Fabrication of nickel foam/ nickel phosphide (Ni/Ni2P) composite for dendrite-free and long-life lithium metal anodes
Wenting Xu, Yaning Li, Yaping Wang, Na Xin, Kui Wang, Huanhuan Li, Chaochun Yuan
Abstract
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.