Electrolyte and secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-2024274884-A1
Application number	US-202418627456-A
Country	US
Kind code	A1
Filing date	Apr 5, 2024
Priority date	Oct 4, 2021
Publication date	Aug 15, 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 having an atomic group with 3 to 5 atoms represented by Formula 1 or 2 in an amount of 15 weight % or less 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 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 Formulas 1 and 2, a solid line is a bond.

2 . The electrolyte according to claim 1 ,
wherein the first additive is at least one selected from compounds represented by Formulas 3 to 6 below:

wherein in Formula 3, R 1 , R 2 and R 3 are independently an alkyl group with 1 to 5 carbon atoms or an aryl group with 6 to 10 carbon atoms,

wherein in Formulas 4 to 5, A is phosphorus (P), sulfur (S), or nitrogen (N); X 1 , X 2 , X 3 , X 1 ′, X 2 ′ and X 3 ′ are independently a bond or oxygen; n is an integer of 0 to 3; and R 1 , R 2 , R 3 , R 1 ′, R 2 ′ and R 3 ′ are independently a bond, substituted or unsubstituted alkylene with 1 to 10 carbon atoms and have at least one carbon,

wherein in Formula 6, Ra is OR 5 or R 6 ; R 5 is RA; A is

 and Re and R 7 are independently an alkyl group with 1 to 5 carbon atoms or an aryl group with 6 to 10 carbon atoms.

3 . The electrolyte according to claim 1 ,
wherein the first additive is at least one selected from compounds represented by Formulas 7 to 13 below:

wherein in Formulas 7 to 13, a solid line is a bond; a point where a bond meets a bond is carbon when a separate element is not described; and the number of hydrogens satisfying the atom value of the carbon is omitted.

4 . 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 14 below:

wherein in Formula 14, 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.

5 . The electrolyte according to claim 4 ,
wherein in the anion represented by Formula 14, the halogen substituent is fluorine.

6 . 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 15 to 17 below:

wherein in Formulas 15 to 17, h is an integer of 1 to 10.

7 . 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).

8 . 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 , LiAlO 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 ) (CbF 2b+1 SO 2 ) (where a and b are natural numbers), LiCl, LiI, and LiB(C 2 O 4 ) 2 .

9 . 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).

10 . 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.

11 . An electrolyte additive, comprising:
at least one compound selected from compounds represented by Formulas 3 to 6 below; and a compound containing a pair of cesium cation and an anion represented by Formula 14 below:

wherein in Formula 3, R 1 , R 2 and R 3 are independently an alkyl group with 1 to 5 carbon atoms or an aryl group with 6 to 10 carbon atoms,

wherein in Formulas 4 to 5, A is phosphorus (P), sulfur (S), or nitrogen (N); X 1 , X 2 , X 3 , X 1 ′, X 2 ′ and X 3 ′ are independently a bond or oxygen; n is an integer of 0 to 3; and R 1 , R 2 , R 3 , R 1 ′, R 2 ′ and R 3 ′ are independently a bond, substituted or unsubstituted alkylene with 1 to 10 carbon atoms and have at least one carbon,

wherein in Formula 6, R 4 is OR 6 or R 6 ; R 5 is RA; A is

 and R 6 and R 7 are independently an alkyl group with 1 to 5 carbon atoms or an aryl group with 6 to 10 carbon atoms,

wherein in Formula 14, 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.

12 . The electrolyte additive according to claim 11 ,
wherein the at least one compound selected from compounds represented by Formulas 3 to 6 and the compound containing a pair of cesium cation and an anion represented by Formula 14 are included at a weight ratio of 1:0.5 to 2.5 (first additive: second additive).

13 . 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 .

14 . The lithium secondary battery according to claim 13 ,
wherein the secondary battery has a discharge resistance value of 28 m(2 or less at 60° C.

15 . The lithium secondary battery according to claim 13 ,
wherein the secondary battery has a recovery capacity of 585 mAh or more at 60° C

Assignees

• Soulbrain Co Ltd

Inventors

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

Classifications

• H01M2300/0025

  Organic electrolyte · 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

• C07D497/10

  Spiro-condensed systems · CPC title

• C07D327/10

  two oxygen atoms and one sulfur atom, e.g. cyclic sulfates · CPC title