Endowing the Lithium Metal Surface with Self-Healing Property via an in Situ Gas–Solid Reaction for High-Performance Lithium Metal Batteries

The property of the solid electrolyte interphase (SEI) layer is of prime importance for the performance of lithium metal anodes. Replacing the spontaneously formed inhomogeneous and unstable SEI layer with a high-performance artificial SEI is an effective strategy. Herein, a self-healing SEI layer with high lithium-ion conductivity and a stable framework to address the issues of poor performance of lithium metal anodes is achieved. C, Li 2 S, and LiI are uniformly distributed on the lithium surface via a “sauna” reaction between CS 2 –I 2 mixed steam and metal lithium, which has the potential to be applied to large-scale preparation. The obtained SEI layer possesses high mechanical strength and facilitated lithium-ion transport capability, which are inherited from the amorphous C and lithium compounds (Li 2 S and LiI). Most importantly, the LiI component can migrate through the electrolyte and cover the exposed lithium caused by flaws and cracks, leading to a self-healing property. As a result, the C–Li 2 S–LiI@Li electrode exhibits excellent electrochemical performance with low overpotential and long lifespan.