Lithium chloride protective layer for stable lithium metal anode via a facile surface chemistry

Li metal anode is a potential candidate for high-energy–density batteries. However, Li dendrites and the side reactions bring challenges to the application of Li metal anode. Herein, a LiCl protective layer is fabricated on the surface of Li metal anode by a facile chemistry process. Attributing to the low Li ion diffusion energy barrier and high stability of LiCl, the Li metal with LiCl layer (LiCl@Li) shows a dendrite-free deposition, forming a robust LiF-riched SEI and effectively suppresses the interfacial side reactions during cycling. The LiCl@Li anode sustains repeated plating/stripping over 500 h with flat overpotential and shows 2.8 times longer lifetime than bare Li anode at a current density of 2 mA cm−2. We believe this work would inspire more opportunities in Li surface engineering and accelerate the development of high-reliability Li metal anode.