Electrochemical deposition of Li₂S₂/Li₂S in aprotic Li–S batteries

Lithium–sulfur (Li–S) batteries stand out the energy storage systems because of extremely high energy density (2600 W h Kg⁻¹) and low-cost sulfur cathode. Unfortunately, the sluggish deposition from liquid Li polysulfides (LiPSs) to solid Li₂S leads to mild power density and short cycle life. Understanding and regulating Li₂S₂/Li₂S deposition are conceived to be importance to deliver second-plateau capacity in acceptable kinetics, which has the potential to operation Li–S batteries under electrolyte-lean conditions. This perspective aims to summarize the proposed models that can describe the nucleation and propagation of three-dimensional Li₂S₂/Li₂S, as well as affords critical views how electrolyte dictates LiPS conversion from liquid to solid. It hopes to encourage necessary scaffold strategies and electrolyte formulations to further improve energy density and life span of Li–S batteries.