LITHIUM-SULFUR BATTERY - EVALUATION OF DIOXOLANE-BASED ELECTROLYTES

The lithium-sulfur battery recently developed in our laboratory shows 95%+ sulfur utilization but low rate capability due to its poorly conducting electrolyte, which is based on the THF:toluene solvent mixture. In order to increase the rate capability of this cell, dioxolane-based electrolytes have been evaluated. The conductivitiy of LiClO, electrolytes consisting of mixtures of THF, toluene, and dioxolane were measured in the temperature range -30° to +60°C. The compatibility of lithium with these electrolytes was also studied. It was found that dioxolane-rich electrolytes are compatible with lithium and have one order of magnitude higher conductivity than do THF:toluene-rich electrolytes. However, sulfur utilization in dioxolane-rich electrolytes is only 50%, even at a very low discharge rate. This is due to a different discharge product, namely, Li2S2.