Conductivity and Electrochemical Stability of Electrolytes Containing Organic Solvent Mixtures with Lithium tris(Trifluoromethanesulfonyl)methide

The effort to develop improved electrolytes which satisfy the requirements of a high voltage lithium rechargeable battery has prompted the search for new conductive salts which are thermally and electrochemically stable. We have identified a ternary solvent mixture containing the electrolyte lithium tris (trifluoromethanesulfonyl)methide, LiC ( CF 3 SO 2 ) 3 , that is conductive and electrochemically stable at cell potentials exceeding 4.0 V. Ionic conductivities were measured between −30 and 55°C, and electrochemical stability determined by cyclic voltammetry on glassy carbon, platinum, and aluminum substrates.