Synthesis and characterization of nickel cobalt Sulfide (NiCo2S4) for electrodes

Abstract

In this study, we have synthesized the Nickel Cobalt Sulfide (NiCo2S4) using the hydrothermal method. We have optimized synthesis parameters such as reaction precursor concentration, temperature, and time to gain various morphologies, including nanoparticles, nanoplates, and nanoflakes. The morphology of the synthesized NiCo2S4 (NCS) sample is confirmed by Field emission scanning electron microscopy (FESEM). The X-ray diffraction spectra confirm that the obtained morphologies are of cubic crystal structure with better crystallinity without any impurity. Furthermore, the chemical and electronic properties of NCS samples were performed from Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS). After that, NCS samples were drop cast over the Ni foam (1× 1.5 cm in size) and used for electrochemical measurements. Cyclic voltammetry (CV) showed that the NCS samples behave like a battery-type electrode. Galvanostatic charge-discharge (GCD) studies revealed that the NCS supercapacitor electrode consisting of nanoflakes arranged in mesoporous microflowers format gained a favorable power density of 2750 W/kg at an energy density of 14.254 Wh/kg, and excellent specific capacitance of 1968.870 F/g at 2 A/g. We also performed the cyclic stability at the current density of 10 A/g, and 88.86% capacitance retained was observed after continuous 5000 charge-discharge cycles. Therefore, NCS nanoflakes are promising electrode materials to fabricate hybrid supercapacitor devices.