Non-aqueous electrolyte for lithium secondary battery and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11557791-B2
Application number	US-201816638514-A
Country	US
Kind code	B2
Filing date	Aug 7, 2018
Priority date	Sep 6, 2017
Publication date	Jan 17, 2023
Grant date	Jan 17, 2023

Abstract

The present invention relates to a non-aqueous electrolyte for a lithium secondary battery and a lithium secondary battery comprising the same, the non-aqueous electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive including at least one of compounds represented by chemical formulas 1 to 4, and a second additive comprising a cyclic sulfide-based compound, wherein the mixing ratio of the first additive and the second additive is a weight ratio of 0.2:1 to 10:1.

First claim

The invention claimed is:

1. A non-aqueous electrolyte for a lithium secondary battery, comprising
a non-aqueous organic solvent;
a lithium salt;
a first additive including at least one of compounds represented by Chemical Formulae 1 to 4; and
a second additive, the second additive including ethylene sulfate, methylene methane disulfonate, 2,4-butane sultone, propylene sulfite, or a combination thereof,
wherein a mixing ratio of the first additive and the second additive is a weight ratio of 0.2:1 to 10:1:

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

2. The non-aqueous electrolyte of claim 1 , wherein a mixing ratio of the first additive and the second additive is a weight ratio of 0.5:1 to 5:1.

3. The non-aqueous electrolyte of claim 1 , wherein the second additive comprises a first cyclic additive including the ethylene sulfate, methylene methane disulfonate, 2,4-butane sultone, propylene sulfite, or combination thereof and a second cyclic additive comprising a cyclic compound, the first cyclic additive and the second cyclic additive being different from each other.

4. The non-aqueous electrolyte for a lithium secondary battery of claim 3 , wherein a mixing ratio of the first cyclic additive and the second cyclic additive is a weight ratio of 0.5:1 to 1:1.

5. The non-aqueous electrolyte for a lithium secondary battery of claim 1 , wherein a content of the first additive is 0.5 wt % to 5 wt % based on a total weight of the electrolyte.

6. The non-aqueous electrolyte for a lithium secondary battery of claim 1 , wherein a content of the second additive is 0.5 wt % to 5 wt % based on a total weight of the electrolyte.

7. The non-aqueous electrolyte for a lithium secondary battery of claim 1 , wherein the first additive is the compound represented by Chemical Formula 1, the compound represented by Chemical Formula 3, or a combination thereof.

8. A lithium secondary battery comprising
a negative electrode including a negative active material;
a positive electrode including a positive active material; and
the non-aqueous electrolyte of claim 1 .

9. The lithium secondary battery of claim 8 , wherein the positive active material is a lithium nickel-based compound.

10. The lithium secondary battery of claim 9 , wherein the positive active material is a lithium nickel-based compound of Chemical Formula 5:
Chemical Formula 5
Li a1 Ni x1 Co y1 Mn z1 O 2

In Chemical Formula 5,
0.9≤a1≤1.1, 0.6≤x1≤0.9, 0≤y1≤0.3, 0≤z1≤0.3, and x1+y1+z1=1.

Assignees

• Samsung Sdi Co Ltd

Inventors

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

Classifications

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M10/0525

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