Free-standing films of nickel nanowires anchored with Ni3S2 nanosheets for stable Li anodes

Abstract

Lithium (Li) metal is widely recognized as the most promising material for anodes in next-generation high-energy rechargeable batteries. However, challenges such as an unstable solid–electrolyte interphase (SEI) and significant volume changes leading to uncontrolled growth of Li dendrites have hindered the practical application of Li metal batteries. Herein, a free-standing three-dimensional (3D) scaffold of nickel nanowires (NiNWs) decorated with lithiophilic Ni₃S₂ nanosheets (NiNWs@Ni₃S₂) was successfully constructed for stable Li anodes. Various characterization studies and density functional theory simulations confirmed that the lithiophilic surface of Ni₃S₂ nanosheets could reduce the Li nucleation barrier, facilitating uniform Li ion deposition. Remarkably, the Li₂S-rich nanoscale SEI layer that forms after the initial activation process effectively enhances ion transfer kinetics, leading to rapid Li ion transport and enhanced cycling performance. Furthermore, the 3D porous structure of NiNWs@Ni₃S₂ provides sufficient space to accommodate the volume changes of Li during the plating/stripping process. As a result, the NiNWs@Ni₃S₂ symmetrical cell demonstrates a long-term stability of over 2250 hours at 1 mA cm⁻² and 900 hours at 5.0 mA cm⁻² with low voltage hysteresis. The assembled Li-NiNWs@Ni₃S₂‖LiFePO₄ full cell exhibits improved rate and cycling performances over 2000 cycles at 5C. Overall, the unique structure of NiNWs@Ni₃S₂ offers a straightforward method for creating a 3D lithiophilic host and introduces the concept of interfacial engineering by incorporating an artificial Li₂S-rich nanoscale SEI layer for high-performance Li metal anodes.