Lithophilic secondary structure enables robust solid electrolyte interface for highly stable lithium metal battery

The 3D substrates with large specific surface area which can reduce the volume change of anodes have been used to realize stable lithium metal batteries (LMBs). However, the capacity and long-term stability of LMBs are hampered by the growth of lithium dendrites and side reactions of the electrode-electrolyte interface, which are still unable to be addressed by the enlarged specific surface. In this study, CuO/Cu₃N foam current collector with fiber secondary structure is constructed, where the increased active sites and lithophilic surface layer accelerate the kinetics of lithium transport, and the sturdy Li₂O/Li₃N solid electrolyte interface (SEI) is generated during the lithium plating, which effectively reduces the adverse side reactions and promotes the uniform deposition of Li. The symmetric cell of CuO/Cu₃N foam@Li cycles stably for more than 1500 h and exhibits an outstanding cycle life of more than 500 h at high current density and capacity of 5 mA cm⁻² and 5 mAh cm⁻². And CuO/Cu₃N foam@Li||LFP full cell exhibits an excellent cycling performance of 350 cycles with a high capacity retention rate of 78 %. This work provides valuable insights into the development of advanced current collectors for high-energy LMBs.