Binder for nonaqueous electrolyte secondary battery electrode, manufacturing method therefor and use therefor

Patent metadata

Field	Value
Publication number	US-2017352886-A1
Application number	US-201615532672-A
Country	US
Kind code	A1
Filing date	Oct 26, 2016
Priority date	Oct 30, 2015
Publication date	Dec 7, 2017
Grant date	—

Abstract

Provided is a binder for a nonaqueous electrolyte secondary battery electrode. The binder contains a crosslinked polymer having a carboxyl group, or salt thereof, a use therefor, and a method for manufacturing a carboxyl group-containing crosslinked polymer or salt thereof for use in the binder. The crosslinked polymer contains a structural unit derived from an ethylenically unsaturated carboxylic acid monomer in the amount of 50 to 100 mass % of total structural units, and after the crosslinked polymer neutralized to a degree of a neutralization of 80 to 100 mol % has been subjected to water swelling in water and then dispersed in a 1 mass % NaCl aqueous solution, the particle diameter thereof is 0.1 to 7.0 μm in a volume-based median diameter.

First claim

1 . A binder for a nonaqueous electrolyte secondary battery electrode, the binder comprising a crosslinked polymer having a carboxyl group, or salt thereof, wherein
the crosslinked polymer comprises a structure derived from an ethylenically unsaturated carboxylic acid monomer in an amount of 50 to 100 mass % of total structural units of the crosslinked polymer, and the particle diameter of the crosslinked polymer is 0.1 to 7.0 μm in a volume-based median diameter, when the crosslinked polymer is neutralized to a degree of a neutralization of 80 to 100 mol %, subjected to water swelling in water and then dispersed in a 1 mass % NaCl aqueous solution.

2 . The binder according to claim 1 , wherein the crosslinked polymer is crosslinked with a crosslinkable monomer, and an amount of the crosslinkable monomer used is 0.02 to 0.7 mol % of a total amount of the non-crosslinkable monomers.

3 . The binder according to claim 2 , wherein the crosslinkable monomer is a compound having a plurality of allyl ether groups in the molecule.

4 . The binder according to claim 1 , wherein the crosslinked polymer or salt thereof has a viscosity of 500 mPa·s or less in a 1 mass % aqueous solution and 5,000 mPa·s or more in a 3 mass % aqueous solution.

5 . A method for manufacturing a crosslinked polymer having a carboxyl group, or salt thereof, for use in a binder for a nonaqueous electrolyte secondary battery electrode,
the method comprising polymerizing a monomer composition by precipitation-polymerizing, the monomer composition comprising ethylenically unsaturated carboxylic acid monomers in 50 to 100 mass %, wherein the particle diameter of the crosslinked polymer is 0.1 to 7.0 μm in a volume-based median diameter, when the crosslinked polymer is neutralized to a degree of a neutralization of 80 to 100 mol %, subjected to water swelling in water and then dispersed in a 1 mass % NaCl aqueous solution.

6 . The method according to claim 5 , wherein a polymerization medium containing acetonitrile is used in the polymerizing.

7 . The method according to claim 5 , wherein the degree of neutralization of the ethylenically unsaturated carboxylic acid monomer in the polymerizing is equal to or less than 10 mol %.

8 . The method according to claim 5 , further comprising:
drying following the polymerizing; and neutralizing the polymer following the polymerizing and before the drying, by adding an alkali compound to the polymer dispersion obtained in the polymerizing.

9 . The method according to claim 5 , further comprising: solid-liquid separating; washing; and drying following the polymerizing.

10 . An electrode mixture layer composition for a nonaqueous electrolyte secondary battery, comprising the binder according to claim 1 , an active material, and water.

11 . The electrode mixture layer composition according to claim 10 , further containing a styrene/butadiene latex as a binder.

12 . The electrode mixture layer composition according to claim 10 , comprising either a carbon material or a silicon material as a negative electrode active material.

13 . The electrode mixture layer composition according to claim 10 , comprising a lithium-containing metal oxide as a positive electrode active material.

14 . A nonaqueous electrolyte secondary battery electrode, comprising, on a surface of a collector side, a mixture layer comprising the electrode mixture layer composition according to claim 10 .

Assignees

• Toagosei Co Ltd

Inventors

• Matsuzaki Hideo
• Saito Naohiko
• OGURA Kinuko
• Nishiwaki Atsushi
• SHIBATA Akitsugu

Classifications

• C08F220/06

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

• H01M4/13

  Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof · CPC title

• H01M4/622 Primary

  being polymers · CPC title

• C09D133/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title

• C08J3/14

  by precipitation from solutions {(C08J3/122 takes precedence)} · CPC title