Electrolyte for lithium-sulfur battery and lithium-sulfur battery comprising same

Patent metadata

Field	Value
Publication number	US-10930975-B2
Application number	US-201716082484-A
Country	US
Kind code	B2
Filing date	Feb 14, 2017
Priority date	Jun 28, 2016
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

The present invention relates to a ternary liquid electrolyte for a lithium-sulfur battery and a lithium-sulfur battery including the same.
The liquid electrolyte for a lithium-sulfur battery according to the present invention exhibits an excellent sulfur utilization rate when used in a lithium-sulfur battery, and exhibits excellent stability. Accordingly, the liquid electrolyte for a lithium-sulfur battery according to the present invention is capable of enhancing a life time property while securing a capacity property of a lithium-sulfur battery.

First claim

The invention claimed is:

1. A lithium-sulfur battery comprising a liquid electrolyte, said liquid electrolyte comprising:
a lithium salt; and
a non-aqueous solvent,
wherein the non-aqueous solvent includes consists of a mixture of three solvents:
i) a cyclic ether selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 2,3-dimethyltetrahydrofuran, 2,4-dimethyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, 2-methoxytetrahydrofuran, 3-methoxytetrahydrofuran, 2,5-dimethoxytetrahydrofuran, 2-ethoxytetrahydrofuran, 3-ethoxytetrahydrofuran, tetrahydropyran, 2-methyltetrahydropyran, 3-methyltetrahydropyran, and 4-methyltetrahydropyran;
ii) a glycol ether selected from the group consisting of 1,2-dimethoxyethane, ethylene glycol diethyl ether, ethylene glycol ethylmethyl ether, ethylene glycol dipropyl ether, ethylene glycol ethylmethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, and tetraethylene glycol diethyl ether; and
iii) a linear ether selected from the group consisting of dimethyl ether, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, dipentylether, dihexyl ether, ethylmethyl ether, methylpropyl ether, butylmethyl ether, ethylpropyl ether, butylpropyl ether, phenylmethyl ether, diphenylether, dibenzyl ether, ethylene glycol ethylmethyl ether, ethylene glycol diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, and diisobutyl ether,
wherein the glycol ether is different from the linear ether,
wherein the cyclic ether is present in an amount less than 50% by volume of the non-aqueous solvent;
and wherein the electrolyte does not comprise any additional solvents.

2. The lithium-sulfur battery of claim 1 , wherein the cyclic ether is present in an amount of 10% by volume to 40% by volume of the non-aqueous solvent.

3. The lithium-sulfur battery of claim 1 , wherein the cyclic ether is tetrahydropyran.

4. The lithium-sulfur battery of claim 1 , wherein the glycol ether is one type selected from the group consisting of 1,2-dimethoxyethane, ethylene glycol ethylmethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether.

5. The lithium-sulfur battery of claim 1 , wherein the linear ether is one type selected from the group consisting of ethylene glycol ethylmethyl ether, ethylene glycol diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether and diisobutyl ether.

6. The lithium-sulfur battery of claim 1 , wherein the cyclic ether is included in 10% by volume to less than 50% by volume of a total weight of the non-aqueous solvent.

7. The lithium-sulfur battery of claim 1 , wherein the glycol ether and the linear ether are included in a volume ratio of 1:3 to 3:1.

8. The lithium-sulfur battery of claim 1 , wherein the lithium salt includes one type selected from the group consisting of LiCl, LiBr, LiI, LiClO 4 , LiBF 4 , LiB 10 Cl 10 , LiPF 6 , LiCF 3 SO 3 , LiCF 3 CO 2 , LiC 4 BO 8 , LiAsF 6 , LiSbF 6 , LiAlCl 4 , CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2 ) 2 NLi, (C 2 F 5 SO 2 ) 2 NLi, (SO 2 F) 2 NLi, (CF 3 SO 2 ) 3 CLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenylborate, lithium imide and combinations thereof.

9. The lithium-sulfur battery of claim 1 , wherein the lithium salt is included in a concentration of 0.1 M to 4.0 M.

10. The lithium-sulfur battery of claim 1 , further comprising an additive having N—O bonds in a molecule.

11. The lithium-sulfur battery of claim 10 , wherein the additive is one or more types selected from the group consisting of lithium nitrate, potassium nitrate, cesium nitrate, barium nitrate, ammonium nitrate, lithium nitrite, potassium nitrite, cesium nitrite, ammonium nitrite, methyl nitrate, dialkyl imidazolium nitrate, guanidine nitrate, imidazolium nitrate, pyridinium nitrate, ethyl nitrite, propyl nitrite, butyl nitrite, pentyl nitrite, octyl nitrite, nitromethane, nitropropane, nitrobutane, nitrobenzene, dinitrobenzene, nitro pyridine, dinitropyridine, nitrotoluene, dinitrotoluene, pyridine N-oxide, alkylpyridine N-oxide and tetramethylpiperidinyloxyl.

12. The lithium-sulfur battery of claim 10 , wherein the additive is included in an amount of 0.01% by weight to 10% by weight with respect to 100% by weight of the liquid electrolyte.

13. The lithium-sulfur battery of claim 1 , wherein the liquid electrolyte suppresses gas generation.

14. The lithium-sulfur battery of claim 1 , wherein the volume ratio of the cyclic ether to the glycol ether to the linear ether is from 1:1:1 to 1:2:2.

15. The lithium-sulfur battery of claim 1 , wherein the non-aqueous solvent of the liquid electrolyte includes tetrahydrofuran as the cyclic ether, 1,2-dimethoxyethane as the glycol ether, and ethylene glycol ethylmethyl ether as the linear ether.

16. The lithium-sulfur battery of claim 1 , wherein the non-aqueous solvent of the liquid electrolyte includes tetrahydrofuran as the cyclic ether, 1,2-dimethoxyethane as the glycol ether, and dipropyl ether as the linear ether.

17. The lithium-sulfur battery of claim 1 , wherein the non-aqueous solvent of the liquid electrolyte includes tetrahydrofuran as the cyclic ether, ethylene glycol ethylmethyl ether as the glycol ether, and ethylene glycol diethyl ether as the linear ether.

18. The lithium-sulfur battery of claim 1 , wherein the non-aqueous solvent of the liquid electrolyte includes tetrahydrofuran as the cyclic ether, ethylene glycol ethylmethyl ether as the glycol ether, and dipropyl ether as the linear ether.

19. The lithium-sulfur battery of claim 1 , wherein the non-aqueous solvent of the liquid electrolyte includes tetrahydrofuran as the cyclic ether, ethylene glycol ethylmethyl ether as the glycol ether, and diisobutyl ether as the linear ether.

Assignees

• Lg Chemical Ltd

Inventors

• Park Intae
• Hong Sungwon
• Song Charles Kiseok
• Ohk Youhwa
• Yang Doo Kyung
• Lee Changhoon

Classifications

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/38

  of elements or alloys · CPC title

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M10/0568

  characterised by the solutes · CPC title