Fabrication of nickel foam/ nickel phosphide (Ni/Ni2P) composite for dendrite-free and long-life lithium metal anodes

Lithium metal batteries, with high theoretical specific capacity, hold promise as next-generation high-energy-density batteries; however, challenges like lithium dendrite formation and volume expansion adversely affects their cycle life and safety. To address the problems of lithium dendrite growth and interface instability in lithium metal batteries, a novel Ni@Ni₂P-Li composite anode was proposed, which was prepared by physical compression and sodium hypophosphite-induced phosphating of nickel foam. The in-situ formed Ni₂P coating significantly enhanced the lithium affinity of the nickel foam substrate, making lithium deposition uniform and effectively inhibiting the formation of dendrites. Compared with the conventional Ni-Li anode, the Ni@Ni₂P-Li composite exhibited excellent electrochemical stability, achieving ultra-low overpotential (<29.9 mV) and stable cycling for more than 3000 h in symmetric cells. Full cell tests of NCM622 cathode further demonstrated the excellent rate capability and cycling durability. The hierarchical three-dimensional porous structure and the lithophilic Ni₂P interface synergistically reduced the local current density and mitigated the volume fluctuation. This study provides new ideas and methods for the further development of lithium metal anodes.