JP2002170574A - Electrode substrate for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode substrate for a fuel cell which comprises a carbon film structure where the surface other than an open hole is smooth, with a porous structure comprising a fine communicating hole, so that the gas is widely and evenly distributed with no short path while conductivity and heat transmission characteristics are high, with low contact resistance and heat loss at the interface when a battery cell is formed. SOLUTION: The carbon film structure is flexible and rigid and comprises a porous structure containing a fine communicating hole, with the surface except for an open hole being smooth. The metal particle comprising a catalytic function is carried at nano level. So, when used as the electrode substrate for a fuel cell, the surface contact to another layer on an interface becomes possible when laminated, reducing the contact resistance and heat loss on the interface, for wide and even distribution of gas, causing more efficient catalytic reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a member for a fuel cell. In particular, the present invention relates to a fuel cell electrode base material suitable for a gas diffusion electrode of a solid polymer electrolyte fuel cell or a phosphoric acid fuel cell.

[0002]

2. Description of the Related Art In recent years, fuel cells have been developed and put into practical use. For example, in the case of a solid polymer electrolyte fuel cell, a thickness of 0.1 to 0.3 m is provided on both sides of the polymer solid electrolyte layer.
m. A porous carbon plate made of a carbon fiber paper body is provided, a platinum-based catalyst as an electrode catalyst is supported on the surface of the porous carbon plate to form a gas diffusion electrode, and a gas channel groove having a thickness of 1
A battery cell is configured by providing a separator made of a dense carbon plate of about 3 mm. In the case of a phosphoric acid type fuel cell, a porous carbon plate made of a carbon fiber paper having a thickness of 0.1 to 0.3 mm is provided on both sides of an electrolyte layer in which phosphoric acid is retained in a phosphoric acid retainer, A gas diffusion electrode is formed by supporting a platinum-based catalyst as an electrode catalyst on the surface thereof, and a separator having a thickness of 1 to 3 mm with a gas flow channel is provided outside the gas diffusion electrode to constitute a battery cell. Japanese Patent Application Laid-Open No. 9-15336 discloses a publication in which a platinum-based catalyst is supported on such a carbon electrode.
No. 6, JP-A-2000-215899, and the like.

A base material of a gas diffusion electrode in a solid polymer electrolyte fuel cell or a phosphoric acid fuel cell can uniformly and easily supply a fuel gas or an oxidizing gas to a reaction site, and a drain such as water. It has a high gas flowability that can easily discharge gas, and it has excellent conductivity, thermal conductivity, mechanical strength, corrosion resistance, etc., and the cell is laminated with an electrolyte layer and separator. When formed, the contact resistance at the interface between the electrolyte layer and the separator and the electrode is required to be small, and high conductivity at the interface is required to be ensured.

Conventionally, a carbon fiber paper made of carbon fiber impregnated with a phenol resin or the like is heat-formed into a sheet by a hot press or the like as the gas diffusion electrode base material.
A base material is used in which a phenol resin is carbonized and carbon fibers are bonded by a phenol resin carbide.

[0005] However, the above-mentioned electrode substrate has a carbon fiber forming a paper body having a diameter of about 7 µm or more, and has a porous structure of a network structure, so that gas is likely to cause a short path. There was a question in that the distribution was wide and uniform. Furthermore, since the electrode substrate has a structure in which fibers are in contact with each other at points, it is difficult to increase conductivity and heat conductivity, and a battery cell is formed by laminating an electrolyte layer, a gas diffusion electrode, and a separator. Also, there is a problem in that each interface becomes a point contact and the contact resistance and heat loss increase. For this reason, there is an attempt to reduce the contact resistance by increasing the number of contact points by making the diameter of the carbon fiber forming the paper body smaller, but the electrode substrate formed of the thin fiber is affected by the gas and drain gas distributed. In some cases, it was easily torn off and fall off.

On the other hand, for a high-performance fuel cell having high power generation efficiency and high durability, a uniform gas distribution by uniform gas distribution, a reduction in internal resistance of the battery, and a reduction in battery reaction are required. Efficient dissipation of heat is required. For this reason, there has been a demand for an electrode substrate capable of uniformly distributing gas, having high conductivity and heat conductivity, and particularly capable of reducing contact resistance and heat loss at an interface.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a porous carbon film structure having fine communication holes, a surface other than the open holes, made of a carbon film structure having a smooth surface. An object of the present invention is to provide a fuel cell electrode base material that can be distributed uniformly over a wide area, has high conductivity and high heat conductivity, and in particular, can reduce contact resistance and heat loss at an interface when a battery cell is formed. .

[0007]

The present invention has a porous structure having fine communicating holes, and has an average pore diameter of 0.05 to 10 mm.
The present invention relates to a fuel cell electrode substrate comprising a carbon film structure having a porosity of 15 to 85% in μm. Further, the surface of the carbon film structure other than the open pores is smooth, the graphitization ratio of the carbon film structure is 50% or more, and the carbon film structure has a high heat resistance having a porous structure. The polymer film was obtained by heating and carbonizing under an anaerobic atmosphere, and the carbon film structure was integrated by heating and carbonizing a laminate obtained by laminating a plurality of the high heat-resistant polymer films under an anaerobic atmosphere. It relates to the fact that the high heat-resistant polymer is a polyimide.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The electrode substrate for a fuel cell of the present invention comprises
It has a porous structure having fine communication holes, and the surface other than the open holes is formed of a smooth carbon film structure. In the present specification, a porous structure having fine communication holes is a so-called open hole in which pores are continuous from an arbitrary surface to another surface in a passage form, and a space between adjacent pores has a wall-like structure. And the pores extend non-linearly while bending. That is, when the gas flows, the carbon film structure is guided to the non-linearly extending passage-like pores and is non-linearly distributed, so that a short path does not occur. Further, the surface of the carbon film structure having a porous structure of the present invention has a smooth surface except for the open holes formed by the pores extending from the inside of the film and reaching the surface, and when laminated with a separator or the like. The interface with another layer is brought into surface contact with the smooth surface. In order to further explain the above-mentioned porous structure and surface smoothness,
FIGS. 1 and 2 show scanning electron micrographs of a surface and a cross section of a typical example of a carbon film structure having a porous structure which constitutes an electrode substrate for a fuel cell of the present invention. Since the surface of the carbon film structure of the present invention has smoothness as shown in FIG. 1 except for the open holes, the carbon film structure comes into surface contact at the interface when the laminate is formed.

Further, the carbon film structure serving as the electrode substrate of the present invention has an average pore diameter of 0.05 to 10 μm and a porosity of 15 to 85%. The average pore size on the surface is 0.
If it is less than 05, the gas cannot be efficiently distributed due to a pressure loss, and if the average pore diameter exceeds 10 μm, the gas tends to flow linearly and it becomes difficult to uniformly distribute the gas over a wide range. Absent. On the other hand, if the porosity is less than 15%, the flow rate of the gas is reduced, and if the porosity exceeds 85%, the mechanical strength of the film is undesirably reduced.

The carbon film structure has a graphitization rate of 5%.
0% or more, preferably 80% or more, particularly preferably 90%
% Is preferable. A graphitization ratio of 50% or more is preferable because the mechanical strength of the film is increased and the flexibility is improved, and the conductivity and thermal conductivity are also improved.

The carbon membrane structure as the electrode substrate for a fuel cell according to the present invention has a porous structure having fine communication holes, and a high heat-resistant polymer membrane having a smooth surface other than the open pores in an anaerobic atmosphere. And carbonized by heating. If a polymer that is not a high heat-resistant polymer is used, the porous structure cannot be maintained when heated. The high heat-resistant polymer is not particularly limited as long as it can form a porous film having fine communication holes and can maintain a porous structure including fine communication holes even when carbonized by heating. It does not do. Polyimide, polyamide, cellulose,
Polymers such as furfural resin-based and phenolic resin-based polymers can be suitably mentioned. In particular, aromatic polyimides are preferred because a carbon film structure having high mechanical strength can be easily obtained by heating and carbonizing. Here, the aromatic polyimide includes a polyamic acid that is a precursor of the aromatic polyimide and a polyamic acid that is partially imidized.

A highly heat-resistant polymer film having a porous structure having fine communication holes and having a smooth surface other than the open holes,
It can be suitably produced by a phase inversion method using a polymer solution. A solution in which a polymer is dissolved in an organic solvent (solvent) is cast on, for example, a glass plate, and the cast film is coated with an organic solvent or water that is compatible with the organic solvent and insoluble with the polymer (non-solvent). ), And at that time, a so-called phase inversion method in which pores are formed by utilizing a phase separation phenomenon caused by substitution between a solvent and a non-solvent. However, a dense layer is formed on the surface by the usual phase inversion method. Unexamined-Japanese-Patent No. 11-31, which is explicitly referred to as a part of the specification of the present invention
No. 0658, Japanese Patent Application Laid-Open No. 2000-306568, and Japanese Patent Application No. 2000-284651, the phase change method of adjusting the solvent replacement speed using a solvent replacement speed adjusting material easily allows a porous porous material having fine communication holes. It is preferable because a molecular film can be obtained. Specifically, first, a casting film of a polymer solution having a smooth surface is formed, and then a solvent replacement rate adjusting material (porous film) is laminated on the surface of the casting film. And depositing a porous polymer film while forming pores by phase separation. Since the surface of the porous polymer film formed by this method (the surface other than the opening) retains the surface smoothness of the original casting film, the surface of the porous polymer film has a porous structure having communication holes, and the surface other than the open holes has A smooth porous polymer membrane can be easily obtained.

A highly heat-resistant polymer film having a porous structure having fine communication holes and having a smooth surface other than the open holes is heated and carbonized in an anaerobic atmosphere to form a porous structure having fine communication holes. A carbon film structure having a smooth surface other than the open holes can be obtained. The anaerobic atmosphere is not particularly limited, but is preferably in an inert gas such as a nitrogen gas, an argon gas, or a helium gas, or in a vacuum. Heat carbonization is
If the temperature is rapidly increased, decomposition products may be dissipated or carbon content may be distilled off to lower the carbon yield.

For this purpose, it is preferable to raise the temperature at a sufficiently low rate of 20 ° C./min or less, particularly about 1 to 10 ° C./min, and to gradually carbonize. The heating temperature and heating time may be any temperature and time as long as sufficient carbonization is performed,
In order to increase the graphitization rate of the obtained carbon structure to increase mechanical strength, electrical conductivity, and thermal conductivity, 2400 to 3500
° C, particularly preferably in the range of 2600 to 3000 ° C, and the temperature is preferably 20 to 180 minutes.

It is also preferable to apply pressure during heating during the heating and carbonization, since it is possible to increase the graphitization rate and obtain a carbon film structure having high mechanical strength and high electrical and thermal conductivity. The pressurization suppresses changes in shape due to shrinkage during heating carbonization and enhances the orientation of the carbon part being carbonized to promote graphitization, resulting in mechanical strength, conductivity, and heat conduction. A carbon film structure having high properties can be obtained. Pressure is 1-250MPa, especially 100-250M
It is preferable to apply with Pa. Pressurization is suitably performed using a high-temperature compressor or an isostatic hot press (HIP).

Further, in order to promote graphitization, a compound having an effect of promoting graphitization, such as a boron compound, is added in advance to a highly heat-resistant polymer film having a porous structure having fine communication holes to be heated. Is preferred. Fine powders of these compounds are uniformly dispersed in a polymer solution as a raw material, and a high heat-resistant polymer film having a porous structure is produced by the above-mentioned method using the solution. A highly heat-resistant polymer film having a uniformly dispersed porous structure can be manufactured.

In the present invention, the heat-resistant polymer film having a porous structure having fine communicating holes and having a smooth surface other than the open holes is heated and carbonized individually one by one to obtain a desired thickness. Although they may be used in a stacked state, it is not preferable because interfaces are formed between the layers and the contact resistance of each interface needs to be controlled, which complicates the handling. In the method of bonding with an adhesive, the adhesive may reduce battery performance. There is also a method of bonding with a phenolic adhesive or the like, heating again to carbonize the adhesive, and integrating it, but it is not preferable because complicated processing is required. When heating and carbonizing a laminate of a plurality of high heat-resistant polymer films having a porous structure having fine communication holes and having a smooth surface other than the open holes, the carbonized carbon film structure of the present invention is carbonized and integrated. It is particularly preferred because it can be obtained. In this method, carbon film structures having various thicknesses can be obtained from the same thin polymer film. Also, by laminating precursor films having different pore diameters and the like, a gradient film having a gradient pore diameter can be formed.

The electrode substrate of the present invention is impregnated with a solution containing a metal fine particle precursor such as a metal ion or a metal complex.
After performing a treatment such as immersion, a gas diffusion electrode can be manufactured by supporting a catalyst by a method of chemically reducing with a reducing agent. Here, examples of the metal ion include platinum group metal ions such as platinum, rhodium, ruthenium, iridium, palladium, and osnium. As a metal fine particle precursor, for example, [M (NH3) n]
A platinum group ammine complex represented by Xm (M; platinum group metal, X; Cl, NO3, n; 4 or 6, m; 2 or 4 or 6), potassium chloroplatinate (K ₂ PtCl ₄ )
And the like.

In particular, since no heat is applied in this method, aggregation due to diffusion of metal atoms can be prevented, and the method is suitable for supporting metal particles having a catalytic function on the order of nanometers. Here, the nano-order metal particles or metal fine particles mean particles having a size of 100 nm or less, preferably particles having a size of 2 to 40 nm.

Further, since the electrode substrate of the present invention has many fine communication holes, it can be supported on a wider surface than a carbon fiber paper body which is a usual electrode substrate.
Therefore, it is suitable as an electrode substrate for a high-performance fuel cell capable of providing a reaction field for a cell reaction which is widely and uniformly dispersed.

Next, the present invention will be described with reference to examples in which an aromatic polyimide suitable as a high heat-resistant polymer is used. However, the present invention is not limited to the following examples. In the present invention, the air permeability, the porosity, the average pore diameter, and the graphitization rate were measured by the following methods. Air permeability Measured according to JIS P8117. A B-type Gurley densometer (manufactured by Toyo Seiki Co., Ltd.) was used as a measuring device. The membrane of the sample is fastened to a circular hole having a diameter of 28.6 mm and an area of 645 mm ² , and the air in the cylinder is allowed to pass from the test hole to the outside of the cylinder with an inner cylinder weight of 567 g. The time during which 100 ml of air passed was measured and defined as the air permeability (Gurley value). Porosity The thickness, area and weight of the film cut into a predetermined size were measured, and the porosity was determined from the basis weight by the following formula. S of the following formula
Is the film area, d is the film thickness, w is the measured weight, D is the density, 1.34 for polyimide, and the density for each sample in consideration of the graphitization rate obtained by the method described later for the carbon film structure. Calculated. Porosity = (1−W / (S × d × D)) × 100 Average pore diameter A scanning electron microscope photograph of the film surface is taken, the pore area is measured for 50 or more openings, and the average of the pore areas is measured. From the values, the average diameter assuming that the hole shape was a perfect circle was calculated by the following equation. Sa in the following equation means the average value of the hole area. Average pore size = 2 × (Sa / π) ^1/2 graphitization ratio X-ray diffraction was measured and determined by the Landau method.

[0022]

EXAMPLES Example 1 Preparation of Porous Polyimide Membrane As a tetracarboxylic acid component, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (hereinafter s-BPDA)
May be abbreviated as a), 4,4′- as a diamine component
N-methyl-2-pyrrolidone was prepared by using diaminodiphenyl ether (hereinafter sometimes abbreviated as DADE) such that the molar ratio of DADE to S-BPDA was 0.997 and the content of the monomer component was 6% by weight. (Less than,
NMP), at a temperature of 40 ° C, 10
Polymerization was performed for a time to obtain a polyamic acid solution as a polyimide precursor. The solution viscosity (temperature: 25 ° C., E-type rotational viscometer) of this polyamic acid solution was 3000 poise. To this solution, boron carbide powder having a particle diameter of 20 μm or less was added so as to be 2% by weight based on the polyamic acid, and the mixture was sufficiently stirred until it became uniform.

The above-mentioned polyamic acid solution is cast on a glass plate so as to have a thickness of about 100 μm, and the surface of the casting film of the polyamic acid solution is subjected to a gas exchange rate of 550 seconds / 100 ml, which is a solvent replacement rate adjusting material. Was covered with a microporous polyolefin membrane (UPORE UP2015, manufactured by Ube Industries, Ltd.) so that wrinkles did not occur on the surface. By immersing the laminate in methanol for 5 minutes and performing solvent replacement via a solvent replacement rate adjusting material, a polyamic acid film having a porous structure having fine communication holes and having a smooth surface other than the open holes is obtained. Was deposited.

Next, the polyamic acid film is placed in water for 1 hour.
After immersion for 0 minutes, the film was peeled off from the glass plate and fixed to a pin tenter.
Heat treatment was performed for minutes. The imidation ratio of the obtained porous polyimide film was 80%, the film thickness was 20 μm, and the air permeability was 1%.
9 seconds / 100 ml, porosity 72%, average pore size 0.18μ
m.

Preparation of Porous Carbide Film A laminate of the three porous polyimide films was sandwiched on both sides with a gas-permeable carbon sheet in an atmosphere of argon gas, and the temperature was raised from room temperature at a rate of 10 seconds / minute. The temperature was raised to 1000 ° C. Further, the temperature was raised to 3000 ° C. at a pressure of 200 MPa and a temperature rising rate of 5 ° C./min, and held for 60 minutes. After cooling, the obtained carbon membrane structure having a porous structure is glossy,
Flexible and tough, with a film thickness of 45 μm and air permeability of 58 seconds /
Min, porosity 68%, average pore diameter 0.13 μm, degree of graphitization 9
From observation of a scanning electron micrograph, it had a porous structure with fine communicating holes, and the surface other than the open holes was smooth. In addition, a drop of methanol with a diameter of 1 mm
When the droplet was dropped such that it reached the back surface after 1 second, a circular spread having a diameter of 20 mm or more was observed.

Example 2 Preparation of a Porous Polyimide Membrane A polyamic acid solution was prepared in the same manner as in Example 1 except that the content of the monomer component was 20% by weight, and the solution was reduced to a thickness of about 150 μm. It was then cast in the same manner as in Example 1 to obtain a porous polyimide film. The imidation ratio of the obtained porous polyimide film was 80%, the film thickness was 60 μm, the air permeability was 1500 seconds / 100 ml, and the porosity was 16%.
%, Average pore diameter 0.40 μm.

Preparation of Porous Carbonized Film The porous polyimide film was heated and carbonized in the same manner as in Example 1. After cooling, the obtained carbon film structure having a porous structure is glossy, flexible and tough, and has a film thickness of 125 μm.
m, air permeability 2,500 sec / min, porosity 13%, average pore diameter 0.30 μm, degree of graphitization 95%, and from observation of a scanning electron micrograph, it has a porous structure with fine communicating holes. The surface other than the open holes was smooth. When a methanol droplet is dropped on the surface so that the diameter becomes 1 mm, 5
A second later, a circular spread having reached the back surface and having a diameter of about 6 mm was observed.

Example 3 Preparation of Porous Polyimide Membrane A symmetric biphenyltetracarboxylic dianhydride (s-BPDA) was used as an acid dianhydride, and paraphenylenediamine (PDA) was used as a diamine component. 1-methyl-2 so that the molar ratio of PDA to BPDA is 0.996 and the total weight of the monomer components is 10% by weight.
-It was dissolved in pyrrolidone (NMP) and polymerized at a temperature of 40 ° C for 10 hours to obtain a polyimide precursor solution. The solution viscosity of the polyimide precursor solution was 7,000 poise.

The obtained polyimide precursor solution was cast onto a mirror-polished stainless steel substrate so as to have a thickness of about 100 μm.
The surface was covered with a 0 second / 100 ml polyolefin microporous membrane (manufactured by Ube Industries, Ltd.) so as not to cause wrinkles. The laminate was immersed in 2-propanol for 5 minutes, and the solvent was replaced via a solvent replacement speed adjusting material, thereby depositing the polyimide precursor and making it porous.

After the deposited polyimide precursor porous film is immersed in water for 15 minutes, it is peeled off from the stainless steel plate and the solvent displacement rate adjusting material, and is heat-treated at 400 ° C. for 30 minutes in the air while being fixed to a pin tenter. Was done. The polyimide porous film thus created is
The film had continuous holes in the cross-sectional direction of the film. The measurement results of the film thickness, air permeability, porosity, and average pore size of the obtained polyimide porous film are shown below. On the other hand, from a scanning electron micrograph (SEM photograph) of the surface of the polyimide porous film and a scanning electron micrograph of the cross section, it was confirmed that the film had fine continuous holes in the film cross-sectional direction. Film thickness 30 μm Air permeability 200 sec / 100 ml Porosity 55% Average pore size 0.35 μm

Preparation of Porous Carbonized Film The above polyimide porous film was placed in a nitrogen gas stream,
Heating rate 10 ° C /
Temperature from 20 ° C to 1200 ° C in 1 minute,
Hold for 20 minutes. The obtained film was dull but glossy, and the appearance was flat without any breakage and kept the state before carbonization. FIGS. 1 and 2 show scanning electron micrographs (surface, cross section, and enlargement) of the carbonized porous film. The pores were smaller than the pore diameter before carbonization, the average pore diameter was 0.28 μm, and the porosity was 53%.
According to the result obtained by X-ray diffraction, the carbonized film showed a slightly crystalline appearance, and the crystallinity determined by the Ruland method was 28%. The cross section of the carbonized porous film was observed with a scanning electron microscope, and methanol passed through the carbonized porous film. Thus, it was confirmed that the film had fine continuous pores.

Preparation of Platinum-Supported Porous Carbonized Film Potassium chloroplatinate (K ₂ PtCl ₄ ) was dissolved in a mixed solvent of pure water and methanol at a mixing ratio of 60:40 to a concentration of 2% by weight, A platinum precursor solution was obtained. The amount of the platinum precursor solution measured to a height of about 3 mm was measured on a Petri dish, and the porous carbonized film was allowed to stand still in the Petri dish so that the whole was immersed. This petri dish was covered with filter paper and left in an atmosphere at a temperature of 20 ° C. and a humidity of 30% for 48 hours. After 48 hours, the solvent in the petri dish was volatilized and dried.

Next, sodium borohydride (NaBH)
₄ ) was dissolved in a mixed solvent of pure water and methanol at a mixing ratio of 60:40 so that the concentration became 2% by weight, and the mixture was poured into a petri dish on which a porous carbonized film was allowed to stand.
The platinum precursor was reduced by being allowed to stand for about 0 minutes. Thereafter, the solution in the Petri dish was diluted with pure water, and then the porous carbonized film was taken out. The film taken out was washed with pure water and dried in a vacuum at 90 ° to obtain a platinum-supported porous carbonized film.

Characterization SEM observation of the obtained film was performed (FIG. 3). EPMA indicates that the finely dispersed particles in the figure are platinum.
Confirmed by elemental analysis. Elements in the film other than platinum and carbon were in amounts below the detection sensitivity. As a result of SEM observation, it was confirmed that the platinum fine particles were uniformly finely dispersed on the surface of the film and the surface of the continuous pores inside. Also, TE
Observation with M was also performed (FIG. 4). The observation sample was prepared by crushing and dispersing a sample in a silicon nitride mortar by pouring butanol, and then subjecting the supernatant to carbon deposition.
It was created by pouring on a microgrid for EM observation. Electron diffraction confirmed that platinum was crystallized (FIG. 5). It can also be confirmed that the size of the particles is several tens of nanometers. Considering the procedure for preparing the sample for TEM observation, the supported platinum particles also have an adhesive property such that they do not easily peel off due to some interaction with carbon as the support. it is obvious.

Comparative Example 1 Platinum fine particles were loaded in the same manner as in Example 3 except that carbon fibers having a fiber diameter of 7 μm were used. SEM observation of the obtained fiber showed that almost no platinum fine particles were observed. In addition, a lint-like structure was attached around the fiber, but as a result of analysis such as elemental analysis, it was found that the platinum precursor was not reduced.

Comparative Example 2 Platinum fine particles were loaded in the same manner as in Example 1 except that carbon black having an arithmetic average particle diameter of 9 nm was used. As a result of SEM observation and EPMA elemental analysis of the obtained carbon black, it was found that fine platinum particles in the form of fine particles and an unreduced platinum precursor structure in the form of lint were adhered to the surface.

[0037]

The present invention is as described above, and has the following effects. That is, the carbon film structure of the present invention is flexible and tough, has a porous structure having fine communication holes, and has a smooth surface other than the open holes. Further, metal particles having a catalytic function can be supported at a nano level. Therefore, when used as a fuel cell electrode substrate, when laminated, surface contact with other layers is possible at the interface, contact resistance and heat loss at the interface can be reduced, and gas can be distributed uniformly and widely. Therefore, a catalytic reaction can be caused more efficiently.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of a typical example of the surface of an electrode substrate for a fuel cell of the present invention.

FIG. 2 is a scanning electron microscope photograph of a cross section of a representative example of the fuel cell electrode substrate of the present invention.

FIG. 3 is a scanning electron micrograph of a typical example of a fuel cell electrode device supporting platinum as a metal catalyst in the present invention.

FIG. 4 is a transmission electron micrograph of a typical example of a fuel cell electrode material supporting platinum as a metal catalyst in the present invention.

FIG. 5 is a diffraction image of a representative example of a fuel cell electrode material supporting platinum as a metal catalyst in the present invention.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C01B 31/04 101 C01B 31/04 101A C04B 35/52 H01M 4/88 C H01M 4/88 8/10 8/10 C04B 35/54 AEF term (reference) 4G032 AA13 AA41 BA05 GA12 4G046 EA03 EB02 EB04 EC03 EC06 4G069 AA01 AA03 AA08 BA08A BA08B BA22C BB02A BC75B CC32 DA05 EA08 EB19 EC16X EC17X EC17 AS03 A02 FB01 AS02 A02 FB02 HH04 HH05 5H026 AA04 AA06 BB01 EE05 HH04 HH05

Claims (10)

[Claims] (1) a porous structure having fine communication holes,
Average pore size is 0.05 to 10 µm and porosity is 15 to 85%
An electrode substrate for a fuel cell comprising the carbon membrane structure according to (1). 2. The fuel cell electrode substrate according to claim 1, wherein the surface of the carbon film structure other than the open holes is smooth. 3. The electrode substrate for a fuel cell according to claim 1, wherein the carbon film structure has a graphitization ratio of 50% or more. 4. The carbon film structure according to claim 1, wherein the carbon film structure is obtained by heating and carbonizing a highly heat-resistant polymer film having a porous structure in an anaerobic atmosphere. Electrode substrate for fuel cells. 5. The carbon film structure according to claim 1, wherein the carbon film structure is obtained by heating and carbonizing a laminate obtained by laminating a plurality of the high heat-resistant polymer films in an anaerobic atmosphere.
5. The electrode substrate for a fuel cell according to any one of 4. 6. The electrode substrate for a fuel cell according to claim 1, wherein the high heat-resistant polymer is polyimide. 7. The electrode substrate for a fuel cell according to claim 6, wherein the polyimide is a polyimide containing biphenyltetracarboxylic acid or an anhydride thereof as a monomer component. 8. A fine metal dispersed carbon film structure, wherein a metal is supported on the carbon film structure according to any one of claims 1 to 7 as nano-order fine particles. 9. A fuel cell electrode using the metal finely dispersed carbon film structure according to claim 8. 10. A metal catalyst supporting a carbon structure using the finely dispersed metal carbon film structure according to claim 8.