Electrolyte having eutectic mixture of hetero cyclic compound and lithium salt and electrochemical device containing the same

Patent metadata

Field	Value
Publication number	US-9711823-B2
Application number	US-201414268638-A
Country	US
Kind code	B2
Filing date	May 2, 2014
Priority date	Jan 18, 2008
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

An electrolyte includes an eutectic mixture composed of (a) a hetero cyclic compound having a predetermined chemistry figure, and (b) an ionizable lithium salt. An electrochemical device having the electrolyte. The eutectic mixture included in the electrolyte exhibits inherent characteristics of an eutectic mixture such as excellent thermal stability and excellent chemical stability, thereby improving the problems such as evaporation, ignition and side reaction of an electrolyte caused by the usage of existing organic solvents.

First claim

The invention claimed is:

1. An electrolyte, comprising an eutectic mixture comprising:
(a) a hetero cyclic compound selected from the group consisting of imidazole, pyrazole, triazole, pyrimidine, 4-isopropylimidazole, 4-methylimidazole, ethoxypyridine and N-ethylimidazole; and
(b) an ionizable lithium salt,

wherein the eutectic mixture exists in a liquid state at 25° C.

2. The electrolyte according to claim 1 , wherein an anion of the lithium salt is any one selected from the group consisting of F − , Cl − , Br − , I − , NO 3 − , N(CN) 2 − , BF 4 − , ClO 4 − , PF 6 − , (CF 3 ) 2 PF 4 − , (CF 3 ) 3 PF 3 − , (CF 3 ) 4 PF 2 − , (CF 3 ) 5 PF − , (CF 3 ) 6 P − , CF 3 SO 3 − , CF 3 CF 2 SO 3 − , (CF 3 SO 2 ) 2 N − , (FSO 2 ) 2 N − , CF 3 CF 2 (CF 3 ) 2 CO − , (CF 3 SO 2 ) 2 CH − , (SF 5 ) 3 C − , (CF 3 SO 2 ) 3 C − , CF 3 (CF 2 ) 7 SO 3 − , CF 3 CO 2 − , CH 3 CO 2 − , SCN − and (CF 3 CF 2 SO 2 ) 2 N − .

3. The electrolyte according to claim 1 , wherein the eutectic mixture contains the hetero cyclic compound and the lithium salt at a mole ratio of 1˜8:1.

4. The electrolyte according to claim 1 , wherein the eutectic mixture has a viscosity of 2000 cP or less.

5. The electrolyte according to claim 1 , wherein the electrolyte further comprises a lithium salt.

6. The electrolyte according to claim 5 , wherein an anion of the lithium salt is identical to an anion of the ionizable lithium salt in the eutectic mixture.

7. The electrolyte according to claim 5 , wherein a concentration of the lithium salt is more than 0 to 1 M/L or less.

8. The electrolyte according to claim 1 , wherein the electrolyte is a liquid electrolyte, and the amount of the eutectic mixture in the electrolyte is 50 to 100 weight %, based on the total weight of the electrolyte.

9. The electrolyte according to claim 1 , wherein the electrolyte is a polymer electrolyte.

10. The electrolyte according to claim 9 , wherein the polymer electrolyte is a gel-type polymer electrolyte formed by polymerization of (i) the eutectic compound, and (ii) a precursor solution containing a monomer that forms a polymer by polymerization reaction.

11. The electrolyte according to claim 10 , wherein the monomer is a vinyl monomer.

12. The electrolyte according to claim 11 , wherein the vinyl monomer is any one selected from the group consisting of acrylonitrile, methylmethacrylate, methylacrylate, methacrylonitrile, methylstyrene, vinylester, vinyl chloride, vinylidene chloride, acrylamide, tetrafluoroethylene, vinylacetate, methylvinylketone, ethylene, styrene, paramethoxystyrene and paracyanostyrene, or their mixtures.

13. The electrolyte according to claim 10 , wherein a content ratio of the eutectic mixture and the monomer in the precursor solution is 0.5˜0.95:0.05˜0.5.

14. The electrolyte according to claim 10 , wherein the gel-type polymer electrolyte is obtained by in-situ polymerization in an electrochemical device.

15. The electrolyte according to claim 9 , wherein the polymer electrolyte is obtained by impregnating the eutectic mixture in a polymer.

16. The electrolyte according to claim 15 , wherein the polymer is polymethylmethacrylate, polyvinylidene difluoride, polyvinyl chloride, polyethylene oxide, polyhydroxyethylmethacrylate, or a mixture thereof.

17. An electrochemical device, comprising a cathode, an anode and the electrolyte of claim 1 .

18. The electrochemical device according to claim 17 , wherein the electrochemical device is a lithium secondary battery.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Byoung-Bae
• Oh Jae-Seung
• Park Ji-Won
• Choi Shin-Jung
• Park Jae-Duk
• Kim Dong-Su
• Lee Hyo-Jin

Classifications

• Y02E60/13

  Energy storage using capacitors · CPC title

• H01G11/56

  Solid electrolytes, e.g. gels; Additives therein · CPC title

• H01M10/0525

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

• H01M10/052

  Li-accumulators · CPC title

• H01M10/0566

  Liquid materials · CPC title