Gel polymer electrolyte and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-10276893-B2
Application number	US-201515516146-A
Country	US
Kind code	B2
Filing date	Oct 1, 2015
Priority date	Oct 2, 2014
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

The present invention relates to a composition for a gel polymer electrolyte comprising a liquid electrolyte solvent, a lithium salt, a polymerization initiator, and a mixed compound of a first compound and a second compound, and a lithium secondary battery comprising a positive electrode, a negative electrode, a separator, and a gel polymer electrolyte, wherein the gel polymer electrolyte is formed by polymerizing the composition for a gel polymer electrolyte. By comprising a mixed compound of a first compound and a second compound in which the first compound is an amine-based compound comprising polyethylene glycol as a functional group and the second compound is an epoxy-based compound, a composition for a gel polymer electrolyte of the present invention exhibits, when used in a lithium secondary battery, enhanced battery lifespan, excellent high temperature storability, and enhanced battery capacity property by readily inducing a hopping phenomenon.

First claim

What is claimed is:

1. A composition for a gel polymer electrolyte comprising a liquid electrolyte solvent, a lithium salt, a polymerization initiator; and a mixed compound of a first compound and a second compound,
wherein the first compound is an amine-based compound comprising polyethylene glycol as a functional group, and
wherein the second compound is an epoxy-based compound.

2. The composition for a gel polymer electrolyte of claim 1 , wherein the mixed compound is comprised in an amount of 0.1% by weight to 10% by weight with respect to a total weight of the composition.

3. The composition for a gel polymer electrolyte of claim 1 , wherein a weight ratio of the first compound and the second compound is 1:0.2 to 1:0.6.

4. The composition for a gel polymer electrolyte of claim 1 , wherein the lithium salt is any one selected from the group consisting of LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiClO 4 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , CF 3 SO 3 Li, LiC(CF 3 SO 2 ) 3 and LiC 4 BO 8 , or a mixture of two or more thereof.

5. The composition for a gel polymer electrolyte of claim 1 , wherein the liquid electrolyte solvent is linear carbonate, cyclic carbonate or a combination thereof.

6. The composition for a gel polymer electrolyte of claim 5 , wherein the linear carbonate comprises any one selected from the group consisting of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, ethylmethyl carbonate, methylpropyl carbonate and ethylpropyl carbonate, or a mixture of two or more types thereof, and the cyclic carbonate comprises any one selected from the group consisting of ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, vinylene carbonate, and halides thereof, or a mixture of two or more types thereof.

7. The composition for a gel polymer electrolyte of claim 1 , wherein the polymerization initiator is one or more types selected from the group consisting of organic peroxides such as benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, t-butyl peroxy-2-ethyl-hexanoate, cumyl hydroperoxide and hydrogen peroxide; hydroperoxides; and azo compounds such as 2,2′-azobis(2-cyanobutane), 2,2′-azobis(methylbutyronitrile), 2,2′-azobis(iso-butyronitrile) (AIBN) and 2,2′-azobisdimethyl-valeronitrile (AMVN).

8. A lithium secondary battery comprising a positive electrode; a negative electrode; a separator; and a gel polymer electrolyte,
wherein the gel polymer electrolyte is formed by polymerizing the composition for a gel polymer electrolyte of claim 1 .

9. The lithium secondary battery of claim 8 , wherein the gel polymer electrolyte comprises oligomers represented by the following Chemical Formulae 1 and 2:

wherein, n and m are each an integer of 1 to 20, R 1 to R 5 are each independently hydrogen or —CO(CH 2 ) 3 COO—(CH 2 CH 2 O)x-CH 3 , x is an integer of 1 to 100, and at least 3 or more of R 1 to R 5 are —CO(CH 2 ) 3 COO—(CH 2 CH 2 O) x —CH 3 ;

Wherein, a is an integer of 1 to 100.

10. The lithium secondary battery of claim 8 , which has a charging voltage of 3.0 V to 5.0 V.

11. The lithium secondary battery of claim 8 , wherein the positive electrode comprises a positive electrode active material, and the positive electrode active material is any one selected from the group consisting of LiCoO 2 , LiNiO 2 , LiMnO 2 , LiMn 2 O 4 , LiNi 1-y Co y O 2 (O=y<1), LiCo 1-y Mn y O 2 (O=y<1), LiNi 1-y Mn y O 2 (O=y<1), and Li[Ni a Co b Mn c ]O 2 (0<a, b, c=1, a+b+c=1), or a mixture of two or more thereof.

Assignees

• Lg Chemical Ltd

Inventors

• Park Sol Ji
• Ahn Kyoung Ho
• Oh Jeong Woo
• Lee Chul Haeng
• Jung Yi Jin

Classifications

• H01M2300/0085

  Immobilising or gelification of electrolyte · CPC title

• H01M10/052

  Li-accumulators · CPC title

• C08G2220/00

  Compositions for preparing gels other than hydrogels, aerogels and xerogels · CPC title

• H01M10/0565 Primary

  Polymeric materials, e.g. gel-type or solid-type · CPC title

• H01M10/0525

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