Micro-porous layer and manufacturing method therefor, gas diffusion electrode substrate, and fuel battery

Patent metadata

Field	Value
Publication number	US-11621426-B2
Application number	US-201816763266-A
Country	US
Kind code	B2
Filing date	Nov 21, 2018
Priority date	Nov 29, 2017
Publication date	Apr 4, 2023
Grant date	Apr 4, 2023

Abstract

The present invention provides a micro-porous layer which provides a fuel battery having high productivity, high power generation performance, and high durability. The present invention provides a micro-porous layer including fibrous carbohydrate having a fiber diameter of 5 nm-10 μm and an aspect ratio of 10 or more. The carbohydrate has an oxygen/carbon element ratio of 0.02 or more.

First claim

The invention claimed is:

1. A gas diffusion electrode substrate in which a micro-porous layer is provided on a conductive porous substrate, wherein the micro-porous layer comprises (i) a fibrous carbide having a Aber diameter of 5 nm or more and 10 μm or less and an aspect ratio of 10 or more and (ii) a conductive material,
wherein an oxygen/carbon element ratio of the whole fibrous carbide is 0.02 or more, and wherein the oxygen/carbon element ratio is measured by performing a scanning electron microscope (SEM)-EDX measurement, under the conditions of an acceleration voltage of 10 kV and a magnification of 100,000 times, on a cross section in a thickness direction of the gas diffusion electrode substrate produced by an ion milling device.

2. The gas diffusion electrode according to claim 1 , wherein the carbide has a fiber diameter of 5 nm or more and 100 nm or less.

3. The gas diffusion electrode according to claim 1 , wherein the carbide has a fiber diameter of 500 nm or more and 10 μm or less.

4. The gas diffusion electrode according to claim 1 , wherein a fluorine/carbon element ratio of the carbide is smaller than an average fluorine/carbon element ratio of the micro-porous layer.

5. The gas diffusion electrode according to claim 1 , wherein a cross section of the micro-porous layer contains the carbides in an amount of 1,000/mm 2 or more.

6. The gas diffusion electrode according claim 1 , comprising carbon black, a water-repellent substance, and the carbide.

7. A micro-porous layer having a contact angle with a droplet obtained by mixing 2-propanol and water at a ratio of 1:2 of 80° or more, comprising:
(i) a conductive material having an aspect ratio of les 20, and comprising substantially no crack; and
(ii) a water-repellent substance having a melt viscosity of 10 9 Pa·s or less.

8. The micro-porous layer according to claim 7 , having an average pore size of 200 nm or less.

9. The gas diffusion electrode according to claim 1 , wherein the fibrous carbide does not include carbon nanofiber and milled carbon fiber, and wherein the carbon nanofiber includes a single-walled carbon nanotube, a multi-walled carbon nanotube, and/or a vapor grown carbon fiber.

10. The gas diffusion electrode substrate according to claim 1 , wherein the fibrous carbide is obtained by heat-treating an acrylic resin, a styrene resin, cellulose, starch, or a polylactic acid resin.

11. The gas diffusion electrode substrate according to claim 1 , wherein the fibrous carbide is obtained by heat-treating pulp, rayon fiber, cellulose nano fiber (CNF), or PMMA fiber.

12. The gas diffusion electrode substrate according to claim 1 , wherein the oxygen/carbon element ratio of the whole fibrous carbide is 0.02 or more and 0.05 or less.

13. A fuel battery comprising a micro-porous layer comprising (i) a fibrous carbide having a fiber diameter of 5 nm or more and 10 μm or less and an aspect ratio of 10 or more and (ii) a conductive material,
wherein an oxygen/carbon element ratio of the whole fibrous carbide is 0.02 or more, and wherein the oxygen/carbon element ratio is measured by performing a scanning electron microscope (SEM)-EDX measurement, under the conditions of an acceleration voltage of 10 kV and a magnification of 100,000 times, on a cross section in a thickness direction of the gas diffusion electrode substrate produced by an ion milling device.

Assignees

• Toray Industries

Inventors

• Utsunomiya Masamichi
• Kajiwara Kentaro
• Watanabe Fumitaka
• Tanimura Yasuaki

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/0234

  Carbonaceous material · CPC title

• H01M4/8882

  Heat treatment, e.g. drying, baking · CPC title

• H01M4/8636

  with a gradient in another property than porosity (H01M4/861 takes precedence) · CPC title

• H01M4/8807

  Gas diffusion layers · CPC title