Artificial SEI Transplantation: A Pathway to Enabling Lithium Metal Cycling in Water-Containing Electrolytes

The activity of metallic anodes, such as Li, in water-containing electrolytes is essential for the development and realization of high-energy-density battery systems like Li–air. Due to the inherent incompatibility between Li and water, pathways must be established to allow these two materials to coexist in a battery system. In this work, the formation and transplantation of water-protective SEIs on the surface of Li metal using ionic liquid electrolytes allowed for the cycling of Li metal in water-containing organic electrolytes. Further, we found that these SEIs could be utilized to successfully cycle Li from air-containing organic electrolytes as well. This discovery opens an avenue of research wherein Li metal anodes find a practical use in Li–air batteries, allowing further development of a battery system capable of delivering the highest theoretical specific energy among rechargeable battery systems.