1st Paragraph: Cobalt sulfide (CoS) and Copper sulfide (CuS) are both considered as promising electrode materials for supercapacitor (SC) due to their high theoretical capacity, low cost and environmental friendliness. In this work, CoS-CuS composite in micron size is successfully synthesized via a simple hydrothermal method. As compared samples, CoS and CuS are also prepared under the same condition. XRD and SEM are employed to examine their structures and morphologies. The as-obtained CoS-CuS composite exhibits a high specific capacitance of 60.5 Fg-1 at a current density of 1 Ag-1, compared to 42 Fg-1 for CoS and 35 Fg-1 for CuS. The Nuquist diagram of the as-obtained CoS-CuS composite displays smaller impedance than that of CoS and CuS. The better electrochemical performances of the CoS-CuS composite are owing to the double-layer structure, which provides unique architecture facilitating charge transport and electrolyte diffusion.
Authors: Yu Zhang, Mengqi Zhang, Xiongyan Fan and Xingyuan Yu
Keywords: Cobalt sulfide, Copper sulfide, Electrode materials, Specific capacitance, Supercapacitor