Investigation of a Fluorine-Free Phosphonium-Based Ionic Liquid Electrolyte and Its Compatibility with Lithium Metal.

A novel fluorine-free ionic liquid electrolyte comprising lithium dicyanamide (LiDCA) and trimethyl(isobutyl)phosphonium tricyanomethanide (PTCM) in a 1:9 molar ratio is studied as an electrolyte for lithium metal batteries. At room temperature, it demonstrates high ionic conductivity and viscosity of about 4.5 mS cm and 64.