Gas diffusion electrode substrate and method for producing gas diffusion electrode substrate

Patent metadata

Field	Value
Publication number	US-11329293-B2
Application number	US-202117345222-A
Country	US
Kind code	B2
Filing date	Jun 11, 2021
Priority date	Nov 11, 2014
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

The purpose of the present invention is to provide: a method for producing a gas diffusion electrode base which enables the achievement of a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane; and a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane. For the purpose of achieving the above-described purpose, the present invention has the configuration described below. Namely, a specific gas diffusion electrode base which has a carbon sheet and a microporous layer, and wherein the carbon sheet is porous and the DBP oil absorption of a carbon powder contained in the microporous layer is 70-155 ml/100 g.

First claim

The invention claimed is:

1. A method for producing a gas diffusion electrode substrate including a carbon sheet and a microporous layer, wherein
the carbon sheet is porous,
the method comprises an application step of applying a coating liquid for forming the microporous layer (hereinafter, described as an MPL coating liquid) onto at least one surface of the carbon sheet by a slit die coater (hereinafter, described as an MPL application step),
the slit die coater has a lip-tip length of 0.10 to 10.00 mm, and
the MPL coating liquid contains a carbon powder having a DBP oil absorption of 70 to 155 ml/100 g and an ash content of less than 0.10% by mass, and contains a dispersion medium.

2. The method for producing a gas diffusion electrode substrate according to claim 1 , wherein the MPL coating liquid has a viscosity of 1.0 to 20.0 Pa·s at a shear rate of 17 s −1 .

3. The method for producing a gas diffusion electrode substrate according to claim 1 , wherein
after the application of the MPL coating liquid in the MPL application step, the MPL coating liquid-applied carbon sheet is retained horizontally for 1 second or more and 5 minutes or less, and
subsequently, the carbon sheet is dried and sintered.

4. The method for producing a gas diffusion electrode substrate according to claim 1 , comprising water as the dispersion medium.

5. The method for producing a gas diffusion electrode substrate according to claim 1 , wherein all carbon powder(s) contained in 100% by mass of the MPL coating liquid is 10 to 50% by mass.

6. The method for producing a gas diffusion electrode substrate according to claim 1 , wherein
one surface of the carbon sheet has a covering rate of 70 to 90%, the other surface has a covering rate lower than the covering rate of the one surface by 5 to 20 points, and
the MPL coating liquid is applied onto the one surface of the carbon sheet in the MPL application step.

Assignees

• Toray Industries

Inventors

• Utsunomiya Masamichi
• Tanimura Yasuaki
• Kamae Toshiya

Classifications

• Y02P70/50

  Manufacturing or production processes characterised by the final manufactured product · CPC title

• Y02E60/50

  Fuel cells · CPC title

• B32B9/04

  comprising such {particular} substance as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a glass layer B32B17/06; layered products with at least two ceramic layers composed mainly of ceramic B32B18/00)} · CPC title

• H01M4/8657

  layered · CPC title

• H01M8/10

  Fuel cells with solid electrolytes · CPC title