Optimizing the sulfur precursor for the synthesis of NiCo2S4 nanoparticles as high performance supercapacitor electrodes

Abstract

In this report, NiCo2S4 nanoparticles (NPs) are successfully synthesized by a simple cost effective one step hydrothermal method using dissimilar sulfur sources (thiourea- NTU, thioacetamide- NTA) separately. The influence of sulfur source on structure, morphological, surface area and electrochemical performance are examined carefully. The X-Ray Diffraction Pattern of both samples displays the cubic phase of spinel NiCo2S4 crystal structures. TEM studies reveal Uniform Spherical (19–21 nm) and spheroidal (22–23 nm) shaped NPs. XPS spectra of both sample conforms the coexistence of Ni3+ and Ni2+ valence states of spinel cubic NiCo2S4. The surface area of NTA- NiCo2S4 found superior (91.23 m2 g−1) than NTU- NiCo2S4 (43.12 m2 g−1). The Electrochemical performance of NTA based NiCo2S4/Ni foam electrode results in showing high specific capacity values of 1051.49 C g−1 (292 m A h g−1) compare with NTU- NiCo2S4 (690 C g−1/191 m A h g−1) at a current density of 2 A g−1 moreover, NTA- NiCo2S4 holds exceptional Capacity retention of 98 % after 10,000 GCD cycles at current density of 6 A g−1 with excellent energy density of 88.377 W h Kg−1 with power density of 2179.15 W kg−1. The admirable electrochemical performance of NTA- NiCo2S4 brings out potential anticipation in supercapacitor applications.