NiCo2S4 nanosheet-decorated 3D, porous Ni film@Ni wire electrode materials for all solid-state asymmetric supercapacitor applications.

Wire type supercapacitors with high energy and power densities have generated considerable interest in wearable applications. Herein, we report a novel NiCo2S4-decorated 3D, porous Ni film@Ni wire electrode for high performance supercapacitor application. In this work, a facile method is introduced to fabricate a 3D, porous Ni film deposited on a Ni wire as a flexible electrode, followed by decoration with NiCo2S4 as an electroactive material. The fabricated NiCo2S4-decorated 3D, porous Ni film@Ni wire electrode displays a superior performance with an areal and volumetric capacitance of 1.228 F cm-2 and 199.74 F cm-3, respectively, at a current density of 0.2 mA cm-1 with a maximum volumetric energy and power density (EV: 6.935 mW h cm-3; PV: 1.019 W cm-3). Finally, the solid state asymmetric wire type supercapacitor is fabricated using the fabricated NiCo2S4-decorated 3D, porous Ni film@Ni wire as a positive electrode and N-doped reduced graphene oxide (N-rGO) as a negative electrode and this exhibits good areal and volumetric capacitances of CA: 0.12 F cm-2 and CV: 19.57 F cm-2 with a higher rate capability (92%). This asymmetric wire type supercapacitor demonstrates a low leakage current and self-discharge with a maximum volumetric energy (EV: 5.33 mW h cm-3) and power (PV: 855.69 mW cm-3) density.