Lithium bis(fluorosulfonyl)imide (LiFSI) favored by industry and academia

Lithium bis(fluorosulfonyl)imide (LiFSI) is a important high-performance electrolyte material in new energy devices such as lithium-ion batteries and supercapacitors. The LiFSI has good structural stability and excellent electrochemical performance, not only has high industrial application value, but also is favored by researchers in academia.

By fluorinating the bischlorosulfonimide, the bisfluorosulfonimide lithium salt product can be prepared. Most of the existing synthetic methods for LiFSI are to first synthesize bischlorosulfonimide (HClSI), and then react with fluorometal salt to prepare the corresponding bisfluorosulfonimide Salt intermediate, the intermediate is cation exchanged with lithium hydroxide (LiOH) or lithium carbonate (Li₂CO₃) to prepare LiFSI.

The disadvantage of this type of method is that it is difficult to continue to complete the cation exchange after reaching equilibrium, and it is difficult to completely separate the unreacted intermediate from LiFSI, so that high-quality products cannot be obtained. In order to increase the yield of bisfluorosulfonimide lithium salt and avoid the above-mentioned problems, people have improved the preparation process of bisfluorosulfonimide lithium salt, and directly use bisfluorosulfonimide to react with LiOH or Li₂CO₃ to produce LiFSI . For example, the patent ^[1] CN 104925765A, firstly obtain bisfluorosulfonimide by reacting bischlorosulfonimide with hydrogen fluoride, and then bisfluorosulfonimide and lithium hydroxide or lithium carbonate in the low electrode The reaction in a neutral solvent generates bisfluorosulfonimide lithium salt.

However, the preparation process of LiFSI still has disadvantages such as complex preparation process, high raw material cost, low product purity, etc. LiFSI is commonly used in electrolytes, especially in power batteries such as lithium batteries, which can improve the cycle performance and rate of power batteries Performance, in order to make the quality of LiFSI to meet the requirements of different electrolytes, its purification process of has become a research focus.

Related Links: Lithium bis(fluorosulfonyl)imide (LiFSI)

references:

1. Preparation method for difluorosulfimide lithium salt. CN104925765A