Cation substituted Ni3S2 nanosheets wrapped Zn0.76Co0.24S nanowire arrays prepared with in-situ oxidative etching strategy for high performance solid-state asymmetric supercapacitors

Abstract

Engineering the electrodes with multicomponent materials and rational structure are the most effective strategies for high-performance supercapacitors. However, one of the remained challenges is synchronously increasing the structural complexity and promoting redox kinetics. Herein, Zn0.76Co0.24S@Zn.Co-doped Ni3S2 core-shell electrodes (ZCS@ZCNS) were synthesized through an in-situ oxidative etching and sulfidation process. This process realizes sulfidation and metal atoms doping at the same time, and maintains the efficient interface connection between core and shell materials, which can realize the synergistic effect of each component and hence not only induce more active sites but also enhance conductivity and structural stability. The obtained ZCS@ZCNS electrode exhibits the high specific capacitance of 6.4 F cm−2 at 2 mA cm−2, out-standing rate capabilities of 64% capacity retention at 40 mA cm−2, and excellent cycling stability. Moreover, the obtained ZCS@ZCNS//active carbon liquid-state and solid-state asymmetric supercapacitors can both deliver the high energy density of 50.8 W h kg−1 and 43.9 W h kg−1, respectively. This strategy offers a scalable, simple, and cost-effective approach for the large-scale fabrication of other high-performance metal-sulfide-based electrodes in next-generation electronics.