Air electrode, metal-air battery, and method for manufacturing air electrode

Patent metadata

Field	Value
Publication number	US-2020014035-A1
Application number	US-201916446302-A
Country	US
Kind code	A1
Filing date	Jun 19, 2019
Priority date	Jul 3, 2018
Publication date	Jan 9, 2020
Grant date	—

Abstract

An air electrode, when disposed in a metal-air battery, capable of maintaining the output of the metal-air battery to a desired value or more and a method for manufacturing the air electrode are provided. The air electrode includes a porous water repellent layer and a catalyst layer being in contact with the water repellent layer. The rate of hole area in a surface of the water repellent layer is 30 area % or more and less than 45 area %. The contact angle with water of the water repellent layer is 100 degrees or more and 120 degrees or less. The method for manufacturing the air electrode includes a water repellent layer-forming step of stretching a water repellent layer-forming material to form the water repellent layer, and a press-bonding step of press-bonding the water repellent layer and the catalyst layer.

First claim

What is claimed is:

1 . An air electrode comprising:
a porous water repellent layer; and a catalyst layer being in contact with the water repellent layer, wherein the water repellent layer has a surface having a rate of hole area of 30 area % or more and less than 45 area %; and the water repellent layer has a contact angle with water of 100 degrees or more and 120 degrees or less.

2 . The air electrode according to claim 1 , wherein
a number-average hole diameter in the surface of the water repellent layer is 250 nm or less.

3 . The air electrode according to claim 1 , wherein
a maximum hole diameter in the surface of the water repellent layer is 500 nm or less.

4 . The air electrode according to claim 1 , wherein
the water repellent layer contains at least one selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, perfluoroalkoxy fluororesins, and poly (vinylidene fluoride).

5 . The air electrode according to claim 1 , further comprising:
a current collector, wherein the current collector is in contact with a surface of the catalyst layer on the opposite side of the surface of the catalyst layer being in contact with the water repellent layer.

6 . A metal-air battery comprising:
the air electrode according to claim 1 ; a metal electrode; and an electrolyte.

7 . A method for manufacturing the air electrode according to claim 1 , the method comprising:
stretching a water repellent layer-forming material to form a water repellent layer; and press-bonding the water repellent layer and a catalyst layer.

8 . The method for manufacturing the air electrode according to claim 7 , wherein
the water repellent layer is formed so as to have a large number of holes by stretching the water repellent layer-forming material in such a manner that a rate of hole area in a surface of the water repellent layer is 40 area % or more.

9 . The method for manufacturing the air electrode, wherein
a pressure is applied to the water repellent layer in the press-bonding to decrease and adjust a rate of hole area in a surface of the water repellent layer to 30 area % or more and less than 45 area %, where a decreasing rate A of the rate of hole area in the surface of the water repellent layer is 20.0% or more when calculated by the following expression (1):
A −100×( A 1 −A 2 )/ A 1   (1)

where, A 1 represents the rate of hole area in the surface of the water repellent layer before the press-bonding; and A 2 represents the rate of hole area in the surface of the water repellent layer after the press-bonding.

Assignees

• Sharp Kk

Inventors

• Mitamura Keigo

Classifications

• H01M4/8657 Primary

  layered · CPC title

• H01M4/8605

  Porous electrodes · CPC title

• H01M12/065

  with plate-like electrodes or stacks of plate-like electrodes · CPC title

• H01M4/8896

  Pressing, rolling, calendering (membrane electrode assemblies H01M8/1004) · CPC title

• H01M4/8892

  Impregnation or coating of the catalyst layer, e.g. by an ionomer · CPC title