A study on MnCo2S4@NiCo(OH)2 core-shell nanocomposite for high-performance solid-state supercapacitor applications

Abstract

A three-dimensional MnCo2S4@NiCo(OH)2 (MCS@NCOH) core-shell nanostructure is grown on nickel foam by a simple and facile method which includes a hydrothermal treatment and an electrochemical deposition. The MnCo2S4 (MCS) nanorod arrays not only show excellent electrochemical performance by themselves, but also use as effective scaffolds to load additional active materials for enhancing the capacitance of the electrode. After adding a thin layer of NiCo(OH)2 nanosheet on Ni foam-MnCo2S4 electrode, the mechanical stability of the whole electrode is reinforced with larger electro-active surface area, richer redox reactions and good electrical conductivity to facilitate electron transport and ion diffusion, resulting in higher charge storage capacity. The Ni foam-MnCo2S4-NiCo(OH)2 hybrid electrodes are further assembled into a solid-state supercapacitor (SC) which exhibits a high energy density of 95 mWh/m², power density of 55.4 W/m² and good rate capability.