JP2007179893A - Catalyst layer-electrolyte membrane laminate, and manufacturing method of same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst layer-electrolyte membrane laminate provided with excellent battery characteristics, capable of effectively supplying fuel to electrolyte membranes, and to provide a manufacturing method of the same. <P>SOLUTION: The catalyst layer-electrolyte membrane laminate contains catalyst carrying carbon particles and hydrogen ion conductive polymer electrolyte, and two or more layers of catalyst layer having cracks are laminated on one face or both faces of the electrolyte membrane. At least a part of the catalyst layer is embedded in the electrolyte membrane. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a catalyst layer-electrolyte membrane laminate and a method for producing the same.

  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.

  The polymer electrolyte fuel cell has a structure in which a hydrogen ion conductive polymer electrolyte membrane is used as an electrolyte membrane, a catalyst layer is arranged on both sides thereof, an electrode base material is arranged on both sides thereof, and this is further sandwiched between separators. I am doing. Those in which the catalyst layers are arranged on both sides of the electrolyte membrane are referred to as catalyst layer-electrolyte membrane laminates, and those in which the electrode base material is further arranged on both sides thereof are referred to as electrode-electrolyte membrane assemblies.

  The performance of the catalyst layer-electrolyte membrane laminate has a great influence on the cell performance of the fuel cell, and is regarded as particularly important. As measures to improve the performance of this catalyst layer-electrolyte membrane laminate, measures such as (1) increasing the thickness of the catalyst layer to increase the amount of platinum supported and (2) increasing the surface area of the catalyst layer-electrolyte membrane interface are proposed. (Patent Documents 1 and 2).

  Patent Document 1 includes a gas diffusion layer and a plurality of catalyst layers disposed between the gas diffusion layer and the polymer electrolyte membrane, and ion exchange of an ion exchange resin contained in the catalyst layer. Disclosed is a polymer electrolyte fuel cell including a catalyst layer-electrolyte membrane laminate having a capacity satisfying a predetermined condition.

  However, the catalyst layer-electrolyte membrane laminate described in Patent Document 1 is one in which two or more layers are formed on the electrolyte membrane by applying the catalyst layer forming ink twice and spraying. In the case of producing a laminate by such a method, the catalyst layer forming ink enters the voids and pores of the catalyst layer formed first, and the voids and pores are blocked. As a result, there is a problem that the manufactured laminate cannot efficiently supply the fuel gas and cannot give excellent battery performance such as high power density to the battery.

  Patent Document 2 discloses a fuel cell electrolyte membrane having fine protrusions on one or both sides of a polymer electrolyte membrane.

  However, this electrolyte membrane for fuel cells is subject to restrictions on the method of supporting the catalyst on the electrolyte membrane due to the shape of the minute projections on the surface of the electrolyte membrane, and the adhesion between the catalyst layer and the electrolyte membrane is weakened. Therefore, it is difficult to form a large amount of catalyst on the electrolyte membrane. As a result, there is a problem that a high output density cannot be achieved.

Therefore, the main object of the present invention is to provide a catalyst layer-electrolyte membrane laminate and a method for producing the same that can efficiently supply fuel to the electrolyte membrane and have excellent battery performance. .
JP 2001-338654 A JP 2005-108822 A

  In view of such a situation, the present inventors have intensively studied to achieve the above object. As a result, the inventors have found that the above object can be achieved by using a catalyst layer-electrolyte membrane laminate having a specific structure manufactured by a manufacturing method including a specific process, and completed the present invention.

Item 1. A catalyst layer-electrolyte membrane laminate in which two or more layers of catalyst layers containing catalyst-carrying carbon particles and hydrogen ion conductive polymer electrolyte and having cracks are laminated on one side or both sides of the electrolyte membrane,
A catalyst layer-electrolyte membrane laminate, wherein at least a part of the catalyst layer is buried in the electrolyte membrane.

  Item 2. Item 2. The catalyst layer-electrolyte membrane laminate according to Item 1, wherein at least one of the catalyst layers is buried in the electrolyte membrane.

  Item 3. Item 3. The catalyst layer-electrolyte membrane laminate according to Item 1 or 2, wherein cracks of the catalyst layers do not overlap each other, and cracks do not substantially penetrate in the thickness direction as the entire catalyst layer.

  Item 4. Item 4. The catalyst layer-electrolyte membrane laminate according to any one of Items 1 to 3, wherein the catalyst supported on the catalyst-supporting carbon particles is platinum or a platinum compound.

Item 5. The supported amount of platinum contained in the catalyst layer, respectively ^{0.1mg / cm 2 ~1.3mg / cm 2} , the catalyst layer according to claim 4 - membrane laminate.

  Item 6. Item 6. The catalyst layer-electrolyte membrane laminate according to any one of Items 1 to 5, wherein each catalyst layer has a thickness of 1 μm to 80 μm.

  Item 7. Item 7. An electrode-electrolyte membrane assembly comprising the catalyst layer-electrolyte membrane laminate according to any one of Items 1 to 6.

Item 8. A method for producing a catalyst layer-electrolyte membrane laminate in which two or more catalyst layers having cracks are laminated on one side or both sides of an electrolyte membrane, and at least a part of the catalyst layer is buried in the electrolyte membrane,
A catalyst layer is formed on a transfer substrate using a paste composition for forming a catalyst layer comprising (1) an aqueous dispersion of catalyst-supporting carbon particles, (2) a hydrogen ion conductive polymer electrolyte, and (3) a solvent for adjusting viscosity. A first step of forming a catalyst layer transfer sheet by forming
The catalyst layer transfer sheet obtained in the first step is hot-pressed on the electrolyte membrane, the second step of laminating the catalyst layer on the electrolyte membrane, and the catalyst layer of the laminate obtained in the second step, A third step of laminating the catalyst layer by hot pressing the catalyst layer transfer sheet;
A method for producing a catalyst layer-electrolyte membrane laminate comprising:

(A) Catalyst layer-electrolyte membrane laminate The catalyst layer-electrolyte membrane laminate of the present invention comprises:
A catalyst layer-electrolyte membrane laminate in which two or more layers of catalyst layers containing catalyst-carrying carbon particles and hydrogen ion conductive polymer electrolyte and having cracks are laminated on one side or both sides of the electrolyte membrane,
At least a part of the catalyst layer is buried in the electrolyte membrane.

Catalyst Layer The catalyst layer of the present invention contains catalyst-supporting carbon particles and hydrogen ion conductive polymer electrolyte, and has cracks.

  The catalyst layer of the present invention consists essentially of catalyst-supporting carbon 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.

  As the carbon particles as the support, for example, acetylene black, ketjen black, furnace black, activated carbon, carbon nanotube, fullerene, or the like can be used.

The specific surface area of the carbon particles is not limited, usually ^{50m 2} / ^g~1500m 2 / g approximately, and more preferably 500m ² / g~1300m ² / g approximately. By setting it within this range, the catalytic activity can be improved, and a battery having a higher power density can be obtained.

  Generally, the catalyst particles when used as the cathode catalyst layer are platinum, and the catalyst particles when used as the anode catalyst layer are the alloys described above.

  Examples of the hydrogen ion conductive polymer electrolyte include perfluorosulfonic acid-based fluorine ion exchange resins. By introducing a fluorine atom having a high electronegativity, it is chemically very stable, the degree of sulfonic acid group detachment is high, and high ionic conductivity can be realized. Specific examples of such a hydrogen ion conductive polymer electrolyte include “Nafion” manufactured by DuPont, “Flemion” manufactured by Asahi Glass Co., Ltd., “Aciplex” manufactured by Asahi Kasei Co., Ltd., and Gore manufactured by Gore. Examples include “Gore Select”.

  The blending ratio of the hydrogen ion polymer electrolyte is usually about 0.3 to 3 parts by weight, preferably 0.4 to 2 parts by weight with respect to 1 part by weight of the catalyst-supporting carbon particles.

  Each catalyst layer of the present invention has a crack. The cracks in each catalyst layer are substantially penetrated in the thickness direction of the catalyst layer. The crack may be continuous or discontinuous in the planar direction of the catalyst layer.

  The crack rate (opening ratio) of each catalyst layer of the present invention is usually about 2 to 50%, preferably about 3 to 40%. When the crack is in the above range, a certain strength can be imparted to the catalyst layer, and the fuel can easily penetrate into the catalyst layer, so that a battery having a high output density can be obtained.

  The crack rate of the present invention is determined by the following formula (1) by taking the catalyst layer into a photograph, binarizing (white / black), calculating the area ratio (%) of the catalyst layer portion and the crack portion. It is what is done. In binarization, the color of a photograph is divided into 255 steps, and 0 to 50 are judged as catalyst layer portions and 51 to 255 portions without cracks (crack portions).

[Crack rate] = [Crack part] ÷ [Total area of catalyst layer] (1)
Although the average maximum width of cracks is not limited, it is usually about 0.5 μm to 15 μm from the viewpoint of facilitating fuel penetration.

  The thickness of the catalyst layer is not limited, but is usually about 1 μm to 80 μm, preferably about 10 μm to 60 μm.

Supported amount of platinum in the catalyst layers, respectively is typically 0.1mg ^/ cm ² ~1.3mg ^/ cm 2 approximately. Thereby, a higher power density can be achieved.

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

Catalyst layer-electrolyte membrane laminate The catalyst layer-electrolyte membrane laminate of the present invention comprises two or more layers of the catalyst layer laminated on one or both sides of the electrolyte membrane, and at least a part of the catalyst layer is the above. It is buried in the electrolyte membrane. An example of a cross-sectional view of the catalyst layer-electrolyte membrane laminate of the present invention is shown in FIG.

  The number of catalyst layers laminated on one side may be two or more, and preferably 3 to 6 layers.

  Since the catalyst layer-electrolyte membrane laminate of the present invention is formed by laminating a plurality of catalyst layers, cracks (voids) do not substantially penetrate through the entire catalyst layer. That is, the cracks of the individual catalyst layers are substantially penetrated, but by laminating a plurality of catalyst layers, the cracks are not penetrated as a whole catalyst layer. This can more effectively prevent crossover (a phenomenon in which the fuel supplied to the fuel electrode passes through the electrolyte membrane and reacts at the oxidation electrode, thereby canceling power generation at the fuel electrode). In addition, when reformed gas is used for the fuel, oxygen monoxide generated by the reformed gas can be prevented from entering the catalyst layer, and deterioration of the catalyst activity of the catalyst layer can be more effectively prevented. it can.

  At least a part of the catalyst layer of the present invention is buried in the electrolyte membrane. That is, a part of at least one catalyst layer among the plurality of catalyst layers enters the electrolyte membrane, and a part of the electrolyte membrane is filled in the crack of the layer. By adopting such a configuration, the distance (proton conduction path) between the anode catalyst layer and the cathode catalyst layer is shortened, the electric resistance is reduced, and the voltage can be improved. Further, since the side wall portion of the crack is also in contact with the electrolyte, the contact area between the catalyst layer and the electrolyte membrane is increased, and the output density is improved. Furthermore, since it is fixed by the buried catalyst layer, the electrolyte membrane is prevented from swelling and shrinking, and thus the electrolyte membrane is prevented from deteriorating.

  Although the thickness of the catalyst layer buried in the electrolyte membrane is not limited, the catalyst layer located closest to the electrolyte membrane among the plurality of stacked catalyst layers (that is, the catalyst layer buried first is shown below). This layer is also referred to as a “first catalyst layer.”) Is usually buried about ½ or more. When seen from the thickness of the entire catalyst layer (all the plurality of catalyst layers), it is usually buried about 1/5 to 1/2. If it is less than that, there is a possibility that the above voltage improvement and high output density cannot be achieved. If it is buried thicker than that, the durability of the electrolyte membrane during long-term operation may be reduced. In addition, the electrolyte membrane becomes too thin, and the deterioration of the catalyst layer-electrolyte membrane laminate during long-term operation may be accelerated.

  In the present invention, it is particularly preferable that at least one of the two or more laminated catalyst layers is buried. That is, it is preferable that the first catalyst layer is completely buried. The upper limit of the buried catalyst layer is not limited, but is usually about 3 layers. By burying one or more layers, the electrolyte permeates from the crack portion of the first catalyst layer, and the electrolyte also contacts the electrolyte side surface of the next catalyst layer (second catalyst layer). For this reason, the contact area of the catalyst layer-electrolyte membrane increases in addition to the side wall portion of the crack of the first catalyst layer, and the power density can be further improved.

Electrode-electrolyte membrane assembly The electrode-electrolyte membrane assembly of the present invention is produced by placing an electrode substrate on both sides of the catalyst layer-electrolyte membrane laminate and pressurizing it.

  The electrode base material is well-known, and various carbon papers, carbon cloths, etc. constituting the fuel electrode and the air electrode can be used.

The pressure level is usually about 0.1 Mpa to 100 Mpa, preferably about 5 Mpa 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. At this time, the conductive layer laminated on the catalyst layer electrically connects the electrode substrate and the catalyst layer. The electrode base material is preferably highly water-repellent to prevent flooding, and the conductive layer material is preferably water-repellent carbon.
(B) Method for producing catalyst layer-electrolyte membrane laminate
The method for producing the catalyst layer-electrolyte membrane laminate of the present invention comprises:
A method for producing a catalyst layer-electrolyte membrane laminate in which two or more catalyst layers having cracks are laminated on one side or both sides of an electrolyte membrane, and at least a part of the catalyst layer is buried in the electrolyte membrane,
A catalyst layer is formed on a transfer substrate using a paste composition for forming a catalyst layer comprising (1) an aqueous dispersion of catalyst-supporting carbon particles, (2) a hydrogen ion conductive polymer electrolyte, and (3) a solvent for adjusting viscosity. A first step of forming a catalyst layer transfer sheet by forming
The catalyst layer transfer sheet obtained in the first step is hot-pressed on the electrolyte membrane, the second step of laminating the catalyst layer on the electrolyte membrane, and the catalyst layer of the laminate obtained in the second step, A third step of laminating the catalyst layer by hot pressing the catalyst layer transfer sheet;
It is characterized by providing.

First Step The first step of the present invention comprises (1) an aqueous dispersion of catalyst-supporting carbon particles, (2) a hydrogen ion conductive polymer electrolyte, and (3) a paste composition for forming a catalyst layer containing a solvent for adjusting viscosity. In this step, a catalyst layer transfer sheet is obtained by forming a catalyst layer on a transfer substrate using a product.

  The catalyst layer transfer sheet is transferred using a paste composition for forming a catalyst layer containing (1) an aqueous dispersion of catalyst-supporting carbon particles, (2) a hydrogen ion conductive polymer electrolyte, and (3) a solvent for viscosity adjustment. A catalyst layer is formed on a substrate.

  As (1) catalyst-supporting carbon and (2) hydrogen ion conductive polymer electrolyte, those described above can be used.

  (3) Examples of the viscosity adjusting solvent include various alcohols, various ethers, various dialkyl sulfoxides, water, and mixtures thereof. Among these solvents, alcohol is preferable. Examples of the alcohol include monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, s-butanol, and t-butanol, propylene glycol, ethylene glycol, diethylene glycol, and glycerin. Various polyhydric alcohols are mentioned. These solvents may be used alone or in combination of two or more.

  The proportion of the above components (1) to (3) contained in the catalyst layer forming paste composition of the present invention is not limited and can be appropriately selected within a wide range.

  For example, in the paste composition for forming a catalyst layer of the present invention, the component (2) is 0.3 to 3 parts by weight (preferably 0.4 to 4 parts per 1 part by weight of the catalyst-supporting carbon particles of (1). 2 parts by weight, and the component (3) should be contained in an amount of about 5 to 50 parts by weight (preferably 10 to 25 parts by weight), with the balance being water. On the other hand, the weight is equal to 10 times the weight.

  The catalyst layer forming paste composition is produced by mixing the components (1) to (3). The order of mixing the components (1) to (3) is not particularly limited. For example, a paste composition for forming a catalyst layer can be prepared by mixing and dispersing component (1), component (2), and component (3) sequentially or simultaneously. For mixing, known mixing means can be widely applied.

  As the transfer substrate, for example, polyimide, polyethylene terephthalate, polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, polyethylene naphthalate, polypropylene And the like. 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, in addition to the polymer film, the transfer substrate may be paper such as art paper, coated paper, lightweight coated paper, or other non-coated paper such as notebook paper or copy paper.

  The thickness of the transfer substrate is usually about 6 μm to 100 μm, preferably about 10 μm to 35 μm, more preferably about 10 μm to 25 μm, from the viewpoints of handleability and economy.

  Therefore, as the transfer substrate, a polymer film that is inexpensive and easily available is preferable, and polyethylene terephthalate or the like is more preferable.

  The method for forming the paste composition on the transfer substrate is not particularly limited. For example, knife coater, bar coater, spray, dip coater, spin coater, roll coater, die coater, curtain coater, screen printing, etc. The general coating method can be applied.

  After applying such a paste, the catalyst layer of the present invention is formed by drying. The drying temperature is desirably not higher than the melting point of the wax, and is usually about 40 to 100 ° C., preferably about 60 to 80 ° C. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 30 minutes to 1 hour. By appropriately changing the drying temperature, time, solvent of the paste composition, and the like, cracks formed in the catalyst layer can be appropriately adjusted.

Further, a catalyst layer may be formed on at least one surface of the transfer substrate via a release layer. The release layer is made of wax, for example. Specific examples of the wax include petroleum wax, plant wax, animal wax, mineral wax, and synthetic wax. The wax used in the present invention includes, for example, an ester of a C ₁₆ -C ₃₂ fatty acid and an alcohol. In the present invention, these waxes are used singly or in combination of two or more.

  The wax used in the present invention preferably has a melting point of 60 to 140 ° C, more preferably a melting point of 60 to 100 ° C.

  In the present invention, preferred waxes are plant-based waxes, and more preferred waxes are carnauba wax and candelilla wax.

  The release layer may be made of a plastic film (for example, a film of polyethylene terephthalate or the like) coated with a known fluorine-based resin.

  The thickness of the release layer is usually about 0.1 μm to 3 μm, preferably about 0.5 μm to 1 μm.

  In forming the release layer on the transfer substrate, the wax is preferably applied according to a known method so as to have a desired layer thickness.

Second Step The second step of the present invention is a step of laminating the catalyst layer on the electrolyte membrane by hot pressing the catalyst layer transfer sheet obtained in the first step onto the electrolyte membrane.

  Specifically, the transfer sheet may be disposed so that the catalyst layer surface of the catalyst layer transfer sheet faces the electrolyte membrane surface and hot-pressed, and then the transfer substrate of the transfer sheet is peeled off.

  In consideration of workability, the catalyst layer surface is preferably laminated on both surfaces of the electrolyte membrane at the same time. In this case, for example, the transfer sheet may be disposed such that the catalyst layer surface of the catalyst layer transfer sheet faces both surfaces of the electrolyte membrane, and after pressing, the transfer substrate of the transfer sheet may be peeled off.

  Hot pressing can be performed according to a conventional method. The pressure level is usually about 0.5 Mpa to 20 Mpa, preferably about 1 Mpa to 10 Mpa in order to avoid transfer defects. In addition, it is preferable to heat the pressure surface during this pressure operation in order to avoid further transfer defects. 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. By appropriately changing these conditions, the depth of the catalyst layer buried in the electrolyte membrane can be adjusted as appropriate.

3rd process The 3rd process of this invention is a process of laminating | stacking a catalyst layer on the catalyst layer of the laminated body obtained at the 2nd process by further hot-pressing the said catalyst layer transfer sheet. By obtaining this step, the above-described catalyst layer-electrolyte membrane laminate of the present invention can be produced.

  The catalyst layer transfer sheet is the catalyst layer transfer sheet obtained in the first step.

  The conditions for hot pressing are the same as in the second step, and by appropriately changing these conditions, the depth of the catalyst layer buried in the electrolyte membrane can be adjusted as appropriate.

  When it is desired to stack three or more catalyst layers, this third step may be repeated once or a plurality of times.

  According to the present invention, since the catalyst layer has cracks of an appropriate size, fuel can be efficiently supplied to the entire catalyst layer. As a result, the fuel cell using the catalyst layer-electrolyte membrane laminate of the present invention can exhibit excellent battery performance such as high output density.

  Since the catalyst layer-electrolyte membrane laminate of the present invention has a structure in which a plurality of catalyst layers are laminated and cracks are not substantially penetrated as a whole catalyst layer, crossover can be prevented more effectively. Further, when the reformed gas is used as the fuel, it is possible to more effectively prevent the catalytic activity of the catalyst layer from being deteriorated by oxygen monoxide. Furthermore, since it is fixed by the buried catalyst layer, the electrolyte membrane is prevented from swelling and shrinking, and thus the electrolyte membrane is prevented from deteriorating. Accordingly, the fuel cell using the catalyst layer-electrolyte membrane laminate of the present invention has excellent battery performance such as high durability.

  The present invention will be further clarified by the following examples and comparative examples. In addition, this invention is not limited to the following Example.

Example 1
(1) Preparation of anode catalyst layer paste composition A Platinum ruthenium catalyst-supported carbon (Pt: 29.7%, Ru: 23.1%, manufactured by Tanaka Kikinzoku Kogyo, "TEC61V54", (carbon particles: "Vulcan XC- 72R ", manufactured by Cabot, specific surface area of 254 m ^{2 /} g) and 1.00 g of water and 10.00 g of water were stirred and mixed in a disperser to prepare an aqueous dispersion of platinum-ruthenium-supported carbon. A paste composition A for an anode catalyst layer was prepared by blending 6.00 g of a 5 wt% Nafion solution (DE521, manufactured by DuPont) and 0.30 g of propylene glycol into the liquid and stirring and mixing them.

(2) Preparation of cathode catalyst layer paste composition Platinum catalyst-supported carbon (Pt: 46.7%, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., TEC10E50E) 1.00 g and water 10.00 g were stirred and mixed with a disperser, platinum An aqueous dispersion of supported carbon was prepared. For the cathode catalyst layer, 4.00 g of 5 wt% Nafion solution (DE521, manufactured by DuPont), 4.00 g of n-butanol and 4.00 g of t-butanol were mixed in the prepared aqueous dispersion and stirred. A paste composition was prepared.

(3) Production of catalyst layer transfer sheet The anode catalyst layer paste composition and the cathode catalyst layer paste composition were each dried on a PET film (E3120, manufactured by Toyobo Co., Ltd., thickness 13 μm) with a doctor blade. The anode catalyst layer transfer sheet A and the cathode catalyst layer transfer sheet were obtained by coating and drying so as to have a thickness of 50 μm. The platinum loading and crack rate of these catalyst layers were 0.9 mg / cm ² and 35% for the anode catalyst layer and 1.0 mg / cm ² and 39% for the cathode catalyst layer, respectively.

(4) Production of catalyst layer-electrolyte membrane laminate Hot press (pressure level 6 Mpa, pressure time) with electrolyte membrane Nafion 115 (manufactured by DuPont) sandwiched between anode catalyst layer transfer sheet A and cathode catalyst layer transfer sheet 2.5 minutes), an anode catalyst layer and a cathode catalyst layer were formed on both surfaces of the electrolyte membrane, respectively.

This operation was repeated two more times only on the anode catalyst layer side. Thus, a catalyst layer-electrolyte membrane laminate (anode catalyst layer A / anode) having a platinum loading on the anode catalyst layer side of 2.7 mg / cm ² and a platinum loading on the cathode catalyst layer side of 1.0 mg / cm ^2. Catalyst layer A / anode catalyst layer A / electrolyte membrane / cathode catalyst layer).

  When the cross section of this laminate was observed with an SEM, both the first catalyst layer of the anode catalyst layer and the cathode catalyst layer (the catalyst layer laminated by the first heat press) were completely buried in the electrolyte membrane.

Example 2
(1) Preparation of anode catalyst layer paste composition B The platinum-ruthenium-supported carbon of Example 1 was prepared from TEC61V54 (Pt: 29.7%, Ru23.1%, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd. (carbon particles: “Vulcan XC-72R”). , TEC61E54 (Pt: 30.3%, Ru: 23.1%, Tanaka Kikinzoku Kogyo Co., Ltd., (carbon particles: “Ketjen Black”, manufactured by Cabot, specific surface area 254 m ^{2 /} g)) The anode catalyst layer paste composition B was prepared in the same manner as in Example 1 except that the specific surface area was 800 m ^{2 /} g, manufactured by AKUZO Corporation, and 1.00 g.

(2) Paste composition for cathode catalyst layer The paste composition for cathode catalyst layer of Example 1 was used.

(3) Preparation of anode catalyst layer transfer sheet B The anode catalyst layer paste B was dried on a PET film (E3120, manufactured by Toyobo Co., Ltd., thickness 13 μm) with a doctor blade so that the thickness after drying was 50 μm. The anode catalyst layer transfer sheet B was obtained by coating and drying. The platinum loading and crack rate of this film B were 1.1 mg / cm ² and 37%, respectively.

(4) Production of catalyst layer-electrolyte membrane laminate First, an electrolyte membrane Nafion 115 (manufactured by DuPont) is sandwiched between the anode catalyst layer transfer sheet A and the cathode catalyst layer transfer sheet, and a hot press (pressure level 6 Mpa, applied) Pressure time 2.5 minutes), an anode catalyst layer and a cathode catalyst layer were formed on both surfaces of the electrolyte membrane, respectively.

Further, by repeating this operation twice for the anode catalyst layer transfer sheet A and once for the anode catalyst layer transfer sheet B, the platinum loading on the anode side is 3.8 mg / cm ² and the platinum loading on the cathode side is 1.0 mg. / Cm ² catalyst layer-electrolyte membrane laminate (anode catalyst layer B / anode catalyst layer A / anode catalyst layer A / anode catalyst layer A / electrolyte membrane / cathode catalyst layer) was obtained.

  When the cross section of this laminate was observed with an SEM, all of the first catalyst layers (catalyst layers laminated by the first heat press) of the anode catalyst layer and the cathode catalyst layer were all buried in the electrolyte membrane.

Comparative Example 1
The anode catalyst layer paste composition A used in Example 1 was applied to a PET film so that the thickness after drying was 80 μm, and dried to prepare an anode catalyst transfer sheet A ′ of Comparative Example 1. did. Moreover, the cathode catalyst layer transfer sheet of Comparative Example 1 was prepared by applying the cathode catalyst layer paste composition used in Example 1 to a PET film so that the thickness after drying was 50 μm and drying.

  The anode catalyst layer transfer sheet A ′ and the cathode catalyst layer transfer sheet of Comparative Example 1 are hot pressed (pressure level 6 Mpa, pressure time 2.5 minutes) with an electrolyte membrane Nafion 115 (manufactured by DuPont) interposed therebetween. Thus, an anode catalyst layer and a cathode catalyst layer were formed on both surfaces of the electrolyte membrane, respectively, and a catalyst layer-electrolyte membrane laminate of Comparative Example 1 was produced.

The amount of platinum supported on the anode catalyst layer side was 3.0 mg / cm ² , and the crack rate was 48%. The amount of platinum supported on the cathode catalyst layer side was 1.2 mg / cm ² , and the crack rate was 45%.

Test Example Using the catalyst layer-electrolyte membrane laminate obtained in Examples 1 and 2 and Comparative Example 1, a unit cell was assembled. Synthetic air (cathode flow rate 200 ml / min) was introduced into the cathode electrode, and 3% methanol (anode flow rate 4 ml / min) was introduced into the anode electrode, and battery performance (cell temperature 60 ° C.) was measured.

  The results are shown in Table 1 below. In the durability test, a case where the output density after 100 hours is 90% or more at the beginning of the measurement is evaluated as “◯”, and a case where the output density after 100 hours is 90% or less at the beginning of the measurement is evaluated as “×”. did.

FIG. 1 shows an example of a cross-sectional view of the catalyst layer-electrolyte membrane laminate of the present invention.

Claims (8)

A catalyst layer-electrolyte membrane laminate in which two or more layers of catalyst layers containing catalyst-carrying carbon particles and hydrogen ion conductive polymer electrolyte and having cracks are laminated on one side or both sides of the electrolyte membrane,
A catalyst layer-electrolyte membrane laminate, wherein at least a part of the catalyst layer is buried in the electrolyte membrane.   The catalyst layer-electrolyte membrane laminate according to claim 1, wherein at least one of the catalyst layers is buried in the electrolyte membrane.   The catalyst layer-electrolyte membrane laminate according to claim 1 or 2, wherein cracks of each catalyst layer do not overlap each other, and cracks do not substantially penetrate through the thickness of the catalyst layer as a whole.     The catalyst layer-electrolyte membrane laminate according to any one of claims 1 to 3, wherein the catalyst supported on the catalyst-supporting carbon particles is platinum or a platinum compound. The supported amount of platinum contained in the catalyst layer, respectively ^{0.1mg / cm 2 ~1.3mg / cm 2} , the catalyst layer according to claim 4 - membrane laminate.     The catalyst layer-electrolyte membrane laminate according to claim 1, wherein each catalyst layer has a thickness of 1 μm to 80 μm.     An electrode-electrolyte membrane assembly comprising the catalyst layer-electrolyte membrane laminate according to claim 1. A method for producing a catalyst layer-electrolyte membrane laminate in which two or more catalyst layers having cracks are laminated on one side or both sides of an electrolyte membrane, and at least a part of the catalyst layer is buried in the electrolyte membrane,
A catalyst layer is formed on a transfer substrate using a paste composition for forming a catalyst layer comprising (1) an aqueous dispersion of catalyst-supporting carbon particles, (2) a hydrogen ion conductive polymer electrolyte, and (3) a solvent for adjusting viscosity. A first step of forming a catalyst layer transfer sheet by forming
The catalyst layer transfer sheet obtained in the first step is hot-pressed on the electrolyte membrane, the second step of laminating the catalyst layer on the electrolyte membrane, and the catalyst layer of the laminate obtained in the second step, A third step of laminating the catalyst layer by hot pressing the catalyst layer transfer sheet;
A method for producing a catalyst layer-electrolyte membrane laminate comprising:

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