Inducing the Formation of In Situ Li₃N-Rich SEI via Nanocomposite Plating of Mg₃N₂ with Lithium Enables High-Performance 3D Lithium-Metal Batteries

Lithium metals fit the growing demand of high-energy density rechargeable batteries because of their high specific capacity and low redox potential. However, the lithium-metal anodes are abandoned because of various defects. In this study, we apply composite plating into the protection of lithium-metal anodes. We confirmed that the Mg3N2 nanoparticle dispersed in the ether electrolyte can be easily composite-plated with lithium, resulting in a flat, dense, and dendrite-free lithium deposition layer during the electrodeposition process. In addition, the Mg3N2 plated in the lithium metal phase would react with lithium and then generate a Li3N-rich solid electrolyte interphase (SEI) layer, mitigating continuous side reactions of the electrolyte on the Li metal. In addition, another product of the reaction is Mg which can work as lithiophilic sites in electrodeposition. The combined effect of the two fields can effectively improve the performance of lithium metal anodes. The Li3N-rich SEI layer would grow well on the surface of the three-dimensional (3D) lithium anode by composite plating. Furthermore, composite plating with the Mg3N2-containing electrolyte is a viable route that can be used for various 3D current collectors easily with a small volume effect. Here, we show that the composite plating 3D lithium metal anode is successfully applied in the Li–S battery with a long lifetime.