Thermochemical and Electrochemical Stability of Electrolyte Systems based on Sulfolane

Abstract

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 LiBF₄ > LiClO₄ ≈ LiN(CF₃SO₂)₂ > LiCF₃SO₃. 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.