Electrolyte for lithium secondary battery, and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11539075-B2
Application number	US-201816629297-A
Country	US
Kind code	B2
Filing date	Apr 5, 2018
Priority date	Jul 21, 2017
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

Disclosed are an electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same. The electrolyte for a lithium secondary battery, according to an embodiment, can comprise: a nonaqueous organic solvent; a lithium salt; a first additive comprising a compound represented by a specific chemical formula; and a second additive including at least one of lithium difluorophosphate (LiPO2F2), a cyclic carbonate including a fluorine atom, and a dinitrile compound.

First claim

The invention claimed is:

1. An electrolyte for a lithium secondary battery comprising
a non-aqueous organic solvent;
a lithium salt;
a first additive including compound represented by Chemical Formula 1; and
a second additive comprising at least one of lithium difluorophosphate (LiPO 2 F 2 ), a cyclic carbonate including a fluorine atom, and a dinitrile compound,

wherein, in Chemical Formula 1, A is a substituted or unsubstituted aliphatic chain or (—C 2 H 4 —O—C 2 H 4 —)n and n is an integer of 1 to 10.

2. The electrolyte of claim 1 , wherein in Chemical Formula 1, A is a C2 to C20 hydrocarbon chain or (—C 2 H 4 —O—C 2 H 4 —)n and n is an integer of 1 to 5.

3. The electrolyte of claim 1 , wherein the compound represented by Chemical Formula 1 is a compound represented by Chemical Formula 1-1:

4. The electrolyte of claim 1 , wherein the cyclic carbonate including the fluorine atom is fluorinated ethylene carbonate (FEC).

5. The electrolyte of claim 1 , wherein the dinitrile compound is succinonitrile.

6. The electrolyte of claim 1 , wherein an amount of the first additive is 0.1 wt % to 2 wt % based on a total amount of the electrolyte for the lithium secondary battery.

7. The electrolyte of claim 1 , wherein an amount of the second additive is 0.1 wt % to 20 wt % based on a total amount of the electrolyte for the lithium secondary battery.

8. The electrolyte of claim 1 , wherein an amount of the lithium difluorophosphate (LiPO 2 F 2 ) is 0.1 wt % to 2 wt % based on a total amount of the electrolyte for the lithium secondary battery.

9. The electrolyte of claim 1 , wherein an amount of the cyclic carbonate including the fluorine atom is 0.1 wt % to 20 wt % based on a total amount of the electrolyte for the lithium secondary battery.

10. The electrolyte of claim 1 , wherein an amount of the dinitrile compound is 0.1 wt % to 5 wt % based on a total amount of the electrolyte for the lithium secondary battery.

11. The electrolyte of claim 1 , wherein an amount ratio of the first additive and the second additive, in a weight ratio, ranges from 0.1:1 to 1:1.

12. The electrolyte of claim 1 , wherein the electrolyte for the lithium secondary battery further comprises a third additive comprising a sultone compound.

13. The electrolyte of claim 12 , wherein the sultone compound is represented by Chemical Formula 2:

wherein, in Chemical Formula 2,
X is a single bond, a substituted or unsubstituted C1 to C10 alkylene group, or a substituted or unsubstituted C2 to C10 alkenediyl, and
R 1 to R 4 are independently selected from a hydrogen atom, a C1 to C10 alkyl group, a C3 to C30 cycloalkyl group, a C1 to C10 alkoxy group, a halogen, a C1 to C10 haloalkyl group, C6 to C30 aryl group, and a combination thereof.

14. The electrolyte of claim 12 , wherein the sultone compound comprises propane sultone (PS) or 1-propene 1,3-sultone (PST).

15. The electrolyte of claim 12 , wherein an amount of the third additive is 0.1 wt % to 5 wt % based on a total amount of the electrolyte for the lithium secondary battery.

16. The electrolyte of claim 1 , wherein the electrolyte for the lithium secondary battery further comprises at least one auxiliary additive of vinylethylene carbonate (VC), lithium tetrafluoroborate (LiBF 4 ), and hexane tricyanide (HTCN).

17. A lithium secondary battery, comprising
a negative electrode;
a positive electrode; and
the electrolyte for a lithium secondary battery according to claim 1 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Choi Hyunbong
• Shatunov Pavel
• TSAY Olga
• Kim Aeran
• Shin Woo Cheol
• Shin Jeongmin

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M10/0525 Primary

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

• H01M10/0569

  characterised by the solvents · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M10/052

  Li-accumulators · CPC title