Facile preparation and high capacitance performance of copper sulfide microspheres as supercapacitor electrode material

摘要

Copper sulfide (Cu2S) microspheres were easily prepared by reducing copper sulphate with ascorbic acid in sodium thiosulfate solution at room temperature and employed copper sulphate and sodium thiosulfate as Cu and S sources, respectively. The as-prepared Cu2S microspheres were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical properties including cyclic voltammetry, galvanostatic charge-discharge measurements and electrochemical impedance spectroscopy were also investigated. The experimental results showed that the as-prepared Cu2S microspheres based on the three-electrode test system exhibited a maximum specific capacitance of 444.2 F g(-1), and the energy density was up to 25.4 Wh.kg(-1) with high power density of 4.1 kW kg(-1) at the current density of 1 A g(-1). Furthermore, Cu2S microspheres also showed outstanding long-term cycling stability with more than 87% capacitance retention over 6000 cycles due to their microspheres structure, which facilitate efficient charge transport and promote electrolyte diffusion. The Cu2S-1:1.5 was used as a positive electrode for the fabrication of asymmetric supercapacitor along with reduced GO as the negative electrode, which delivered the high energy density up to 18.6 Wh.kg(-1) along with long cycling life and retains up to 89% specific capacitance after 6000 cycles. The excellent results suggest that the Cu2S microsphere is a promising candidate as electrode material for high performance supercapacitors.