Purification method of lithium bis(fluorosulfonyl)imide

A technology for the purification of lithium bisfluorosulfonyl imide, which is applied in the direction of nitrosyl chloride, nitrogen and non-metallic compounds, etc., can solve the problems of easy decomposition, difficulty, and poor thermal stability of substances, and achieve high purity and process simple effect

Active Publication Date: 2017-07-25
JIANGSU GUOTAI SUPER POWER NEW MATERIALS
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a salt used in the electrolyte, the purity of lithium bisfluorosulfonylimide needs to be above 99.9%, the water content should be below 100ppm, and the trace impurities of anions and cations should be controlled at the ppm level. Special physical properties such as water absorption and great solubility in common organic solvents make it very difficult to purify the prepared lithium bisfluorosulfonyl imide, especially when lithium bisfluorosulfonyl imide absorbs water, the thermal stability of the substance becomes poor , resulting in the use of conventional physical methods can hardly remove water and easy to decompose
[0004] Shanghai Kangpeng Chemical's patent CN201510261089.1 chooses to use thionyl chloride to remove water from lithium bisfluorosulfonyl imide, but the Cl introduced by this method - and SO 3 2- There will be obvious residues of ions, which will increase the difficulty of the subsequent purification operation of lithium bisfluorosulfonyl imide

Method used

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  • Purification method of lithium bis(fluorosulfonyl)imide
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  • Purification method of lithium bis(fluorosulfonyl)imide

Examples

Experimental program
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Effect test

Embodiment 1

[0040] Add 200 g of butyl acetate and 37.4 g (0.2 mol) of crude lithium bisfluorosulfonyl imide (purity 98.1%, moisture 0.5%) into 500 mL reaction flask A, stir to dissolve, and filter to remove insoluble matter.

[0041] In the 500mL reaction flask B, add the filtered filtrate, add acetic anhydride 10g (R in formula I 1 and R 2 Both are -CH 3 compound) was passed through dry nitrogen, and stirred at 50°C for 3h. The treated solution was transferred and concentrated by evaporation under reduced pressure until the remaining 60 g of the solution was concentrated. The concentrated solution was transferred to an anhydrous glove box, 120 g of dichloromethane was added thereto, stirred for 0.5 h, left to stand for crystallization, and filtered after 12 h. The obtained crystal weighed 25.2 g after vacuum drying to obtain a pure product. The yield of the purification method provided by Example 1 of the present invention is 67.4%, the water content in the pure product is 52ppm, and ...

Embodiment 2

[0043] Add 200 g of dimethyl carbonate and 37.4 g (0.2 mol) of crude lithium bisfluorosulfonyl imide (purity 98.1%, moisture 0.5%) into 500 mL reaction flask A, stir to dissolve, and filter to remove insoluble matter.

[0044] In the 500mL reaction bottle B, add the filtered filtrate, add trifluoroacetic anhydride 10g (R in formula I 1 and R 2 Both - CF 3 compound) was passed through dry nitrogen, and stirred at 60°C for 3h. The treated solution was transferred and concentrated by evaporation under reduced pressure until the remaining 60 g of the solution was concentrated. The concentrated solution was transferred to an anhydrous glove box, 120 g of toluene was added thereto, stirred for 0.5 h, left to stand for crystallization, and filtered after 12 h. The obtained crystal weighed 26.3g after vacuum drying to obtain a pure product. The yield of the purification method provided by Example 2 of the present invention is 70.3%, the water content in the pure product is 37ppm, a...

Embodiment 3

[0046] Add 200 g of diethyl ether and 37.4 g (0.2 mol) of crude lithium bisfluorosulfonyl imide (98.1% purity, 0.5% moisture) into 500 mL reaction flask A, stir to dissolve, and remove insoluble matter by filtration.

[0047] In the 500mL reaction bottle B, add the filtered filtrate, add trifluoroacetic anhydride 50g (R in formula I 1 and R 2 Both - CF 3 compound), heated to about 34° C. and stirred for 3 h under dry nitrogen gas. The treated solution was transferred and concentrated by evaporation under reduced pressure until the remaining 45 g of the solution was stopped. The concentrated solution was transferred to an anhydrous glove box, 150 g of dichloromethane was added thereto, stirred for 0.5 h, left to stand for crystallization, and filtered after 12 h. The obtained crystal weighed 29.2g after vacuum drying to obtain a pure product. The yield of the purification method provided by Example 3 of the present invention is 78.1%, the water content in the pure product is...

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Abstract

The invention provides a purification method of lithium bis(fluorosulfonyl)imide. The method comprises the following steps of (1) dissolving a lithium bis(fluorosulfonyl)imide crude product in an organic solvent; filtering to remove insoluble substances and obtain filter liquid; (2) mixing the filter liquid and organic acid anhydride and then heating to obtain mixed liquid, wherein the organic acid anhydride has a structure shown as a formula I, and in the formula I, R1 and R2 are independently selected from C1-C5 alkyls or C1-C5 halogen alkyls; (3) performing evaporation treatment on the mixed liquid to remove the organic solvent and obtain an intermediate product; (4) crystallizing the intermediate product in a low-polarity organic solvent to obtain a lithium bis(fluorosulfonyl)imide pure product, wherein the polarity of the low-polarity organic solvent is lower than 4. The purification method provided by the invention has the advantages that the organic acid anhydride is used for removing moisture in the lithium bis(fluorosulfonyl)imide crude product; other impurities are not introduced; the recrystallization is performed through solvent polarity regulation. The purification method provided by the invention has the advantages that the process is simple; the obtained lithium bis(fluorosulfonyl)imide has high purity.

Description

technical field [0001] The invention relates to the technical field of lithium bisfluorosulfonyl imide, in particular to a method for purifying lithium bisfluorosulfonyl imide. Background technique [0002] Lithium bisfluorosulfonyl imide has the characteristics of good electrochemical stability, good hydrolysis resistance and high conductivity, and can be widely used in electrolytes, especially in power batteries, which can improve the cycle performance and rate performance of power batteries. [0003] There are many reports on the preparation method of bisfluorosulfonimide lithium at home and abroad (such as Japan Catalyst patent CN201180026278.0, Japan Soda’s patent CN103384641A and CN103347811A, Shanghai Kangpeng Chemical’s patent CN201510261089.1), and the existing technologies are all Using lithium hydroxide as the final reaction raw material, one of the obtained by-products is water. As a salt used in the electrolyte, the purity of lithium bisfluorosulfonylimide need...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B21/086
CPCC01B21/086C01P2006/80
Inventor 朱幼仙
Owner JIANGSU GUOTAI SUPER POWER NEW MATERIALS
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