Suppressing electrode passivation by electrodeposition control of Li2S for high-performance Li-S batteries

Abstract

Lithium-Sulfur Batteries with high theoretical energy density (>2600 Wh/kg) are very promising for next generation batteries. However, despite of its high theoretical energy density, higher sulfur utilization is impeded because $Li_2S$ which has low electrical conductivity covers the electrode. Herein, we successfully controlled electrodeposition of $Li_2S$ from synergistic effect of electrode and electrolyte design. From introducing CoP nanoneedle arrays with high electrical conductivity, $Li_2S$ nucleation could be focused on near the top surface of needle. Moreover, with LiBr electrolyte with high $Li_2S$ solubility, $Li_2S$ could be grown near the top surface, so the bottom part of needles was not passivated. From electrodeposition control of $Li_2S$, electrode passivation could be successfully retarded and it showed more than 1400 mAh/gs.