Lithium secondary battery

Patent metadata

Field	Value
Publication number	US-2020373617-A1
Application number	US-201816638526-A
Country	US
Kind code	A1
Filing date	Aug 1, 2018
Priority date	Sep 6, 2017
Publication date	Nov 26, 2020
Grant date	—

Abstract

The present invention relates to a lithium secondary battery comprising: a negative electrode comprising a negative electrode active material containing Si or Sn, a positive electrode comprising a positive electrode active material, and a non-aqueous electrolyte. The non-aqueous electrolyte comprises: a non-aqueous organic solvent; a lithium salt; fluoroethylene carbonate; a first additive containing at least one compound among compounds resented by chemical formulas 1 to 4; and a second additive containing at least one compound among compounds represented by chemical formula 5 or 6.

First claim

1 . A lithium secondary battery, comprising
a negative electrode comprising a negative electrode active material comprising Si or Sn; a positive electrode comprising a positive electrode active material; and a non-aqueous electrolyte comprising a non-aqueous organic solvent; a lithium salt; fluoroethylene carbonate; a first additive comprising at least one of compounds represented by Chemical Formulae 1 to 4; and a second additive comprising at least one of compounds represented by Chemical Formula 5 or 6:

wherein, in Chemical Formulae 1 to 4,
R 1 to R 9 are independently a substituted or unsubstituted, primary, secondary, or tertiary alkyl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted aryl group, X is a hydrogen or a halogen atom,
n is an integer of 0 to 3, and
m1 and m2 are independently an integer of 0 to 3,

wherein, in Chemical Formulae 5 and 6,
R g , R h , R i , and R j are independently a halogen or a halogen substituted or unsubstituted alkyl group or at least two of R g , R h , R i , and R j are linked with each other to form an oxalate group, and
R k and R p are independently a halogen or a halogen substituted or unsubstituted alkyl group or R k and R p are linked with each other to form an oxalate group.

2 . The lithium secondary battery of claim 1 , wherein an amount of the first additive is 0.1 wt % to 5 wt % based on a total weight of the electrolyte.

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

4 . The lithium secondary battery of claim 1 , wherein a mixing ratio of the first additive and the second additive is a weight ratio of 10:1 to 0.066:1.

5 . The lithium secondary battery of claim 1 , wherein an amount of the fluoroethylene carbonate is 0.1 wt % to 7 wt % based on a total weight of the electrolyte.

6 . The lithium secondary battery of claim 1 , wherein the first additive is bis(trimethylsilyl) sulfate, di-t-butylsilylbis(trifluoromethane sulfonate), trimethylsilyl methane sulfonate, trimethylsilyl benzenesulfonate, trimethylsilyl trifluoromethane sulfonate, triethylsilyl trifluoromethane sulfonate, or a combination thereof.

7 . The lithium secondary battery of claim 1 , wherein the second additive is lithium difluorobis(oxalato)phosphate, lithium tetrafluoro(oxalato)phosphate, lithium tris(oxalato)phosphate, lithium difluorobis(oxalato)borate, lithium bis(oxalato)borate, or a combination thereof.

8 . The lithium secondary battery of claim 1 , wherein the negative electrode further comprises a carbon-based negative electrode active material.

9 . The lithium secondary battery of claim 1 , wherein the negative electrode active material comprises a silicon-carbon composite.

10 . The lithium secondary battery of claim 9 , wherein the silicon-carbon composite further comprises an amorphous carbon layer.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Yunhee
• Kim Kyoung Soo
• You Yongchan
• Cho Erang
• Choi Seonju

Classifications

• H01M4/362

  Composites · CPC title

• H01M2300/0034

  Fluorinated solvents · CPC title

• H01M4/387

  Tin or alloys based on tin · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title