Binder for a secondary battery electrode and use thereof

Patent metadata

Field	Value
Publication number	US-2022013785-A1
Application number	US-201917417744-A
Country	US
Kind code	A1
Filing date	Dec 10, 2019
Priority date	Dec 26, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

A binder is for a secondary battery electrode and exhibits high binding properties in an electrode mixture layer and is capable of exhibiting superior cycle characteristics than before. This binder for a secondary battery electrode includes a cross-linked polymer or salt thereof, and the cross-linked polymer or salt thereof has a sol fraction of 5.0 mass % or more and 40 mass % or less. The cross-linked polymer or salt thereof may contain 50 mass % or more and 100 mass % or less of structural units derived from an ethylenic unsaturated carboxylic acid monomer.

First claim

1 . A binder for a secondary battery electrode, the binder containing a crosslinked polymer or salt thereof, wherein a sol fraction of the crosslinked polymer or salt thereof is 5.0 mass % or more and 40 mass % or less.

2 . The binder for a secondary battery electrode according to claim 1 , wherein the crosslinked polymer or salt thereof contains a structural unit derived from an ethylenically unsaturated carboxylic acid monomer in an amount of 50 mass % or more and 100 mass % or less of the polymer.

3 . The binder for a secondary battery electrode according to claim 1 , wherein when the crosslinked polymer or salt thereof has been neutralized to a degree of neutralization of from 80 to 100 mol %, the particle size thereof as measured in an aqueous medium is a volume-based median diameter of 0.1 μm or more and 10 μm or less.

4 . The binder for a secondary battery electrode according to claim 1 , wherein the crosslinked polymer or salt thereof contains a structural unit derived from a hydroxyl group-containing ethylenically unsaturated monomer in an amount of 0.5 mass % or more and 50 mass % or less of the polymer.

5 . The binder for a secondary battery electrode according to claim 1 , wherein a degree of water swelling of the crosslinked polymer or salt thereof at pH 8 is 3.0 or more and 100 or less.

6 . The binder for a secondary battery electrode according to claim 1 , wherein a weight-average molecular weight of the sol component is not more than 300,000 in terms of polyethylene oxide/polyethylene glycol.

7 . A secondary battery electrode mixture layer composition containing the binder for a secondary battery electrode according to claim 1 together with an active material and water.

8 . A secondary battery electrode comprising an electrode mixture layer containing the binder for a secondary battery electrode according to claim 1 on the surface of a collector.

9 . A secondary battery comprising the secondary battery electrode according to claim 8 .

Assignees

• Toagosei Co Ltd

Inventors

• Nakano Tomoko
• HIGASAYAMA Ayano
• Saito Naohiko

Classifications

• H01M4/622 Primary

  being polymers · CPC title

• C08L9/08

  Latex · CPC title

• C08L33/064 Primary

  containing anhydride, COOH or COOM groups, with M being metal or onium-cation · CPC title

• C08F20/06

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title