A facile one-step hydrothermal synthesis of Ni1-xCoxS as active electrode material in non-aqueous electrolyte for supercapacitors application

In this present work, a one-step hydrothermal approach was employed for the synthesis of ternary metal sulfides (TMS) for the preparation of high performance electrochemical supercapacitor electrode materials. Powder X-ray diffraction confirmed the formation of rhombohedral structure of NiS, hexagonal structure of the CoS and cubic structure of Ni1-xCoxS. The peaks obtained in the Fourier transform infrared spectroscopy (FTIR) also confirmed the formation of NiS, CoS, Ni1-xCoxS (x = 0.1,0.2 & 0.3) compounds. Field emission scanning electron microscopy revealed severe agglomeration and spongy microstructure with decreasing Ni content, while fine distribution of particles with less porosity with low Ni content in Ni1-xCoxS.The electrochemical behaviour of the fabricated Ni0.8Co0.2S electrode exhibited high specific capacitance of 71.92F/g at 5 mV/s in a potential window range from 0.25 to −0.3 V in 0.1 M non-aqueous electrolyte of TEABF4 in acetonitrile (AN) at room temperature. An excellent cycling stability was obtained up to 5,000 cycles with 87% capacitance retention.