Self-Regulated Phenomenon of Inorganic Artificial Solid Electrolyte Interphase for Lithium Metal Batteries

Solid electrolyte interphase (SEI) is crucial for suppressing Li dendrite growth in high-energy lithium metal (LiM) batteries. Unfortunately, the naturally formed SEI on the LiM anode surface in carbonate electrolytes cannot suppress Li dendrites, resulting in a continuous consumption of electrolytes and LiM during cycling. Artificial SEI normally lacks self-healing and self-regulating capability, gradually losing the effectiveness during cycling. In this work, we report the self-regulating phenomenon of LiRAP-ASEI that can effectively suppress Li dendrites and is investigated using in situ optical microscopy and COMSOL multiphysics simulation. The effectiveness of self-regulated LiRAP-ASEI is further evaluated in the most aggressive Li/sulfur cells with a lean electrolyte (10 μL mAh^-1) and LiRAP-ASEI/LiM (2.5-fold excess of LiM). The LiRAP@Cu∥sulfur@C cells show a stable 3000 cycle life at a current density of 11.5 mA cm^-2. The self-regulated phenomenon holds great promise for the development of high-energy-density LMBs.