A novel high-performance electrode: in-situ growth of copper sulfide film on copper foil for the application of supercapacitor

Copper sulfide (CuS) microspheres were directly grown on a copper foil via the redox reaction between CuSO4 and Na2S2O3. The morphology of the CuS film was observed by SEM and TEM, while the crystalline and structure were revealed by XRD pattern and UV spectrum. The electrochemical properties of the CuS electrodes were investigated by the cyclic voltammetry, galvanostatic charge–discharge and cycle stability technologies in 1 mol L−1 KCl electrolyte. The dependence of the concentration of CuSO4 and Na2S2O3 and reaction time on the properties of CuS films was discussed in detail. By means of these above comparisons, the CuS electrode that was obtained in 0.1 mol L−1 reactants concentration and 18 h reaction time possessed the homogeneous morphology, excellent electrochemical properties and good energy storage capacity. The specific capacitance was as high as 1443 F g−1 at a discharge density of 1 A g−1 and remained 1098 F g−1 after 2500 circles in the cycle life test.