Regulating Li deposition by constructing homogeneous LiF protective layer for high-performance Li metal anode

Abstract

Uniform lithium (Li) deposition and stable interface between anode and electrolyte are crucial factors for realizing the practical application of Li metal anode. Herein, a homogeneous lithium fluoride (LiF) protective layer with many nano slits is constructed on the Li anode by a facile vacuum evaporation method. It can uniformize the Li ion flux at surface of anode via its homogeneity and suppress the violent side reaction between Li and electrolyte via its good compactness. The existence of nano-slits allows the penetration of electrolyte and thus providing sufficient lithium ions transmission channels. Therefore, such a homogeneous LiF layer effectively inhibits the growth of Li dendrites and alleviates the consumption of active Li metal, significantly improving the stability of Li anode during long-term cycles. With the LiF-protected Li anode, the full cell with LiFePO4 cathode delivers 2.5 times longer lifespan and slower capacity attenuation than control cells. This work highlights significant roles of homogeneous protective layer in stabilizing Li anode and supplies new insights in the design of anode interphase for rechargeable lithium metal batteries (LMBs).