Electrolyte for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-12230759-B2
Application number	US-202318135365-A
Country	US
Kind code	B2
Filing date	Apr 17, 2023
Priority date	Apr 3, 2020
Publication date	Feb 18, 2025
Grant date	Feb 18, 2025

Abstract

An electrolyte for a lithium secondary battery according to exemplary embodiments of the present inventing includes an organic solvent, a lithium salt, a first additive represented by a predetermined chemical formula, and a second additive represented by a predetermined chemical formula. A protective film is formed by the additives to suppress an expansion of a lithium secondary battery and improve storage property at high temperature.

First claim

What is claimed is:

1. An electrolyte for a lithium secondary battery, comprising:
an organic solvent;
a lithium salt;
a first additive represented by Chemical Formula 1; and
a second additive represented by Chemical Formula 2,
wherein a weight ratio of the first additive and the second additive is from 1:0.25 to 1:3:

wherein, in Chemical Formula 1, R 1 is a saturated hydrocarbon backbone structure having 3 to 10 carbon atoms, and n is an integer of 1 to 3,

wherein, in Chemical Formula 2, R 11 to R 13 are each independently hydrogen, or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, and A is a substituent represented by Chemical Formula 3 or Chemical Formula 4,

wherein, in Chemical Formulae 3 and 4, R 14 and R 15 are each independently a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or —OR 16 , and
R 16 is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or an alkynyl group having 2 to 6 carbon atoms.

2. The electrolyte for a lithium secondary battery according to claim 1 , wherein, in Chemical Formula 1, the saturated hydrocarbon backbone structure of R 1 is linear.

3. The electrolyte for a lithium secondary battery according to claim 1 , wherein the first additive includes at least one of compounds represented by Chemical Formulae 1-1 to 1-3:

4. The electrolyte for a lithium secondary battery according to claim 1 , wherein the second additive includes a compound represented by Chemical Formula 4-1:

5. The electrolyte for a lithium secondary battery according to claim 1 , wherein each amount of the first additive and the second additive is independently in a range from 0.01 wt % to 5 wt % based on a total weight of the electrolyte.

6. The electrolyte for a lithium secondary battery according to claim 1 , wherein an amount of the first additive is in a range from 0.1 wt % to 3 wt % based on the total weight of the electrolyte.

7. The electrolyte for a lithium secondary battery according to claim 1 , wherein an amount of the first additive is in a range from 0.1 wt % to 2 wt % based on the total weight of the electrolyte.

8. The electrolyte for a lithium secondary battery according to claim 1 , wherein an amount of the second additive is in a range from 0.1 wt % to 3 wt % based on the total weight of the electrolyte.

9. The electrolyte for a lithium secondary battery according to claim 1 , wherein the organic solvent includes at least one selected from the group consisting of ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), and diethyl carbonate (DEC).

10. The electrolyte for a lithium secondary battery according to claim 1 , wherein the lithium salt includes at least one selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ) and lithium difluorophosphate (LiPO 2 F 2 ).

11. The electrolyte for a lithium secondary battery according to claim 1 , further comprising a cyclic carbonate-based compound containing a double bond or a fluorine-substituted cyclic carbonate-based compound.

12. The electrolyte for a lithium secondary battery according to claim 1 , further comprising a sultone-based compound.

13. The electrolyte for a lithium secondary battery according to claim 1 , further comprising a cyclic sulfonate-based compound.

14. A lithium secondary battery, comprising:
a cathode;
an anode;
a separation layer interposed between the cathode and the anode; and
the electrolyte for a lithium secondary battery according to claim 1 .

Assignees

• Sk On Co Ltd

Inventors

• Cho In Haeng
• Lee Dong Gun
• Lee Joo Hyun
• Kim Sung Jin

Classifications

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0525

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

• C07F9/062

  Organo-phosphoranes without P-C bonds · CPC title