Non-aqueous electrolyte solution for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-11876177-B2
Application number	US-201816606972-A
Country	US
Kind code	B2
Filing date	Aug 24, 2018
Priority date	Aug 24, 2017
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same are disclosed herein. In some embodiments, a non-aqueous electrolyte solution for a lithium secondary battery, includes an additive having metal ion adsorbability and capable of forming a stable ion conductive film on the surface of an electrode. In some embodiments, a lithium secondary battery including the same has an improved an abnormal voltage drop phenomenon.

First claim

The invention claimed is:

1. A non-aqueous electrolyte solution for a lithium secondary battery, consisting of:
a first lithium salt that is lithium bis(fluorosulfonyl)imide (LiFSI);
a second lithium salt excluding the LiFSI;
an organic solvent selected from an ether-based solvent, an ester-based solvent, an amide-based solvent or as a mixture thereof, wherein the ester-based solvent is at least one selected from the group consisting of a cyclic carbonate compound, a linear carbonate compound, an alkyl ether-based compound, an alkyl acetate-based compound, and an alkyl propionate-based compound, and the cyclic carbonate compound is at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and fluoroethylene carbonate (FEC);
a compound represented by Formula 1; and
optionally, an additive selected from the group consisting of a sultone-based compound, a halogen-substituted carbonate-based compound, a nitrile-based compound, a cyclic sulfite-based compound, and a cyclic carbonate-based compound that is vinyl ethylene carbonate, wherein the sultone-based compound is at least one of 1,3-propane sultone (PS), 1,4-butane sultone, ethene sultone, 1,4-butene, sultone, or 1-methyl-1,3-propene sultone,
wherein a molar ratio of the second lithium salt to the first lithium salt is in a range of 1:1 to 1:2, and
wherein the compound represented by Formula 1 is included in an amount of 0.1 wt % to 7 wt % based on a total amount of the non-aqueous electrolyte solution:

wherein, in Formula 1,
R 1 to R 3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and
A is

wherein, R 5 is hydrogen, an aryl group having 6 to 8 carbon atoms that is unsubstituted or substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms.

2. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1 , wherein the first lithium salt is included in a concentration of 0.01 M to 3 M in the non-aqueous electrolyte solution.

3. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1 , wherein R 5 is hydrogen, an unsubstituted aryl group having 6 to 8 carbon atoms, a phenyl group substituted with an alkyl group having 1 to 3 carbon atoms, a phenyl group substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms.

4. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1 , wherein the compound represented by Formula 1 comprises at least one a compound represented by Formulae 1l:

5. The non-aqueous electrolyte solution for a lithium secondary battery of claim 1 , wherein the compound represented by Formula 1 is included in an amount of 0.5 wt % to 7 wt % based on a total amount of the non-aqueous electrolyte solution.

6. A lithium secondary battery comprising the non-aqueous electrolyte solution of claim 1 .

7. A non-aqueous electrolyte solution for a lithium secondary battery, consisting of:
a first lithium salt that is lithium bis(fluorosulfonyl)imide (LiFSI);
a second lithium salt that is LiPF 6 ;
an organic solvent selected from an ether-based solvent, an ester-based solvent, an amide-based solvent or as a mixture thereof, wherein the ester-based solvent is at least one selected from the group consisting of a cyclic carbonate compound, a linear carbonate compound, an alkyl ether-based compound, an alkyl acetate-based compound, and an alkyl propionate-based compound, and the cyclic carbonate compound is at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate, and fluoroethylene carbonate (FEC);
a compound represented by Formula 1; and
optionally, an additive selected from the group consisting of a sultone-based compound, a halogen-substituted carbonate-based compound, a nitrile-based compound, a cyclic sulfite-based compound, and a cyclic carbonate-based compound that is viny 1 ethylene carbonate, wherein the sultone-based compound is at least one of 1,3-propane sultone, (PS), 1,4-butane sultone, ethene sultone, 1,4-butene sultone, or 1-methyl-1,3-propene sultone,
wherein a molar ratio of the second lithium salt to the first lithium salt is in a range of 1:1 to 1:2, and
wherein the compound represented by Formula 1 is included in an amount of 0.1 wt % to 7 wt % based on a total amount of the non-aqueous electrolyte solution:

wherein, in Formula 1,
R 1 to R 3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms, and
A is

wherein, R 4 is hydrogen, an alkyl group having 1 to 6 carbon atoms that is unsubstituted or substituted with at least one fluorine atom, an aryl group having 6 to 8 carbon atoms that is unsubstituted or substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms, and
R 5 is hydrogen, an aryl group having 6 to 8 carbon atoms that is unsubstituted or substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms.

8. The non-aqueous electrolyte solution for a lithium secondary battery of claim 7 , wherein the first lithium salt is included in a concentration of 0.01 M to 3 M in the non-aqueous electrolyte solution.

9. The non-aqueous electrolyte solution for a lithium secondary battery of claim 7 , wherein R 4 is hydrogen, an alkyl group having 1 to 6 carbon atoms that is unsubstituted or substituted with at least one fluorine atom, an unsubstituted aryl group having 6 to 8 carbon atoms, a phenyl group substituted with an alkyl group having 1 to 3 carbon atoms, a phenyl group substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms, and
R 5 is hydrogen, an unsubstituted aryl group having 6 to 8 carbon atoms, a phenyl group substituted with an alkyl group having 1 to 3 carbon atoms, a phenyl group substituted with at least one fluorine atom, or an alkynyl group having 2 to 6 carbon atoms.

10. The non-aqueous electrolyte solution for a lithium secondary battery of claim 7 , wherein the compound represented by Formula 1 comprises at least one compound represented by Formulae 1a to 1g, or 1l:

11. The non-aqueous electrolyte solution for a lithium secondary battery of claim 7 , wherein the compound represented by Formula 1 is included in an amount of 0.5 wt % to 7 wt % based on a total amount of the non-aqueous electrolyte solution.

12. A lithium secondary battery comprising the non-aqueous electrolyte solution of claim 7 .

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Yu Sung Hoon
• Lee Chul Haeng
• Kim Hyun Seung

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• C07C69/96

  Esters of carbonic or haloformic acids · CPC title

• C07C305/14

  being acyclic and unsaturated · CPC title

• C07C305/18

  containing six-membered aromatic rings · CPC title

• C07C309/67

  of an unsaturated carbon skeleton · CPC title