Electrolyte and second battery comprising same

Patent metadata

Field	Value
Publication number	US-2024258569-A1
Application number	US-202418627460-A
Country	US
Kind code	A1
Filing date	Apr 5, 2024
Priority date	Oct 4, 2021
Publication date	Aug 1, 2024
Grant date	—

Abstract

Disclosed is an electrolyte and a secondary battery containing the same. According to the present disclosure, charging efficiency and output may be improved due to low discharge resistance, and gas generation and thickness increase may be suppressed to provide a secondary battery with long-term lifespan and excellent high temperature capacity retention.

First claim

What is claimed is:

1 . An electrolyte, which includes an organic solvent, lithium salt, a first additive and a second additive,
wherein the first additive contains a compound containing a pair of a lithium or sodium cation and an anion represented by Formula 1 in an amount of 15 weight % or less based on 100 weight % of the electrolyte, wherein the second additive contains a compound having an atomic group with 3 to 5 atoms and a symmetric structure in an amount of 0.01 to 10 weight % based on 100 weight % of the electrolyte, the atomic group having 2 to 4 atoms with electronegativity of 3 or more and having at least one double bond:

wherein in Formula 1, R 1 and R 2 are independently hydrogen, halogen, or a straight-chain or branched alkyl group containing a halogen substituent with 1 to 7 carbon atoms, and h is an integer of 1 to 10.

2 . The electrolyte according to claim 1 ,
wherein in the anion represented by Formula 1, the halogen substituent is fluorine.

3 . The electrolyte according to claim 1 ,
wherein the first additive is a compound containing a pair of a lithium cation and at least one anion selected from the group represented by Formulas 2 to 5 below:

wherein in Formulas 2 to 5, h is an integer of 1 to 10.

4 . The electrolyte according to claim 1 ,
wherein the second additive has an atomic group represented by Formula 6 below:

wherein in Formula 6, a solid line is a bond.

5 . The electrolyte according to claim 1 ,
wherein the second additive is a compound containing a pair of at least one cation selected from the group consisting of alkali metal ions (excluding lithium) and an anion represented by Formula 1 below:

wherein in Formula 1, R 1 and R 2 are independently hydrogen, halogen, or a straight-chain or branched alkyl group containing a halogen substituent with 1 to 7 carbon atoms, and h is an integer of 1 to 10.

6 . The electrolyte according to claim 5 ,
wherein in the anion represented by Formula 1, the halogen substituent is fluorine.

7 . The electrolyte according to claim 1 ,
wherein the second additive is a compound containing a pair of a cation of cesium or sodium and at least one anion selected from the group represented by Formulas 3 to 5 below:

wherein in Formulas 3 to 5, h is an integer of 1 to 10.

8 . The electrolyte according to claim 1 ,
wherein the first additive and the second additive are included at a weight ratio of 1:0.5 to 2.5 (first additive:second additive).

9 . The electrolyte according to claim 1 ,
wherein the lithium salt includes at least one selected from the group consisting of LiPF 6 , LiClO 4 , LiAsF 6 , LiBF 4 , LiBF 6 , LiSbF 6 , LiAl0 4 , LiAlCl 4 , LiClO 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN(C 2 F 5 SO 3 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiN(CF 3 SO 2 ) 2 , LiN(CaF 2a+1 SO 2 ) (C b F 2b+1 SO 2 ) (where a and b are natural numbers), LiCl, LiI, and LiB(C 2 O 4 ) 2 .

10 . The electrolyte according to claim 1 ,
wherein the organic solvent includes at least two selected from the group consisting of ethylene carbonate (EC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), dimethyl carbonate (DMC), propylene carbonate (PC), dipropyl carbonate (DPC), butylene carbonate, methylpropyl carbonate, ethylpropyl carbonate, methyl propionate (MP), ethyl propionate (EP), and propyl propionate (PP).

11 . The electrolyte according to claim 1 , further comprising:
at least one third additive selected from the group consisting of boron compound, phosphorus compound, sulfur compound, and nitrogen compound in an amount of 10 weight % or less based on a total of 100 weight % of the electrolyte.

12 . An electrolyte additive, comprising:
a compound containing a pair of a lithium or sodium cation and an anion represented by Formula 1; and a compound containing a pair of cesium cation and an anion represented by Formula 1 below:

wherein in Formula 1, R 1 and R 2 are independently hydrogen, halogen, or a straight-chain or branched alkyl group containing a halogen substituent with 1 to 7 carbon atoms, and h is an integer of 1 to 10.

13 . The electrolyte additive according to claim 12 ,
wherein the compound containing a pair of a lithium or sodium cation and an anion represented by Formula 1 and the compound containing a pair of cesium cation and an anion represented by Formula 1 are included at a weight ratio of 1:0.5 to 2.5 (first additive:second additive).

14 . A lithium secondary battery, which includes a negative electrode, a positive electrode, a separator interposed between the negative electrode and the positive electrode, and an electrolyte,
wherein the electrolyte is an electrolyte according to claim 1 .

15 . The lithium secondary battery according to claim 14 ,
wherein the secondary battery has a discharge resistance value of 28 mΩ or less at 60° C.

16 . The lithium secondary battery according to claim 14 ,
wherein the secondary battery has a recovery capacity of 585 mAh or more at 60° C.

17 . The lithium secondary battery according to claim 14 ,
wherein the secondary battery has a thickness increase rate of 2.6% or less at 60° C. calculated using Equation 1 below:

Thickness
⁢

increase
⁢

rate
⁢

(
%
)

=

{

(

thickness
⁢

after
⁢

high
⁢

temperature
⁢

storage

-

initial
⁢

thickness

)

⁠
/
initial

Assignees

• Soulbrain Co Ltd

Inventors

• Kim Min Goo
• Jang Min Jung
• Kim Jae Yoon
• Lee Sang Ho
• Yun Jong Cheol
• Han Ji Seong

Classifications

• C01B21/093

  containing also one or more sulfur atoms · CPC title

• C01B21/086

  containing one or more sulfur atoms · CPC title

• H01M10/054

  Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium · CPC title

• H01M10/0569

  characterised by the solvents · CPC title

• H01M10/0568

  characterised by the solutes · CPC title