Binder composition for lithium secondary battery, electrode for lithium secondary battery including the binder composition, and lithium secondary battery including the electrode

Patent metadata

Field	Value
Publication number	US-10340522-B2
Application number	US-201715648646-A
Country	US
Kind code	B2
Filing date	Jul 13, 2017
Priority date	Jul 28, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A binder composition for a lithium secondary battery, an electrode, and a lithium secondary battery, the binder composition including an interpenetrating network structure that includes a cyclic polymer, the cyclic polymer including a repeating unit represented by Formula 1 or a repeating unit represented by Formula 2; and a copolymer, the copolymer including a repeating unit represented by Formula 3 and a repeating unit represented by Formula 4, wherein an amount of the repeating unit represented by Formula 3 is about 40 mol % to about 70 mol %, based on a total amount of the copolymer:

First claim

What is claimed is:

1. A binder composition for a lithium secondary battery, the binder composition comprising an interpenetrating network structure that includes:
a cyclic polymer, the cyclic polymer including a repeating unit represented by Formula 1 or a repeating unit represented by Formula 2; and
a copolymer, the copolymer including a repeating unit represented by Formula 3 and a repeating unit represented by Formula 4,
wherein an amount of the repeating unit represented by Formula 3 is about 40 mol % to about 70 mol %, based on a total amount of the copolymer:

wherein, in Formulae 1 and 2, R 1 , R 2 , R 11 , R 12 , R 14 , and R 15 are each independently a hydrogen atom, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, a substituted or unsubstituted C2-C5 alkynyl group, or —(CH 2 ) p —COOX 1 , in which p is an integer of 1 to 5 and X 1 is an alkali metal,
R 3 , R 13 , and R 16 are each independently —OR 4 , —NHR 5 , or —COOX 2 ,
R 4 is a hydrogen atom, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, a substituted or unsubstituted C2-C5 alkynyl group, or —(CH 2 ) p —COOX 1 , in which p is an integer of 1 to 5 and X 1 is an alkali metal,
R 5 is a hydrogen atom or —COCH 3 ,
X 2 is an alkali metal, and
n and m are each independently an integer of 5 to 20,000,

wherein, in Formula 3, R 6 and R 7 are each independently a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, or a substituted or unsubstituted C2-C5 alkynyl group,

wherein, in Formula 4, R 4 and R 5 are each independently a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, or a substituted or unsubstituted C2-C5 alkynyl group.

2. The binder composition as claimed in claim 1 , wherein a molar ratio of the cyclic polymer and the copolymer is about 1:9 to about 5:5.

3. The binder composition of claim 1 , wherein the copolymer including the repeating unit represented by Formula 3 and the repeating unit represented by Formula 4 is a copolymer represented by Formula 5:

wherein, in Formula 5, n is about 0.4 to about 0.7, and m is about 0.3 to about 0.6.

4. The binder composition as claimed in claim 1 , wherein the cyclic polymer includes a repeating unit represented by one of Formulae 3-1 to 3-6:

wherein, in Formulae 3-1 to 3-6, n1 to n5 and m1 are each independently an integer of 5 to 20,000.

5. The binder composition as claimed in claim 1 , wherein a weight average molecular weight of the copolymer is about 700,000 g/mol to about 900,000 g/mol.

6. The binder composition as claimed in claim 1 , wherein a weight average molecular weight of the cyclic polymer is about 2,000 g/mol to about 2,000,000 g/mol.

7. The binder composition as claimed in claim 1 , wherein a pH of the binder composition is about 6.0 to about 8.0.

8. An electrode for a lithium secondary battery, the electrode comprising:
an electrode active material; and
the binder composition as claimed in claim 1 .

9. The electrode as claimed in claim 8 , wherein the electrode active material includes Si, SiO x , in which 0<x<2, a Si—C composite, a Si-Q alloy, in which Q is an alkali metal, an alkaline-earth metal, an element of Group 13 to Group 16, a transition metal, a rare-earth element, or a combination thereof, but not Si, graphite, or a combination thereof.

10. The electrode as claimed in claim 8 , wherein a molar ratio of the cyclic polymer and the copolymer is about 1:9 to about 5:5.

11. The electrode as claimed in claim 8 , wherein the copolymer including the repeating unit represented by Formula 3 and the repeating unit represented by Formula 4 is a copolymer represented by Formula 5:

wherein, in Formula 5, n is about 0.4 to about 0.7, and m is about 0.3 to about 0.6.

12. The electrode as claimed in claim 8 , wherein the cyclic polymer includes a repeating unit represented by one of Formulae 3-1 to 3-6:

wherein, in Formulae 3-1 to 3-6, n1 to n5 and m1 are each independently an integer of 5 to 20,000.

13. The electrode as claimed in claim 8 , wherein a weight average molecular weight of the copolymer is about 700,000 g/mol to about 900,000 g/mol.

14. The electrode as claimed in claim 8 , wherein a weight average molecular weight of the cyclic polymer is about 2,000 g/mol to about 2,000,000 g/mol.

15. The electrode as claimed in claim 8 , wherein a pH of the binder composition is about 6.0 to about 8.0.

16. A lithium secondary battery, comprising:
a cathode;
an anode; and
an electrolyte,
wherein at least one of the cathode and the anode is the electrode as claimed in claim 8 .

Assignees

• Samsung Sdi Co Ltd
• Aekyung Chemical Co Ltd

Inventors

• Suh Soonsung
• Kwon Seunguk
• Kim Jaehyuk
• Kim Namseon
• Kim Soojung
• Choi Kwangshik

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title

• H01M4/622 Primary

  being polymers · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• C08L1/286

  substituted with acid radicals, e.g. carboxymethyl cellulose [CMC] (C08L1/282 takes precedence) · CPC title