Electrolyte and secondary lithium battery

Patent metadata

Field	Value
Publication number	US-2019267671-A1
Application number	US-201916410938-A
Country	US
Kind code	A1
Filing date	May 13, 2019
Priority date	Nov 29, 2016
Publication date	Aug 29, 2019
Grant date	—

Abstract

The present disclosure provides an electrolyte and a secondary lithium battery. The electrolyte comprises a lithium salt, an organic solvent and an additive. The additive comprises fluoroborate and lithium difluorophosphate. When the electrolyte of the present disclosure is applied to the secondary lithium battery, the secondary lithium battery can have excellent high temperature cycle performance, high temperature storage performance, low temperature discharge performance and large rate charging performance at the same time, and low temperature lithium precipitation of the secondary lithium battery can be significantly inhibited.

First claim

What is claimed is:

1 . An electrolyte, comprising:
a lithium salt; an organic solvent; and an additive; wherein, the additive comprises fluoroborate and lithium difluorophosphate.

2 . The electrolyte according to claim 1 , wherein fluoroborate is one or more selected from a group consisting of compounds represented by formula 1;

Where, R 1 , R 2 and R 3 each independently are one selected from a group consisting of C1˜C20 alkyl group and C6˜C16 aryl group, and at least one of R 1 , R 2 and R 3 makes a hydrogen atom substituted with a fluorine atom.

3 . The electrolyte according to claim 2 , wherein
the C1˜C20 alkyl group is one selected from a group consisting of methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neo-pentyl group, cyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, heptyl group, cycloheptyl group, octyl group, cyclooctyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group and eicosyl group; the C6˜C16 aryl group is one selected from a group consisting of phenyl group, benzyl group, biphenylyl group, p-methylphenyl group, o-methylphenyl group, m-methylphenyl group, p-ethylphenyl group, m-ethylphenyl group, o-ethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,5-diethylphenyl group, 2,6-diethylphenyl group, 3,5-diisopropylphenyl, 2,6-diisopropylphenyl, 3,5-di-n-propyl phenyl group, 2,6-di-n-propyl phenyl group, 3,5-dibutylphenyl group, 2,6-dibutylphenyl group, 3,5-diisobutylphenyl group, 2,6-diisobutylphenyl group, 3,5-di-tert-butylphenyl group, 2,6-di-tert-butylphenyl group, triphenylmethyl group, 1-naphthyl group and 2-naphthyl group.

4 . The electrolyte according to claim 2 , wherein each of R 1 , R 2 and R 3 makes the hydrogen atom substituted with the fluorine atom.

5 . The electrolyte according to claim 2 , wherein R 1 , R 2 and R 3 are the same.

6 . The electrolyte according to claim 4 , wherein R 1 , R 2 and R 3 are the same

7 . The electrolyte according to claim 4 , wherein fluoroborate is one or more selected from a group consisting of tris(2,2,2-trifluoroethyl) borate, tris(2,2,3,3-tetrafluoropropyl) borate, tris(hexafluoroisopropyl) borate and tris(pentafluorophenyl) borate.

8 . The electrolyte according to claim 1 , wherein
a content of lithium difluorophosphate is 0.1%˜3% of a total mass of the electrolyte; a content of fluoroborate is 0.01%˜5% of the total mass of the electrolyte.

9 . The electrolyte according to claim 1 , wherein the lithium salt is one or more selected from a group consisting of LiPF6, LiBF4, LiClO4, LiAsF6, LiTFSI, LiTFS, LiFSI, LiDFOB and LiBOB.

10 . The electrolyte according to claim 1 , wherein the organic solvent is one or more selected from a group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, ethyl acetate, ethyl propionate, propyl propionate, dimethyl sulfoxide, tetramethylene sulfone, methyl sulfonyl mathane and tetrahydrofuran.

11 . A secondary lithium battery, comprising an electrolyte,
wherein, the electrolyte comprises a lithium salt, an organic solvent and an additive, the additive comprises fluoroborate and lithium difluorophosphate.

12 . The secondary lithium battery according to claim 11 , wherein fluoroborate is one or more selected from a group consisting of compounds represented by formula 1;

Where, R 1 , R 2 and R 3 each independently are one selected from a group consisting of C1˜C20 alkyl group and C6˜C16 aryl group, and at least one of R 1 , R 2 and R 3 makes a hydrogen atom substituted with a fluorine atom.

13 . The secondary lithium battery according to claim 12 , wherein
the C1˜C20 alkyl group is one selected from a group consisting of methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neo-pentyl group, cyclopentyl group, n-hexyl group, isohexyl group, cyclohexyl group, heptyl group, cycloheptyl group, octyl group, cyclooctyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group and eicosyl group; the C6˜C16 aryl group is one selected from a group consisting of phenyl group, benzyl group, biphenylyl group, p-methylphenyl group, o-methylphenyl group, m-methylphenyl group, p-ethylphenyl group, m-ethylphenyl group, o-ethylphenyl group, 3,5-dimethylphenyl group, 2,6-dimethylphenyl group, 3,5-diethylphenyl group, 2,6-diethylphenyl group, 3,5-diisopropylphenyl, 2,6-diisopropylphenyl, 3,5-di-n-propyl phenyl group, 2,6-di-n-propyl phenyl group, 3,5-dibutylphenyl group, 2,6-dibutylphenyl group, 3,5-diisobutylphenyl group, 2,6-diisobutylphenyl group, 3,5-di-tert-butylphenyl group, 2,6-di-tert-butylphenyl group, triphenylmethyl group, 1-naphthyl group and 2-naphthyl group.

14 . The secondary lithium battery according to claim 12 , wherein each of R 1 , R 2 and R 3 makes the hydrogen atom substituted with the fluorine atom.

15 . The secondary lithium battery according to claim 12 , wherein R 1 , R 2 and R 3 are the same.

16 . The secondary lithium battery according to claim 14 , wherein R 1 , R 2 and R 3 are the same.

17 . The secondary lithium battery according to claim 14 , wherein fluoroborate is one or more selected from a group consisting of tris(2,2,2-trifluoroethyl) borate, tris(2,2,3,3-tetrafluoropropyl) borate, tris(hexafluoroisopropyl) borate and tris(pentafluorophenyl) borate.

18 . The secondary lithium battery according to claim 11 , wherein
a content of lithium difluorophosphate is 0.1%˜3% of a total mass of the electrolyte; a content of fluoroborate is 0.01%˜5% of the total mass of the electrolyte.

19 . The secondary lithium battery according to claim 11 , wherein the lithium salt is one or more selected from a group consisting of LiPF6, LiBF4, LiClO4, LiAsF6, LiTFSI, LiTFS, LiFSI, LiDFOB and LiBOB.

20 . The secondary lithium battery according to claim 11 , wherein the organic solvent is one or more selected from a group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, γ-butyrolactone, methyl formate, ethyl formate, ethyl acetate, ethyl propionate, propyl propionate, dimethyl sulfoxide, tetramethylene sulfone, methyl sulfonyl mathane and tetrahydrofuran.

Assignees

• Contemporary Amperex Technology Co Ltd

Inventors

• Zhang Ming
• Han Changlong
• Zhang Cui
• Zhou Xiaochong
• Ju Feng

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M2300/0025

  Organic electrolyte · 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

• Y02E60/10

  Energy storage using batteries · CPC title