What are the advantages and preparation process of LiFSI?

LiFSI is an important new fluorine-containing material and a new type of electrolyte lithium salt. LiFSI has good electrochemical properties and thermal stability, and is low in toxicity and environmentally friendly; therefore, it is a promising electrolyte in lithium ion batteries.

LiFSI is considered to be a lithium salt promising to replace LiPF6, and LiFSI has replaced LiPF6 in some new power battery formulas.Compared with LiPF6, LiFSI has the following adwantages:

1.     LiFSI has a larger anion radius, which is easier to dissociate lithium ions and improve the conductivity of lithium ion batteries;

2.     LiFSI has a wider operating temperature range and better stability: when the temperature is greater than 200 ° C, LiFSI can still exist stably, without decomposition, and has good thermal stability, thereby improving the safety performance of lithium-ion batteries;

3.     The specific energy density of LiFSI is greater, which can effectively improve the discharge load characteristics at low temperatures and maintain the capacity retention rate after high-temperature storage. The electrolyte with LiFSI as the electrolyte maintains good compatibility with the positive and negative electrode materials, which can significantly improve the high and low temperature performance of lithium ion batteries.

Due to its excellent structural stability and electrochemical performance, LiFSI is not only widely concerned in the academic community, but also favored by researchers in the industry. Research on the preparation process of LiFSI has also been the focus of attention.

There are usually three processes for the preparation of LiFSI, including the synthesis of BCSA, the fluorination reaction of BCSA to prepare bisfluorosulfonimide and the preparation of LiFSI. In recent years, in order to further improve the quality of LiFSI and meet the requirements of battery applications, some purification methods for LiFSI have been developed.