Revealing the High Salt Concentration Manipulated Evolution Mechanism on the Lithium Anode in Quasi‐Solid‐State Lithium‐Sulfur Batteries

Lithium-sulfur batteries are promising candidates of energy storage devices. Both adjusting salt/solvent ratio and applying quasi-solid-state electrolytes are regarded as effective strategies to improve the lithium (Li) anode performance. However, reaction mechanisms and interfacial properties in quasi-solid-state lithium-sulfur (QSSLS) batteries with high salt concentration are not clear. Here we utilize in-situ characterizations and molecular dynamics simulations to unravel aforesaid mysteries, and construct relationships of electrolyte structure, interfacial behaviour and performance. The generation mechanism, formation process, and mechanical/chemical/electrochemical properties of the anion-derived solid electrolyte interphase (SEI) are deeply explored. Li deposition uniformity and dissolution reversibility are further tuned by the sustainable SEI. These straightforward evidences and deepgoing studies would guide the electrolyte design and interfacial engineering of QSSLS batteries.