Electrolytes for electrochemical cells

Patent metadata

Field	Value
Publication number	US-11735776-B2
Application number	US-202117412895-A
Country	US
Kind code	B2
Filing date	Aug 26, 2021
Priority date	Aug 26, 2021
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

The present disclosure provides an electrolyte system for an electrochemical cell that cycles lithium ions. The electrolyte system may include an aliphatic fluorinated disulfonimide lithium salt in a mixture of organic solvents. The mixture of organic solvents may include a first solvent and a second solvent. The first solvent may include an ether solvent, a carbonate solvent, or a mixture of ether and carbonate solvents. The second solvent may include a fluorinated ether. A molar ratio of the aliphatic fluorinated disulfonimide lithium salt to the first solvent may be greater than or equal to about 1:1.2 to less than or equal to about 1:2. A molar ratio of the first solvent to the second solvent may be greater than or equal to about 1:1 to less than or equal to about 1:4.

First claim

What is claimed is:

1. An electrolyte system for an electrochemical cell that cycles lithium ions, the electrolyte system comprising:
an aliphatic fluorinated disulfonimide lithium salt comprising lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide) in a mixture of organic solvents, wherein the mixture of organic solvents comprises a first solvent and a second solvent, the first solvent comprising an ether solvent, a carbonate solvent, or a mixture of ether and carbonate solvents, and the second solvent comprising a fluorinated ether wherein the fluorinated ether is selected from the group consisting of: bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether, and combinations thereof.

2. The electrolyte system of claim 1 , wherein the aliphatic fluorinated disulfonimide lithium salt further comprises lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, or a combination of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide.

3. The electrolyte system of claim 1 , wherein a molar ratio of the aliphatic fluorinated disulfonimide lithium salt to the first solvent is greater than or equal to about 1:1.2 to less than or equal to about 1:2.

4. The electrolyte system of claim 1 , wherein a molar ratio of the first solvent to the second solvent is greater than or equal to about 1:1 to less than or equal to about 1:4.

5. The electrolyte system of claim 1 , wherein the ether solvent is a chain ether selected from the group consisting of: 1,2-dimethoxyethane (DME), 1-2-diethoxyethane, ethoxymethoxyethane, and combinations thereof.

6. The electrolyte system of claim 1 , wherein the ether solvent is a cyclic ether selected from the group consisting of: tetrahydrofuran, 2-methyltetrahydrofuran, and combinations thereof.

7. The electrolyte system of claim 1 , wherein the ether solvent is selected from the group consisting of: 1,2-dimethoxyethane (DME), 1-2-diethoxyethane, ethoxymethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, and combinations thereof.

8. The electrolyte system of claim 1 , wherein the carbonate solvent is a cyclic carbonate selected from the group consisting of: ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), and combinations thereof.

9. The electrolyte system of claim 1 , wherein the carbonate solvent is a linear carbonate selected from the group consisting of: dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethylcarbonate (EMC), and combinations thereof.

10. The electrolyte system of claim 1 , wherein the carbonate solvent is selected from the group consisting of: ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethylcarbonate (EMC), and combinations thereof.

11. An electrochemical cell that cycles lithium ions, the electrochemical cell comprising:
a first electrode comprising a first electroactive material;
a second electrode comprising a second electroactive material;
a separator disposed between the first and second electrodes; and
an electrolyte system disposed within at least one of the first electrode, the second electrode, and the separator, wherein the electrolyte system comprising:
an aliphatic fluorinated disulfonimide lithium salt comprising lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide) in a mixture of organic solvents, wherein the mixture of organic solvents comprises a first solvent and a second solvent, the first solvent comprising an ether solvent, a carbonate solvent, or a mixture of ether and carbonate solvents, and the second solvent comprising a fluorinated ether wherein the fluorinated ether is selected from the group consisting of: bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether, and combinations thereof.

12. The electrochemical cell of claim 11 , wherein the aliphatic fluorinated disulfonimide lithium salt further comprises lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, or a combination of lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide.

13. The electrochemical cell of claim 11 , wherein the first electroactive material is a high-nickel positive electroactive material represented by Ni x Mn y Co z O 2 , where x, y, and z are all ≤1 and x+y+z=1.

14. The electrochemical cell of claim 11 , wherein the first electroactive material is a sulfur-containing positive electroactive material selected from the group consisting of: sulfur (S), sulfur-selenium (S—Se), sulfur-silicon (S—Si), sulfur-polyacrylonitrile (S-PAN), and combinations thereof.

15. The electrochemical cell of claim 11 , wherein the second electroactive material comprises a lithium metal.

16. The electrochemical cell of claim 11 , wherein a molar ratio of the aliphatic fluorinated disulfonimide lithium salt to the first solvent is greater than or equal to about 1:1.2 to less than or equal to about 1:2.

17. The electrochemical cell of claim 11 , wherein a molar ratio of the first solvent to the second solvent is greater than or equal to about 1:1 to less than or equal to about 1:4.

18. The electrochemical cell of claim 11 , wherein the ether solvent is selected from the group consisting of: 1,2-dimethoxyethane (DME), 1-2-diethoxyethane, ethoxymethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, and combinations thereof, and
the carbonate solvent is selected from the group consisting of: ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), fluoroethylene carbonate (FEC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethylcarbonate (EMC), and combinations thereof.

19. An electrolyte system for an electrochemical cell that cycles lithium ions, the electrolyte system comprising:
an aliphatic fluorinated disulfonimide lithium salt comprising lithium (fluorosulfonyl)(trifluoromethanesulfonyl)imide) in a mixture of organic solvents, wherein the mixture of organic solvents comprises a first solvent and a second solvent, a molar ratio of the first solvent to the second solvent is greater than or equal to about 1:1 to less than or equal to about 1:4, a molar ratio of the aliphatic fluorinated disulfonimide lithium salt to the first solvent is greater than or equal to about 1:1.2 to less than or equal to about 1:2, the first solvent comprising an ether solvent, a carbonate solvent, or a mixture of ether and carbonate solvents, and the second solvent comprising a fluorinated ether wherein the fluorinated ether is selected from the group consisting of: bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether (TTE), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl 2,2,2-trifluoroethyl ether, and combinations thereof.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Chen Shuru
• He Meinan
• Dai Fang
• Verbrugge Mark
• Cai Mei

Classifications

• H01M10/0569 Primary

  characterised by the solvents · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/505

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

• H01M4/525

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

• H01M4/5815

  Sulfides · CPC title