Method for preparing imidodisulfuryl fluoride lithium

Abstract

The invention provides a method for preparing imidodisulfuryl fluoride lithium. The method comprises the following steps: (1) reacting imidodisulfuryl fluoride with antimony trifluoride under a solvent free condition, and distilling to obtain imidodisulfuryl fluoride lithium intermediate; (2) reacting metal lithium with anhydrate low alcohol, and concentrating and drying to obtain anhydrate low alcohol lithium; and (3) reacting the imidodisulfuryl fluoride lithium with lithium alkoxide, concentrating, pulping, filtering and drying to obtain a high-purity imidodisulfuryl fluoride lithium product. The method for preparing the imidodisulfuryl fluoride lithium has the characteristics of low cost, high purity and simple operation, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a lithium battery electrolyte additive, in particular to a preparation method of lithium bisfluorosulfonyl imide. Background technique [0002] Lithium bisfluorosulfonyl imide (Li[N(SO 2 F) 2 ], hereinafter referred to as LiFSI), is a very important lithium battery electrolyte additive, which has the advantages of high electrical conductivity, good thermal stability, high electrochemical stability, good cycle performance, and good safety performance. Compared with a wide range of LiPF6, it has many excellent properties, and is a better choice for lithium battery electrolytes. [0003] In the prior art, the preparation methods of lithium bisfluorosulfonyl imide mainly contain the following types: [0004] Chinese patent CN103524387A has reported that bischlorosulfonimide (HClSI) reacts with lithium chloride in thionyl chloride to generate bischlorosulfonimide lithium (LiClSI), and then utilizes metal fluoride (KF, ZnF 2 etc....

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Problems solved by technology

[0004] Chinese patent CN103524387A has reported that bischlorosulfonimide (HClSI) reacts with lithium chloride in thionyl chloride to generate bischlorosulfonimide lithium (LiClSI), and then utilizes metal fluoride (KF, ZnF 2 etc.) the fluorinating agent reacts with LiClSI to obtain LiFSI, and the introduction of the second step metal salt in this reaction route will cause difficulties in separation from the final product, thereby failing to obtain high-purity LiFSI

[0005] Chinese patent CN101747242 discloses potassium bisfluorosulfonimide (KFSI) to obtain LiFSI after carrying out ion exchange reaction with lithium perchlorate in solvent, but the product that this reaction route obtains can always remain a small amount of perchlorate (ClO 4- ) and potassium ions (K + ), unable to obtain high-quality LiFSI

[0006] U.S. Patent US2004097757 uses lithium fluoride (LiF) to directly fluorinate HClSI and form a salt. This process will generate a large amount of HF gas, which is highly corrosive to equipment and highly toxic, and has a great impact on the environment and human body.

[0007] Chinese patent CN106365132A uses sulfamic acid or sulfamoyl fluoride and fluorosulfonic acid to react with fluorosulfoxide to prepare HSFI, and then reacts with lithium compounds such as lithium carbonate or lithium bicarbonate to prepare LiFSI, wherein fluorosulfoxide is a gas , the operation is more difficult and the risk is higher, and the use of carbonate method can lead to the production of products with crystal water, which makes drying very difficult

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