# US 12,763,371 B2 · Preparation method for lithium bis(fluorosulfonyl)imide including multiple ammonia source additions, electrolytic solution and secondary battery

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- Number: US 12,763,371 B2
- Document ID: US12763371B2
- Status: Granted
- Kind: B2
- Application number: 18/366,251
- Filed: 2023-08-07
- Published: 2023-11-23
- Granted: 2026-10-13
- Earliest claimed: 2022-01-29
- Assignees: Contemporary Amperex Technology Co., Limited; Catl-Sicong Novel Materials Co., Ltd
- Applicants: Contemporary Amperex Technology Co., Limited; Catl-Sicong Novel Materials Co., Ltd
- Inventors: Sicong Cheng; Qisen Huang
- Web page: https://patentgrep.com/patent/US12763371B2

## CPC

- H01M 10/0568: characterised by the solutes
- C01B 21/086: containing one or more sulfur atoms
- C01P 2006/40: Electric properties
- H01M 2300/0025: Organic electrolyte
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS

## Abstract

A method for preparing lithium bis(fluorosulfonyl)imide, including (1) adding an organic solvent and an absorbent A to a reaction kettle, then adding part of an ammonia source, and finally adding SO2X2 and a remaining ammonia source simultaneously for reaction, to obtain a solution of a salt (SO2F—NH—SO2F)·A containing bis(fluorosulfonyl)imide and the absorbent A, where in the SO2X2, X is independently fluorine or chlorine; (2) performing filtration, concentration and washing on the solution obtained in step (1) to obtain a purified salt (SO2F—NH—SO2F)·A of the bis(fluorosulfonyl)imide and the absorbent A; (3) adding a lithium source to the purified salt (SO2F—NH—SO2F)·A of the bis(fluorosulfonyl)imide and the absorbent A obtained in step (2) for reaction to obtain a solution containing lithium bis(fluorosulfonyl)imide; and (4) performing dehydration, concentration, crystallization with a non-aqueous poor solvent, and drying on the solution obtained in step (3) to obtain the lithium bis(fluorosulfonyl)imide is described.

## Claims

### Claim 1

A method for preparing lithium bis(fluorosulfonyl)imide, comprising
(1) adding an organic solvent and an absorbent A to a reaction kettle, then adding part of an ammonia source, and finally adding SO2X2 and a remaining ammonia source simultaneously for reaction, to obtain a solution of a salt (SO2F—NH—SO2F)·A containing bis(fluorosulfonyl)imide and the absorbent A, wherein in the SO2X2, X is independently fluorine or chlorine;
(2) performing filtration, concentration and washing on the solution obtained in step (1) to obtain a purified salt (SO2F—NH—SO2F)·A of the bis(fluorosulfonyl)imide and the absorbent A;
(3) adding a lithium source to the purified salt (SO2F—NH—SO2F)·A of the bis(fluorosulfonyl)imide and the absorbent A obtained in step (2) for reaction to obtain a solution containing lithium bis(fluorosulfonyl)imide; and
(4) performing dehydration, concentration, crystallization with a non-aqueous poor solvent, and drying on the solution obtained in step (3) to obtain the lithium bis(fluorosulfonyl)imide, wherein in step (1), a mass of the part of the ammonia source accounts for 3%-10% of a total mass of the ammonia source.

### Claim 2 (depends on 1)

The method according to claim 1, wherein in step (1), a molar ratio of the SO2X2 to the ammonia source is (greater than 2 to less than or equal to 3):1, optionally (2.01-2.1):1.

### Claim 3 (depends on 1)

The method according to claim 1, wherein in step (1), a molar ratio of the absorbent A to the ammonia source is (1-5):1.

### Claim 4 (depends on 1)

The method according to claim 1, wherein in step (1), the ammonia source is one or more of ammonia gas, fluorinated amine, sulfonamide, sulfamic acid and difluorinated amine.

### Claim 5 (depends on 1)

The method according to claim 1, wherein in step (1), the absorbent A is one or more of pyridine, picoline, N-methylpyrrolidone, imidazole, trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine and diisopropylethylamine.

### Claim 6 (depends on 1)

The method according to claim 1, wherein in step (1), the organic solvent is one or more of acetonitrile, propionitrile, isopropionitrile, diethyl ether, propyl ether, isopropyl ether, tetrahydrofuran, acetone, butanone, methyl isobutyl ketone and methyl pyrrolidone.

### Claim 7 (depends on 1)

The method according to claim 1, wherein in step (3), the lithium source is one or more of lithium hydroxide, lithium carbonate, lithium nitride, lithium oxide and lithium hydride.

### Claim 8 (depends on 1)

The method according to claim 1, wherein in step (3), temperature of the reaction is 15° C. to 40° C.; and in step (3), time of the reaction is 0.5 h to 6 h.

### Claim 9 (depends on 1)

The method according to claim 1, wherein in step (2) and step (4), the concentration comprises reduced-pressure distillation, falling film evaporation or scraper evaporation.

### Claim 10 (depends on 1)

The method according to claim 1, wherein in step (4), the poor solvent is one or more of C1-C8 alkanes, benzene, toluene, xylene, dichloromethane, dichloroethane, trichloroethane, tetrachloroethane and carbon tetrachloride.

### Claim 11 (depends on 1)

The method according to claim 1, wherein in step (1), temperature of the reaction is −10° C. to 50° C.; and in step (1), time of the reaction is 2 h to 8 h.

### Claim 12 (depends on 5)

The method according to claim 5, wherein the temperature of the reaction is −5° C. to 35° C.