JP2000260435A - Catalyst electrode layer for fuel cell and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst electrode layer and its manufacturing method to form a power generating layer of a solid high polymer fuel cell capable of efficiently and stably materializing a cell output. SOLUTION: Due to a catalyst electrode layer, although a part of catalysts 4 is not utilized for a cell reaction because it is embedded in a sintered body, its majority forms an effective three-phase interface and is efficiently utilized for the cell reaction. The catalyst 4 can be rigidly bonded since it is directly carried by a high polymer electrolyte 9, and a cell output does not get unstable due to changes of the three-phase interface by incoming and outgoing gas caused by the cell reaction. The catalysts 4 are electrically connected each other through carbon corpuscles 7, and a current obtained by the cell reaction is speedily sent to a collector. Since the carbon corpuscle 7 is not very fine, the carbon corpuscles 7 form a network structure by themselves and its thickness is thin, the gas incoming and outgoing through its slender hole to the three-phase interface is not impeded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst electrode layer for forming a power generation layer of a polymer electrolyte fuel cell capable of providing a stable and efficient battery output, and a method for producing the same. A catalyst electrode layer having a catalyst electrode having a network structure in which a catalyst is supported on a surface portion of a porous structure formed by electrolyte fine powder, and the supported catalyst and the electronic conductor fine particles are in electrical contact with each other. About.

[0002]

2. Description of the Related Art As shown in a schematic sectional view of a power generation layer of a fuel cell shown in FIG. 3, a polymer electrolyte fuel cell comprises a polymer solid electrolyte membrane 1 and two opposed polymer electrolyte membranes sandwiching the polymer solid electrolyte membrane. Catalyst electrode 2 (oxygen electrode 21 (cathode), hydrogen electrode 22
(Anode)), and a power generation layer 30 composed of the current collector 3 in electrical contact with the catalyst electrode 2. In this power generation layer, by supplying a gas containing oxygen as a main component and a gas containing hydrogen as a main component to respective poles, reactions shown in the following formulas (1) and (2) are performed, and as a result, , H ₂ + (1/2) can be directly taken out electrical energy from the O ₂ = H ₂ O for chemical reaction energy.

Oxygen electrode (cathode) 2H ⁺ + 2e ⁻ + (１ ／) O ₂ → H ₂ O (1) Hydrogen electrode (anode) H ₂ → 2H ⁺ + 2e ⁻ (2) It is considered to have both functions of a conductor and an electronic conductor.

FIG. 4 is a schematic sectional view showing the reaction principle at the three-phase interface 5 between the polymer solid electrolyte membrane 11, the catalyst 41, and the gas phase (source gas) 6 in a fuel cell. FIG. 4B is a schematic cross-sectional view of a three-phase interface between an oxygen electrode (cathode) and a hydrogen electrode (anode), respectively. The reactions (1) and (2) can occur only at the three-phase interface, so-called triple junction. That is, a battery reaction occurs only at the outer peripheral edge of the catalyst 41 in contact with the polymer solid electrolyte membrane 11.

[0005] In order to improve the performance of the fuel cell, the fuel cell reactions (1) and (2) are performed continuously and smoothly.
It is required to efficiently extract electric energy to the outside. In order to improve the continuity and smoothness of the fuel cell reactions (1) and (2), the reaction rates of (1) and (2) are increased, and the raw material gas is supplied promptly and efficiently to both catalyst electrodes. It is important to efficiently and promptly remove H ₂ O, which is a generated gas, from the catalyst electrode (cathode). Furthermore, since a highly efficient fuel cell can be provided by reducing the internal resistance, it is also important to reduce the resistance of the polymer solid electrolyte membrane and the catalyst electrode.

Therefore, in order to make the catalyst highly active in order to improve the performance of the battery, a catalyst having a small particle size of several nm is supported on the electron conductor instead of the planar polymer solid electrolyte membrane. By mixing with a polymer electrolyte solution to form a network-like three-dimensional porous structure in which the surface area is increased and the catalyst is highly dispersed, a catalyst electrode having an increased three-phase interface has been developed.

More specifically, a catalyst paste comprising a catalyst-supporting carbon fine particle in which platinum is supported on carbon fine particles as an electron conductor and a polymer electrolyte solution is prepared, and the catalyst paste is applied to a porous carbon electrode substrate. And a method for manufacturing a catalyst electrode to be joined by hot pressing with a polymer solid electrolyte is disclosed in Matsushita Technical Journal, Vol. 44. No
4, Aug. P. 468, 1998.

Further, in order to create a pore structure of carbon carrying a catalyst, for example, Japanese Patent Application Laid-Open No. 6-36771,
As disclosed in JP-A-6-203852, a sheet-like material mixed with carbon carrying a catalyst by using a powder of a metal such as zinc, aluminum, and chromium or an inorganic salt such as a metal salt thereof as a pore-forming agent. There has been proposed a method of manufacturing an electrode having a plurality of pores therein by forming an electrode member, immersing the formed electrode member in a solution to elute and remove an internal pore-forming agent.

[0009]

However, as shown in FIG. 2, in the conventional method for manufacturing a catalyst electrode, the catalyst 41 is supported on carbon fine particles 71 which are electron conductors. Therefore, a sufficient bonding strength with the polymer electrolyte 91 coated thereon cannot be obtained, and only an unstable three-phase interface is formed, so that the three-phase interface fluctuates due to the inflow and outflow of gas due to the battery reaction, and thus the stable battery output. Was difficult to obtain.

Further, the probability of contact between the catalyst 41 and the polymer electrolyte 91 is low, or the catalyst 41 supported in the fine pores 81 formed of carbon fine particles does not allow the polymer electrolyte solution to penetrate into the fine pores. There is a problem that the utilization rate of an expensive platinum catalyst is remarkably low, for example, it is not used at all.

Further, as can be seen from FIG. 5 showing an enlarged schematic cross section of the three-phase interface in the conventional catalyst electrode, the raw material gas enters through the pores of the polymer electrolyte 91 coating, and the polymer electrolyte 91 coating and the carbon fine particles. It must reach the three-phase interface through a gap that is not in close contact with the base material 71, and since the pores are extremely small and long, diffusion of the raw material gas is unlikely to occur, and the performance is low over the entire range from low to high current density. Is low. On the other hand, low boiling H 2 generated by the battery reaction
_{Since the 2} O gas is removed in the reverse order, it is condensed and the like, and the voltage is remarkably reduced particularly at a high current density at which the influence of gas permeability becomes large.

An object of the present invention is to provide a catalyst electrode layer forming a power generation layer of a polymer electrolyte fuel cell capable of providing a stable and efficient battery output, and a method for producing the same. Specifically, an object of the present invention is to use a catalyst effectively, and a solid polymer electrolyte and a catalyst are firmly joined,
An object of the present invention is to provide a catalyst electrode layer that allows gas to enter and exit quickly, and a method for producing the same.

[0013]

Means for Solving the Problems In order to solve such problems, the present inventor has proposed a method for forming a surface layer of a porous structure formed of polymer electrolyte fine powder in a catalyst electrode layer of a polymer electrolyte fuel cell. It has been found that a stable battery output can be efficiently provided by using a catalyst electrode having a network structure in which a catalyst is supported in a portion and the supported catalyst and the electronic conductor fine particles are in electrical contact.

That is, the catalyst electrode layer comprising the catalyst electrode of the present invention, a current collector and a polymer solid electrolyte membrane joined with the catalyst electrode interposed therebetween is a polymer electrode having a porous structure. The catalyst is characterized by comprising a catalyst supported on the surface layer of the electrolyte, and a network structure of fine particles of the electronic conductor in electrical contact with the catalyst.

According to another aspect of the present invention, there is provided a current collector;
A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell including a catalyst electrode and a polymer solid electrolyte membrane includes: (1) a step of preparing a catalyst-supporting polymer electrolyte from a polymer electrolyte fine powder and a catalyst; A) preparing a catalyst electrode paste by mixing the obtained catalyst-carrying polymer electrolyte and electron conductor fine particles in a solvent, and (3) applying the obtained catalyst electrode paste to a current collector, drying and collecting the resultant. A step of forming a catalyst electrode on the current collector; and (4) a step of bonding a polymer solid electrolyte membrane to the catalyst electrode formed on the current collector.

In still another embodiment, (1) a step of preparing a catalyst-supporting polymer electrolyte from a polymer electrolyte fine powder and a catalyst; and (2) the catalyst-supporting polymer electrolyte and electron conductor fine particles in a solvent. After mixing, a catalyst electrode paste is prepared by further mixing a pore-forming agent, or the catalyst is prepared by mixing the catalyst-supporting polymer electrolyte, the electron conductor fine particles, and the pore-forming agent together in a solvent. Preparing an electrode paste, (3) applying the catalyst electrode paste to the current collector and drying to form a catalyst electrode on the current collector;
(4) a step of removing the pore-forming agent from the catalyst electrode formed on the current collector, and (5) a step of joining the polymer solid electrolyte membrane to the catalyst electrode formed on the current collector. It is characterized by

In still another embodiment, (1) a step of preparing a catalyst-supporting polymer electrolyte from a polymer electrolyte fine powder and a catalyst, and (2) the catalyst-supporting polymer electrolyte and electron conductor fine particles in a solvent. After the mixing, the catalyst electrode paste is prepared by further mixing the polymer electrolyte solution and the pore-forming agent, or the catalyst-carrying polymer electrolyte, the electron conductor fine particles, the polymer electrolyte solution, and the pore-forming agent. To prepare a catalyst electrode paste by mixing together in a solvent; (3) a step of applying the catalyst electrode paste to the current collector and drying to form a catalyst electrode on the current collector; (4) Removing the pore-forming agent from the catalyst electrode formed on the current collector, and (5) joining the polymer solid electrolyte membrane to the catalyst electrode formed on the current collector. Features.

Still another mode is as follows: (1) After mixing the polymer electrolyte fine powder and the electron conductor fine particles in a solvent, the polymer electrolyte solution and the pore-forming agent are further mixed to form an electrode paste. Preparing an electrode paste by mixing or mixing together a polymer electrolyte fine powder, an electron conductor fine particle, a polymer electrolyte solution, and a pore-forming agent in a solvent; (3) removing the pore-forming agent from the electrode formed on the current collector, (4) supporting the catalyst on the electrode, and (5) A) joining the polymer solid electrolyte membrane to the catalyst electrode formed on the current collector.

In still another embodiment, (1) a step of preparing a catalyst-supporting polymer electrolyte from a polymer electrolyte fine powder and a catalyst, and (2) the catalyst-supporting polymer electrolyte and electron conductor fine particles in a solvent. After mixing, an electrode paste is prepared by further mixing the polymer electrolyte solution and the pore-forming agent, or the catalyst-supporting polymer electrolyte, the electron conductor fine particles, the polymer electrolyte solution, and the pore-forming agent are mixed with a solvent. Preparing an electrode paste by mixing together in
(3) a step of applying the electrode paste to the current collector and drying to form an electrode; (4) a step of removing a pore-forming agent from the electrode formed on the current collector; A step of supporting a catalyst; and (6) a step of joining the polymer solid electrolyte membrane to a catalyst electrode formed on a current collector.

Still another aspect of the present invention is the above-mentioned catalyst electrode layer or the method for producing a catalyst electrode layer, wherein the catalyst is a noble metal catalyst containing platinum as a main component, and the electron conductor fine particles are carbon fine particles. It is selected from the group consisting of noble metal fine particles containing platinum as a main component and oxide fine particles.

[0021]

DETAILED DESCRIPTION OF THE INVENTION The catalyst electrode layer of the polymer electrolyte fuel cell according to the present invention comprises a catalyst electrode, a current collector and a polymer electrolyte membrane joined to each other with the catalyst electrode interposed therebetween. The catalyst is supported on the polymer electrolyte. In the catalyst-supporting polymer electrolyte, the polymer electrolyte has a porous structure, and the catalyst is supported on the surface layer of the porous structure composed of the polymer electrolyte. A three-phase interface can be formed.

The catalyst is a noble metal catalyst containing platinum as a main component, and may contain other noble metals such as rhodium and palladium.

The amount of the catalyst supported on the polymer electrolyte is about 1% or less based on the volume of the polymer electrolyte.

The polymer electrolyte having a porous structure for supporting a catalyst is formed from a polymer electrolyte fine powder. The polymer electrolyte fine powder is a fine powder of perfluorocarbon sulfonic acid. The porosity of the catalyst electrode is controlled by the particle size of the polymer electrolyte fine powder, and the porosity is not hindered by the electron conductor fine particles. By controlling the pore diameter, it becomes possible to quickly introduce the source gas and remove the generated gas. Usually, the particle size is between 0.1 and 1
00 μm, preferably 0.5 to 10 μm,
More preferably, it is 1 to 5 μm. Particle size 0.1 μm
If the diameter is smaller, the diameter of the pores formed after the firing is too small, so that the diffusion of the raw material gas and the produced gas is impaired, and the pores are clogged due to condensation of water. On the other hand, 100 μm
If it is larger, the resistance becomes too large.

The fine powder of perfluorocarbon sulfonic acid having an appropriate particle size can be produced by a conventionally known method. For example, fine powder having a particle size of 1 to 5 μm can be obtained by spraying a perfluorocarbon sulfonic acid solution onto an alcohol solution using a spray dryer in a nitrogen stream and drying. In addition, a perfluorocarbon sulfonic acid fine powder having a relatively large particle size can be obtained by previously dropping a perfluorocarbon sulfonic acid solution into a butyl acetate solution and spray-drying a colloidal dispersion of a perfluorocarbon sulfonic acid polymer. Can be.

According to the present invention, the electron conductor fine particles are in electrical contact with the catalyst carried on the surface layer of the polymer electrolyte having a porous structure to form a network structure. For this reason, the generated electricity flows from the network structure of the electron conductor fine particles to the current collector.

Electron conductor fine particles include conductive carbon fine particles, noble metal fine particles containing platinum as a main component such as platinum black, and L
These are fine particles of a complex oxide such as aMnO ₃ , and platinum black and LaMnO ₃ are preferable because of their catalytic action, but conductive carbon fine particles are preferable from the viewpoint of economy. The particle size of the electron conductor fine particles is smaller than 1 μm,
Preferably it is smaller than 0.1 μm, more preferably smaller than 0.05 μm. If it is larger than 1 μm, contact between the solid polymer fine particles is hindered.

The electron conductor fine particles are 20% based on the combined volume of the catalyst-supporting polymer electrolyte and the electron conductor fine particles.
Accounts for ~ 80%. If the volume ratio is less than 20%, the chance of contact between the electronic conductor fine particles is small, and the electric resistance of the electronic conductor fine particles as a network structure increases. If it is more than 80%, the electrical resistance of the electron conductor fine particles as a network structure decreases, but the chance of contact between the polymer electrolytes decreases, and the resistance of the polymer electrolyte increases. Alternatively, the catalyst is undesirably coated with the fine particles of the electron conductor, which increases the amount of the catalyst not used for the battery reaction.

In order to prevent clogging of pores due to condensation of water as a generated gas, a part or all of the electron conductor fine particles are coated in advance with polytetrafluoroethylene to obtain water repellency. May be increased.

In the catalyst electrode layer of the present invention, the current collector joined to the catalyst electrode is porous carbon. To prevent clogging due to condensation of water, a current collector comprising a layer of a mixture of carbon fibers coated on the surface of porous carbon with polytetrafluoroethylene and uncoated carbon fibers is preferred. In addition, a metal such as a sponge-like stainless steel can be used as the current collector.

The polymer electrolyte membrane bonded to the catalyst electrode is a perfluorocarbon sulfonic acid polymer membrane having a thickness of 20 to 100 μm, for example, a product name “Nafion” manufactured by DuPont. it can.

In the method for producing a catalyst electrode layer of a polymer electrolyte fuel cell according to the present invention, first, a catalyst-supporting polymer electrolyte is prepared from a polymer electrolyte fine powder and a catalyst. Specifically, a perfluorocarbon sulfonic acid fine powder having an appropriate particle size is suspended in an aqueous solution of chloroplatinic acid, left at room temperature for 1 hour, and then dried in a vacuum dryer at 50 ° C. for 4 hours to carry chloroplatinic acid. Prepare perfluorocarbon sulfonic acid fine powder,
The resulting fine powder is subjected to a reduction treatment in a humidified hydrogen stream at 100 to 130 ° C. for 72 hours to obtain a fine powder of perfluorocarbonsulfonic acid carrying a platinum catalyst. The reduction step may be a generally known wet reduction using formalin or the like.

Next, the catalyst-carrying polymer electrolyte and the electron conductor fine particles are mixed in a solvent to prepare a catalyst electrode paste. The solvent used in the present invention must disperse, but do not react, the electron conductor fine particles used. Furthermore, a solvent which has a viscosity suitable for coating and which volatilizes at a relatively low temperature but does not easily ignite is used. Specific examples of such a solvent include cyclohexanol, and the amount of the solvent to be used is appropriately determined.

After mixing the catalyst-supporting polymer electrolyte and the electron conductor fine particles in the solvent, or together with mixing the catalyst-supporting polymer electrolyte and the electron conductor fine particles in the solvent, the pore-forming agent is used. The pore-forming agent may be mixed with the polyelectrolyte solution. In particular, when the particle size of the polymer electrolyte used is smaller than 1 μm, it is preferable to add a pore-forming agent. After forming the catalyst electrode, the porous electrode is immersed in an appropriate solution to remove the pore-forming agent, whereby an appropriate pore diameter can be formed.

From the viewpoint of further improving the bonding strength after hot pressing in the subsequent step, a perfluorocarbon sulfonic acid solution of up to about 10% may be further mixed when preparing the catalyst electrode paste. . However, it should be noted that as the mixing amount increases, the strength increases, but at the same time increases the amount of catalyst that is coated and not utilized in the cell reaction.

The mixing of the catalyst-carrying polymer electrolyte and the electron conductor fine particles in the solvent may be carried out by any method as long as they are uniformly mixed. And the electron conductor fine particles are preferably uniformly dispersed.

Next, the prepared catalyst electrode paste is applied to a current collector and dried to form a catalyst electrode on the current collector. The paste is applied by printing or spraying. Specifically, the catalyst electrode paste was coated on the current collector with a thickness of 20 to 500 μm using a doctor blade type printing device.
m, preferably 50 to 300 μm. Then, the printed matter is heated at 40 to 100 ° C., preferably 60 ° C.
Vacuum dry at ~ 80 ° C. The thickness of the catalyst electrode paste applied by vacuum drying is reduced to about １ ／. After vacuum drying, the catalyst electrode formed on the current collector may be impregnated with polytetrafluoroethylene to improve the water repellency of the pores, but as the amount increases, the catalyst becomes polytetrafluoroethylene. It should be noted that this will increase the amount of catalyst that is coated with and not utilized in the battery reaction.

In the production method of the present invention, the catalyst electrode paste may be prepared after the catalyst is supported on the polymer electrolyte, or the polymer electrolyte and the fine particles of the electron conductor are mixed in a solvent to prepare the electrode. A paste may be prepared, and the obtained electrode paste may be applied to a current collector and dried to form an electrode, and then a catalyst may be supported to form a catalyst electrode. Specifically, the surface of the electrode is impregnated with, for example, an aqueous solution of chloroplatinic acid, and then reduced to allow the electrode to carry a platinum catalyst.

Further, in order to improve the performance, first, a catalyst-supporting polymer electrolyte is prepared from the polymer electrolyte fine powder and the catalyst, and the paste is applied to a current collector and dried to form an electrode. Alternatively, the catalyst electrode may be completed by carrying a catalyst.

Finally, a solid polymer electrolyte membrane is bonded to the catalyst electrode formed on the current collector. 5 MPa to 10 MPa at a temperature of 110 to 130 ° C. in a sandwich structure with the catalyst electrode sandwiched between the current collector and the polymer solid electrolyte membrane
The solid polymer electrolyte membrane, the catalyst electrode, and the current collector are joined by a hot press method of joining by applying the pressure described above.

[0041]

EXAMPLES The present invention will be described with reference to examples, but the present invention is not limited to these examples.

A 10% by weight perfluorocarbon sulfonic acid solution was sprayed onto an alcohol solution using a spray dryer in a nitrogen stream and dried to obtain a fine powder of perfluorocarbon sulfonic acid having a particle size of 1 to 5 μm. 10% by weight of the obtained fine powder of perfluorocarbon sulfonic acid
Was suspended in an aqueous solution of chloroplatinic acid for 1 hour at room temperature, and then dried in a vacuum dryer at 50 ° C. for 4 hours to obtain fine powder of perfluorocarbonsulfonic acid carrying chloroplatinic acid. Next, a reduction treatment of the chloroplatinic acid-supported perfluorocarbon sulfonic acid fine powder was performed in a humidified hydrogen stream at a temperature of 100 to 130 ° C. for 72 hours to obtain a platinum catalyst-supported perfluorocarbon sulfonic acid fine powder.

Next, in an appropriate amount of cyclohexanol, the obtained fine powder of platinum-supported perfluorocarbon sulfonic acid and fine conductive carbon particles having an average particle diameter of 0.1 μm were mixed with the volume of fine carbon particles in the catalyst electrode. Was mixed so as to be 40% based on the combined volume of the platinum-supported perfluorocarbon sulfonic acid and the carbon fine particles, and irradiated with ultrasonic waves to prepare a uniformly dispersed catalyst electrode paste.

Then, the prepared paste was printed on a current collector made of porous carbon to a thickness of 100 μm using a doctor blade type printing device, and the printing was performed at 60 to 80 μm.
Vacuum dried at ℃. A catalyst electrode in which the thickness of the applied paste was reduced to 1/5 or less by vacuum drying was formed. Next, a 50 μm-thick perfluorocarbon sulfonic acid polymer membrane (trade name “Nafion” manufactured by DuPont) was sandwiched between the current collector and the polymer membrane so that the polymer membrane and the catalyst electrode were in contact with each other. Temperature, 110-130 ° C,
By hot press method of pressure 5MPa ~ 10MPa,
It was joined to the catalyst electrode.

FIG. 1 shows the thus-produced catalyst electrode layer. For comparison, a conventional catalyst electrode layer is shown in FIG.

In FIG. 1, the matrix of the porous structure of the catalyst electrode 2 is a sintered body of the polymer electrolyte 9 supporting the platinum catalyst 4, and a network structure of carbon fine particles 7 is formed on the surface layer thereof. In FIG. 2, a matrix having a porous structure is a sintered body of carbon fine particles 71 supporting a platinum catalyst 41, and the surface layer is covered with a polymer electrolyte 91 in FIG. The structure is shown.

According to the catalyst electrode layer of the present invention shown in FIG.
Although a part of the catalyst 4 is buried inside the sintered body and is not used for the battery reaction, most forms an effective three-phase interface and is efficiently used for the battery reaction. Further, since the catalyst 4 is directly supported on the polymer electrolyte 9, strong bonding is possible, and the three-phase interface does not fluctuate due to the inflow and outflow of gas accompanying the battery reaction, and the battery output does not become unstable. The catalysts 4 are electrically connected to each other through the carbon fine particles 7, and the current obtained by the battery reaction flows quickly to the current collector 3. Since the carbon microparticles 7 are not dense, the carbon microparticles 7 form a network structure and have a small thickness, gas flow into and out of the three-phase interface through the pores is not hindered.

In the polymer electrolyte fuel cell using the power generation layer provided with the catalyst electrode layer of the present invention, the relationship between the current density and the voltage was examined, and it was found that the performance was improved over the entire range from low to high current density. Was seen. In particular, at a high current density at which the influence of gas permeability becomes large, a remarkable improvement is recognized as compared with the conventional polymer electrolyte fuel cell.

[0049]

The power generation layer provided with the catalyst electrode layer of the present invention comprises:
By enabling a strong increase in the three-phase interface and rapid inflow and outflow of gas accompanying the battery reaction, a stable and stable battery output can be provided. In particular, the improvement of the performance is remarkable as compared with the conventional fuel cell at a high current density where the influence of the gas permeability becomes large.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a catalyst electrode layer showing an example of the present invention.

FIG. 2 is a schematic sectional view of a conventional catalyst electrode layer.

FIG. 3 is a schematic sectional view of a power generation layer of a polymer electrolyte fuel cell.

FIGS. 4A and 4B are schematic cross-sectional views showing a reaction principle at a three-phase interface, where (a) is a cathode and (b) is an anode.

FIG. 5 is an enlarged schematic sectional view of a three-phase interface of a conventional catalyst electrode.

[Explanation of symbols]

 Reference Signs List 1,11 Polymer solid electrolyte membrane 2,21 Catalyst electrode 3,31 Current collector 4,41 Catalyst 5 Three-phase interface 6 Gas phase 7,71 Carbon fine particles 8,81 Pores 9,91 Polymer electrolyte 20 Catalyst electrode layer 30 Power generation layer

Claims (8)

[Claims] 1. A catalyst electrode layer of a polymer electrolyte fuel cell comprising a catalyst electrode, a current collector joined with the catalyst electrode interposed therebetween, and a polymer solid electrolyte membrane, wherein the catalyst electrode is porous. A catalyst electrode layer for a fuel cell, comprising: a catalyst supported on a surface layer of a polymer electrolyte having a structure; and a network structure of electron conductor fine particles in electrical contact with the catalyst. 2. The method according to claim 1, wherein the catalyst is a noble metal catalyst containing platinum as a main component, and the electron conductor fine particles are selected from the group consisting of carbon fine particles, noble metal fine particles containing platinum as a main component, and oxide fine particles. Claim 1.
The catalyst electrode layer of the fuel cell according to the above. 3. A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell comprising a current collector, a catalyst electrode, and a polymer solid electrolyte membrane, comprising: A step of preparing a molecular electrolyte, (2) a step of preparing a catalyst electrode paste by mixing the catalyst-carrying polymer electrolyte and electron conductor fine particles in a solvent,
(3) applying the catalyst electrode paste to the current collector and drying to form a catalyst electrode on the current collector; and (4) applying the polymer solid electrolyte membrane to the catalyst electrode formed on the current collector. A method for producing a catalyst electrode layer of a fuel cell, comprising a step of joining. 4. A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell comprising a current collector, a catalyst electrode, and a polymer solid electrolyte membrane, comprising: A step of preparing a molecular electrolyte; (2) mixing the catalyst-supporting polymer electrolyte and the fine particles of an electron conductor in a solvent, and further mixing a pore-forming agent to prepare a catalyst electrode paste, or A step of preparing a catalyst electrode paste by mixing together the catalyst-carrying polymer electrolyte, the electron conductor fine particles and the pore-forming agent in a solvent,
(3) applying the catalyst electrode paste to the current collector and drying to form a catalyst electrode on the current collector; and (4) removing the pore-forming agent from the catalyst electrode formed on the current collector. And (5) bonding the polymer solid electrolyte membrane to a catalyst electrode formed on a current collector. 5. A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell comprising a current collector, a catalyst electrode, and a polymer solid electrolyte membrane, comprising: (2) mixing the catalyst-carrying polymer electrolyte and the electron conductor fine particles in a solvent, and then further mixing the polymer electrolyte solution and a pore-forming agent to form a catalyst electrode paste. Preparing or preparing a catalyst electrode paste by mixing together the catalyst-carrying polymer electrolyte, the electron conductor fine particles, the polymer electrolyte solution, and the pore-forming agent in a solvent, (3) the catalyst electrode Applying the paste to the current collector and drying to form a catalyst electrode on the current collector; (4) removing the pore-forming agent from the catalyst electrode formed on the current collector; and (5) Catalyst formed on current collector Bonding the solid polymer electrolyte membrane to an electrode. A method for producing a catalyst electrode layer for a fuel cell, comprising: 6. A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell comprising a current collector, a catalyst electrode, and a polymer solid electrolyte membrane, wherein (1) polymer electrolyte fine powder and electron conductor fine particles are formed. After mixing in a solvent, an electrode paste is prepared by further mixing a polymer electrolyte solution and a pore forming agent, or a polymer electrolyte fine powder, an electron conductor fine particle, a polymer electrolyte solution, and a pore forming agent. Preparing an electrode paste by mixing the agents together in a solvent,
(2) a step of applying the electrode paste to the current collector and drying to form an electrode; (3) a step of removing a pore-forming agent from the electrode formed on the current collector; and (4) a catalyst applied to the electrode. And (5) joining the polymer solid electrolyte membrane to the catalyst electrode formed on the current collector. A method for producing a catalyst electrode layer for a fuel cell, comprising: 7. A method for producing a catalyst electrode layer of a polymer electrolyte fuel cell comprising a current collector, a catalyst electrode, and a polymer solid electrolyte membrane, comprising: A step of preparing a molecular electrolyte, (2) preparing an electrode paste by mixing the catalyst-carrying polymer electrolyte and the fine particles of the electron conductor in a solvent, and then further mixing the polymer electrolyte solution and a pore-forming agent. Or preparing an electrode paste by mixing together a catalyst-supporting polymer electrolyte, electron conductor fine particles, a polymer electrolyte solution, and a pore-forming agent in a solvent; (3) collecting the electrode paste A step of forming an electrode by coating and drying the electric body,
(4) a step of removing a pore-forming agent from an electrode formed on the current collector, (5) a step of supporting a catalyst on the electrode, and (6) a step of: Bonding a molecular solid electrolyte membrane. A method for producing a catalyst electrode layer of a fuel cell, comprising: 8. The method according to claim 1, wherein the catalyst is a noble metal catalyst containing platinum as a main component, and the electron conductor fine particles are selected from the group consisting of carbon fine particles, noble metal fine particles containing platinum as a main component, and oxide fine particles. Claim 3
8. The method for producing a catalyst electrode layer for a fuel cell according to any one of claims 1 to 7.