Porous electrode substrate and manufacturing method therefor

Patent metadata

Field	Value
Publication number	US-2018108920-A1
Application number	US-201615562041-A
Country	US
Kind code	A1
Filing date	Apr 1, 2016
Priority date	Apr 2, 2015
Publication date	Apr 19, 2018
Grant date	—

Abstract

There has been a demand for providing a porous electrode substrate having reduced bulk density, having good handling properties and gas permeability, which has conventionally been difficult to produce. A porous electrode substrate having a structure wherein carbon fibers (A) are joined by carbides, the porous electrode substrate having a bulk density of 1.0-2.0×10 −1 g/cm 3 or less when a pressure of 1.5×10 −1 MPa is applied, and having a bending strength of at least 10 MPa.

First claim

1 . A porous electrode substrate, comprising
a structure having a carbon fiber (A) bonded by a carbide, wherein the porous electrode substrate has a bulk density of 1.0×10 −1 g/cm 3 or more and 2.0×10 −1 g/cm 3 or less and a bending strength of 10 MPa or more when a pressure of 1.5×10 −1 MPa is applied to the porous electrode substrate.

2 . The porous electrode substrate according to claim 1 , wherein the porous electrode substrate has a thickness of 50 μm or more and 500 μm or less when the pressure of 1.5×10 −1 MPa is applied to the porous electrode substrate.

3 . The porous electrode substrate according to claim 1 , wherein the porous electrode substrate has an air permeability of 500 ml/cm 2 /hr/Pa or more in a thickness direction.

4 . The porous electrode substrate according to claim 1 , wherein a thickness of the porous electrode substrate when a pressure of 3 MPa is applied to the porous electrode substrate is 10% or more and 70% or less of a thickness of the porous electrode substrate when a pressure of 5.0×10 −2 MPa is applied to the porous electrode substrate.

5 . The porous electrode substrate according to claim 1 , wherein a thickness of the porous electrode substrate when the pressure is decreased to 5.0×10 −2 MPa after a pressure of 3 MPa is applied to the porous electrode substrate is 40% or more and 95% or less of a thickness of the porous electrode substrate when a pressure of 5.0×10 −2 MPa is applied before the pressure of 3 MPa is applied to the porous electrode substrate.

6 . The porous electrode substrate according to claim 1 , wherein the porous electrode substrate has an electric resistance value of 1.0 mΩ·cm 2 or more and 10.0 mΩ·cm 2 or less in a thickness direction when a pressure of 3 MPa is applied to the porous electrode substrate.

7 . A membrane electrode assembly, comprising
the porous electrode substrate according to claim 1 .

8 . A polymer electrolyte fuel cell, comprising
the membrane electrode assembly according to claim 7 .

9 . A manufacturing method for a porous electrode substrate, the method comprising:
(i) manufacturing a precursor sheet having a carbon fiber (A) and a thermoplastic resin-containing fiber (B) dispersed; (ii) subsequently obtaining a molded precursor sheet 1 by heating and pressurizing the precursor sheet to melt the thermoplastic resin-containing fiber (B) and to fuse the thermoplastic resin-containing fiber (B) with the carbon fiber (A) and molding the fused material; (iii) subsequently adding a thermosetting resin to the molded precursor sheet 1 ; (iv) subsequently obtaining a molded precursor sheet 2 by heating the molded precursor sheet 1 to which a thermosetting resin is added to cure the thermosetting resin; and (v) subsequently obtaining the porous electrode substrate by carbonizing the molded precursor sheet 2 at a temperature of 1000° C. or higher.

10 . The manufacturing method according to claim 9 , wherein in (iv), the molded precursor sheet 2 is obtained by heating the molded precursor sheet 1 to which the thermosetting resin is added to cure the thermosetting resin, to melt the thermoplastic resin-containing fiber (B), and to increase a thickness of the molded precursor sheet 1 .

11 . The manufacturing method according to claim 9 , wherein in (i), the precursor sheet further having a carbon fiber precursor fiber (C) dispersed together with the carbon fiber (A) and the thermoplastic resin-containing fiber (B).

12 . The manufacturing method according to claim 9 , wherein a carbon powder (D) is added in (i).

13 . The manufacturing method according to claim 9 , wherein a carbon powder (D) is added together with the thermosetting resin in (iii).

14 . The manufacturing method according to claim 9 , wherein the thermosetting resin is a water-soluble phenolic resin and/or a water-dispersible phenolic resin.

Assignees

• Mitsubishi Chem Corp

Inventors

• HIDESHIMA Kota

Classifications

• H01M8/0245

  in the form of layered or coated products · CPC title

• H01M4/96 Primary

  Carbon-based electrodes · CPC title

• H01M8/0234 Primary

  Carbonaceous material · CPC title

• H01M8/1055

  Inorganic layers on the polymer electrolytes, e.g. inorganic coatings · CPC title

• C08J2300/22

  Thermoplastic resins · CPC title