Electrolyte solution additive for lithium secondary battery, and non-aqueous electrolyte solution and lithium secondary battery including the additive

Patent metadata

Field	Value
Publication number	US-9614253-B2
Application number	US-201414418683-A
Country	US
Kind code	B2
Filing date	Oct 31, 2014
Priority date	Oct 31, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

Provided is a non-aqueous electrolyte solution including a non-aqueous organic solvent, an imide-based lithium salt, and at least one additive selected from the group consisting of lithium difluoro bis(oxalato)phosphate (LiDFOP), (trimethylsilyl)propyl phosphate (TMSPa), 1,3-propene sultone (PRS), and ethylene sulfate (ESa), as an electrolyte solution additive.
According to the electrolyte solution additive for a lithium secondary battery of the present invention, the electrolyte solution additive may improve output characteristics at high and low temperatures and may prevent a swelling phenomenon by suppressing the decomposition of PF 6 − on the surface of a cathode, which may occur during a high-temperature cycle of a lithium secondary battery including the electrolyte solution additive, and preventing an oxidation reaction of an electrolyte solution.

First claim

The invention claimed is:

1. A non-aqueous electrolyte solution comprising:
a non-aqueous organic solvent;
an imide-based lithium salt; and
lithium difluoro bis(oxalato)phosphate (LiDFOP), (trimethylsilyl)propyl phosphate (TMSPa), 1,3-propene sultone (PRS), and ethylene sulfate (ESa), as electrolyte solution additives,
wherein the imide-based lithium salt is Li(SO 2 F) 2 N (lithium bis(fluorosulfonyl)imide, LiFSI) and,
wherein the non-aqueous organic solvent comprises at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).

2. The non-aqueous electrolyte solution of claim 1 , wherein the non-aqueous organic solvent comprises ethylene carbonate (EC), propylene carbonate (PC), ethylmethyl carbonate (EMC), and dimethyl carbonate (DMC).

3. The non-aqueous electrolyte solution of claim 2 , wherein the non-aqueous organic solvent comprises ethylene carbonate (EC)/propylene carbonate (PC)/ethylmethyl carbonate (EMC)/dimethyl carbonate (DMC) respectively in an amount of 1.0 part by weight to 1.5 parts by weight: 1.0 part by weight to 1.5 parts by weight: 4.0 parts by weight to 4.5 parts by weight: and 4.0 parts by weight to 4.5 parts by weight.

4. The non-aqueous electrolyte solution of claim 1 , wherein the lithium difluoro bis(oxalato)phosphate (LiDFOP), the 1,3-propene sultone (PRS), and the ethylene sulfate (ESa) are each independently included in an amount of 0.5 wt % to 1.5 wt % based on a total amount of the electrolyte solution, and the (trimethylsilyl)propyl phosphate (TMSPa) is included in an amount of 0.1 wt % to 0.5 wt % based on the total amount of the electrolyte solution.

5. The non-aqueous electrolyte solution of claim 1 , further comprising LiPF 6 .

6. The non-aqueous electrolyte solution of claim 5 , wherein a mixing ratio of the imide-based lithium salt to LiPF 6 is in a range of 10:90 to 50:50 as a molar ratio.

7. A lithium secondary battery comprising:
a cathode;
an anode;
a separator; and
the non-aqueous electrolyte solution of claim 1 .

8. The lithium secondary battery of claim 7 , wherein the anode comprises a carbon-based anode active material selected from the group consisting of crystalline carbon, amorphous carbon, artificial graphite, and natural graphite.

9. The lithium secondary battery of claim 7 , wherein the cathode comprises a lithium metal oxide.

10. The lithium secondary battery of claim 7 , wherein the lithium secondary battery is a lithium ion secondary battery or a lithium polymer secondary battery.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Gwang Yeon
• Lee Chul Haeng
• Yang Doo Kyung
• Lim Young Min
• Kim Shul Kee
• An Yu Ha
• Park Jin Hyun

Classifications

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/052 Primary

  Li-accumulators · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title