Methods of producing composite material, filter and diffusion layer of fuel cell

Abstract

The composite material is constituted by a substrate and a carbonized nanofiber layer and capable of being widely applied. The method of producing the composite material comprises the steps of: disposing an electrically conductive substrate on an electrode plate of an electro spinning apparatus; spraying a polymer solution or a molten polymer, to which high voltage is applied from a capillary of a capillary electrode of the electro spinning apparatus, toward the substrate on the electrode plate so as to form a large number of nanofibers on the substrate; and burning the substrate, on which a large number of the nanofibers have been formed, so as to form a carbonized nanofiber layer on the substrate.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way of examples and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic explanation view of a cell structure of a fuel cell;

FIG. 2 is an electron micrograph of carbon fiber cloth formed by burning a knitted fabric of silk;

FIG. 3 is an FE-SEM graph of silk fibers burned at temperature of 2000° C.;

FIG. 4 is an electron micrograph of a surface of a conventional diffusion layer made of carbon paper;

FIG. 5 is an FE-SEM graph of a section of a carbon nanofabric layer;

FIG. 6 is a graph showing battery characteristics of the fuel cell of the embodiment;

FIG. 7 is a graph showing battery characteristics of a fuel cell of a comparative example; and

FIG. 8 is a schematic explanation view of the cell structure of the conventional fuel cell;

Claims

1. A method of producing a composite material, which is constituted by a substrate and a carbonized nanofiber layer, comprising the steps of:disposing an electrically conductive substrate on an electrode plate of an electro spinning apparatus;spraying a polymer solution or a molten polymer, to which high voltage is applied from a capillary of a capillary electrode of the electro spinning apparatus, toward the substrate on the electrode plate so as to form a large number of nanofibers on the substrate; andburning the substrate, on which a large number of the nanofibers have been formed, so as to form a carbonized nanofiber layer on the substrate.

2. The method according to claim 1, wherein the substrate is formed by burning a cloth-shaped silk material.

3. The method according to claim 1, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

4. The method according to claim 2, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

5. A method of producing a filter, which is constituted by a substrate and a carbonized nanofiber layer, comprising the steps of:disposing an electrically conductive substrate on an electrode plate of an electro spinning apparatus;spraying a polymer solution or a molten polymer, to which high voltage is applied from a capillary of a capillary electrode of the electro spinning apparatus, toward the substrate on the electrode plate so as to form a large number of nanofibers on the substrate; andburning the substrate, on which a large number of the nanofibers have been formed, so as to form a carbonized nanofiber layer on the substrate.

6. The method according to claim 5, wherein the substrate is formed by burning a cloth-shaped silk material.

7. The method according to claim 5, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

8. The method according to claim 6, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

9. A method of producing a diffusion layer of a fuel cell, in which a cathode layer and an anode layer, each of which has the diffusion layer and a catalyst layer, are located to sandwich an electrolytic membrane, the catalyst layers face the electrolytic membrane, and an oxidation-reduction reaction is caused by a fuel, such as hydrogen, and an oxidizing agent, such as oxygen, through the electrolytic membrane so as to generate an electromotive force, comprising the steps of:disposing an electrically conductive substrate, which constitutes a part of the diffusion layer, on an electrode plate of an electro spinning apparatus;spraying a polymer solution or a molten polymer, to which high voltage is applied from a capillary of a capillary electrode of the electro spinning apparatus, toward the substrate on the electrode plate so as to form a large number of nanofibers on the substrate; andburning the substrate, on which a large number of the nanofibers have been formed, so as to form a carbonized nanofiber layer on the substrate.

10. The method according to claim 9, further comprising the step of forming the catalyst layer on the carbonized nanofiber layer.

11. The method according to claim 9, wherein the substrate is formed by burning a cloth-shaped silk material.

12. The method according to claim 9, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

13. The method according to claim 11, wherein the polymer is a synthetic polymer, such as rayon, polyacrylonitrile resin, phenol resin, polyamide resin and polyimide precursor, or a natural polymer, such as silk and cellulose.

14. The method according to claim 9, wherein said burning step includes a primary burning step and a secondary burning step, anda temperature of the secondary burning step is higher than that of the primary burning step.