Acrylic binder for lithium-sulfur secondary battery cathode

Patent metadata

Field	Value
Publication number	US-10586987-B2
Application number	US-201615571308-A
Country	US
Kind code	B2
Filing date	Oct 26, 2016
Priority date	Oct 29, 2015
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

The present invention relates to a binder for a lithium-sulfur secondary battery cathode, and a composition containing the same. The binder of the present application enables a cathode active material electrolyte to have excellent resistance.

First claim

The invention claimed is:

1. An acrylic binder for a lithium-sulfur secondary battery cathode, comprising a polymerized units of a polymerizable monomer having a polar functional group interacting with a cathode active material,
wherein the polar functional group comprises an alkylene oxide group, and optionally further comprises at least one selected from the group consisting of a nitrogen-containing functional group, a hydroxy group and an alkoxysilyl group.

2. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 1 ,
wherein the polymerizable monomer having a polar functional group is contained in the polymerized unit in an amount of 30 to 100 parts by weight.

3. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 1 ,
further comprising a polymerized unit of alkyl (meth)acrylate.

4. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 3 ,
wherein the alkyl (meth)acrylate is contained in the polymerized unit in an amount of 5 to 30 parts by weight.

5. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 1 ,
having a particle diameter of 10 nm or less.

6. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 1 ,
having a glass transition temperature in a range of −80° C. to 50° C.

7. The acrylic binder for a lithium-sulfur secondary battery cathode according to claim 1 ,
having a weight average molecular weight in a range of 5,000 to 3,000,000.

8. A composition for forming a cathode active layer of a lithium-sulfur secondary battery comprising the acrylic binder according to claim 1 , a cathode active material and a conductive material.

9. The composition for forming a cathode active layer of a lithium-sulfur secondary battery according to claim 8 ,
wherein the acrylic binder is contained in an amount of 0.01 to 10 parts by weight, relative to 100 parts by weight of a solid content of the composition.

10. The composition for forming a cathode active layer of a lithium-sulfur secondary battery according to claim 8 ,
wherein the cathode active material is a sulfur-carbon composite.

11. The composition for forming a cathode active layer of a lithium-sulfur secondary battery according to claim 8 ,
wherein the cathode active material is contained in an amount of 30 to 95 parts by weight, relative to 100 parts by weight of a solid content of the composition.

12. The composition for forming a cathode active layer of a lithium-sulfur secondary battery according to claim 8 ,
further comprising a non-acrylic binder.

13. The composition for forming a cathode active layer of a lithium-sulfur secondary battery according to claim 8 ,
wherein the conductive material is contained in an amount of 2 to 70 parts by weight, relative to 100 parts by weight of a solid content of the composition.

14. A cathode for a lithium-sulfur secondary battery having:
a current collector; and
an active layer formed on the current collector and comprising the acrylic binder according to claim 1 .

15. The cathode for a lithium-sulfur secondary battery according to claim 14 , wherein the active layer has a thickness in a range of 1 to 200 μm.

16. A lithium-sulfur secondary battery comprising the cathode of claim 14 .

17. The cathode for a lithium-sulfur secondary battery according to claim 14 , wherein a cathode active material has a compound comprising a sulfur element.

18. The cathode for a lithium-sulfur secondary battery according to claim 17 , wherein the cathode active material is a sulfur-carbon composite.

19. The cathode for a lithium-sulfur secondary battery according to claim 17 , wherein the polar functional group of the acrylic binder interacts with the sulfur element.

Assignees

• Lg Chemical Ltd

Inventors

• Yoon Jeong Ae
• Song Charles Kiseok
• Kwon Ki Young
• Yoon Sung Soo
• Chi Han Na
• Yang Doo Kyung

Classifications

• H01M10/052

  Li-accumulators · CPC title

• H01M4/621

  Binders · CPC title

• H01M10/0525

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

• C08F22/1006

  of polyhydric alcohols or polyhydric phenols, e.g. ethylene glycol dimethacrylate · CPC title

• H01M10/056

  characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes · CPC title