Lithium bis(trifluoromethanesulfonyl)imide solution

Lithium bis(trifluoromethanesulfonyl)imide in ethylene carbonate and diethylcarbonate, 1.0 M LiTFSI in EC/DEC=25/75 (w/w) is a solution of battery-grade LiTFSI dissolved in binary mixture of EC/DEC (25:75) wt%. The product is a clear solution with strictly minimized impurities including low moisture (<100 ppm), low trace metals (≤10 ppm Na and K), low chloride (<10 ppm), and low sulfate (<10 ppm).

The main application of 1.0 M LiTFSI in EC/DEC=25/75 (w/w) is as an electrolyte in Li-ion batteries. LiTFSI-based electrolytes have advantages over LiPF₆-based electrolytes because they are less sensitive to hydrolysis, safer to handle, and are more stable thermally and electrochemically. In a study it has been observed that LiTFSI electrolyte exhibit a better reversible redox reaction and hence the full-cell battery using LiTFSI electrolyte exhibited higher specific capacity than the battery cell using LiPF₆ electrolyte, namely 83.1 mAh/g and 101.5 mAh/g for the LiPF₆ and LiTFSI electrolytes, respectively. The main drawback of the concentrated EC–LiTFSI electrolytes is the relatively low ionic conductivity (<1.0 mS cm⁻¹) at ambient temperature. A mixture of EC/DEC with LiTFSI, significantly increase the conductivity of the concentrated electrolytes, especially at low temperatures. Also, the concentrated LiTFSI EC/DEC electrolyte effectively suppress the Al corrosion at high voltage in LIBs.