JP2002075407A - Electrode structure for fuel cell and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode structure for a fuel cell which has high durabil ity even in a temperature cycle from below zero degrees up to more than 85 deg.C with prevention of peel off of an interface between an electrolyte membrane M and an electrolyte catalyst layer 1. SOLUTION: The electrode structure composed of a pair of electrode catalyst layers and an electrolyte membrane pinched by them, catalyst of at least one side face of which former infiltrates into the latter to integrate the electrode catalyst layers and the electrolyte membrane, catalyst-dispersed organic solvent slurries in which the catalyst is dispersed in an organic solvent dissolving the electrolyte membrane are directly applied at least on one face of the electrolyte membrane, and then, the catalyst is made to infiltrate into the electrolyte membrane by heating under pressure, to integrally form the electrode catalyst layers on the electrolyte membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell electrode structure used for a fuel cell and a method of manufacturing the same. More specifically, the present invention relates to a fuel cell electrode structure in which an electrode catalyst layer and an electrolyte membrane are integrally formed, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A fuel cell system comprises a fuel cell which supplies hydrogen as a fuel gas to a hydrogen electrode side of the fuel cell and supplies an oxidizing gas containing oxygen to an oxygen electrode side of the fuel cell to generate electric power. It is a system that did. Fuel cells, which form the core of this fuel cell system, convert chemical energy directly into electrical energy, and have recently been receiving attention because of their high power generation efficiency and extremely low emission of harmful substances.

First, a single fuel cell constituting a fuel cell will be described with reference to FIG. As shown in FIG. 1, the fuel cell unit cell CE has a fuel cell electrode composed of electrode catalyst layers 1 (1 _H , 1 _O ) provided on both sides of the electrolyte membrane M on the hydrogen electrode side and the oxygen electrode side. Diffusion layers 2 _H , 2 _O and separators 3 _H , 3 _O are laminated on both sides of the structure MEA, respectively. The member on the hydrogen electrode side has a suffix H after the number, and the member on the oxygen electrode side has a suffix O after the number. Is not followed by a subscript.

As the electrolyte membrane M, a solid polymer membrane, for example, a perfluorocarbon sulfonic acid membrane which is a proton (ion) exchange membrane is generally used. The electrolyte membrane M has a large number of proton exchange groups in the solid polymer, exhibits a low specific resistance of 20 Ω / cm or less at room temperature by containing saturated water, and functions as a proton conductive electrolyte. As described above, since the solid polymer membrane is used for the single cell CE of the fuel cell, the fuel cell configured by layering the single cell CE is called a solid polymer fuel cell.

The electrode catalyst layer 1 is formed by oxidizing platinum or the like.
It is configured by dispersing catalyst particles in which a catalyst metal having a reduction catalyst function is supported on a carrier such as carbon, in an ionic (proton) conductive resin.

[0006] The diffusion layer 2 is provided in contact with the flow channel 4 on the surface of the separator 3, and allows electrons to pass through the electrode catalyst layer 1.
And a function of diffusing fuel gas (hydrogen gas) and oxidizing gas (air) and supplying them to the electrode catalyst layer 1. Generally, carbon paper, carbon cloth, carbon It is formed from a carbon-based material such as felt. The separator 3 is
It is made of a material having excellent airtightness and thermal conductivity, has a function of separating fuel gas, oxidizing gas and cold heat, has a flow path 4, and has an electron transfer function.

[0007] The fuel cell unit cell CE is composed of a separator 3
_{When the} supply air flows through the oxygen electrode side gas flow path 4 _O of _O and the supply hydrogen H ₂ is supplied to the hydrogen electrode side gas flow path 4 _H of the separator 3 _H , hydrogen is supplied to the electrode catalyst layer on the hydrogen electrode side. Protons are generated by ionization due to the catalytic action of the catalyst at 1 _H , and the generated protons move through the electrolytic membrane M and reach the oxygen electrode side. The protons that have reached the oxygen electrode side immediately react with oxygen ions generated from the oxygen of the supply air in the presence of the catalyst in the electrode catalyst layer 1 _O to generate water. The supply air containing the generated water and unused oxygen is discharged from the outlet on the oxygen electrode side of the fuel cell FC as exhaust air (the exhaust air contains a large amount of moisture). On the hydrogen electrode side, electrons e ⁻ are generated when hydrogen is ionized, and the generated electrons e ⁻ reach the oxygen electrode side via an external load such as a motor (FIG. 1). Arrow)). Hundreds of such fuel cell single cells CE are stacked and used as a fuel cell, for example, mounted on a vehicle or the like.

[0008]

Conventionally, in a fuel cell unit CE having such a structure, the electrode catalyst layer 1 is bonded by thermocompression using a hot press or the like after the electrode catalyst layer 1 is attached to the electrolytic film M. Was composed. However, the electrode catalyst layer 1 formed by such a method has a bite due to the unevenness of the electrode catalyst layer C1 at the interface between the electrode catalyst layer 1 and the electrolytic film M, but the bonding interface is almost flat. Therefore, for example, when a fuel cell is used by being mounted on a vehicle or the like, the fuel cell is operated at an outside air temperature (a temperature below freezing in winter).
Has a temperature cycle of about 85 ° C. or more when the vehicle is running, but in a high temperature environment such as driving at a high temperature, the adhesive strength may not be sufficiently obtained, and a peeling phenomenon may occur, In such a temperature cycle, the interface between the electrolyte membrane and the electrode catalyst layer is fatigued, and there is room for improvement in durability.

Accordingly, an object of the present invention is to provide an electrode structure for a fuel cell which prevents separation at the interface between the electrolytic membrane M and the electrode catalyst layer 1 and has high durability even at a temperature cycle of about 85 ° C. or more from below freezing. Is to provide the body. Another object of the present invention is to provide a method for manufacturing a fuel cell electrode structure for efficiently manufacturing such a highly durable fuel cell electrode structure.

[0010]

Means for Solving the Problems The present inventors have made intensive studies in view of the state of the prior art, and as a result, have been formed of a pair of electrode catalyst layers and an electrolytic membrane sandwiched between the electrode catalyst layers, The present inventors have found that the problem can be solved by the catalyst of the electrode catalyst layer on one surface penetrating into the electrolytic film and integrally forming the electrode catalyst layer and the electrolytic film, thereby completing the present invention.

That is, the present invention comprises a pair of electrode catalyst layers and an electrolytic film sandwiched between the electrode catalyst layers, and the catalyst of the electrode catalyst layer on at least one surface penetrates into the electrolytic film to form the electrode catalyst. An electrode structure for a fuel cell in which a catalyst layer and the electrolyte membrane are integrally formed, and a catalyst-dispersed organic solvent slurry in which the catalyst is dispersed in a soluble organic solvent of the electrolyte membrane is at least one of the electrolyte membranes. After applying directly to the surface, the electrode catalyst layer is integrally formed on the electrolytic film by heating under pressure to cause the catalyst to penetrate into the electrolytic film (claim 1). . With this configuration, when the electrode catalyst layer is formed,
The composition of the electrode catalyst layer and the electrolyte membrane is continuously changed at the interface between the two to form an integral body. No separation occurs at the interface between the electrolyte membrane and the electrode catalyst layer. The durability of the body can be increased.

[0012] In the fuel cell electrode structure, the ion exchange capacity of the electrolytic membrane is A, the ion exchange capacity of the formed electrode catalyst layer is B, and the thickness of the electrolytic membrane before heating under the pressure is described. Is defined as C (μm), and D (μm) is defined as the thickness of the portion of the electrolyte membrane where the catalyst has not penetrated after heating under the pressure, and the following formula (1): (AB) / (C− D) The ion exchange density gradient coefficient at the interface between the electrode catalyst layer and the electrolytic membrane calculated in (1) is 3.5 × 10 ³ meq /
g / cm or less (claim 2). By thus defining the integral part of the electrode catalyst layer and the electrolytic membrane, the durability can be further ensured.

[0013] In the fuel cell electrode structure, it is preferable that a penetration depth of the catalyst into the electrolyte membrane is in a range of 5 µm to 20 µm. Similarly, by defining an integral part of the electrode catalyst layer and the electrolytic membrane, the durability can be further ensured.

A method of manufacturing an electrode structure for a fuel cell according to another embodiment of the present invention comprises a pair of electrode catalyst layers and an electrolytic film sandwiched between the electrode catalyst layers, and the electrode on at least one surface thereof. A method for producing an electrode structure for a fuel cell, wherein a catalyst of a catalyst layer penetrates into the electrolyte membrane to integrally form the electrode catalyst layer and the electrolyte membrane, wherein the catalyst constituting the electrode catalyst layer is electrolyzed. A catalyst-dispersed organic solvent slurry having a viscosity of 5,000 to 25,000 mPa · s is prepared by dispersing in an organic solvent soluble in the membrane, and the catalyst-dispersed organic solvent slurry thus prepared is applied to at least one surface of the electrolytic membrane. The electrode catalyst layer is formed integrally with the electrolyte membrane by applying the catalyst directly to the electrolyte membrane by heating under pressure and causing the catalyst to penetrate into the electrolyte membrane (claim 4). With this configuration, it is possible to easily and reliably manufacture an electrode structure having excellent durability.

In another embodiment of the present invention, in the method for manufacturing an electrode structure for a fuel cell, the organic solvent in the catalyst-dispersed organic solvent slurry directly applied to the electrolyte membrane is adjusted to 20 m.
g / cm ² ~100mg / cm ² of that heated under pressure while remaining in an amount to penetrate the catalyst to the electrolyte membrane preferably (claim 5). With such a configuration, an electrode structure having more excellent durability can be easily formed.
And it becomes possible to manufacture reliably.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to these embodiments. FIG. 1 is a schematic diagram showing an outline of a single fuel cell to which the present invention is applied;
FIG. 2 is a cross-sectional view of the electrode structure for a fuel cell of the present invention (hereinafter, referred to as “electrode structure”). FIG. 3 is a schematic diagram showing the structure of the catalyst particles. It is a mimetic diagram showing a situation of manufacture of an electrode structure.

[Structure of Electrode Structure (Single Cell of Fuel Cell)] As shown in FIG. 1, an electrode structure MEA according to one embodiment includes an electrolytic film M and an electrode catalyst layer 1 laminated on both sides of the electrolytic film M. The diffusion layer 2 and the separator 3 are laminated on both sides of the electrode structure MEA thus configured to form a fuel cell unit cell CE. A large number of such fuel cell single cells CE are stacked to form a fuel cell.

As the electrolyte membrane M of the electrode structure MEA, for example, a perfluorocarbon sulfonic acid membrane which is a proton (ion) exchange membrane is generally used. This electrolytic membrane M is
As described above, the solid polymer has many proton exchange groups,
It exhibits low specific resistance of 20 Ω / cm proton or less at room temperature by being saturated with water, and functions as a proton conductive electrolyte. The electrolytic membrane M that can be used in the present invention is not limited to this, as long as it is used in the fuel cell unit cell CE.

Further, the electrode structure ME according to this embodiment is
The electrode catalyst layer 1 in A is configured by dispersing catalyst particles (see FIG. 3) composed of a carrier in which a catalyst metal is supported on an ionic (proton) conductive resin. At this time,
Usually, a platinum group metal, generally platinum, is used as a catalyst metal and supported on carbon as a carrier. However, the present invention is not limited to these as long as it can be used as a fuel cell catalyst. Further, a base layer (not shown) may be provided between the diffusion layer 2 and the separator 3 for the purpose of enhancing the water repellent effect and the water storage effect, or for preventing the electrode catalyst layer 2 from biting into the diffusion layer 3. The underlayer is composed of a carbon black powder and a Teflon (registered trademark) powder or a carbon black powder and an electrolyte solution.

In the electrode structure MEA, as shown in FIG.
It is characterized in that a part of the catalyst particles in the electrode catalyst layer 1 penetrates both sides of the electrolytic membrane M by a predetermined distance. That is, instead of having a clear interface between the electrolyte membrane and the electrode catalyst layer as in the conventional electrode structure, a catalyst (a material constituting the electrode catalyst layer 1) is applied to a part of the electrolyte membrane M by a predetermined amount. The electrolyte membrane M and the electrode catalyst layer 1 are integrally formed. At this time, the degree of penetration of the catalyst (catalyst particles) into the electrolytic membrane M is represented by A as the ion exchange capacity of the electrolytic membrane M and B as the ion exchange capacity of the electrode catalyst layer 1 (the ion exchange capacity is the electrolytic membrane M). M when no catalyst particles have penetrated into M), the thickness of the electrolytic membrane before heating under pressure is C (μm), and the distance between the catalyst particles permeated from both sides is Dw (μm). It can be expressed as the ion exchange density gradient coefficient at the interface between the electrode catalyst layer 1 and the electrolytic membrane M calculated by the following equation (1): (AB) / (C-Dw) / 2 (1) it can. Note that the distance Dw is the thickness of a portion of the electrolyte membrane M where the catalyst particles have not penetrated.

That is, when the electrode catalyst layer 1 penetrates into the electrolytic membrane M by the length (C−Dw) / 2, it is shown as an increase in ion exchange capacity per unit length. In the present invention, such an ion exchange density gradient coefficient is 3.5 × 10 ³ meq.
/ G / cm or less was experimentally found to be preferable. That is, the ion exchange density gradient coefficient is 3.5.
If it exceeds 10 ³ meq / g / cm, the integral formation of the electrode catalyst layer 1 and the electrolytic membrane M is insufficient (that is, the part where the two 1 and M are integrally formed [gradation] Part), the electrode catalyst layer 1 and the electrolytic membrane M
This is not preferable from the viewpoint of preventing peeling of the resin.

Another measure for determining the degree of penetration of the electrode catalyst layer 1 into the electrolyte membrane M is the depth of penetration of catalyst particles into the electrolyte membrane (ie, (C-Dw) / 2 itself). Can be The depth of penetration into the electrolytic membrane M is 5 μm.
Preferably, it is in the range of m to 20 μm. If the penetration of the catalyst particles into the electrolytic film M is too shallow, it is not preferable from the viewpoint of preventing the electrode catalyst layer 1 and the electrolytic film M from peeling off. On the other hand, when the penetration is too deep, the performance of the electrolytic film M is reduced.

In the present invention, in order to achieve such a structure, the electrode catalyst layer 1 is formed by dissolving a catalyst particle-dispersed organic solvent slurry in which catalyst particles are dispersed in an organic solvent soluble in the electrolytic film. After being directly applied to M, heating is performed under pressure to cause the catalyst particles to penetrate into the electrolyte membrane M, thereby forming an integral part with the electrolyte membrane M. That is, in the present invention, the organic solvent dissolves the electrolyte membrane M, thereby causing the catalyst particles to penetrate from the surface of the electrolyte membrane M to the inside, and forming the electrode catalyst layer 1 on a part of the electrolyte membrane M to form the electrode structure MEA. It is something to make. By the way,
The thickness of the electrolyte membrane M before the formation of the electrode catalyst layer 1 and the thickness of the electrolyte membrane M after the formation of the electrode catalyst layer 1 (that is, the electrode structure ME
The thickness of A) is almost the same, or the thickness of the electrode section structure MEA after the formation of the electrode catalyst layer 1 is slightly larger.

The concentration distribution of the catalyst particles in the electrode structure MEA will be supplementarily described with reference to FIG. As shown in FIG. 2, at a certain depth from the surface of the electrode structure MEA, a portion where the concentration of the catalyst particles is high is formed. This is the portion where the electrode catalyst layer 1 is formed. After that, when the depth increases, the concentration of the catalyst particles starts to decrease, and eventually becomes a portion where the catalyst does not enter. By performing a manufacturing method described later, an electrode structure MEA as shown in FIG. 2 is obtained.

The organic solvent used at this time is used to allow the catalyst particles in the slurry to enter the electrolytic membrane M, and a polar solvent soluble in the electrolytic membrane M is used. The organic solvent that can be used in the present invention is not particularly limited as long as the electrolyte membrane and the electrode catalyst layer can be integrally formed. For example, dimethylacetamide (boiling point: 165.5 ° C.), dimethylformamide (boiling point: 153 ° C.), dimethyl Sulfoxide (boiling point: 189 ° C.), triethyl phosphate (boiling point: 115 ° C.), N-methylpyrrolidone (boiling point: 202
° C), and these can be used alone or as a mixture of two or more.

In the present invention, when the catalyst-dispersed organic solvent slurry is applied, the slurry may be applied to one side and heated under pressure (hot press) to be laminated one by one. However, since there is a possibility that the electrode structure MEA may be bent due to thermal strain or the like, it is preferable to apply slurry to both surfaces of the electrolytic film to integrally form the electrolytic film and the electrode catalyst layer. The pressurizing pressure, heating temperature, and hot pressing time at this time are appropriately selected depending on the solvent used, the viscosity of the slurry, and the like. Typically, the pressure is 1.5 to 2.5 MPa (15 to 2.5 MPa).
Hot pressing is preferably performed at a pressure of 25 kgf / cm ² ) and a temperature of 120 to 180 ° C. for 30 to 60 seconds.
At this time, if the solvent is allowed to remain in an amount of 20 mg / cm ² or more, it becomes possible to dissolve the surface of the electrolytic film M with the solvent remaining in the slurry at the time of hot pressing in combination with the above conditions, This is preferable because it facilitates the penetration of the catalyst into the electrolyte membrane M and allows the catalyst to be pushed into a certain depth.

The viscosity of the slurry at this time is not particularly limited as long as it can be applied directly to the electrolytic membrane and can form a predetermined electrode catalyst layer defined in the present invention. But preferably 5,000 to 2
It is in the range of 5,000 mPa · s. That is, if the slurry viscosity is less than 5,000 mPa · s, there is a possibility that the slurry will leak when hot-pressed, and if the slurry viscosity exceeds 25,000 mPa · s, the handling of the slurry may be difficult. is there.

As described above, in the present invention, the pressure-bonding strength at the interface between the electrolytic film M and the electrode catalyst layer 1 is increased by integrally molding with the electrolytic layer M in the electrode structure MEA. It is possible to prevent peeling of the interface of the substrate and thermal peeling due to a temperature cycle.

(Production of Electrode Structure) Hereinafter, a method for producing an electrode structure of the present invention in which the electrolytic membrane and the electrode catalyst layer are integrally formed will be described with reference to FIG. In producing the electrode structure of the present invention, first, the catalyst particles are dissolved in a polar solvent in which the electrolyte membrane M is soluble, and the viscosity is 5,000 to 25,000.
A catalyst-dispersed organic solvent slurry is formed so as to have a pressure of mPa · s. Next, a predetermined amount of the catalyst-dispersed organic solvent slurry prepared as described above is directly applied to the electrolytic membrane M as shown in FIG. If necessary, a slurry for forming an underlayer composed of carbon black powder and Teflon powder or a mixture of carbon black powder and electrolyte solution (ion conductive polymer solution) is applied on the catalyst-dispersed organic solvent slurry. It is also possible to form an underlayer by doing.

4 (b) to 4 (e) are cross-sectional views in which a part of FIG. 4 (a) is enlarged, and show how the catalyst layer 1 is integrally formed with the electrolytic membrane M according to the present invention. Things. FIG.
As shown in (b), first, a polar solvent that is soluble in the electrolytic film M in the applied slurry for forming an electrode catalyst starts to dissolve the electrolytic film M. Next, as shown in FIG. 4C, the polar solvent dissolves a part of the electrolyte membrane. Next, as shown in FIG. 4D, when hot pressing is performed on the slurry for forming the electrode catalyst, the catalyst particles Ca are deposited on the portion where the polar solvent is dissolved in the electrolytic membrane.
t invades. At this time, the polar solvent (organic solvent) was
It is preferable to perform hot pressing from a state where the amount is left at g / cm ² or more. When the temperature and the pressure are released after performing the hot pressing in this manner, as shown in FIG. 4E, an electrode structure MEA in which the electrolytic film M and the electrode catalyst layer 1 are integrally formed is formed. As described above, it is possible to manufacture the desired highly durable electrode structure MEA by a simple process. In the present invention, the electrode catalyst layer 1 is formed over a predetermined depth from the surface of the original electrolytic film M, but the boundary between the two (the electrolytic film M and the electrode catalyst layer 1) is completely integrated. I have.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments, but the present invention is not limited to the following embodiments. Example 1 A catalyst-dispersed organic solvent slurry was prepared by adding a catalyst (Cat) to a polar solvent (N-methylpyrrolidone) so that the viscosity became 5,000 mPa · s. The catalyst-dispersed organic solvent slurry thus prepared is dried until the residual amount of the polar solvent (remaining solvent amount) becomes 100 mg / cm ^2, and then hot-pressed and joined to the diffusion layer to thereby obtain the present invention. The electrode structure 1 and the electrolytic film M were integrally formed. Table 1, FIG. 5 and FIG. 6 show the physical properties of the obtained electrode structure MEA. In Table 1, the penetration depth of the catalyst was determined by actually measuring with a scanning electron microscope (SEM), and the gradient density was similarly calculated for the catalyst (catalyst particles) penetrating from both sides.
The average distance between them is obtained and calculated by the above equation (1). The thermal peeling rate was 9 minutes at −40 ° C. for 9 minutes.
A cold environment and a hot environment at 0 ° C. for 30 minutes were repeated 100 cycles, and the peeled state of the surface was image-processed. Numerical values were obtained by converting the peeled area in the unit observation area. The cross leak amount (gas permeability cc / cm ² · min) was determined by assembling the sample into a single cell of the fuel cell and then submerging the sample gas. The amount of sample gas supplied from the supply port and discharged from the gas discharge port through the membrane sample was measured and obtained.

Examples 2 to 9 and Comparative Example 1 Example 1 was repeated except that the viscosity of the catalyst-dispersed organic solvent slurry and the amount of residual solvent were changed as shown in Table 1. The results are shown in Table 1, FIG. 5 and FIG.

[0033]

[Table 1]

As shown in Table 1 and FIG. 5, the electrode catalyst layer 1
The electrode structure MEA in which the electrode structure MEA and the electrolytic film M are integrally formed is excellent.
High heat release rate and cross leak rate (gas permeability cc /
cm ^TwoMin), especially the penetration depth of the catalyst particles 5 to 20 μm
It is understood that a range of m is particularly preferable. On the other hand,
In Comparative Example 1 in which the electrode catalyst layer and the electrolyte membrane were not integrally formed,
It can be seen that the thermal delamination rate is significantly inferior. By the way,
If the penetration depth is shallow, the density gradient coefficient decreases,
It can be seen that the separation rate tends to increase. Conversely, penetration depth
It is clear that the thermal delamination rate tends to decrease when the
Call To increase the depth of catalyst penetration, use slurry
It can be seen that the smaller the viscosity of the sample, the better. At the same time,
It is better to have more residual solvent to increase the penetration depth
I understand. Also, as shown in FIG. 6, the electrode structure of the present invention
MEA was measured in comparison with the electrode structure of Comparative Example 1.
It can be seen that the terminal voltage is high in the current density range of FIG. Follow
Thus, the electrode structure MEA of the present invention is different from the conventional electrode structure.
Higher power as well as better durability
Can be supplied.

[0035]

As described above, in the electrode structure of the present invention, when the electrode catalyst layer is formed, the composition of the electrode catalyst layer and the electrolytic film is continuously changed at the boundary between them, and the electrode structure is integrated. It is formed. Therefore, no separation occurs at the interface between the electrolytic membrane and the electrode catalyst layer, and the durability of the electrode structure can be increased even in a predetermined temperature cycle (claim 1). The fuel cell including the electrode structure of the present invention in which the electrolyte membrane and the electrode catalyst layer are integrally formed does not cause separation at the interface between the electrolyte membrane and the electrode catalyst layer in the electrode structure of the fuel cell. It is possible to improve the overall durability. Moreover, this fuel cell can obtain a higher output than that of the prior art. Further, when the ion exchange density gradient coefficient at the interface between the electrode catalyst layer and the electrolytic membrane is 3.5 × 10 ³ meq / g / cm or less, higher durability can be obtained (Claim 2). Further, in the fuel cell electrode structure, when the penetration depth of the catalyst particles into the electrolyte membrane is in the range of 5 μm to 20 μm, higher durability can be obtained (Claim 3). Such an excellent electrode structure for a fuel cell has a viscosity of 5,000 to 25,000 mPa · s obtained by dissolving catalyst particles constituting an electrode catalyst layer in a polar solvent.
Secondly, a slurry of the catalyst-dispersed organic solvent is prepared, and the slurry thus prepared is directly applied to the electrolyte membrane, and heated under pressure to cause the catalyst to penetrate the electrolyte membrane to form the electrode catalyst layer integrally with the electrolyte membrane. Thereby, it can be easily manufactured (claim 4). Further, the organic solvent of the catalyst particle-dispersed ion conductive polymer directly applied to the electrode diffusion layer was 20 mg / cm.
^When the catalyst particles are infiltrated into the electrolytic membrane by heating under pressure while remaining in an amount of ^{2 to} 100 mg / cm ² , it is possible to easily and surely produce an electrode structure having more excellent durability. (Claim 5).

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an outline of a single fuel cell to which the present invention is applied.

FIG. 2 is an electrode structure of the present invention (electrode structure for a fuel cell).
FIG.

FIG. 3 is a schematic diagram showing a configuration of a catalyst particle.

FIG. 4 is a schematic view showing a state of manufacturing the electrode structure of the present invention.

FIG. 5 is a graph showing the relationship between the penetration depth of an electrode catalyst layer, gas permeability, and the thermal delamination rate in the present invention and a comparative example.

FIG. 6 is a graph showing the relationship between current density and terminal voltage in the present invention and a comparative example.

[Explanation of symbols]

 FC fuel cell MEA electrode structure (electrode structure for fuel cell) M electrolyte membrane 1 electrode catalyst layer 2 diffusion layer 3 separator 4 flow path

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nagayuki Kanaoka 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Inventor Nobuhiro Saito 1-4-1 Chuo, Wako-shi, Saitama No. Inside Honda R & D Co., Ltd. (72) Inventor Masaaki Nanami 1-4-1 Chuo, Wako-shi, Saitama F-term inside Honda R & D Co., Ltd. 5H026 AA06 BB01 BB04 BB08 CC03 CX05 HH00 HH03

Claims (5)

[Claims] 1. An electrocatalyst comprising a pair of electrode catalyst layers and an electrolytic film sandwiched between the electrode catalyst layers, wherein a catalyst of the electrode catalyst layer on at least one surface penetrates the electrolytic film to form the electrode catalyst layer and the electrode catalyst layer. An electrode structure for a fuel cell integrally formed with an electrolyte membrane, wherein a catalyst-dispersed organic solvent slurry in which the catalyst is dispersed in a soluble organic solvent for the electrolyte membrane is directly applied to at least one surface of the electrolyte membrane. After that, heating is performed under pressure to cause the catalyst to penetrate into the electrolyte membrane, thereby integrally forming the electrode catalyst layer with the electrolyte membrane. 2. The method according to claim 1, wherein the ion exchange capacity of the electrolytic membrane is A,
The ion exchange capacity of the formed electrode catalyst layer is B, and the thickness of the electrolytic membrane before heating under the pressure is C.
(Μm), and the thickness of the portion of the electrolyte membrane where the catalyst has not penetrated after heating under the pressure is D (μm).
m), the ion exchange density gradient coefficient at the interface between the electrode catalyst layer and the electrolytic membrane calculated by the following formula (1): (AB) / (CD) (3) 5 × 10 ³ meq /
The fuel cell electrode structure according to claim 1, wherein the fuel cell electrode structure has a g / cm or less. 3. The penetration depth of the catalyst particles into the electrolyte membrane is 5
The electrode structure for a fuel cell according to claim 1, wherein the electrode structure is in a range of μm to 20 μm. 4. An electrocatalyst comprising a pair of electrode catalyst layers and an electrolyte membrane sandwiched between the electrode catalyst layers, wherein a catalyst of the electrode catalyst layer on at least one surface penetrates the electrolyte membrane to form the electrode catalyst layer and the electrode catalyst layer. A method for producing a fuel cell electrode structure integrally formed with an electrolyte membrane, wherein the catalyst constituting the electrode catalyst layer is dispersed in an organic solvent soluble in the electrolyte membrane, and has a viscosity of 5,000 to 25,000 mPa. Prepare a catalyst-dispersed organic solvent slurry for 2 seconds, apply the catalyst-dispersed organic solvent slurry thus prepared directly to at least one surface of the electrolytic membrane, and heat under pressure to apply the catalyst to the electrolytic membrane. A method for manufacturing an electrode structure for a fuel cell, wherein the electrode catalyst layer is integrally formed with the electrolyte membrane by infiltrating the electrode membrane. 5. An organic solvent of a catalyst particle-dispersed ion-conductive polymer directly applied to an electrode diffusion layer, in an amount of 20 mg / cm ² to 1 mg / cm ^2.
Method for manufacturing a fuel cell electrode structure according to claim 4, characterized in that 200 mg / cm and heated under pressure in the remaining state in an amount of ² to penetrate the catalyst particles into the electrolyte membrane.