WO2018124764A1 - Membrane-electrode assembly, method for manufacturing same, and fuel cell comprising same - Google Patents

Abstract

The present invention relates to a membrane-electrode assembly, a method for manufacturing the same, and a fuel cell comprising the same. The membrane-electrode assembly comprises: a catalyst layer; an interfacial adhesion layer disposed on the catalyst layer, an interface between the interface adhesion layer and the catalyst layer penetrating to some depth of the catalyst layer; and an ion exchange membrane disposed on the interfacial adhesion layer and binding with the catalyst layer via the interfacial adhesion layer, wherein the interfacial adhesion layer contains a fluorine-based ionomer having an equivalent weight (EW) of 500 g/eq to 1000 g/eq. In the membrane-electrode assembly, the problem of deterioration in hydrogen ion conductivity performance of the membrane-electrode assembly can be overcome through the improvement of the interfacial binding and interfacial stability between the electrode and the ion-exchange membrane; the hydrogen gas crossover can be reduced through the reduction in gas permeability without increasing interfacial resistance and interfacial binding problems; and the performance and durability under high temperature/low humidity conditions can be improved.

Description

Membrane-electrode assembly, manufacturing method thereof and fuel cell comprising same

The present invention relates to a membrane-electrode assembly, a method for manufacturing the same, and a fuel cell including the same, wherein the membrane-electrode assembly has improved interfacial adhesion and interfacial stability between the catalyst layer and the ion exchange membrane, and thus hydrogen ion conduction performance of the membrane-electrode assembly. Membrane-electrode capable of overcoming degradation issues, reduced gas permeability without increasing interfacial resistance and interfacial bonding problems, resulting in reduced hydrogen gas crossover, and improved performance and durability at high / low humid conditions An assembly, a method of manufacturing the same, and a fuel cell including the same.

A fuel cell is a battery having a power generation system that directly converts chemical reaction energy such as oxidation / reduction reaction of hydrogen and oxygen contained in hydrocarbon-based fuel materials such as methanol, ethanol and natural gas into electrical energy. Eco-friendly features with low efficiency and low pollutant emissions make it a popular next-generation clean energy source that can replace fossil energy.

This fuel cell has a merit that it can produce a wide range of output by stacking by stacking unit cells, and has attracted attention as a small and portable portable power source because it shows an energy density of 4 to 10 times compared to a small lithium battery. have.

A stack that substantially generates electricity in a fuel cell is made up of several to dozens of unit cells consisting of a membrane-electrode assembly (MEA) and a separator (also called a bipolar plate). In general, the membrane-electrode assembly has a structure in which an anode (Anode, or fuel electrode) and a cathode (Cathode, or air electrode) are formed on both sides of an electrolyte membrane.

Fuel cells may be classified into alkali electrolyte fuel cells and polymer electrolyte fuel cells (PEMFCs) according to the state and type of electrolyte. Among them, polymer electrolyte fuel cells may have a low operating temperature of less than 100 ° C, The advantages of fast start-up, response characteristics, and excellent durability have attracted much attention as portable, automotive, and home power supplies.

Representative examples of polymer electrolyte fuel cells include hydrogen exchange gas fuel cells (Proton Exchange Membrane Fuel Cell, PEMFC), and direct methanol fuel cell (DMFC) using liquid methanol as fuel. Etc. can be mentioned.

Summarizing the reaction occurring in the polymer electrolyte fuel cell, first, when a fuel such as hydrogen gas is supplied to the anode, hydrogen ions (H ⁺ ) and electrons (e ⁻ ) are produced by the oxidation of hydrogen at the anode. The generated hydrogen ions are transferred to the reduction electrode through the polymer electrolyte membrane, and the generated electrons are transferred to the reduction electrode through an external circuit. Oxygen is supplied from the reduction electrode, and oxygen is combined with hydrogen ions and electrons to generate water by a reduction reaction of oxygen.

Meanwhile, miniaturization of a fuel cell system is essential for applying the fuel cell to a FCV (Fuel Cell Vehicle). To this end, the development of a membrane electrode assembly (MEA), which can exhibit an excellent power density per unit area, is required. In particular, increasing the durability of the MEA catalyst layer is necessary for the actual operation of the FCV.

Currently, the MEA for a polymer electrolyte fuel cell for FCV has technical limitations such as a decrease in MEA performance and a significant decrease in durability due to long time operation, and major MEA durability / performance degradation issues are as follows.

That is, the catalyst layer and the catalyst are deteriorated by potential cycling occurring during load cycling, and the carbon carrier is supported by the high cathode potential at startup / shutdown. Problems of corrosion, degradation of physical and chemical durability of thin-film polymer electrolyte membranes to increase conductivity, degradation of performance and durability of MEA due to degradation of functionality and increased resistance at interfaces.

In addition, the degradation of MEA and end-of-life performance during the operation of the polymer electrolyte fuel cell are caused by catalyst degradation, carbon carrier corrosion, durability of the polymer electrolyte membrane, and problems at the interface between the components. It is known.

Of these, in order to solve the problems caused by the degradation in performance and degradation caused by the phenomenon occurring at the MEA interface, it is necessary to develop a technology that can improve the interface adhesion without degradation of the MEA performance.

An object of the present invention is to improve the interfacial bonding and interfacial stability between the catalyst layer and the ion exchange membrane to overcome the problem of deterioration of hydrogen ion conduction performance of the membrane-electrode assembly, the gas permeability is reduced without increasing the interfacial resistance and interfacial bonding problems It is to provide a membrane-electrode assembly in which gas crossover is reduced and performance and durability in high temperature / low humidity conditions can be improved.

Another object of the present invention is to provide a method of manufacturing the membrane-electrode assembly.

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

According to an embodiment of the present invention, the catalyst layer, positioned on the catalyst layer, the interface with the catalyst layer is formed on the interface adhesive layer formed soaking to a depth of the catalyst layer, and is located on the interface adhesive layer, the interface adhesive layer through the An ion exchange membrane is bonded to the catalyst layer, and the interfacial adhesive layer provides a membrane-electrode assembly including a fluorine-based ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq.

The membrane-electrode assembly includes a first interfacial adhesion layer and a first catalyst layer positioned on one surface of the ion exchange membrane, a second interfacial adhesion layer and a second catalyst layer positioned on the other surface of the ion exchange membrane, and the first interfacial adhesion layer, Any one selected from the group consisting of the second interfacial adhesion layer and both may be the interfacial adhesion layer, and any one selected from the group consisting of the first catalyst layer, the second catalyst layer and both may be the catalyst layer. .

The interfacial adhesive layer may be to infiltrate any one selected from the group consisting of pores (surface recesses) formed on the surface of the catalyst layer, pores present at a predetermined depth from the surface of the catalyst layer, and both.

The average depth of the interfacial adhesive layer penetrating the catalyst layer may be 1% to 10% of the average thickness of the catalyst layer.

The average thickness of the interfacial adhesive layer may be 0.01 μm to 5 μm.

The interfacial adhesive layer may include a mixture of the fluorine ionomer and a hydrocarbon ionomer having an ion exchange capacity (IEC) of 0.8 meq / g to 4.0 meq / g.

The weight ratio of the fluorine-based ionomer and the hydrocarbon-based ionomer may be 20: 1 to 1:20.

The interfacial adhesive layer may further include nano powder having an average particle diameter of 1 nm to 50 nm.

The interfacial adhesive layer may include 0.1 wt% to 20 wt% of the nanopowder based on the total weight of the interfacial adhesive layer.

The nano powder may be any one selected from the group consisting of an ionic conductor, a radical scavenger, an oxygen evolution reaction (OER) catalyst, and a mixture thereof.

The ion conductor is SnO ₂ , fumed silica, clay, alumina, mica, zeolite, phosphotungstic acid, silicon tungstic acid ), Zirconium hydrogen phosphate, and any one hydrophilic inorganic additive selected from the group consisting of a mixture thereof.

The radical scavengers are cerium, tungsten, ruthenium, palladium, silver, rhodium, cerium, zirconium, yttrium, manganese, molybdenum, lead, vanadium, titanium, ionic forms thereof, oxide forms thereof, salt forms thereof and their It may be any one selected from the group consisting of a mixture.

The oxygen generation reaction catalyst may be any one platinum-based catalyst selected from the group consisting of platinum, gold, palladium, rhodium, iridium, ruthenium, osmium, platinum alloys, alloys thereof, and mixtures thereof.

According to another embodiment of the present invention, applying the composition for forming an interface adhesive layer on the catalyst layer to form an interface adhesive layer, and bonding the catalyst layer and the ion exchange membrane formed with the interface adhesive layer, the interface adhesive layer is An interface with the catalyst layer penetrates to a depth of the catalyst layer, wherein the interface adhesive layer includes a fluorine-based ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq. It provides a manufacturing method.

The interfacial adhesive layer may be formed by spray coating the composition for forming the interfacial adhesive layer on the catalyst layer.

The interfacial adhesive layer may include a mixture of the fluorine ionomer and a hydrocarbon ionomer having an ion exchange capacity (IEC) of 0.8 meq / g to 4.0 meq / g.

The interfacial adhesive layer may further include nano powder having a particle diameter of 1 nm to 50 nm.

According to another embodiment of the present invention, there is provided a fuel cell including the membrane-electrode assembly.

The membrane-electrode assembly of the present invention can overcome the problem of deterioration of hydrogen ion conduction performance of the membrane-electrode assembly by improving the interfacial adhesion and interfacial stability between the catalyst layer and the ion exchange membrane, and the gas permeability without increasing the interfacial resistance and interfacial bonding problems. Reduced hydrogen gas crossover can be reduced, and performance and durability in high temperature / low humid conditions can be improved.

1 is a schematic view showing an interface structure of an ion exchange membrane, an interface adhesive layer, and a catalyst layer of a membrane-electrode assembly according to an embodiment of the present invention.

2 is a schematic diagram showing the overall configuration of a fuel cell according to an embodiment of the present invention.

3 is a graph showing the hydrogen gas permeability measured in Experimental Example 2 of the present invention.

4 is a graph showing an open circuit voltage (OCV) retention rate measured in Experimental Example 5 of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. However, this is presented as an example, by which the present invention is not limited and the present invention is defined only by the scope of the claims to be described later.

Unless stated otherwise in the present specification, when a part such as a layer, a film, an area, or a plate is 'above' another part, it is not only when the other part is 'just above', but also when there is another part in the middle. Include.

Membrane electrode assembly according to an embodiment of the present invention is located on the catalyst layer, the catalyst layer, an interface adhesive layer formed by the interface with the catalyst layer penetrates to a depth of the catalyst layer, and is located on the interface adhesive layer, the interface adhesive layer It includes an ion exchange membrane bonded to the catalyst layer via a.

1 is a schematic diagram showing an interface structure of an ion exchange membrane, an adhesive layer, and a catalyst layer in a membrane-electrode assembly according to an embodiment of the present invention.

As shown in FIG. 1, an interfacial adhesion layer 20 is interposed between the ion exchange membrane 10 of the membrane-electrode assembly and the catalyst layer 30 including the catalyst particles 31, and the catalyst particles 31. The interface between the catalyst layer 30 and the interfacial adhesion layer 20 made of) has a form penetrated between the catalyst particles 31 of the catalyst layer 30. The membrane-electrode assembly may further include an electrode substrate 40 on the outer side of the catalyst layer 30.

The membrane-electrode assembly includes a first interfacial adhesive layer and a first catalyst layer positioned on one surface of the ion exchange membrane 10, a second interfacial adhesive layer and a second catalyst layer positioned on the other surface of the ion exchange membrane 10, Any one selected from the group consisting of the first interfacial adhesive layer, the second interfacial adhesive layer, and both of them is the interfacial adhesive layer 20, and is selected from the group consisting of the first catalyst layer, the second catalyst layer, and both. Any one of which may be the catalyst layer 30. Here, the first catalyst layer may be a cathode catalyst layer, the second catalyst layer may be an anode catalyst layer.

The interfacial adhesive layer 20 permeates any one selected from the group consisting of pores (surface recesses) formed on the surface of the catalyst layer 30, pores present at a predetermined depth from the surface of the catalyst layer 30, and both. For example, it can be formed while filling them.

Accordingly, the interfacial adhesive layer 20 fills all empty spaces between the catalyst particles 31 and the ion exchange membrane 10 to maximize the contact area between the catalyst particles 31 and the ion exchange membrane 10. can do. There are no voids between the ion exchange membrane 10 and the catalyst particles 31, and an interface between the catalyst layer 30 and the interface adhesive layer 20 is formed along the surface curvature of the catalyst particles 31. Due to the increased interface area, the ion transfer path increases, and the adhesion strength between the catalyst layer 30 and the ion exchange membrane 10 may be improved.

The average depth of the interfacial adhesive layer 20 penetrating the catalyst layer 30 may be 1% to 10%, 2% to 5% of the average thickness of the catalyst layer 30, and the permeable interfacial adhesion layer When the average depth of (20) is in the above range, the binding effect between the catalyst layer 30 and the interfacial adhesion layer 20 is high and the output performance is excellent. The average depth of the catalyst layer 30 or the average thickness of the catalyst layer 30 may be an average value of the depth or the thickness measured with respect to the entirety of the catalyst layer 30, or at one cross section of the catalyst layer 30. It may be an average value per unit length (eg cm). The% (length%) is a percentage value of a value obtained by dividing the average penetration depth of the interfacial adhesive layer 20 in length by the average thickness of the catalyst layer 30 in length.

The interfacial adhesive layer 20 may include a fluorine ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq, and include a fluorine ionomer having an equivalent weight of 550 g / eq to 950 g / eq. Can be. The equivalent weight of the fluorine ionomer is the molecular mass of the fluorine ionomer per one ion conductive functional group contained in the fluorine ionomer.

By controlling the equivalent weight of the fluorine ionomer included in the interfacial adhesive layer 20, it is possible to give a positive effect on the water management of the membrane-electrode assembly under low-humidity conditions, and when using the fluorine ionomer having the equivalent weight, hydrogen It is possible to improve the performance of the membrane-electrode assembly without deteriorating the conductivity of the ions. On the other hand, when the equivalent weight of the fluorine ionomer is less than 500 g / eq, the elution phenomenon of the fluorine ionomer or the permeability of the hydrogen fuel may increase, and when it exceeds 1000 g / eq, the hydrogen ion conductivity may be lowered under high temperature and low humidity conditions. have.

The fluorine ionomer has a cation exchange group such as protons or an anion exchange group such as hydroxy ions, carbonates or bicarbonates, and includes a fluorine-based polymer containing fluorine in the main chain; Or partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer, and the like, and specific examples thereof include poly (perfluorosulfonic acid), Poly (perfluorocarboxylic acid), a copolymer of tetrafluoroethylene and fluorovinyl ether containing a sulfonic acid group, a defluorinated sulfide polyether ketone or a fluoropolymer comprising a mixture thereof. The cation exchange group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, and a combination thereof, and in general, may be a sulfonic acid group or a carboxyl group. have. In addition, the said fluorine-type ionomer can also be used individually or in mixture of 2 or more types.

The fluorine-based ionomer may include a mixture of appropriately fluorine-based ionomers exemplified in order to satisfy the equivalent range.

In addition, the interfacial adhesive layer 20 may include a mixture of the fluorine ionomer and the hydrocarbon ionomer. When the interfacial adhesive layer 20 includes a mixture of the fluorine-based ionomer and the hydrocarbon-based ionomer, gas permeability may be reduced without affecting interfacial bonding, thereby preventing hydrogen crossover.

In this case, the hydrocarbon-based ionomer may have an ion exchange capacity (IEC) of 0.8 meq / g to 4.0 meq / g, and 1.0 meq / g to 3.5 meq / g. When the ion exchange capacity of the hydrocarbon-based ionomer is within the above range, it is possible to improve the performance of the membrane-electrode assembly without deteriorating the conductivity of hydrogen ions under high temperature / low humidification conditions. When the ion exchange capacity of the hydrocarbon-based ionomer is less than 0.8 meq / g, it is possible to reduce the migration of hydrogen ions under high temperature and low humidity conditions, and when it exceeds 4.0 meq / g, the interface and transfer resistance may be increased according to the humidity. have.

In addition, the weight ratio of the fluorine-based ionomer and the hydrocarbon-based ionomer may be 20: 1 to 1:20, and 1: 1 to 1:10. Can be. When the weight ratio of the fluorine-based ionomer and the hydrocarbon-based ionomer is within the above range, hydrogen crossover may be reduced, and interfacial bonding may be increased to improve performance and lifespan of the membrane-electrode assembly. When the weight ratio of the hydrocarbon-based ionomer is less than 1, it may be difficult to express the effect of reducing the hydrogen fuel permeability, and when it exceeds 20, the ionomer blend may be unevenly distributed and the resistance of the electrolyte membrane may be greatly increased.

The hydrocarbon-based ionomer has a cation exchange group such as proton or an anion exchange group such as hydroxy ion, carbonate or bicarbonate, and has benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, Polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, polycarbonate, polystyrene, polyphenylene sulfide, polyether ether ketone, polyether ketone, poly It may include a hydrocarbon-based polymer such as arylether sulfone, polyphosphazene or polyphenylquinoxaline, and specific examples thereof include sulfonated polyimide (S-PI) and sulfonated polyaryl ether sulfone (sulfonated). polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (s ulfonated polyetheretherketone (SPEEK), sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated Polyphosphazene, sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyethersulfone polyether sulfone, sulfonated polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone (sulfonated polyphenylene sulfide sulfone), sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether d polyarylene ether, sulfonated polyarylene ether nitrile, sulfonated polyarylene ether ether nitrile, sulfonated polyarylene ether sulfone ketone And hydrocarbon-based polymers including a mixture thereof, but are not limited thereto. In addition, the hydrocarbon-based ionomer may be used alone or in combination of two or more thereof.

In addition, the interfacial adhesive layer 20 may further include nano powder.

The nanopowder may impart functionality to the interfacial adhesive layer 20 without degrading the interfacial adhesion of the membrane-electrode assembly or increasing interfacial resistance, thereby overcoming the deterioration in durability of the membrane-electrode assembly and improving performance.

The nano powder may be any one selected from the group consisting of an ionic conductor, a radical scavenger, an oxygen evolution reaction (OER) catalyst, and a mixture thereof.

The ion conductor may be excellent in dispersibility to improve hydrogen ion conductivity of the membrane electrode assembly. The ion conductor is a hydrophilic inorganic additive, specifically, SnO ₂ , fumed silica, clay, alumina, mica, zeolite, phosphotungstic acid It may be any one selected from the group consisting of silicon tungstic acid, zirconium hydrogen phosphate, and mixtures thereof. The ion conductor is a hydrophilic inorganic ion additive, it is possible to prevent the phenomenon of deterioration of hydrogen ion conductivity at high temperature and low humidity conditions.

The radical scavenger may be uniformly dispersed in the interfacial adhesion layer 20 to contribute to stabilization of the membrane-electrode assembly. The radical scavenger is a transition metal ion that can decompose hydrogen peroxide into water and oxygen to inhibit the generation of hydroxy radicals, specifically cerium, tungsten, ruthenium, palladium, silver, rhodium, cerium, zirconium, yttrium, manganese. , Molybdenum, lead, vanadium, titanium, and the like, and the metals themselves, their ionic forms, their oxide forms, their salt forms, or other forms are also possible.

More specifically, the radical trapping agent CeO ₂ , MnO ₂ , CsO ₂ , ZrO ₂ , Ru, Ag, RuO ₂ , WO ₃ , Fe ₃ O ₄ , CePO ₄ , CrPO ₄ , AlPO ₄ , FePO ₄ , CeF _{3, FeF 3, Ce 2 (} CO 3) 3 · 8H 2 O, Ce (CHCOO) 3 · H 2 O, CeCl 3 · 6 H 2 O, Ce (NO 3) 6 · 6H 2 O, Ce (NH 4 ) ₂ (NO ₃ ) ₆ , Ce (NH ₄ ) ₄ (SO ₄ ) ₄ · 4H ₂ O, Ce (CH ₃ COCHCOCH ₃ ) ₃ · 3H ₂ O, Fe-porphyrin, Co-porphyrin and mixtures thereof It may be any one selected from the group, and one or more mixtures or compounds thereof may be used.

The oxygen generation reaction catalyst may be atomized / uniformly dispersed in the interfacial adhesion layer 20 to improve durability of the catalyst layer 30 through an effective water decomposition reaction.

The oxygen generation reaction catalyst may include a platinum-based metal active material. The platinum-based metal may be used alone or in combination of two or more selected from the group consisting of platinum, gold, palladium, rhodium, iridium, ruthenium, osmium, platinum alloys, alloys thereof, and mixtures thereof. The platinum alloy is Pt-Pd, Pt-Sn, Pt-Mo, Pt-Cr, Pt-W, Pt-Ru, Pt-Ru-W, Pt-Ru-Mo, Pt-Ru-Rh-Ni, Pt- Ru-Sn-W, Pt-Co, Pt-Co-Ni, Pt-Co-Fe, Pt-Co-Ir, Pt-Co-S, Pt-Co-P, Pt-Fe, Pt-Fe-Ir, Pt-Fe-S, Pt-Fe-P, Pt-Au-Co, Pt-Au-Fe, Pt-Au-Ni, Pt-Ni, Pt-Ni-Ir, Pt-Cr, Pt-Cr-Ir and It can be used individually or in mixture of 2 or more types selected from the group which consists of these combinations.

In addition, the catalyst particles 31 may use a metal black, or may be used by supporting the catalyst metal on a carrier. The carrier may include a porous inorganic oxide such as zirconia, alumina, titania, silica, ceria, ITO, WO, SnO ₂ , ZnO ₂ , or a combination thereof. In addition, as a carbon-based carrier, graphite, carbon fiber, carbon sheet, carbon black, carbon nanotube, carbon nanofiber, carbon nanowire, carbon nanoball, carbon nanohorn, carbon nano cage, graphene, stabilized carbon, activated carbon, And it may be any one selected from the group consisting of a mixture thereof.

The nanoparticles may have an average particle diameter of 1 nm to 50 nm and 2 nm to 35 nm. When the size of the nano-powder is in the above range, it may be uniformly dispersed in the interfacial adhesive layer 20, and may implement the membrane-electrode assembly without a large increase in resistance. When the average particle diameter of the nanopowder is out of the above range, agglomeration phenomenon between the nanopowders or a decrease in dispersibility and phase separation may occur in the composition.

The interfacial adhesive layer 20 may include 0.1 wt% to 20 wt% of the nanopowder, and may include 0.5 wt% to 15 wt%, based on the total weight of the interfacial adhesive layer 20. When the content of the nano powder is within the above range, the interfacial adhesive layer 20 may be uniformly formed without the phase separation in the interfacial adhesive layer 20. When the content of the nano powder is less than 0.1% by weight, hydrogen ion conductivity enhancement effect, radical generation inhibiting effect and effective water decomposition reaction may be difficult to be achieved, and when the content exceeds 20% by weight, high temperature and low temperature humidity due to a decrease in dispersibility of the nano powder. Output performance and durability of the membrane-electrode assembly due to reduced hydrogen ion conductivity, ionic resistance-charge transfer resistance-increased mass transfer resistance and heterogeneous water decomposition reactions under conditions Improvements may not be achieved.

The average thickness of the interfacial adhesive layer 20 may be 0.01 μm to 5 μm, and 0.5 μm to 3 μm. When the interfacial adhesive layer 20 is located on the cathode side, the sum of the thicknesses of the catalyst layer 30, the interfacial adhesive layer 20, and the ion exchange membrane 10 may be 18 μm to 40 μm, and the interfacial adhesive layer When the 20 is located at the anode side, the sum of the thicknesses of the catalyst layer 30, the interfacial adhesive layer 20, and the ion exchange membrane 10 may be 2 μm to 35 μm.

When the average thickness of the interfacial adhesive layer 20 is less than 0.01 μm, the interfacial adhesion between the electrolyte membrane and the electrode may not be improved, and when the interfacial adhesive layer 20 exceeds 5 μm, the interface and the transfer resistance components increase to increase the performance of the membrane-electrode assembly. Can be lowered.

On the other hand, the catalyst particles 31 of the catalyst layer 30 may be any of those that can be used as a catalyst in the hydrogen oxidation reaction, oxygen reduction reaction, it is preferable to use a platinum-based metal.

The platinum-based metal is platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), osmium (Os), platinum-M alloys (the M is palladium (Pd), ruthenium (Ru), iridium ( Ir), osmium (Os), gallium (Ga), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper ( Cu, silver (Ag), gold (Au), zinc (Zn), tin (Sn), molybdenum (Mo), tungsten (W), lanthanum (La) and rhodium (Rh) It may include one selected from the group consisting of) and a combination thereof, and more preferably, a combination of two or more metals selected from the platinum-based catalyst metal group may be used, but is not limited thereto. Platinum-based catalyst metals usable in the art can be used without limitation.

In addition, the catalyst particles 31 may use a metal black, or may be used by supporting the catalyst metal on a carrier.

The carrier may be selected from carbon-based carriers, porous inorganic oxides such as zirconia, alumina, titania, silica, ceria, zeolite, and the like. The carbon-based carrier is graphite, super P, carbon fiber, carbon sheet, carbon black, Ketjen Black, Denka black, acetylene It may be selected from acetylene black, carbon nano tube (CNT), carbon sphere, carbon ribbon, fullerene, activated carbon and one or more combinations thereof, Without being limited thereto, carriers usable in the art may be used without limitation.

The catalyst particles 31 may be located on the surface of the carrier, or may penetrate into the carrier while filling the internal pores of the carrier.

When using the noble metal supported on the carrier as a catalyst, a commercially available commercially available one may be used, or may be prepared by using a noble metal supported on the carrier. The process of supporting the noble metal on the carrier is well known in the art, and thus the detailed description thereof will be easily understood by those skilled in the art.

The catalyst particles 31 may be contained in an amount of 20% to 80% by weight relative to the total weight of the catalyst layer 30, and when contained in less than 20% by weight, there may be a problem of deterioration of activity, and 80% by weight. If it exceeds, the active area is reduced by agglomeration of the catalyst particles 31, so that the catalytic activity may be reversely lowered.

In addition, the catalyst layer 30 may include a binder to improve adhesion of the catalyst layer 30 and transfer hydrogen ions.

It is preferable to use an ionomer having hydrogen ion conductivity as the binder, and the ionomer is a cation conductor having a cation exchange group such as proton or an anion conductor having an anion exchange group such as hydroxy ion, carbonate or bicarbonate. Can be.

The cation exchange group may be any one selected from the group consisting of sulfonic acid groups, carboxyl groups, boronic acid groups, phosphoric acid groups, imide groups, phosphonic acid groups, sulfonimide groups, sulfonamide groups, and combinations thereof, and generally sulfonic acid groups Or a carboxyl group.

The cation conductor includes the cation exchange group, the fluorine-based polymer containing fluorine in the main chain; Benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, poly Hydrocarbon-based polymers such as carbonate, polystyrene, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyaryl ether sulfone, polyphosphazene or polyphenylquinoxaline; Partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer; Sulfone imides and the like.

More specifically, when the cationic conductor is a hydrogen ion cationic conductor, the polymers may include 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 thereof. Specific examples thereof include poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones or mixtures thereof. Fluorine-based polymer comprising; Sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimine Sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated poly Sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyether sulfone, sulfonated polyether ketone polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ether nitrile, Hydrocarbon-based polymers including a sulfonated polyarylene ether ether nitrile, a sulfonated polyarylene ether sulfone ketone, and mixtures thereof, but are not limited thereto. no.

The cation conductor may also replace H with Na, K, Li, Cs or tetrabutylammonium in the cation exchange group at the side chain end. In the cation exchange group at the side chain terminal, when H is replaced with Na, NaOH is substituted during the preparation of the catalyst composition, and when tetrabutylammonium is substituted, tetrabutylammonium hydroxide is used, and K, Li, or Cs is also appropriate. Substitutions may be used. Since the substitution method is well known in the art, detailed description thereof will be omitted.

The cationic conductor may be used in the form of a single substance or a mixture, and may also be optionally used with a nonconductive compound for the purpose of further improving adhesion to the ion exchange membrane 10. It is preferable to adjust the usage-amount so that it may be suitable for a purpose of use.

Examples of the non-conductive compound include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and ethylene / tetrafluoro Ethylene / tetrafluoroethylene (ETFE), ethylene chlorotrifluoro-ethylene copolymer (ECTFE), polyvinylidene fluoride, copolymer of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP), dode One or more selected from the group consisting of silbenzenesulfonic acid and sorbitol can be used.

The anion conductors are polymers capable of transporting anions such as hydroxy ions, carbonates or bicarbonates, and the anion conductors are commercially available in the form of hydroxides or halides (generally chloride), the anion conductors being industrially purified (water purification), metal separation or catalytic processes.

As the anion conductor, a polymer doped with metal hydroxide may be generally used. Specifically, poly (ethersulphone) doped with metal hydroxide, polystyrene, vinyl polymer, poly (vinyl chloride), poly (vinylidene fluoride) , Poly (tetrafluoroethylene), poly (benzimidazole), poly (ethylene glycol) and the like can be used.

Commercially available examples of the ionomer include nafion, aquibion and the like.

The ionomer may be included in an amount of 20 to 80 wt% based on the total weight of the catalyst layer 30. If the content of the ionomer is less than 20% by weight, the generated ions may not be transferred well, and if the amount of the ionomer is greater than 80% by weight, pores may be insufficient to supply hydrogen or oxygen (air). This can be reduced.

The membrane-electrode assembly may further include an electrode substrate 40 outside the catalyst layer 30.

As the electrode substrate 40, a porous conductive substrate may be used to smoothly supply hydrogen or oxygen. Typical examples thereof include a carbon film, a carbon cloth, a carbon felt, or a metal cloth (a porous film composed of a metal cloth in a fibrous state or a metal film formed on a surface of a cloth formed of polymer fibers). May be used, but is not limited thereto. In addition, it is preferable to use the water repellent treated with the fluorine-based resin as the electrode substrate 40 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, the electrode substrate 40 may further include a microporous layer (microporous layer) for enhancing the diffusion effect of the reactants. 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 including a conductive powder, a binder resin, and a solvent on the electrode substrate 40. 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, and the like, water, dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, tetrahydrofuran 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.

On the other hand, the ion exchange membrane 10 includes an ion conductor. The ion conductor may be a cation conductor having a cation exchange group such as proton or an anion conductor having an anion exchange group such as hydroxy ion, carbonate or bicarbonate.

The cation exchange group may be any one selected from the group consisting of a sulfonic acid group, a carboxyl group, a boronic acid group, a phosphoric acid group, an imide group, a sulfonimide group, a sulfonamide group, and a combination thereof, and in general, may be a sulfonic acid group or a carboxyl group. have.

The cation conductor includes the cation exchange group, the fluorine-based polymer containing fluorine in the main chain; Benzimidazole, polyamide, polyamideimide, polyimide, polyacetal, polyethylene, polypropylene, acrylic resin, polyester, polysulfone, polyether, polyetherimide, polyester, polyethersulfone, polyetherimide, poly Hydrocarbon-based polymers such as carbonate, polystyrene, polyphenylene sulfide, polyether ether ketone, polyether ketone, polyaryl ether sulfone, polyphosphazene or polyphenylquinoxaline; Partially fluorinated polymers such as polystyrene-graft-ethylenetetrafluoroethylene copolymer or polystyrene-graft-polytetrafluoroethylene copolymer; Sulfone imides and the like.

More specifically, when the cationic conductor is a hydrogen ion cationic conductor, the polymers may include 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 thereof. Specific examples thereof include poly (perfluorosulfonic acid), poly (perfluorocarboxylic acid), copolymers of tetrafluoroethylene and fluorovinyl ether containing sulfonic acid groups, defluorinated sulfide polyether ketones or mixtures thereof. Fluorine-based polymer comprising; Sulfonated polyimide (S-PI), sulfonated polyarylethersulfone (S-PAES), sulfonated polyetheretherketone (SPEEK), sulfonated polybenzimine Sulfonated polybenzimidazole (SPBI), sulfonated polysulfone (S-PSU), sulfonated polystyrene (S-PS), sulfonated polyphosphazene, sulfonated poly Sulfonated polyquinoxaline, sulfonated polyketone, sulfonated polyphenylene oxide, sulfonated polyether sulfone, sulfonated polyether ketone polyether ketone, sulfonated polyphenylene sulfone, sulfonated polyphenylene sulfide, sulfonated polyphenylene sulfide sulfone polyphenylene sulfide sulfone, sulfonated polyphenylene sulfide sulfone nitrile, sulfonated polyarylene ether, sulfonated polyarylene ether nitrile, Hydrocarbon-based polymers including a sulfonated polyarylene ether ether nitrile, a sulfonated polyarylene ether sulfone ketone, and mixtures thereof, but are not limited thereto. no.

On the other hand, among the cationic conductors, hydrocarbon-based polymers excellent in ion conductivity and advantageous in terms of price can be preferably used. In addition, when a hydrocarbon-based polymer is used as the ion conductor and a hydrocarbon-based polymer is used as the porous support, the hydrocarbon-based polymer included in the hydrocarbon-based ion conductor and the hydrocarbon-based polymer included in the porous support are the same material type. In particular, when using SPI (sulfonated polyimide) as the hydrocarbon-based ion conductor and polyimide as the porous support, adhesion between the hydrocarbon-based ion conductor and the porous support can be further improved. And the interface resistance can be further lowered.

The anion conductors are polymers capable of transporting anions such as hydroxy ions, carbonates or bicarbonates, and the anion conductors are commercially available in the form of hydroxides or halides (generally chloride), the anion conductors being industrially purified (water purification), metal separation or catalytic processes.

As the anion conductor, a polymer doped with metal hydroxide may be generally used. Specifically, poly (ethersulphone) doped with metal hydroxide, polystyrene, vinyl polymer, poly (vinyl chloride), poly (vinylidene fluoride) , Poly (tetrafluoroethylene), poly (benzimidazole), poly (ethylene glycol) and the like can be used.

The ion exchange membrane 10 may be in the form of a reinforcing membrane in which the ion conductor fills pores such as a fluorine-based porous support such as e-PTFE or a porous nanoweb support prepared by electrospinning.

According to another aspect of the present invention, there is provided a method of manufacturing a membrane-electrode assembly, forming an interface adhesive layer 20 by applying a composition for forming an interface adhesive layer on a catalyst layer 30, and a catalyst layer on which the interface adhesive layer 20 is formed. 30 and the ion exchange membrane 10 are bonded.

First, after preparing a composition for forming a catalyst layer including a catalyst, an ionomer and a solvent, the catalyst layer 30 is formed using the composition.

The solvent may be a solvent selected from the group consisting of water, a hydrophilic solvent, an organic solvent and one or more mixtures thereof.

The hydrophilic solvent is one selected from the group consisting of alcohols, ketones, aldehydes, carbonates, carboxylates, carboxylic acids, ethers, and amides containing, as main chain, linear, branched, saturated or unsaturated hydrocarbons having 1 to 12 carbon atoms. It may have a functional group or more, they may include an alicyclic or aromatic cyclo compound as at least part of the main chain. Specific examples of alcohols include methanol, ethanol, isopropyl alcohol, ethoxy ethanol, n-propyl alcohol, butyl alcohol, 1,2-propanediol, 1-pentanol, 1.5-pentanediol, 1.9-nonanediol, and the like; Ketones include heptanone, octanon and the like; Aldehydes include benzaldehyde, tolualdehyde and the like; Examples of the ester include methylpentanoate, ethyl-2-hydroxypropanoate, and the like; Carboxylic acids include pentanoic acid, heptanoic acid and the like; Ethers include methoxybenzene, dimethoxypropane and the like; Amides include propanamide, butylamide, dimethylacetamide, and the like.

The organic solvent may be selected from N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran and mixtures thereof.

The solvent may be contained in an amount of 80 to 95% by weight based on the total weight of the composition for forming the catalyst layer, when less than 80% by weight of the solid content is too high may cause dispersion problems due to cracks and high viscosity when coating the catalyst layer (30) And greater than 95% by weight, which may be detrimental to the catalyst layer 30 activity.

In the preparing of the catalyst layer 30 using the catalyst layer forming composition, a catalyst layer 30 may be manufactured by coating the catalyst layer forming composition on a release film as a specific example.

When coating the catalyst layer-forming composition on the release film, the catalyst-dispersed catalyst layer-forming composition is continuously or intermittently transferred to a coater, and then uniformly dried at a thickness of 10 μm to 200 μm on the release film. It is preferable to apply.

More specifically, the slot die is transferred to a coater such as a die, gravure, bar, comma coater, etc. continuously through a pump according to the viscosity of the composition for forming the catalyst layer. Coating, bar coating, comma coating, screen printing, spray coating, doctor blade coating, brush, etc. may be used to dry the thickness of the catalyst layer 30 on the decal film from 10 μm to 200 μm, more preferably from 10 μm to 100 μm. Apply uniformly in μm, pass through a drying furnace maintained at a constant temperature and volatilize the solvent.

When the composition for forming the catalyst layer is coated with a thickness of less than 1 μm, the activity of the catalyst may be reduced due to the small catalyst content. When the coating with a thickness of more than 200 μm, the resistance of ions and electrons may be increased to increase resistance. have.

The drying process may be to dry at least 12 hours at 25 ℃ to 90 ℃. When the drying temperature is less than 25 ℃ and the drying time is less than 12 hours may cause a problem that may not form a sufficiently dried catalyst layer 30, when drying at a temperature exceeding 90 ℃ of the catalyst layer 30 Cracking may occur. However, the method of applying and drying the composition for forming the catalyst layer is not limited to the above.

Next, the composition for forming the interface adhesive layer is coated on the catalyst layer 30 to form the interface adhesive layer 20.

The composition for forming an interfacial adhesive layer includes a fluorine-based ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq and a solvent. Since the description of the fluorine ionomer is the same as described above, repeated descriptions thereof will be omitted.

The composition for forming an interface adhesive layer may include the fluorine-based ionomer at a concentration of 0.1% to 30%, and may include a concentration of 1% to 20%. Concentration in the context of the present invention means a percentage concentration, the percentage concentration can be obtained as a percentage of the mass of the solute to the mass of the solution.

When the composition for forming the interfacial adhesive layer includes the fluorine-based ionomer in the concentration range, hydrogen ion conductivity and interfacial bonding may be improved without increasing interfacial resistance of the membrane-electrode assembly. When the concentration of the fluorine ionomer is less than 0.1%, the hydrogen ion transport ability may be lowered, and when the concentration of the fluorine ionomer is greater than 30%, the ionomer distribution may be nonuniformly formed.

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.

In addition, the composition for forming an interfacial adhesive layer may include a mixture of the fluorine ionomer and a hydrocarbon ionomer having an ion exchange capacity of 0.8 meq / g to 4.0 meq / g. Since the description of the hydrocarbon-based ionomer is the same as described above, repeated description is omitted.

The composition for forming an interfacial adhesive layer may be prepared by mixing a dispersion of the fluorine-based ionomer at a concentration of 0.1% to 30% and a dispersion of the hydrocarbon-based ionomer at a concentration of 0.1% to 30%.

The composition for forming an interfacial adhesive layer may include the hydrocarbon-based ionomer at a concentration of 0.1% to 30%, and may include a concentration of 1% to 15%. When the composition for forming the interfacial adhesive layer includes the hydrocarbon-based ionomer in the concentration range, hydrogen ion conductivity and interfacial bonding may be improved without increasing interfacial resistance of the membrane-electrode assembly. When the concentration of the hydrocarbon-based ionomer is less than 0.1%, the hydrogen ion transport path may not be effectively formed, and when the concentration of the hydrocarbon-based ionomer is greater than 30%, the nonuniform distribution and resistance components of the ionomer may increase.

In addition, the composition for forming an interface adhesive layer may further include nanoparticles having a particle diameter of 1 nm to 50 nm. Since the description of the nano-powder is the same as described above, repeated description is omitted.

The interfacial adhesive layer 20 may be formed by spray coating the interfacial adhesive layer forming composition on the catalyst layer 30. When the composition for forming the interfacial adhesive layer is applied by spray coating, the interfacial adhesive layer 20 does not penetrate excessively into the catalyst layer 30, but penetrates to a predetermined depth from the surface of the catalyst layer 30 and fills surface curvature. It has a soothing effect. The spray method is applied to the surface of the catalyst layer 30 in a state in which some solvent is volatilized and the viscosity is increased while the composition for forming the interfacial adhesive layer is injected, so that the amount of penetration into the catalyst layer 30 is not excessive and is present on the surface. The pores can be selectively filled.

Next, the catalyst layer 30 and the ion exchange membrane 10 are bonded to each other via the interface adhesive layer 20.

Optionally, the catalyst layer 30 and the release film on which the interfacial adhesive layer 20 is formed may be cut to a required size, and then bonded to the ion exchange membrane 10.

The method of bonding the catalyst layer 30 and the ion exchange membrane 10 through the interfacial adhesive layer 20 may be, for example, a transfer method, and the transfer method may be a metal press alone or a silicon rubber material on a metal press. It may be performed by a hot pressing method of applying heat and pressure by applying a soft plate of the same rubber material.

The transfer method may be performed under the conditions of 80 ℃ to 150 ℃ and 50 kgf / cm ² to 200 kgf / cm ² . When hot pressing at a temperature of 80 ° C. and less than 50 kgf / cm ² , transfer of the catalyst layer 30 on a release film may not be performed properly, and when it exceeds 150 ° C., the polymer of the ion exchange membrane 10 may be There is a risk that structural modification of the catalyst layer 30 may occur, and when hot pressing under a condition exceeding 200 kgf / cm ² , the effect of compressing the catalyst layer 30 is more effective than the transfer of the catalyst layer 30. It may get bigger and may not be able to transcribe properly.

A fuel cell according to another embodiment of the present invention includes the membrane-electrode assembly.

2 is a schematic diagram showing the overall configuration of the fuel cell.

2, the fuel cell 200 includes a fuel supply unit 210 for supplying a mixed fuel in which fuel and water are mixed, and a reforming unit for reforming the mixed fuel to generate a reformed gas including hydrogen gas ( 220, a stack 230 in which a reformed gas including hydrogen gas supplied from the reformer 220 generates an electrical energy by causing an electrochemical reaction with an oxidant, and an oxidant in the reformer 220 and the stack. It includes an oxidant supply unit 240 for supplying to (230).

The stack 230 induces an oxidation / reduction reaction of a reforming gas including hydrogen gas supplied from the reformer 220 and an oxidant supplied from the oxidant supply unit 240 to generate a plurality of unit cells for generating electrical energy. Equipped.

Each unit cell means a cell of a unit for generating electricity, wherein the membrane-electrode assembly for oxidizing / reducing oxygen in an oxidant and a reforming gas containing hydrogen gas, and a reforming gas and an oxidant including hydrogen gas A separator (also referred to as a bipolar plate, hereinafter referred to as a "bipolar plate") for feeding to the membrane-electrode assembly. The separator is disposed on both sides of the membrane-electrode assembly at the center. At this time, the separator plates respectively located at the outermost side of the stack may be specifically referred to as end plates.

The end plate of the separator plate, the pipe-shaped first supply pipe 231 for injecting the reformed gas containing hydrogen gas supplied from the reforming unit 220, and the pipe-shaped second for injecting oxygen gas The supply pipe 232 is provided, and the other end plate has a first discharge pipe 233 for discharging the reformed gas containing hydrogen gas remaining unreacted in the plurality of unit cells to the outside and the unit cell described above. Finally, the second discharge pipe 234 for discharging the remaining unreacted oxidant to the outside is provided.

The following presents specific embodiments of the present invention. However, the embodiments described below are merely for illustrating or explaining the present invention in detail, and the present invention is not limited thereto. In addition, the contents not described herein may be sufficiently technically inferred by those skilled in the art and description thereof is omitted.

[ Production Example : Fabrication of Membrane Electrode Assembly]

( Example  One)

A cathode electrode composition was prepared by dispersing by 88% by weight of PtCo / C Cathode catalyst and 12% by weight of Nafion ^® / H ₂ O / 2-propanol solution as a binder by stirring and ultrasonic methods. The cathode electrode composition was prepared by doctor blade coating on a Teflon release film and then dried at 60 ° C. for 6 hours to prepare an anode electrode. At this time, the catalyst loading in the cathode was about 0.40 mg / cm ² .

Using PtRu / C anode _{^{(Anode) Nafion ® / H 2}} O / 2- propanol solution of 12 wt% to 88 wt% of the catalyst with a binder, were dispersed with stirring and an ultrasonic method for the anode electrode composition was prepared. The anode electrode composition prepared above was doctorblade coated on a Teflon release film, and then dried at 60 ° C. for 6 hours to prepare an anode electrode. At this time, the amount of catalyst loading in the anode was about 0.10 mg / cm ² .

A composition for forming an interfacial adhesive layer was prepared, wherein 5 wt% of a fluorine ionomer poly (perfluorosulfonic acid) (PFSA) having an EW of 700 g / eq and 95 wt% of a H ₂ O / 2-propanol solution was prepared.

The prepared interfacial adhesive layer-forming composition was spray-coated on the prepared electrode in an amount of 0.11 mg / cm ² at room temperature to form an interfacial adhesive layer having a thickness of about 0.5 μm on the electrode surface.

After the fluorine-based polyelectrolyte membrane of perfluorosulfonic acid (PFSA) having a thickness of 15 to 20 μm between the prepared cathode and anode electrode, this was pressed for 3 minutes under heat and pressure at 160 ° C. and 20 kgf / cm ² condition. In addition, a membrane-electrode assembly in which the cathode electrode and the anode electrode were bound to the polymer electrolyte membrane was prepared.

( Example  2)

In Example 1, the fluorine-based ionomer PFSA having an EW of 700 g / eq when manufacturing the composition for forming the interface adhesive layer, and the thickness of the interface adhesive layer was formed in the same manner as in Example 1 except that To prepare a membrane-electrode assembly.

( Example  3)

In Example 1, the fluorine-based ionomer PFSA having an EW of 700 g / eq when manufacturing the composition for forming the interface adhesive layer, and the thickness of the interface adhesive layer was formed in the same manner as in Example 1 except that To prepare a membrane-electrode assembly.

( Example  4)

In Example 1, the fluorine-based ionomer PFSA having an EW of 950 g / eq was used to prepare the composition for forming the interfacial adhesive layer, and the thickness of the interfacial adhesive layer was about 0.5 μm. To prepare a membrane-electrode assembly.

( Example  5)

In Example 1, the fluorine-based ionomer PFSA having an EW of 950 g / eq was used to prepare the composition for forming the interface adhesive layer, and the thickness of the interface adhesive layer was about 1.0 μm, similar to that of Example 1 above. To prepare a membrane-electrode assembly.

( Example  6)

In Example 1, the fluorine-based ionomer PFSA having an EW of 950 g / eq was used to prepare the composition for forming the interfacial adhesive layer, and the thickness of the interfacial adhesive layer was about 2.0 μm, similar to that of Example 1. To prepare a membrane-electrode assembly.

( Comparative example  One)

A membrane-electrode assembly was manufactured in the same manner as in Example 1, except that the interface adhesive layer was not formed in Example 1.

( Comparative example  2)

Example 1, except that Nafion (manufactured by Dupont) having an EW of 1100 g / eq was used to prepare the composition for forming the interface bonding layer in Example 1, and the thickness of the interface bonding layer was formed to about 1.0 μm. The membrane-electrode assembly was prepared in the same manner as described above.

( Example  7)

A membrane-electrode assembly was prepared in the same manner as in Example 1, except that the thickness of the interface adhesive layer was 0.005 μm when the composition for forming the interface adhesive layer was formed in Example 1.

However, when the thickness of the interfacial adhesive layer was formed to 0.005 μm, performance measurement was impossible because a small amount of coated portions and a plurality of uncoated portions of the interfacial adhesive layer were present on the electrodes.

( Example  8)

In Example 1, the fluorine-based ionomer PFSA having an EW of 700 g / eq when manufacturing the composition for forming the interface adhesive layer, and the thickness of the interface adhesive layer was formed in the same manner as in Example 1 except that To prepare a membrane-electrode assembly.

( Example  9)

A cathode electrode composition was prepared by dispersing by 88% by weight of PtCo / C Cathode catalyst and 12% by weight of Nafion ^® / H ₂ O / 2-propanol solution as a binder by stirring and ultrasonic methods. The cathode electrode composition prepared above was doctorblade coated on a Teflon release film and then dried at 60 ° C. for 6 hours to prepare an anode electrode. At this time, the catalyst loading in the cathode was about 0.40 mg / cm ² .

Using PtRu / C anode _{^{(Anode) Nafion ® / H 2}} O / 2- propanol solution of 12 wt% to 88 wt% of the catalyst with a binder, were dispersed with stirring and an ultrasonic method for the anode electrode composition was prepared. The anode electrode composition prepared above was doctorblade coated on a Teflon release film, and then dried at 60 ° C. for 6 hours to prepare an anode electrode. At this time, the catalyst loading at the anode was about 0.10 mg / cm ² .

A composition for forming an interface adhesive layer was prepared using a fluorine / hydrocarbon ionomer blend having a weight ratio of fluorine-based ionomer PFSA having an EW of 700 g / eq and a sulfonated polyether sulfone (IEC 2.3 meq / g) ionomer blend of 1: 2. In this case, the interfacial adhesion layer-forming composition included the fluorine ionomer at a concentration of 1.25%, and the hydrocarbon ionomer at a concentration of 2.5%.

The prepared interfacial adhesive layer-forming composition was spray-coated at room temperature on the prepared electrode to form an interfacial adhesive layer on the electrode surface. At this time, the loading amount of the fluorine-based hydrocarbon ionomer blend composition was 0.13 mg / cm ² , the thickness of the fluorine-based hydrocarbon ion interface blend layer was about 0.5 ㎛.

The fluorine-based polyelectrolyte membrane of perfluorosulfonic acid (PFSA) having a thickness of 15 to 20 μm between the prepared cathode and anode electrode was squeezed for 3 minutes under heat and pressure at 160 ° C. and 20 kgf / cm ^2. In addition, a membrane-electrode assembly in which the cathode electrode and the anode electrode were bound to the polymer electrolyte membrane was prepared.

( Example  10)

A membrane-electrode assembly was prepared in the same manner as in Example 9 except that the thickness of the interface adhesive layer was about 1.0 μm when the composition for forming the interface adhesive layer was formed in Example 9.

( Example  11)

Example 9 except for changing the weight ratio of the fluorine-based / hydrocarbon-based ionomer blend to 1: 4 and the thickness of the interfacial adhesive layer to about 0.5 ㎛ when preparing the composition for forming the interfacial adhesive layer in Example 9 In the same manner as in the film-electrode assembly was prepared.

( Example  12)

Example 9 except that the weight ratio of the fluorine / hydrocarbon-based ionomer blend is changed to 1: 4 and the thickness of the interface adhesive layer is formed to about 1.0 ㎛ when preparing the composition for forming the interface adhesive layer in Example 9 In the same manner as in the film-electrode assembly was prepared.

( Example  13)

A membrane-electrode assembly was prepared in the same manner as in Example 9 except that the thickness of the interface adhesive layer was 0.005 μm when the composition for forming the interface adhesive layer was formed in Example 9.

However, when the thickness of the interfacial adhesive layer was formed to 0.005 μm, performance measurement was impossible because a small amount of coated portions and a plurality of uncoated portions of the interfacial adhesive layer were present on the electrodes.

( Example  14)

In Example 9, except that the weight ratio of the fluorine-based hydrocarbon ionomer blend was changed to 1: 4 and the thickness of the interfacial adhesive layer was 6 μm when the composition for forming the interfacial adhesive layer was formed. In the same manner to prepare a membrane-electrode assembly.

( Example  15)

Except that in Example 1, when preparing the composition for forming the interface adhesive layer, SiO ₂ nanopowder having an average particle diameter of 7 nm was added in 1 wt%, and the thickness of the interface adhesive layer was formed to about 1.0 μm. In the same manner as 1 to prepare a membrane-electrode assembly.

( Example  16)

Except that in Example 1, when preparing the composition for forming the interface adhesive layer, SiO ₂ nanopowder having an average particle diameter of 7 nm was added in 1 wt%, and the thickness of the interface adhesive layer was formed to about 2.0 μm. In the same manner as 1 to prepare a membrane-electrode assembly.

( Example  17)

SiO ₂ having an average particle diameter of 7 nm when preparing the composition for forming an interface adhesive layer in Example 1 A nano-powder was added at 5 wt% and the same procedure as in Example 1 was carried out except that the thickness of the interfacial adhesive layer was about 1.0 μm, thereby preparing a membrane-electrode assembly.

( Example  18)

The preparation of the composition for forming the interface adhesive layer in Example 1 was carried out except that the SiO ₂ nanopowder having an average particle diameter of 7 nm was added in a content of 5 wt% and the thickness of the interface adhesive layer was formed to about 2.0 μm. A membrane-electrode assembly was prepared in the same manner as in Example 1.

( Example  19)

The preparation of the composition for forming an interface adhesive layer in Example 1 was carried out except that SiO ₂ nanopowder having an average particle diameter of 7 nm was added in a content of 0.05 wt%, and the thickness of the interface adhesive layer was formed to about 1.0 μm. A membrane-electrode assembly was prepared in the same manner as in Example 1.

( Example  20)

Except for adding the nano-powder at 25% by weight when preparing the composition for forming the interface adhesive layer in Example 1 was carried out in the same manner as in Example 1.

However, when the nano-powder was added at 25% by weight, aggregation was severe and spray coating was impossible.

( Example  21)

A membrane-electrode assembly was prepared in the same manner as in Example 15 except that the thickness of the interface adhesive layer was formed to 0.005 μm when the composition for forming the interface adhesive layer was formed in Example 15.

However, when the thickness of the interfacial adhesive layer was formed to 0.005 μm, performance measurement was impossible because a small amount of coated portions and a plurality of uncoated portions of the interfacial adhesive layer were present on the electrodes.

( Example  22)

In Example 1, except that 5 wt% of SiO ₂ nanopowder having an average particle diameter of 7 nm was added to prepare the composition for forming the interfacial adhesive layer, and the thickness of the interfacial adhesive layer was 6 μm. The membrane-electrode assembly was prepared in the same manner as described above.

( Example  23)

Except that the CeO ₂ nano powder having an average particle diameter of 25 nm was added in a content of 5 wt% in Example 1, and the thickness of the interfacial adhesive layer was formed to about 1.0 μm. A membrane-electrode assembly was prepared in the same manner as in Example 1.

[ Experimental Example : Performance Measurement of Membrane-electrode Assembly]

( Experimental Example  1: Interfacial Adhesion Measurement)

In order to evaluate the interfacial adhesion, nitrogen was injected into each cathode and anode while maintaining the membrane-electrode assembly prepared in Examples and Comparative Examples at 60 ° C. By repeatedly injecting humidified nitrogen and dried nitrogen, the desorption and expansion by drying and hydration of the membrane-electrode assembly are repeatedly induced to accelerate interfacial desorption. 100% humidified nitrogen and dried nitrogen were repeatedly injected at 10 minute intervals. One cycle of humidified nitrogen and one set of dried nitrogen (total 20 minutes) was carried out for a total of 5,000 cycles, and the ohmic resistance values were compared and shown in Table 1 below.

* Ohm resistance values were measured by comparing the alternating current impedance of 300 mA / cm ² constant current condition of MEA single cell. In impedance, the x-axis is the impedance real part Z ', and the y-axis is the impedance imaginary part Z'. The value of the real part at the point where the impedance curve meets the x-axis is the ohmic resistance, which is the resistance component including the electrolyte membrane resistance and the interface resistance.

	Ohm resistance (Ωcm 2 ) before acceleration evaluation	Ohm resistance after acceleration evaluation (Ωcm 2 )	Ohm Resistance Growth (%)
Example 1	0.1683	0.1955	16.2
Example 2	0.1829	0.1954	6.8
Example 3	0.2182	0.2307	5.7
Example 5	0.1959	0.2076	6.0
Comparative Example 1	0.2421	0.9426	289.3
Comparative Example 2	0.2137	0.2268	6.1
Example 9	0.1789	0.2132	19.2
Example 10	0.1985	0.2175	9.6
Example 12	0.2015	0.2426	20.4
Example 15	0.2022	0.2415	19.4
Example 17	0.2047	0.2468	20.6
Example 18	0.2360	0.2797	18.5
Example 19	0.2136	0.2531	18.5
Example 22	0.2636	0.5986	127.1

As shown in Table 1, the membrane-electrode assembly of Comparative Example 1, in which the interfacial adhesive layer of the present invention was not introduced, exhibited a significant increase in resistance after the accelerated evaluation, while the membrane-electrode assembly of the example in which the interfacial adhesive layer was introduced on the catalyst layer. Showed a low increase. Through this, it is possible to confirm the effect of improving the interfacial adhesion stability of the interfacial adhesive layer.

( Experimental Example  2: hydrogen gas crossover measurement)

Hydrogen gas permeability was measured for the membrane-electrode assemblies prepared in Comparative Example 1, Comparative Example 2 and Example 9, and the results are shown in FIG.

The hydrogen gas permeability was measured by linear sweep voltammetry (LSV). In addition, hydrogen and air were supplied in a fully humidified state for evaluating the linear sweep voltametryl LSV, and hydrogen gas permeability was measured under a potential condition of 0.2V.

Referring to FIG. 3, the membrane-electrode assembly prepared in Example 9 includes a mixture of a fluorine-based ionomer and a hydrocarbon-based ionomer in the interfacial adhesive layer, thereby comparing hydrogen gas permeability without affecting interfacial bonding. It can be seen that the film-electrode assembly prepared in Example 1 has a 35% reduction effect.

In addition, it can be seen that the membrane-electrode assembly prepared in Example 9 is significantly reduced in hydrogen gas permeability compared to the membrane-electrode assembly prepared in Comparative Example 2 including only the fluorine-based ionomer in the interface adhesive layer.

( Experimental Example  3: Measurement of performance of membrane-electrode assembly 1)

For the membrane-electrode assembly prepared in Comparative Examples and Examples, the current density at 0.6 V and the voltage at 1.5 A / cm ² were measured at 65 ° C. and 50% relative humidity (RH). Table 2 shows.

	Current density (A / cm 2 ) @ 65 o C, 50% RH	Cell voltage (V) @ 65 o C, 50% RH
Example 1	1.30	0.565
Example 2	1.40	0.585
Example 3	1.35	0.555
Example 5	1.35	0.575
Comparative Example 1	1.25	0.555
Comparative Example 2	1.25	0.565
Example 8	1.20	0.515
Example 9	1.30	0.565
Example 10	1.35	0.575
Example 12	1.25	0.565
Example 14	1.05	0.505
Example 15	1.30	0.560
Example 17	1.45	0.595
Example 18	1.30	0.565
Example 19	1.25	0.550
Example 22	0.95	0.485

Referring to Table 2, it can be seen that the membrane-electrode assembly prepared in Example shows superior performance compared to the membrane-electrode assembly prepared in Comparative Example. Specifically, when comparing the MEA results including the interfacial adhesive layer of the same thickness, it can be observed that the current density increases as the equivalent (EW) lower under 50% RH conditions.

( Experimental Example  4: Measurement of the performance of the membrane-electrode assembly 2)

In addition, the voltage at 1.5 A / cm ² and 2.2 A / cm ² was measured at 65 ° C. and 50% relative humidity (RH), respectively, for the membrane-electrode assemblies prepared in Comparative Examples and Examples. It is shown in Table 3 below.

	Cell voltage (V) @ 1.5 A / cm 2	Cell voltage (V) @ 2.2 A / cm 2
Example 2	0.585	0.504
Example 5	0.575	0.459
Comparative Example 1	0.555	0.336
Comparative Example 2	0.565	0.383

Referring to Table 3, it can be seen that the MEA manufactured in the Example has a higher voltage at high current density than the MEA manufactured in the Comparative Example. In addition, when the MEA results including the interfacial adhesive layers having the same thickness are compared, the phenomenon that the voltage at the high current density (2.2 A / cm ² ) increases as the equivalent EW decreases.

( Experimental Example  5: Measurement of the performance of the membrane-electrode assembly 3)

The open circuit voltage (OCV) retention rates of the membrane-electrode assemblies prepared in Comparative Example 2 and Example 23 were measured, and the results are shown in FIG. 4.

In order to measure the open-circuit voltage, a unit cell having an electrode area of 25 cm ² and a microporous layer on both sides were configured, and fuel cells were operated by supplying hydrogen and air passing through a humidifier to both electrodes, respectively. The open circuit voltage retention rate was performed through an open circuit voltage operation at 90 ° C. and a relative humidity of 30%, and is represented by a difference between an initial open circuit voltage and an open circuit voltage after 500 hours of operation.

Referring to FIG. 4, the membrane-electrode assembly prepared in Comparative Example 2 includes an interfacial adhesive layer, but the open-circuit voltage retention falls below 80% within 100 hours, but the membrane-electrode assembly prepared in Example 23 As the nano-powder is included in the interfacial adhesive layer, it can be seen that after 500 hours, the open-circuit voltage retention does not fall below 80% and maintains 95%.

While the above has been described in detail with respect to preferred embodiments of the present invention, the above embodiments are presented as a specific example of the present invention, whereby the present invention is not limited by the scope of the present invention claims Various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the scope of the present invention.

[Description of the code]

10: ion exchange membrane

20: interfacial adhesive layer

30: catalyst bed

31: catalyst particles

40: electrode substrate

200: fuel cell

210: fuel supply unit 220: reforming unit

230: stack 231: first supply pipe

232: second supply pipe 233: first discharge pipe

234: second discharge pipe 240: oxidant supply unit

The present invention relates to a membrane-electrode assembly, a method for manufacturing the same, and a fuel cell including the same, wherein the membrane-electrode assembly has improved interfacial adhesion and interfacial stability between an electrode and an ion exchange membrane, thereby improving hydrogen ion conduction performance of the membrane-electrode assembly. The degradation problem can be overcome, the gas permeability can be reduced without increasing the interfacial resistance and the interfacial bonding problem, thereby reducing the hydrogen gas crossover, and improving the performance and durability at high temperature / low humidification conditions.

Claims (18)

1. Catalyst layer,

   An interface adhesive layer positioned on the catalyst layer, the interface with the catalyst layer penetrating to a depth of the catalyst layer, and

   Located on the interfacial adhesive layer, and comprises an ion exchange membrane bonded to the catalyst layer via the interfacial adhesive layer,

   The interfacial adhesive layer includes a fluorine-based ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq.

   Membrane-electrode assembly.
2. The method of claim 1,

   The membrane-electrode assembly is

   A first interfacial adhesive layer and a first catalyst layer positioned on one surface of the ion exchange membrane,

   It includes a second interfacial adhesive layer and a second catalyst layer located on the other side of the ion exchange membrane,

   Any one selected from the group consisting of the first interfacial adhesive layer, the second interfacial adhesive layer, and both is the interfacial adhesive layer,

   Any one selected from the group consisting of the first catalyst layer, the second catalyst layer and both are the catalyst layer

   Membrane-electrode assembly.
3. The method of claim 1,

   The interfacial adhesion layer is a membrane-electrode assembly infiltrating any one selected from the group consisting of pores (surface recesses) formed on the surface of the catalyst layer, pores present at a predetermined depth from the surface of the catalyst layer, and both.
4. The method of claim 1,

   And the average depth of the interfacial adhesive layer penetrating the catalyst layer is 1% to 10% of the average thickness of the catalyst layer.
5. The method of claim 1,

   The average thickness of the interfacial adhesive layer is 0.01 to 5 ㎛ ㎛ electrode assembly.
6. The method of claim 1,

   The interfacial adhesive layer comprises a mixture of the fluorine ionomer and a hydrocarbon ionomer having an ion exchange capacity (IEC) of 0.8 meq / g to 4.0 meq / g.
7. The method of claim 6,

   The weight ratio of the fluorine-based ionomer and the hydrocarbon-based ionomer is 20: 1 to 1:20 membrane-electrode assembly.
8. The method of claim 1,

   The interfacial adhesion layer further comprises a nano-particles having an average particle diameter of 1 nm to 50 nm.
9. The method of claim 8,

   The interfacial adhesive layer is a membrane-electrode assembly containing 0.1 to 20% by weight of the nano-powder relative to the total weight of the interfacial adhesive layer.
10. The method of claim 8,

    The nano-powder is any one selected from the group consisting of an ionic conductor, a radical scavenger, an oxygen evolution reaction (OER) catalyst, and a mixture thereof. .
11. The method of claim 10,

    The ion conductor is SnO ₂ , fumed silica, clay, alumina, mica, zeolite, phosphotungstic acid, silicon tungstic acid ), Zirconium hydrogen phosphate, and any one hydrophilic inorganic additive selected from the group consisting of mixtures thereof.
12. The method of claim 10,

    The radical scavengers are cerium, tungsten, ruthenium, palladium, silver, rhodium, cerium, zirconium, yttrium, manganese, molybdenum, lead, vanadium, titanium, ionic forms thereof, oxide forms thereof, salt forms thereof and their Membrane electrode assembly which is any one selected from the group consisting of a mixture.
13. The method of claim 10,

    The oxygen-generating reaction catalyst is any one platinum-based catalyst selected from the group consisting of platinum, gold, palladium, rhodium, iridium, ruthenium, osmium, platinum alloys, alloys thereof and mixtures thereof.
14. Applying an composition for forming an interface adhesive layer on the catalyst layer to form an interface adhesive layer, and

    Bonding the catalyst layer and the ion exchange membrane on which the interfacial adhesion layer is formed;

    The interfacial adhesive layer is formed by interfacing the interface with the catalyst layer to a part depth of the catalyst layer, wherein the interfacial adhesive layer includes a fluorine-based ionomer having an equivalent weight (EW) of 500 g / eq to 1000 g / eq.

    Method of manufacturing membrane-electrode assembly.
15. The method of claim 14,

    The interfacial adhesive layer is a method of manufacturing a membrane-electrode assembly formed by spray coating the composition for forming the interfacial adhesive layer on the catalyst layer.
16. The method of claim 14,

    The interfacial adhesive layer comprises a mixture of the fluorine-based ionomer and a hydrocarbon-based ionomer having an ion exchange capacity (IEC) of 0.8 meq / g to 4.0 meq / g.
17. The method of claim 14,

    The interfacial adhesive layer further comprises a nano-particle having a particle diameter of 1 nm to 50 nm.
18. A fuel cell comprising the membrane-electrode assembly according to claim 1.

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