Rational Solution-assisted Synthesis of Copper Sulfide Nanoparticles for Ultrahigh-rate Electrochemical Energy Storage

Abstract

The aim of this research work is to explore and compare electrochemical activity of the cupric sulfide (CuS) and cuprous sulfide (Cu2S) nanoparticles. For this purpose, CuS and Cu2S were synthesized by a facile chemical solution method. The morphology, structure, and surface area of the synthesized CuS and Cu2S nanoparticles were characterized by transmission electron microscope, X-ray diffraction, and Brunauer–Emmett–Teller analysis, respectively. The electrochemical activities of the prepared materials were studied by performing cyclic voltammetry and electrochemical impedance spectroscopy analysis in 1 M LiClO4 using a three-electrode system. It was observed that specific capacitance of the CuS (435 Fg−1) is higher than that of Cu2S (273 Fg−1) at the same current density (5 Ag−1). Furthermore, CuS retained 86% while Cu2S retained 75% of their initial capacitance after 6,000 charge–discharge cycles. Therefore, CuS owing to its higher electrochemical activity and cyclic stability is a superior electrode material than Cu2S for supercapacitor applications.