Thiolate-Based Electrolytes with Anion-Dominated Solvation for Highly Stable Lithium Metal Batteries

Lithium metal has been regarded as one of the promising anodes due to its high theoretical specific capacity and low electrochemical potential. However, it is still hampered by the unstable solid electrolyte interface (SEI) and lithium dendrites. Herein, we report a class of thiolate-based salts with low dissociation but moderate ionic conductivity in ether mixture solvents for rechargeable lithium batteries, which leads to an anion-dominated solvation structure at standard concentration and is conducive to the formation of a dense LiF-rich SEI layer on the lithium metal anode surface, thereby inhibiting the continuous decomposition of the electrolyte. In addition, they are simple to prepare and have high solubility, low cost, and excellent lithium-ion transference number. Such an electrolyte is successfully applied in a Li/Li4Ti5O12 half-cell and shows promising battery performance. This work inspires a new direction to construct stable anion-derived SEI via designing the structure of lithium salts.