Method for recovering lithium bis(fluorosulfonyl)imide

Patent metadata

Field	Value
Publication number	US-12110227-B2
Application number	US-202318525902-A
Country	US
Kind code	B2
Filing date	Dec 1, 2023
Priority date	Jan 29, 2022
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

A method for recovering lithium bis(fluorosulfonyl)imide is provided in the present application. The method of the present application may comprise: mixing a slag from lithium bis(fluorosulfonyl)imide production process with a solvent of carbonate ester, to obtain a mixed material; subjecting the mixed material to solid-liquid separation, to obtain a discharged liquid and a solid slag; monitoring the chromaticity of the discharged liquid and comparing the chromaticity of the discharged liquid with a chromaticity reference; recycling the discharged liquid to the mixed material, if the chromaticity of the discharged liquid is higher than the chromaticity reference; and recycling the discharged liquid to lithium bis(fluorosulfonyl)imide production process, if the chromaticity of the discharged liquid is lower than or equal to the chromaticity reference.

First claim

The invention claimed is:

1. A method for recovering lithium bis(fluorosulfonyl)imide, comprising:
mixing a slag from lithium bis(fluorosulfonyl)imide production process with a solvent of carbonate ester, to obtain a mixed material;
subjecting the mixed material to solid-liquid separation, to obtain a discharged liquid and a solid slag;
monitoring chromaticity of the discharged liquid and comparing the chromaticity of the discharged liquid with a chromaticity reference;
recycling the discharged liquid to the mixed material, if the chromaticity of the discharged liquid is higher than the chromaticity reference; and
recycling the discharged liquid to the lithium bis(fluorosulfonyl)imide production process, if the chromaticity of the discharged liquid is lower than or equal to the chromaticity reference.

2. The method according to claim 1 , wherein the chromaticity reference has a value of no more than 300 Hazen.

3. The method according to claim 1 , wherein the solvent of carbonate ester is one or more of diethyl carbonate (DEC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC), ethylene carbonate (EC), or propylene carbonate (PC).

4. The method according to claim 1 , wherein a mass ratio of the slag to the solvent of carbonate ester is 1:1 to 1:5.

5. The method according to claim 1 , wherein the solid-liquid separation is carried out by centrifugation.

6. The method according to claim 1 , wherein the solid-liquid separation is carried out by filtration.

7. The method according to claim 1 , wherein a single recovery rate of bis(fluorosulfonyl)imide is no less than 85%,
wherein the single recovery rate of bis(fluorosulfonyl)imide (LiFSI) is calculated according to below equation:
Single recovery rate of LiFSI=(1−content of LiFSI in the solid slag after processing/content

of LiFSI in the slag before processing)×100%, and

wherein the content of LiFSI in the solid slag after processing and the content of LiFSI in the slag before processing are measured by a chromatography technique.

8. The method according to claim 1 , wherein the chromaticity reference has a value of no more than 300 Hazen and no less than 40 Hazen.

9. The method according to claim 1 , wherein a single recovery rate of bis(fluorosulfonyl)imide is no less than 85% and no more than 97%,
wherein the single recovery rate of bis(fluorosulfonyl)imide (LiFSI) is calculated according to below equation:
Single recovery rate of LiFSI=(1−content of LiFSI in the solid slag after processing/content

of LiFSI in the slag before processing)×100%, and

wherein the content of LiFSI in the solid slag after processing and the content of LiFSI in the slag before processing are measured by a chromatography technique.

Assignees

• Contemporary Amperex Technology Co Ltd
• Catl Sicong Novel Mat Co Ltd

Inventors

• Cheng Sicong
• Huang Qisen

Classifications

• H01M10/0568

  characterised by the solutes · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/54

  Reclaiming serviceable parts of waste accumulators · CPC title

• C01B21/0935

  Imidodisulfonic acid; Nitrilotrisulfonic acid; Salts thereof · CPC title

• B01D9/0054

  Use of anti-solvent · CPC title