of the catalyst layer was peeled off.

After preparing the electrode in the same manner as before and attached to the remaining surface of the polymer electrolyte membrane to prepare a membrane-electrode assembly. The prepared membrane-electrode assembly was 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 prepare a unit cell.

(Example 2)

A commercially available 5 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc., EW = 1,100) solution was stirred at room temperature and evaporated under reduced pressure, and then dimethylacetamide (DMAc) at a concentration of 10 wt%. ) And mechanical stirring at 100 ° C. for 24 hours to prepare a cation exchange resin solution (10 wt% Nafion / DMF) with hydrogen ion conductivity. It was carried out in the same manner as in Example 1 except for using a composition for forming a polymer electrolyte membrane prepared by further dispersing 3 parts by weight of an inorganic additive of phosphotungstic acid supported on montmorillonite with respect to 100 parts by weight of the cation exchange resin A cell was prepared.

(Comparative Example 1)

4.5 g of 10 wt% Nafion (Nafion ^® , manufactured by Dupont) aqueous dispersion was added dropwise to 3.0 g of Pt black (Hispec ^® 1000, manufactured by Johnson Matthey) and Pt / Ru black (Hispec ^® 6000, manufactured by Johnson Matthey), and mechanically By stirring, a composition for forming a catalyst layer was prepared.

The composition for forming the catalyst layer was directly coated on one surface of the carbon paper electrode substrate by screen printing. At this time, the catalyst layer forming area is 5 X 5 cm ^{2 And the} catalyst loading amount is 3 mg / cm ² respectively.

Separately, a commercially available 5 wt% Nafion / H ₂ O / 2-propanol (Solution Technology Inc., EW = 1,100) solution was stirred at room temperature and evaporated under reduced pressure, and then dimethylacetamide (10 wt%) DMAc) was added and mechanically stirred at 100 ° C. for 24 hours to prepare a composition for polymer electrolyte membrane formation.

The prepared polymer electrolyte membrane-forming composition was applied to a glass substrate by screen printing and then dried to form a polymer electrolyte layer. The polymer electrolyte layer was separated from the glass substrate to prepare a polymer electrolyte membrane.

Electrodes were placed on both sides of the polymer electrolyte membrane and then physically bonded to prepare a membrane-electrode assembly. The prepared membrane-electrode assembly was inserted between two gaskets, and then inserted into two separators in which gas flow channels and cooling channels of a certain shape were formed and pressed between copper end plates to prepare a unit cell.

1M methanol solution was used as an anode fuel for the cells prepared in Example 1 and Comparative Example 1, and air was injected into the cathode to observe voltage-current characteristics at 70 ° C.

As a result of the measurement, the unit cell of Example 1 including the polymer electrolyte membrane prepared using the doctor blade showed an excellent power density compared to the unit cell of Comparative Example 1 prepared by a conventional polymer electrolyte membrane production method. This result is because, in Comparative Example 1, the polymer electrolyte membrane and the catalyst layer were damaged in the peeling process from the glass substrate and the bonding process with the electrode during the preparation of the polymer electrolyte membrane, and thus the uniform thickness and pattern were not formed. This is because the cell resistance of 1 decreases the interfacial resistance due to an increase in the bonding force between the polymer electrolyte membrane and the catalyst layer.

The membrane-electrode assembly can be easily formed by the membrane-electrode assembly manufacturing method of the present invention, and damage to the catalyst layer can be minimized during the manufacturing process. In addition, the manufactured membrane-electrode assembly may minimize the resistance between the polymer electrolyte membrane and the catalyst layer to improve the performance of the fuel cell.

Claims (10)

Forming a first electrode by forming a catalyst layer on one surface of the electrode substrate at intervals inwardly from an outer edge of the first electrode substrate; Attaching a release film to an edge of the first electrode substrate; Forming a polymer electrolyte membrane by applying a composition for forming a polymer electrolyte membrane on the first electrode substrate having the release film attached thereto; Removing the release film from the first electrode substrate; And Preparing a second electrode by forming a catalyst layer on a second electrode substrate, and bonding the prepared second electrode to the other surface of the polymer electrolyte membrane Method of manufacturing a membrane-electrode assembly for a fuel cell comprising a. The method of claim 1, The polymer electrolyte membrane-forming composition is a method for producing a fuel cell membrane-electrode assembly comprising a cation exchange resin. The method of claim 2, The cation exchange resin is 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. The method of claim 1, The polymer electrolyte membrane-forming composition further comprises an inorganic additive. The method of claim 1, The polymer electrolyte membrane-forming composition is a method of manufacturing a membrane-electrode assembly for a fuel cell having a viscosity of 2000 to 10000cps. The method of claim 1, The coating process of the composition for forming a polymer electrolyte membrane may include screen printing, spray coating, coating using a doctor blade, gravure coating, dip coating, silk screen, painting, slot die, and the like. The manufacturing method of the membrane-electrode assembly for fuel cells which is implemented by the method chosen from the group which consists of these combinations. The method of claim 1, The method of applying the polymer electrolyte membrane-forming composition is a method for producing a membrane-electrode assembly for a fuel cell that is carried out by a coating method using a doctor blade. The method of claim 1, The release film is a polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene- perfluoroalkyl vinyl ether copolymer, ethylene / tetrafluoroethylene, polyvinylidene fluoride, poly Mead, polyethylene, polypropylene, polyethylene terephthalate, polyester, copolymers thereof, and mixtures thereof.  A membrane-electrode assembly for a fuel cell manufactured by the manufacturing method according to any one of claims 1 to 8. At least one electricity generating unit comprising a membrane-electrode assembly and a separator manufactured by the manufacturing method according to any one of claims 1 to 8, for generating electricity through the electrochemical reaction of the fuel and the oxidant; 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.

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