An in situ formed lithiophilic Ni3S2@Ni current collector for stable lithium metal batteries

Abstract

Attracting immense interest as a lithium storage material, lithium metal anodes boast the highest specific capacity of 3860 mA h g⁻¹ and lowest redox potential of −3.04 V, compared to the standard hydrogen electrode, and sustainability. Nevertheless, extreme dendrite growth, severe lithium deposition, and enormous volume alteration have seriously impeded the practical progress of lithium anodes. To address these problems, researchers have proposed to construct three-dimensional (3D) current collectors, which can adjust Li deposition and improve cycle stability. Herein, we in situ grow lithiophilic Ni₃S₂ nanowire arrays on a porous nickel current collector (hereinafter denoted as Ni₃S₂@Ni) by a simple hydrothermal reaction, which significantly improved the Li metal anode performance. This Ni₃S₂@Ni composite current collector has a relatively uniform and open micro–nano structure, which facilitates Li⁺ ion migration/diffusion and also improves electrode–electrolyte interfacial properties. In addition, the Ni₃S₂@Ni composite current collector achieves a prolonged lithium plating/stripping lifespan of 900 hours at 2 mA cm⁻² without short circuit in symmetrical batteries. Furthermore, a full cell assembled with the composite current collector and a LiFePO₄ cathode demonstrates outstanding cycling stability, where the capacity retention is 80.6% after 500 cycles at 1C. Our proposed 3D Ni₃S₂@Ni composite current collector will further boost the development of stable Li metal anodes.