Intrinsic Shuttle Suppression in Lithium-Sulfur Batteries for Pouch Cell Application

Abstract

A new lithium-sulfur secondary battery concept is presented, realistically portrayed on pouch cell level, with its decisive element being a new electrolyte system, a mixture of a hydrofluoro ether and sulfolane. The hereby suppressed polysulfide solubility enables high discharge capacities and requires only very low electrolyte excess (< 2.6 µl mgS-1) achieving high coulomb efficiencies above 94 % (capacity retention of 77 % over 40 cycles) without the necessity of adding lithium nitrate for shuttle suppression. Due to the low volatility, this new electrolyte concept promises significant benefits for large operational battery units.