An Ether-Based Low Density Electrolyte for the Use of Graphite Anodes in Stable Lithium-Sulfur Batteries

Lithium sulfur (Li-S) batteries represent an interesting technology due to the high theoretical capacity of sulfur and the low cost of the cathode material. Li-S cells with graphite electrodes could be an option for low-cost stationary energy storage as graphite is cheap and the electrode production process is well established. Unfortunately, in most Li-S electrolytes, graphite is not stable due to solvent co-intercalation and degrades fast. In this work, a new low density electrolyte based on hexyl methyl ether (HME) and 1,3-dioxalane (DOL) is presented, which allows to use graphite as anode material for Li-S batteries. In symmetric graphite vs. graphite cells an averaged Coulombic efficiency of 99.94 % per electrode could be reached. For the first time, cycling conditions like voltage window and balancing were optimized for Li-S cells with graphite anodes and the suitability of the concept could be demonstrated in multilayer pouch cells under realistic conditions.