Construction of hierarchical CoS nanowire@NiCo₂S₄ nanosheet arrays via one-step ion exchange for high-performance supercapacitors

In this paper, using CoS@NiCo₂S₄ as an example, we report the successful design and synthesis of a novel hierarchical core/shell metal sulfide with conductive CoS on nickel foam via a facile ion exchange process. The prepared sulfide core/shell nanoarrays exhibit superior redox reactivity for supercapacitors. High areal capacitances of 7.62 F cm^-2 (almost a 2.5-fold enhancement compared with the CoO nanowire@NiCo₂O₄ sheet arrays) at a scan rate of 5 mA cm^-2 and even 5.52 F cm^-2 at 30 mA cm^-2 were achieved. The superior electrochemical performance demonstrates that the CoS nanowire@NiCo₂S₄ sheet arrays are promising for high-performance supercapacitor applications.