Binder for lithium ion secondary battery electrode, production method for lithium ion secondary battery electrode, lithium ion secondary battery electrode, and lithium ion secondary battery
View Patent ↗The present invention provides a binder for a lithium ion secondary battery electrode that has good adhesive properties and a low degree of swelling with respect to an electrolytic solution. There is used a binder for a lithium ion secondary battery electrode, which comprises a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3): (R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms), and (R2 is a functional group containing an ethylenically unsaturated bond).
1. A binder for a lithium ion secondary battery electrode, which comprises a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3):
wherein R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and
wherein R2 is a functional group containing an ethylenically unsaturated bond.
2. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the degree of acetalization of the structural unit represented by the formula (2) is from 10 to 40% by mol.
3. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the degree of crosslinking group modification of the structural unit represented by the formula (3) is from 0.1 to 15% by mol.
4. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein, in the polyvinyl acetal-based resin (A), the content of the structural unit represented by the formula (1) is from 45 to 89.9% by mol.
5. The binder for a lithium ion secondary battery electrode according to claim 1 , wherein the average degree of polymerization of the polyvinyl acetal-based resin (A) is 1,500 or more.
6. The binder for a lithium ion secondary battery electrode according to claim 1 , which contains a solvent (B).
7. The binder for a lithium ion secondary battery electrode according to claim 1 , which contains a polymerization initiator (C).
8. A method for producing a lithium ion secondary battery electrode, which comprises forming an electrode on a collector using the binder for a lithium ion secondary battery electrode according to claim 1 and crosslinking the polyvinyl acetal-based resin (A) by heat or light.
9. A lithium ion secondary battery electrode comprising the binder for a lithium ion secondary battery electrode according to claim 1 and an active material.
10. The lithium ion secondary battery electrode according to claim 9 , wherein the polyvinyl acetal-based resin (A) contained in the binder for a lithium ion secondary battery electrode is from 0.1 to 10 parts by weight based on 100 parts by weight of the active material.
11. A lithium ion secondary battery electrode comprising a crosslinked product of a polyvinyl acetal-based resin (A) containing structural units represented by chemical formulae (1) to (3):
wherein R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and
wherein R2 is a functional group containing an ethylenically unsaturated bond.
12. A lithium ion secondary battery having the lithium ion secondary battery electrode according to claim 9 .
13. A lithium ion secondary battery having the lithium ion secondary battery electrode according to claim 11 .