Long-term stable Li metal anode enabled by strengthened and protected lithiophilic LiZn alloys

Abstract

Li metal are regarded as one of the most promising anodes for next-generation rechargeable batteries. The continuous growth of Li dendrites, however, remains a big challenge for the practical application of Li metal anodes. Herein, an artificial solid-electrolyte interphase layer composed of lithiophilic LiZn alloys under the protection and strengthening of polymer-like [LiNBH]n chains with high Li ion conductivity is built to develop long-term dendrite-free Li metal anodes. The lithiophilic LiZn alloys, acting as homogeneous nucleation sites, effectively reduce the nucleation barrier for Li plating and hence promote uniform Li plating and stripping process. Simultaneously, the homogeneous layer of polymer-like [LiNBH]n chains with high Li ion conductivity that are uniformly built inside of LiZn alloys and on the surface of LiZn alloys facilitates Li diffusion down into LiZn alloys and simultaneously alleviate the volume change of LiZn alloys during long-term Li plating and stripping process. Impressively, the thus-fabricated anode delivers an ultralong lifespan of 1200 h at 5 mA cm−2 with a fixed capacity of 5 mA h cm−2. By pairing with commercial LiFePO4 cathode, the thus-assembled full cell exhibits a specific capacity of 133 mA h g−1, corresponding to a capacity retention of 88%, at 1 C after 400 cycles.