Hierarchical structure lithiophilic current collector for dendrite-free lithium metal anodes

Lithium metal batteries (LMBs) have attracted great attention due to their ultra-high energy density and is expected to assist the upcoming generation of energy storage devices. However, the uncontrollable Li dendrite growth as well as unlimited volume expansion severely inhibited its practical application. Herein, the porous nickel foam current collector modified with hierarchical structure of Ni2P nanorods was constructed to overcome above hurdles. The porous nickel foam provides sufficient buffer space for the volume change generated by lithium deposition, and the Ni2P nanorods array further increases the specific surface area to lower the local current density. Notably, during the discharge process, Ni2P can react with Li to in situ generate lithiophilic Li3P, which forms a hybrid electronic/ionic conductor skeleton with the nickel foam substrate. The experimental and simulation results further confirm its excellent lithium-ion transport kinetics. The symmetric cell therefore stable cycled at 2 mA cm-2 for over 500 h with an ultralow over potential of 30 mV. This work presents a new design of three-dimensional current collector for fabricating high-performance lithium metal batteries.