Electrode for lithium secondary battery, method for preparing same, electrode assembly for lithium secondary battery comprising same, and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-10418633-B2
Application number	US-201615543387-A
Country	US
Kind code	B2
Filing date	Jun 22, 2016
Priority date	Jun 22, 2015
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

The present invention relates to an electrode for a lithium secondary battery, a method for preparing the same, an electrode assembly for a lithium secondary battery comprising the same, and a lithium secondary battery comprising the same, wherein the electrode comprises an electrode active material, an aqueous binder, a compound represented by Formula 1, and a compound represented by Formula 2. Formula 1 and Formula 2 are the same as set forth in the specification. The electrode for a lithium secondary battery improves the physical properties of the aqueous binder in a manner whereby a cross-linking reaction material is combined with the aqueous binder, so that the electrode can improve initial charge/discharge efficiency and the life span of a lithium secondary battery, preferably a lithium sulfur battery, and improve the area capacity of the electrode.

First claim

The invention claimed is:

1. An electrode for a lithium secondary battery, which comprises an electrode active material, an aqueous binder, a compound represented by the following Formula 1 and a compound represented by the following Formula 2:

wherein, in Formula 1 and 2,
R 1 to R 3 are each independently one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms and a halogen atom,
R 4 is one selected from the group consisting of N(R 7 ) 2 , R 8 SH, R 8 Si(OR 7 ) 3 and an alkyl group having 1 to 3 carbon atoms,
R 5 to R 7 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,
R 8 is an alkylene group having 1 to 3 carbon atoms, and
n is an integer selected from 1 to 6.

2. The electrode for a lithium secondary battery of claim 1 , wherein one compound selected from the group consisting of the compound represented by Formula 1, the compound represented by Formula 2 and combinations thereof is a cross-linker which crosslinks the aqueous binder.

3. The electrode for a lithium secondary battery of claim 1 , wherein the compound represented by Formula 1 and the compound represented by Formula 2 are chemically combined to form a compound represented by the following Formula 3:

wherein, in Formula 3,
R 1 to R 3 are each independently one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms and a halogen atom,
R 4 is one selected from the group consisting of N(R 7 ) 2 , R 8 SH, R 8 Si(OR 7 ) 3 and an alkyl group having 1 to 3 carbon atoms,
R 5 to R 7 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,
R 8 is an alkylene group having 1 to 3 carbon atoms, and
n is an integer selected from 1 to 6.

4. The electrode for a lithium secondary battery of claim 1 , wherein, in Formula 1 and 2, all of R 1 to R 3 are an alkoxy group having 1 to 3 carbon atoms and R 4 is one selected from the group consisting of N(R 7 ) 2 , R 8 SH and R 8 Si(OR 7 ) 3 .

5. The electrode for a lithium secondary battery of claim 1 , wherein the aqueous binder is one selected from the group consisting of carboxymethyl cellulose (CMC), alginate, carbonyl-β-cyclodextrine and nafion.

6. The electrode for a lithium secondary battery of claim 1 , wherein the electrode for a lithium secondary battery comprises 0.1 to 40% by weight of the aqueous binder, 0.1 to 20% by weight of the compound represented by Formula 1 and the compound represented by Formula 2 and the remaining content of the electrode active material, based on a total weight of the electrode.

7. The electrode for a lithium secondary battery of claim 1 , wherein the electrode for a lithium secondary battery is a positive electrode.

8. The electrode for a lithium secondary battery of claim 7 , wherein the lithium secondary battery is a lithium sulfur battery, and the positive electrode active material is one selected from the group consisting of elemental sulfur (S 8 ), a sulfur-based compound and mixtures thereof.

9. The electrode for a lithium secondary battery of claim 1 , wherein R 4 in Formula 2 is R 8 SH.

10. The electrode for a lithium secondary battery of claim 3 , wherein R 4 in Formula 3 is R 8 SH.

11. A method for preparing an electrode for a lithium secondary battery, which comprises the steps of
mixing an electrode active material, an aqueous binder, a compound represented by the following Formula 1 and a compound represented by the following Formula 2 to prepare a slurry for forming an electrode, and
coating at least one side of a current collector by the slurry for forming an electrode to prepare the electrode:

wherein, in Formula 1 and 2,
R 1 to R 3 are each independently one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms and a halogen atom,
R 4 is one selected from the group consisting of N(R 7 ) 2 , R 8 SH, R 8 Si(OR 7 ) 3 and an alkyl group having 1 to 3 carbon atoms,
R 5 to R 7 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,
R 8 is an alkylene group having 1 to 3 carbon atoms, and
n is an integer selected from 1 to 6.

12. The method for preparing an electrode for a lithium secondary battery of claim 11 , wherein the compound represented by Formula 1 and the compound represented by Formula 2 are chemically combined to form a compound represented by the following Formula 3:

wherein, in Formula 3,
R 1 to R 3 are each independently one selected from the group consisting of an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms and a halogen atom,
R 4 is one selected from the group consisting of N(R 7 ) 2 , R 8 SH, R 8 Si(OR 7 ) 3 and an alkyl group having 1 to 3 carbon atoms,
R 5 to R 7 are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,
R 8 is an alkylene group having 1 to 3 carbon atoms, and
n is an integer selected from 1 to 6.

13. The method for preparing an electrode for a lithium secondary battery of claim 11 , wherein the step of preparing the slurry for forming an electrode comprises: mixing the aqueous binder, the compound represented by Formula 1 and the compound represented by Formula 2 and then mixing with the electrode active material.

14. An electrode assembly for a lithium secondary battery, which has a positive electrode and a negative electrode which are alternately laminated using a separator as a boundary, and at least one among the positive electrode and the negative electrode are the electrode for a lithium secondary battery according to claim 1 .

15. The method for preparing an electrode for a lithium secondary battery of claim 11 , wherein R 4 in Formula 2 is R 8 SH.

16. The method for preparing an electrode for a lithium secondary battery of claim 12 , wherein R 4 in Formula 3 is R 8 SH.

Assignees

• Lg Chemical Ltd

Inventors

• Song Charles Kiseok
• Jung Byoung Hyo
• Park Seong Eun
• Yang Doo Kyung
• Kwon Ki Young

Classifications

• H01M4/621 Primary

  Binders · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/38

  of elements or alloys · CPC title

• C01B17/00

  Sulfur; Compounds thereof · CPC title

• H01M12/06

  with one metallic and one gaseous electrode · CPC title