Artificial Alloy/Li₃N Double-Layer Enabling Stable High-Capacity Lithium Metal Anodes

The lithium metal battery is regarded as an excellent candidate for next-generation high energy density batteries. Nevertheless, due to the fragile solid electrolyte interphase derived from reaction with electrolytes, plenty of problems, including low Coulombic efficiency (CE) and dendrite growth, lead to rapid battery failure, which restricts its commercial application. Herein, we design a protective alloy/Li3N double-layer on lithium via Li–Sb alloying and further nitridation under mild conditions. The lower Li3Sb layer can adjust electric field distribution and reduce the Li+ nucleation overpotential, while the upper Li3N layer reveals high Li+ conductivity and a low energy barrier for the rapid Li+ transfer channel and benign mechanical strength. The composite anode exhibits stable dendrite-free cycling over 1100 h even under a deep deposition capacity (10 mA h cm–2). When matched with the S@pPAN cathode, it achieves prolonged lifespan over 300 cycles with a remarkable average CE of 99.9%. The easily operated method under mild conditions offers a feasible method toward stable lithium metal anodes and lithium metal batteries.