Thermochemical and Electrochemical Stability of Electrolyte Systems based on Sulfolane

UV spectroscopy and cyclic voltammetry were used to examine the thermochemical and electrochemical stabilities of liquid sulfolane-based electrolyte systems for lithium and lithium-ion batteries. It was found that solutions of lithium salts in sulfolane are stable in prolonged keeping at 100°C. The thermochemical stability of lithium salt solutions in sulfolane changes in the order LiBF 4 > LiClO 4 ≈ LiN(CF 3 SO 2 ) 2 > LiCF 3 SO 3 . It was shown that the electrochemical stability of lithium salt solutions in sulfolane is in the range from 5.5 to 5.9 V (relative to Li/Li + ) and prolonged action of high temperatures (100°C) does not yield electrochemically active thermal destruction products.