Lithium bis(trifluoromethanesulfonyl)imide solution

Lithium bis(trifluoromethanesulfonyl)imide in ethylene carbonate and dimethylcarbonate, 1.0 M LiTFSI in EC/DEC/DMC=1:1:1 (w/w/w) is a solution of battery-grade LiTFSI dissolved in a ternary mixture of EC/DEC/DMC (1:1:1) 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/DMC=1:1:1 (w/w/w) is as an electrolyte in LIBs. Lifetime and power capabilities in lithium-ion batteries (LIBs) depend on the electrolytes. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-based electrolytes are a promising alternative to LiPF₆-based electrolytes and often achieve longer lifetimes at high temperatures. In addition, LiTFSI is far less sensitive to hydrolysis and safer to handle than LiPF₆ because it does not hydrolyze to form HF. Ethylene carbonate (EC), diethyl carbonate (DEC) and dimethyl carbonate (DMC) are key solvents for lithium electrolytes. The role of EC in the electrolyte is to provide a high-dielectric solvent to dissolve the electrolytic salt and to help form an ionically conductive, passivating solid electrolyte interphase (SEI) on the electrodes. Notably, EC-based electrolytes are compatible with a graphite negative electrode. DEC and DMC have lower viscosities and melting points than EC, and when mixed with EC result in an electrolyte with a good balance between desirable electrochemical properties, high dielectric constant, and low viscosity.