JP2007066597A - Transfer sheet, catalyst layer-electrolyte membrane stack, electrode-electrolyte membrane assembly, and manufacturing methods of them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode-electrolyte membrane assembly constituting a fuel cell, and a transfer sheet for manufacturing the electrode-electrolyte membrane assembly. <P>SOLUTION: The transfer sheet has a releasing layer formed on at least one surface of a substrate, a peeling off layer formed on the releasing layer, and a catalyst layer formed on the peeling off layer. The transfer sheet is manufactured by forming the releasing layer on the substrate, forming the peeling off layer on the releasing layer, and forming the catalyst layer on the peeling off layer. The electrode-electrolyte membrane assembly is manufactured in such a way that the transfer sheet is arranged so that the the catalyst layer surface of the transfer sheet comes in contact with the electrolyte membrane, they are pressed, the substrate of the transfer sheet is peeled off to manufacture a catalyst layer-electrolyte membrane laminate, an electrode substrate is arranged on both surfaces of the catalyst layer-electrolyte membrane laminate, and they are pressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transfer sheet, a catalyst layer-electrolyte membrane laminate, an electrode-electrolyte membrane assembly, and methods for producing them.

  A fuel cell is a system that generates electricity by an electrochemical reaction between hydrogen and oxygen by arranging catalyst layers on both sides of an electrolyte membrane, and only water is generated during power generation. Unlike conventional internal combustion engines, fuel cells are attracting attention as a next-generation clean energy system because they do not generate environmentally harmful gases such as carbon dioxide.

  A polymer electrolyte fuel cell uses a hydrogen ion conductive polymer electrolyte membrane as an electrolyte membrane layer, a catalyst layer is arranged on both sides thereof, an electrode substrate is arranged on both sides thereof, and this is further sandwiched between separators. Has a structure. A catalyst layer is arranged on both sides of the electrolyte membrane layer, and then an electrode substrate is arranged on both sides thereof (that is, electrode substrate / catalyst layer / electrolyte membrane / catalyst layer / electrode substrate layer configuration) It is called an electrode-electrolyte membrane assembly.

  Conventionally, as a method for producing an electrode-electrolyte membrane assembly, for example, a catalyst powder slurry liquid in which platinum is supported on carbon powder or a pasted coating liquid can be applied to (1) a printing method on one side of an electrode substrate or A method in which two electrode base materials on which a catalyst layer is formed by applying a spray method are used so that the catalyst layer surface of the electrode base material is in contact with both surfaces of the electrolyte membrane and hot pressing is performed (for example, Patent Document 1, Patent Document 2), (2) A method of forming a catalyst layer by applying a printing method or a spray method on both surfaces of an electrolyte membrane, placing the electrode base material in contact with each catalyst layer surface, and hot pressing (for example, 3), the catalyst layer formed by applying the printing method on the substrate was transferred to the electrolyte membrane under high temperature and high pressure, the substrate was peeled off, and then transferred to both surfaces of the electrolyte membrane. A method in which the electrode base material is in contact with the catalyst layer surface and hot-pressed (for example, Patent Literature Etc.) and the like are known.

  However, these methods have various drawbacks.

  In the method (1), when the catalyst layer is formed on the electrode substrate by applying a printing method or a spray method, the catalyst layer enters the porous electrode substrate. It becomes difficult to form a catalyst layer uniformly on the electrode substrate. Further, the method (1) blocks the surface of the electrode base material or the inside thereof, thereby impeding the gas flow performance. As a result, it is inevitable that the performance of the fuel cell using the electrode-electrolyte membrane assembly obtained by the method (1) deteriorates.

  In the method (2), a catalyst layer is formed by printing or spraying on both surfaces of an electrolyte membrane a solution obtained by dissolving or dispersing the constituent components of the catalyst layer in an organic solvent. However, the electrolyte membrane is swollen and deformed by the organic solvent. This makes it difficult to maintain the shape of the electrolyte membrane. Therefore, it becomes difficult to adjust the thickness of the catalyst layer, and it is difficult to uniformly form the catalyst layer on the electrolyte membrane. As a result, the performance of the fuel cell using the electrode-electrolyte membrane assembly obtained by the method (2) varies. Therefore, the electrode-electrolyte membrane assembly obtained by the method (2) cannot produce a fuel cell with uniform performance.

In the method of (3), it is necessary to transfer the catalyst layer to the electrolyte membrane under high temperature and high pressure. However, when the transfer is performed under high pressure, the electrolyte membrane is excessively compressed, and the electrolyte membrane is locally localized. There is a risk of being destroyed. Further, there is a risk that the electrolyte membrane melts and the membrane itself is denatured during transfer at high temperature. As a result, the fuel cell using the electrode-electrolyte membrane assembly obtained by the method (3) cannot be a fuel cell having desired performance.
Japanese Examined Patent Publication No. 62-61118 Japanese Patent Publication No.62-61119 Japanese Examined Patent Publication No. 2-48632 Japanese Patent Laid-Open No. 10-64574

  An object of the present invention is to provide a method for producing an electrode-electrolyte membrane assembly free from the above drawbacks.

  An object of the present invention is to provide a transfer sheet for producing an electrode-electrolyte membrane assembly free from the above drawbacks.

  The present inventor has intensively studied to solve the above problems. As a result, there was a transfer sheet for producing an electrode-electrolyte membrane assembly in which a catalyst layer was formed on at least one side of a substrate via a release layer and a release layer, and the release layer was given water repellency or hydrophilicity. Using a transfer sheet, place the transfer sheet so that the catalyst layer surface of the transfer sheet faces the electrolyte membrane surface, and after heat-pressing, peel the substrate of the transfer sheet at the boundary surface between the release layer and the release layer Thus, it has been found that a desired electrode-electrolyte membrane assembly can be produced. The present invention has been completed based on such findings.

The present invention provides a transfer sheet, a catalyst layer-electrolyte membrane laminate and a production method thereof, an electrode-electrolyte membrane assembly, a production method thereof and a fuel cell according to the following 1 to 10.
1. One or two or more catalysts in which a release layer that does not peel from the substrate is formed on at least one surface of the substrate, a release layer is formed on the release layer, and carbon particles are contained on the release layer A transfer sheet for producing an electrode-electrolyte membrane assembly, wherein a layer is formed.
2. 2. The transfer sheet according to 1 above, wherein the release layer comprises carbon particles and a polymer resin.
3. 3. The transfer sheet according to 2 above, wherein the carbon particles constituting the release layer have higher water repellency than the carbon particles constituting the catalyst layer.
4). 3. The transfer sheet according to 2 above, wherein the carbon particles constituting the release layer are more hydrophilic than the carbon particles constituting the catalyst layer.
5. 5. The transfer sheet according to any one of 1 to 4, wherein the release layer has conductivity.
6). On one surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer made of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and the release layer is A step of disposing a transfer sheet for producing an electrode-electrolyte membrane assembly, wherein the carbon particles constituting the electrode layer have a higher water repellency than the carbon particles constituting the catalyst layer such that the catalyst layer of the transfer sheet is in contact with the electrolyte membrane;
On the other surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer made of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and the catalyst layer is Arranging a transfer sheet for producing an electrode-electrolyte membrane assembly, which is more hydrophilic than the carbon particles to be formed, such that the catalyst layer of the transfer sheet is in contact with the electrolyte membrane;
Catalyst layer-electrolyte film stack comprising the steps of hot pressing the transfer sheet, electrolyte membrane and transfer sheet laminate, and peeling the substrate of the transfer sheet at the boundary surface between the release layer and the release layer Body manufacturing method.
7). 7. A catalyst layer-electrolyte membrane laminate produced using the method for producing a catalyst layer-electrolyte membrane laminate as described in 6 above.
8). 8. A method for producing an electrode-electrolyte membrane assembly, comprising a step of placing an electrode substrate on both sides of the catalyst layer-electrolyte membrane laminate according to 7 above and applying pressure.
9. 8. An electrode-electrolyte membrane assembly produced using the catalyst layer-electrolyte membrane laminate according to 7 above.
10. 10. A fuel cell incorporating the catalyst layer-electrolyte membrane laminate according to 8 or 9 above.

Electrode-electrolyte membrane assembly production transfer sheet The electrode-electrolyte membrane assembly production transfer sheet of the present invention has one or more catalyst layers on at least one side of a substrate via a release layer and a release layer. It is formed.

  An example of the transfer sheet for producing the electrode-electrolyte membrane assembly of the present invention is shown in FIG. In the transfer sheet shown in FIG. 1, a release layer is formed on one side of a substrate, a release layer is formed on the release layer, and a catalyst layer is further formed on the release layer.

  Another example of the transfer sheet for producing an electrode-electrolyte membrane assembly of the present invention is shown in FIGS. FIG. 2 is a cross-sectional view of a transfer sheet for producing an electrode-electrolyte membrane assembly of the present invention, and FIG. 3 is a plan view of the transfer sheet. In the transfer sheet shown in FIGS. 2 and 3, a release layer is formed on one side of a substrate, a release layer is formed on the release layer, and a plurality of catalyst layers are formed on the release layer. Has been.

The substrate base material, such as polyimide, polyethylene terephthalate, Poriparuban acid aramid, polyamide (nylon), polysulfone, polyether sulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, polyethylene naphthalate Can be mentioned.

  In addition, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Fluorine resin can also be used.

  Further, the base material may be paper such as art paper, coated paper, light coated paper, and other non-coated paper such as notebook paper and copy paper, in addition to the polymer film.

  The thickness of the substrate is usually about 6 to 100 μm, preferably about 6 to 30 μm, and more preferably about 6 to 15 μm from the viewpoints of handleability and economy.

  Accordingly, the base material is preferably a polymer film that is inexpensive and easily available, and more preferably polyethylene terephthalate.

Release layer The release layer is formed on at least one surface of the substrate.

  The release layer can be composed of polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, silicone resin, fluororesin, acrylic resin, polyester resin, urethane resin, cellulose resin such as cellulose acetate, wax, and the like. In order to further improve the transferability of the release layer, the release layer is preferably at least one curable resin selected from polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl alcohol resin, acrylic resin, and polyester resin. These resins are preferably contained in the release layer in an amount of about 50 to 97% by weight. The remaining components are a dispersant, a curing agent and the like. Here, a well-known thing can be widely used as a dispersing agent and a hardening | curing agent.

  In forming the release layer on the substrate, the resin and / or wax is mixed and dispersed in a suitable solvent to form a paste, so that the formed release layer has a desired thickness. In addition, this paste is preferably applied on the substrate according to a known method such as gravure coating or gravure reverse coating.

  Examples of the solvent include various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof.

  The method of applying the paste is not particularly limited, and for example, general methods such as knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater, screen printing, etc. are applied. it can.

  A release layer is formed by applying and then drying such paste. A drying temperature is about 60-200 degreeC normally, Preferably it is about 80-120 degreeC. Although depending on the drying temperature, the drying time is usually about 1 to 10 minutes, preferably about 2 to 6 minutes.

  The thickness of the release layer is usually about 0.5 to 5 μm, preferably about 0.8 to 2 μm.

Release layer In the present invention, the release layer is formed on a release layer formed on a substrate. This release layer is peeled from the substrate together with the catalyst layer at the boundary surface between the release layer and the release layer during thermal transfer.

  The release layer is composed of a conductive material and a polymer resin and / or wax.

  Examples of the conductive material include carbon particles, metal particles, and conductive polymer materials.

  As the carbon particles, known particles can be widely used, but carbon black is preferable. Examples of carbon black include oil furnace black, acetylene black, thermal black, and channel black. Specific examples of the oil furnace black include the Vulcan series manufactured by Cabot, the Black Pearls series, and the Ketjen Black series manufactured by Lion. A specific example of acetylene black is Denka Black manufactured by Denki Kagaku Kogyo.

  The average particle size of the carbon particles is usually about 5 to 500 nm, preferably about 10 to 50 nm. The average particle diameter of the carbon particles is determined by electron microscopy.

  Examples of the conductive polymer material include polypyrrole.

  As the polymer resin, known thermoplastic resins can be widely used. For example, acrylic resin, polyvinyl alcohol resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride-vinyl acetate copolymer, chlorinated polyolefin, silicone resin, fluorine Examples thereof include a resin, a cellulose derivative resin, and a mixture of these resins.

Examples of the wax include petroleum wax, plant wax, animal wax, mineral wax, synthetic wax, and silicone wax. The wax used in the present invention includes, for example, esters of C ₁₆ -C ₃₂ fatty acids and alcohols. In the present invention, these waxes are used singly or in combination of two or more.

  The release layer is preferably composed of carbon particles and a polymer resin.

  In forming the release layer on the release layer, the conductive material and the polymer resin and / or wax are mixed and dispersed in an appropriate solvent to form a paste, and the formed release layer has a desired thickness. The paste is preferably applied on the release layer according to a known method such as a gravure printing method, a screen printing method, a reverse roll coating method using a gravure plate, or the like.

  Examples of the solvent include various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof.

  The method of applying the paste is not particularly limited, and for example, general methods such as knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater, screen printing, etc. are applied. it can.

  After applying such paste, it is dried to form a release layer. A drying temperature is about 60-200 degreeC normally, Preferably it is about 80-120 degreeC. Although depending on the drying temperature, the drying time is usually about 1 to 10 minutes, preferably about 2 to 6 minutes.

  The thickness of the release layer is usually about 0.5 to 5 μm, preferably about 0.8 to 2 μm.

  Furthermore, the release layer can be imparted with a desired shape such as water repellency, hydrophilicity, and surface irregularities, in order to improve the performance of the fuel cell and solve problems.

  In general, during battery operation, hydrogen ions generated on the anode side become hydrated, pass through the electrolyte membrane, and move to the cathode. Therefore, a phenomenon called dry-up occurs that becomes dry on the anode side and inhibits the catalytic reaction. On the other hand, on the cathode side, the generated water fills the gap between the catalyst layer and the gas diffusion layer, obstructs the gas supply, and causes a problem of flooding that stops the cell reaction.

  For this reason, for example, by increasing the hydrophilicity of the release layer on the anode side, a highly hydrophilic layer can be introduced between the catalyst layer and the gas diffusion layer when the cells are assembled. Can be supplied.

  Moreover, by increasing the water repellency of the release layer on the cathode side, a layer with high water repellency can be introduced at the interface between the catalyst layer and the gas diffusion layer, and the drainage performance can be improved.

  By using carbon particles having high hydrophilicity as the carbon particles, hydrophilicity can be imparted to the release layer, and by using carbon particles having high water repellency as the carbon particles, hydrophobicity can be imparted to the release layer.

  As the highly hydrophilic carbon particles, for example, carbon having many surface functional groups such as oil furnace black and high hydrophilicity may be used. Alternatively, a hydrophilic functional group can be introduced on the surface of the carbon particles by subjecting the carbon to acid treatment, alkali treatment, ozone treatment, plasma treatment or the like, and this is used as highly hydrophilic carbon particles. You can also

  As the highly hydrophobic carbon particles, for example, carbon having a small surface functional group and high water repellency such as acetylene black is preferably used. Alternatively, carbon is heat treated to increase the degree of graphitization, or carbon is treated with fluorine treatment, silane coupling treatment, etc., and water repellency is introduced on the surface of carbon particles. It can also be used as high carbon particles.

  In addition, by using a highly hydrophilic polymer resin as the polymer resin, hydrophilicity is imparted to the release layer, and by using a polymer resin having high water repellency as the polymer resin, hydrophobicity is imparted to the release layer. can do.

  As the highly hydrophilic polymer resin, for example, a resin having high water retention such as polyacrylic acid or perfluorosulfonic acid can be used.

  As the polymer resin having high water repellency, for example, PTFE or the like can be used.

  The release layer preferably has conductivity, and by providing the release layer with conductivity, a high-performance fuel cell is manufactured without increasing the electric resistance value of the catalyst layer-electrolyte membrane laminate. be able to.

Catalyst layer The catalyst layer is a known one. The catalyst layer contains carbon particles supporting catalyst particles and a hydrogen ion conductive polymer electrolyte.

  Examples of the catalyst particles include platinum and platinum compounds. Examples of the platinum compound include an alloy of platinum and at least one metal selected from the group consisting of ruthenium, palladium, nickel, molybdenum, iridium, iron and the like. The catalyst contained in the cathode catalyst layer is generally platinum. The catalyst contained in the anode catalyst layer is generally an alloy of the metal and platinum.

  Examples of the hydrogen ion conductive polymer electrolyte include perfluorosulfonic acid-based fluorine ion exchange resins.

  In forming the catalyst layer on the release layer, the carbon particles supporting the catalyst particles and the hydrogen ion conductive polymer electrolyte are mixed and dispersed in an appropriate solvent to form a paste. This paste is preferably applied onto the release layer according to a known method so as to have a desired thickness.

  Examples of the solvent include various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof. Among these solvents, alcohols are preferable. Examples of alcohols include monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol, and various polyhydric alcohols.

  The method for applying the paste is not particularly limited. For example, the paste coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, gravure coater, curtain coater, screen printing, etc. The method can be applied.

  After applying such paste, the catalyst layer is formed by drying. A drying temperature is about 40-100 degreeC normally, Preferably it is about 60-80 degreeC. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 30 minutes to 1 hour.

  The thickness of the catalyst layer is usually about 10 to 200 μm, preferably about 10 to 100 μm, more preferably about 15 to 50 μm.

Catalyst Layer-Electrolyte Membrane Laminate The electrolyte membrane (catalyst layer-electrolyte membrane laminate) on which the catalyst layer of the present invention is laminated is produced, for example, by the method shown below.

  First, on one surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer made of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and the release A transfer sheet for producing an electrode-electrolyte membrane assembly, in which the carbon particles constituting the layer have higher water repellency than the carbon particles constituting the catalyst layer (hereinafter referred to as “transfer sheet A”), It arrange | positions so that a catalyst layer may contact an electrolyte membrane.

  Next, on the other surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer made of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and A transfer sheet for producing an electrode-electrolyte membrane assembly having higher hydrophilicity than the carbon particles constituting the catalyst layer (this transfer sheet is hereinafter referred to as “transfer sheet B”), and the catalyst layer of the transfer sheet B is in contact with the electrolyte membrane Arrange so that.

  Next, the laminate of the transfer sheet A, the electrolyte membrane, and the transfer sheet B is hot pressed.

  Finally, the base material of the transfer sheet A and the base material of the transfer sheet B are peeled at the boundary surface between the release layer and the release layer.

  In consideration of workability, the catalyst layer surface of the transfer sheet A and the catalyst layer surface of the transfer sheet B are preferably laminated simultaneously on both surfaces of the electrolyte membrane. In this case, for example, after the transfer sheet A and the transfer sheet B are arranged so that the catalyst layer surface of the transfer sheet A and the catalyst layer surface of the transfer sheet B face both surfaces of the electrolyte membrane, What is necessary is just to peel the base material of the transfer sheet B.

  The pressure level of the heating press is usually about 0.5 to 20 MPa, preferably about 1 to 10 MPa in order to avoid transfer failure. Further, it is preferable to heat the pressing surface during this pressing operation in order to avoid transfer failure. The heating temperature is usually 200 ° C. or lower, preferably 150 ° C. or lower in order to avoid breakage, modification, etc. of the electrolyte membrane.

  The electrolyte membrane used is a known one. The thickness of the electrolyte membrane is usually about 20 to 250 μm, preferably about 20 to 80 μm.

  The electrolyte membrane is formed, for example, by applying a solution containing a hydrogen ion conductive polymer electrolyte on a substrate and drying. Examples of the hydrogen ion conductive polymer electrolyte include a perfluorosulfonic acid-based fluorine ion exchange resin, more specifically, a perfluorocarbonsulfonic acid-based resin in which the C—H bond of a hydrocarbon ion-exchange membrane is substituted with fluorine. Examples include polymers (PFS polymers). By introducing a fluorine atom having high electronegativity, it is chemically very stable, the dissociation degree of the sulfonic acid group is high, and high ion conductivity can be realized.

  Specific examples of electrolyte membranes include “Nafion” membrane manufactured by DuPont, “Flemion” membrane manufactured by Asahi Glass Co., Ltd., “Aciplex” membrane manufactured by Asahi Kasei Co., Ltd., and “Gore Select” manufactured by Gore. Examples include membranes.

  The concentration of the hydrogen ion conductive polymer electrolyte contained in the hydrogen ion conductive polymer electrolyte-containing solution is usually about 5 to 60% by weight, preferably about 20 to 40% by weight.

  The release layer basically does not transfer and remains on the substrate side.

  FIG. 4 shows an example of the catalyst layer-electrolyte membrane laminate of the present invention (an example using the transfer sheet shown in FIG. 1). FIG. 5 shows another example of the catalyst layer-electrolyte membrane laminate of the present invention (an example using the transfer sheet shown in FIGS. 2 and 3).

Electrode-electrolyte membrane assembly The electrode-electrolyte membrane assembly of the present invention is produced by placing electrode substrates on both sides of a catalyst layer-electrolyte membrane laminate and applying pressure.

  The electrode base material is well known, and various electrode base materials constituting a fuel electrode and an air electrode can be used.

  The pressure level is usually about 0.1 to 100 Mpa, preferably about 5 to 15 Mpa. It is preferable to heat at the time of this pressurization operation, and heating temperature may be about 120-150 degreeC normally.

  An example of the electrode-electrolyte membrane assembly of the present invention is shown in FIG.

Fuel Cell The fuel cell of the present invention is manufactured, for example, as follows.

For example, the fuel cell of the present invention is
(1) A transfer layer A and a transfer sheet B are formed by forming a release layer on at least one surface of the substrate, then forming a release layer on the release layer, and further forming a catalyst layer on the release layer. Obtaining a step,
(2) The transfer sheet A and the transfer sheet B are arranged so that the catalyst layer surfaces of the transfer sheet A and the transfer sheet B obtained in the step (1) face one side or both sides of the electrolyte membrane, and after pressurizing, A step of obtaining a catalyst layer-electrolyte membrane laminate by peeling the substrate of the transfer sheet from the boundary surface between the release layer and the release layer,
(3) A step of obtaining an electrode-electrolyte membrane assembly by placing an electrode substrate on both sides of the catalyst layer-electrolyte membrane laminate obtained in the above step (2) and applying pressure; and
(4) Manufactured through a step of obtaining a fuel cell using the electrode-electrolyte membrane assembly obtained in the step (3).

  The present invention provides a fuel cell incorporating the electrode-electrolyte membrane assembly.

  If the transfer sheet of the present invention is used, a catalyst layer made of a very expensive catalyst material can be reliably transferred to the electrolyte membrane side without remaining on the transfer sheet (base material) side.

  If the transfer sheet of the present invention is used, there is no possibility of the catalyst layer entering the porous electrode substrate, so that the film thickness of the catalyst layer can be easily adjusted, and a uniform catalyst layer can be easily formed on the electrode substrate. Can be formed.

  In addition, if the transfer sheet of the present invention is used, the surface of the electrode base material or the inner hole is not blocked, so there is no possibility of impeding the gas flow performance.

  In the method of the present invention, since there is no need to transfer the catalyst layer to the electrolyte membrane under high temperature and high pressure as in the prior art, the electrolyte membrane does not melt and there is little risk of the membrane itself being denatured.

  Furthermore, in the present invention, dryness and flooding can be prevented by imparting hydrophilicity or water repellency to the release layer.

  Therefore, if the electrode-electrolyte membrane assembly of the present invention is used, a high-quality fuel cell having excellent battery performance can be produced.

  The present invention will be further clarified by the following examples and comparative examples.

Example 1
Various coating solutions as shown below were prepared.

(1) Preparation of release layer forming coating solution 16 parts by weight of acrylic-styrene resin (trade name: Cell Top 226, manufactured by Daicel Chemical Industries), aluminum catalyst (trade name: Cell Top CAT-A, 3 parts by weight of Daicel Chemical Industries, Ltd., 8 parts by weight of methyl ethyl ketone and 8 parts by weight of toluene were mixed to prepare a release layer forming coating solution.

(2) Preparation of coating solution for forming cathode release layer 8 parts by weight of acetylene black (trade name: Denka Black, manufactured by Denki Kagaku Kogyo Co., Ltd.), PTFE (trade name: Polyflon PTFE Dispersion D-1, Daikin Industries ( Co., Ltd.) 2 parts by weight, surfactant (trade name: TRITON X-114, manufactured by Nacalai Tesque) 0.5 part by weight, 38.5 parts by weight of water and 37 parts by weight of ethanol were mixed to prepare a cathode peeling layer. A forming coating solution was prepared.

(3) Preparation of anode release layer forming coating solution Acid-treated oil furnace black (trade name: Vulcan XC-72R, manufactured by Cabot Corp., treated for 1 hour with stirring in 1M sulfuric acid solution, washed and dried 8 parts by weight, 2 parts by weight of perfluorosulfonic acid (trade name: Nafion, manufactured by DuPont), 13 parts by weight of a surfactant (trade name: TRITON X-114, manufactured by Nacalai Tesque), 38 weights of water And 37 parts by weight of ethanol were mixed to prepare a coating solution for forming an anode release layer.

(4) Preparation of catalyst layer forming coating solution 1 part by weight of platinum catalyst (Pt-Ru supported catalyst, manufactured by Tanaka Kikinzoku Co., Ltd.), 7 parts by weight of electrolyte resin (5% by weight Nafion solution, manufactured by DuPont) and ethanol 25 parts by weight was mixed to prepare a catalyst layer forming coating solution.

Example 2 (Production of transfer sheet A)
On one side of a polyethylene terephthalate film (PET, thickness 38 μm, manufactured by Toray Industries, Inc.), the release layer-forming coating solution prepared in (1) above has a release layer of 1.0 g / m ² when dried. After having been applied so as to be, and temporarily dried with a dryer, it was dried in an oven at 110 ° C. for 30 seconds to form a release layer.

Next, the cathode release layer forming coating solution prepared in (2) above was applied to the surface of the release layer so that the release layer when dried was 1.0 g / m ² , and was temporarily dried with a dryer. Thereafter, it was dried in an oven at 110 ° C. for 30 seconds to form a release layer.

Further, the catalyst layer forming coating solution prepared in (4) above was applied to the surface of the release layer so that the catalyst layer at the time of drying was 20 g / m ² and dried in an oven at 70 ° C. for 15 minutes. Thus, a catalyst layer was formed.

  Thus, the transfer sheet A was produced.

Example 3 (Production of transfer sheet B)
On one side of a polyethylene terephthalate film (PET, thickness 38 μm, manufactured by Toray Industries, Inc.), the release layer-forming coating solution prepared in (1) above has a release layer of 1.0 g / m ² when dried. After having been applied so as to be, and temporarily dried with a dryer, it was dried in an oven at 110 ° C. for 30 seconds to form a release layer.

Next, the anode release layer forming coating solution prepared in (3) above was applied to the surface of the release layer so that the release layer when dried was 1.0 g / m ² , and was temporarily dried with a dryer. Thereafter, it was dried in an oven at 110 ° C. for 30 seconds to form a release layer.

Further, the catalyst layer forming coating solution prepared in (4) above was applied to the surface of the release layer so that the catalyst layer at the time of drying was 20 g / m ² and dried in an oven at 70 ° C. for 15 minutes. Thus, a catalyst layer was formed.

  Thus, the transfer sheet B was manufactured.

Comparative Example 1
On one side of a polyethylene terephthalate film (PET, thickness 38 μm, manufactured by Toray Industries, Inc.), apply the catalyst layer forming coating solution prepared in (4) above so that the catalyst layer when dried is 20 g / m ^2. It was applied and dried in an oven at 70 ° C. for 15 minutes to form a catalyst layer.

  In this way, a transfer sheet for comparison was manufactured.

Test example 1
The catalyst layer surface of each transfer sheet obtained in Example 2, Example 3 and Comparative Example 1 was in contact with a hydrogen ion conductive polymer electrolyte membrane (Nafion N112, manufactured by DuPont), at a temperature of 135 ° C., After performing hot pressing at a pressure of 5 kg / cm ² for 1 minute, the PET film was peeled off.

  The weight of the catalyst layer and the release layer remaining on the peeled PET film was measured, and the transfer state of the catalyst layer and the release layer was examined.

The results are shown in Table 1. The unit of numerical values in Table 1 is g / 10 cm ² .

  From Table 1, it is clear that the catalyst layer and the release layer can be satisfactorily transferred to the electrolyte membrane by using the transfer sheets (transfer sheet A and transfer sheet B) of the present invention.

Example 4
The catalyst layer surface of the transfer sheet A obtained in Example 2 is provided on one side of a hydrogen ion conductive polymer electrolyte membrane (Nafion N112, manufactured by DuPont), and the transfer sheet obtained in Example 3 is provided on the other side of the electrolyte membrane. The catalyst layer surface of A was brought into contact with each other and subjected to hot pressing at a temperature of 135 ° C. and a pressure of 5 kg / cm ² for 1 minute, and then the PET film was peeled off to produce the catalyst layer-electrolyte membrane laminate of the present invention.

  Next, electrode base materials (carbon paper made of carbon fiber, TGP-H-90, thickness 0.28 mm, manufactured by Toray Industries, Inc.) are arranged on both sides of the catalyst layer-electrolyte membrane laminate produced above. The electrode-electrolyte membrane assembly of the present invention was manufactured by hot pressing under conditions of 150 ° C. and 5 MPa.

Comparative Example 2
1 at a temperature of 135 ° C. and a pressure of 5 kg / cm ² so that the catalyst layer surface of the transfer sheet A obtained in Comparative Example 1 is in contact with both surfaces of a hydrogen ion conductive polymer electrolyte membrane (Nafion N112, manufactured by DuPont). After performing a hot press for a minute, the PET film was peeled off to produce a catalyst layer-electrolyte membrane laminate.

  Next, electrode base materials (carbon paper made of carbon fiber, TGP-H-90, thickness 0.28 mm, manufactured by Toray Industries, Inc.) are arranged on both sides of the catalyst layer-electrolyte membrane laminate produced above. Then, hot pressing was performed under the conditions of 150 ° C. and 5 MPa to produce an electrode-electrolyte membrane assembly.

Test example 2
The electrode-electrolyte membrane laminate produced in Example 4 and the electrode-electrolyte membrane laminate produced in Comparative Example 2 were incorporated into a single cell (50 × 50 mm) manufactured by Electrochem, and hydrogen gas and oxidant gas were used as fuel gases. The battery performance was examined by performing continuous operation for 500 hours at a constant current of 300 mA using air.

  In the cell incorporating the electrode-electrolyte membrane laminate produced in Example 4, dry-up and flooding phenomena were not observed on the anode side and the cathode side, respectively, even after long-term continuous operation exceeding 500 hours.

  On the other hand, in the cell incorporating the electrode-electrolyte membrane laminate produced in Comparative Example 2, dry-up and flooding phenomena were observed on the anode side and the cathode side, respectively, by continuous operation over 500 hours. It was.

FIG. 1 is a sectional view of a transfer sheet (film) for producing an electrode-electrolyte membrane assembly. FIG. 2 is a cross-sectional view of a transfer sheet (film) for producing an electrode-electrolyte membrane assembly. FIG. 3 is a plan view of a transfer sheet (film) for producing an electrode-electrolyte membrane assembly. FIG. 4 is a cross-sectional view of an electrolyte membrane on which a catalyst layer is laminated. FIG. 5 is a cross-sectional view of the electrode-electrolyte membrane assembly. FIG. 6 is a cross-sectional view of the electrode-electrolyte membrane assembly.

Claims (10)

  One or two or more catalysts in which a release layer that does not peel from the substrate is formed on at least one surface of the substrate, a release layer is formed on the release layer, and carbon particles are contained on the release layer A transfer sheet for producing an electrode-electrolyte membrane assembly, wherein a layer is formed.   The transfer sheet according to claim 1, wherein the release layer comprises carbon particles and a polymer resin.   The transfer sheet according to claim 2, wherein the carbon particles constituting the release layer have higher water repellency than the carbon particles constituting the catalyst layer.   The transfer sheet according to claim 2, wherein the carbon particles constituting the release layer have higher hydrophilicity than the carbon particles constituting the catalyst layer.   The transfer sheet according to claim 1, wherein the release layer has conductivity. On one surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer composed of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and the release layer is A step of disposing a transfer sheet for producing an electrode-electrolyte membrane assembly, wherein the carbon particles constituting the electrode layer have a higher water repellency than the carbon particles constituting the catalyst layer such that the catalyst layer of the transfer sheet is in contact with the electrolyte membrane;
On the other surface of the electrolyte membrane, a release layer that does not peel from the substrate, a release layer made of carbon particles and a polymer resin, and a catalyst layer containing carbon particles are sequentially laminated on at least one surface of the substrate, and the catalyst layer is Arranging a transfer sheet for producing an electrode-electrolyte membrane assembly, which is more hydrophilic than the carbon particles to be formed, such that the catalyst layer of the transfer sheet is in contact with the electrolyte membrane;
Catalyst layer-electrolyte film stack comprising the steps of hot pressing the transfer sheet, electrolyte membrane and transfer sheet laminate, and peeling the substrate of the transfer sheet at the boundary surface between the release layer and the release layer Body manufacturing method.   The catalyst layer-electrolyte membrane laminated body manufactured using the manufacturing method of the catalyst layer-electrolyte membrane laminated body of Claim 6.   The manufacturing method of an electrode-electrolyte membrane assembly provided with the process of arrange | positioning and pressurizing an electrode base material on both surfaces of the catalyst layer-electrolyte membrane laminated body of Claim 7.   An electrode-electrolyte membrane assembly produced using the catalyst layer-electrolyte membrane laminate according to claim 7. A fuel cell incorporating the catalyst layer-electrolyte membrane laminate according to claim 8 or 9.

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