Method for drying and purifying LiFSI

Patent metadata

Field	Value
Publication number	US-11084723-B2
Application number	US-201716331242-A
Country	US
Kind code	B2
Filing date	Dec 7, 2017
Priority date	Dec 8, 2016
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

The present invention relates to a method for drying and purifying a lithium bis(fluorosulfonyl)imide salt in solution in an organic solvent S1, said method comprising the following steps: a) adding deionised water to dissolve and extract the lithium bis(fluorosulfonyl)imide salt, forming an aqueous solution of said salt; b) extracting the lithium bis(fluorosulfonyl)imide salt from said aqueous solution, using an organic solvent S2, said step being repeated at least once; c) concentrating the lithium bis(fluorosulfonyl)imide salt by evaporating said organic solvent S2 and the water, in a short-path thin-film evaporator, under the following conditions: temperature of 30° C. to 95° C., pressure of 10−3 mbar abs to 5 mbar abs, residence time no longer than 15 min; and d) optionally crystallising the lithium bis(fluorosulfonyl)imide salt. The present invention likewise relates to a composition made of lithium bis(fluorosulfonyl)imide salt, and the uses thereof in Li-ion batteries.

First claim

The invention claimed is:

1. A composition C comprising:
at least 99.80% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C;
between 5 ppm and 45 ppm by mass of water relative to the total mass of composition C; and
a mass content of sulfate ions of less than or equal to 100 ppm by mass relative to the total mass of composition C.

2. The composition C as claimed in claim 1 , comprising a mass content of sulfate ions of between 2 and 100 ppm by mass relative to the total mass of said composition C.

3. The composition C as claimed in claim 1 , comprising:
a mass content of water of between 5 and 45 ppm by mass relative to the total mass of said composition C;
a mass content of sulfate ions of less than or equal to 100 ppm relative to the total mass of said composition C;
a mass content of Cl − of less than or equal to 50 ppm by mass relative to the total mass of said composition C.

4. The composition C as claimed in claim 1 , wherein the sum of the water content and of the sulfate content is less than or equal to 100 ppm.

5. A Li-ion battery comprising a composition C as claimed in claim 1 .

6. The Li-ion battery as claimed in claim 5 , wherein the Li-ion battery is in a mobile device, an electric vehicle, or a renewable energy generation system.

7. The composition C as claimed in claim 1 , comprising at least 99.85% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C.

8. The composition C as claimed in claim 1 , comprising at least 99.90% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C.

9. The composition C as claimed in claim 1 , comprising at least 99.95% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C.

10. The composition C as claimed in claim 1 , comprising between 5 and 40 ppm by mass of water relative to the total mass of composition C.

11. The composition C as claimed in claim 1 , comprising a mass content of sulfate ions of less than or equal to 90 ppm by mass relative to the total mass of composition C.

12. The composition C as claimed in claim 1 , comprising a mass content of sulfate ions of less than or equal to 50 ppm by mass relative to the total mass of composition C.

13. The composition C as claimed in claim 1 , comprising a mass content of sulfate ions of less than or equal to 10 ppm by mass relative to the total mass of composition C.

14. The composition C as claimed in claim 1 , comprising a mass content of Cl − of less than or equal to 40 ppm by mass relative to the total mass of said composition C.

15. The composition C as claimed in claim 1 , comprising a mass content of Cl − of less than or equal to 25 ppm by mass relative to the total mass of said composition C.

16. The composition C as claimed in claim 1 , wherein the sum of the water content and of the sulfate content is between 5 and 90 ppm.

17. The composition C as claimed in claim 1 , wherein the sum of the water content and of the sulfate content is between 10 and 60 ppm.

18. The composition C as claimed in claim 1 , comprising:
at least 99.90% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C;
between 5 and 40 ppm by mass of water relative to the total mass of composition C;
a mass content of sulfate ions of less than or equal to 50 ppm by mass relative to the total mass of composition C; and
a mass content of Cl − of less than or equal to 45 ppm by mass relative to the total mass of said composition C.

19. The composition C as claimed in claim 18 , wherein the sum of the water content and of the sulfate content is between 10 and 60 ppm.

20. The composition C as claimed in claim 1 , comprising:
at least 99.95% by weight of lithium bis(fluorosulfonyl)imide salt relative to the total weight of said composition C;
between 5 and 40 ppm by mass of water relative to the total mass of composition C;
a mass content of sulfate ions of less than or equal to 10 ppm by mass relative to the total mass of composition C; and
a mass content of Cl − of less than or equal to 25 ppm by mass relative to the total mass of said composition C.

Assignees

• Arkema France

Inventors

• Schmidt Grégory
• Teissier Rémy

Classifications

• B01D11/0492

  Applications, solvents used · CPC title

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• B01D1/22

  by bringing a thin layer of the liquid into contact with a heated surface {(B01D1/065 takes precedence)} · CPC title

• H01M10/0568

  characterised by the solutes · CPC title