A high rate and long cycling life lithium metal anode with a self-repairing alloy coating

Abstract

Li metal is regarded as the best candidate for anode materials because of its high theoretical capacity and negative electrode potential. However, due to the continuous parasitic side reactions and messy growing Li dendrites, the practical use of the Li metal as an anode is seriously limited. An in situ formed artificial solid electrolyte interface (SEI) can commendably solve the above-mentioned problems; however, inevitable cracks and fractures are found during their long-term service due to the existence of inorganic compounds (or alloys) in the artificial-SEI. Herein, a self-repairing alloy for protecting the Li metal anode was prepared via a facile in situ reaction. A long-term cycling life of more than 1800 h and 1400 h was obtained for the self-repairing alloy protected Li metal anode at a practical current density of 2 mA cm⁻² and 5 mA cm⁻². Even after increasing the deposition capacity to 15 mA h cm⁻², no dendrite formation was detected in the self-repairing alloy protective Li anode. This is expected to be a promising strategy in achieving a stable Li metal anode/electrolyte interface and providing a new way of thinking for the development of Li metal batteries.