Two-Step Synthesis of CuS/C@PANI Nanocomposite as Advanced Electrode Materials for Supercapacitor Applications.

In this study, the dense cloud-like structured CuS nanoparticles were successfully prepared using a simple two-step hydrothermal method. The experimental temperature was the most important factor that affected the microstructure and surface functions of CuS/C. Therefore, the CuS/C electrodes were synthesized at different temperatures (80 °C, 120 °C, and 160 °C). Subsequently, their crystallographic phase and morphologies as well as the structure of the as-prepared electrodes were analyzed in detail. The electrode prepared at 120 °C (CuS/C-120) was determined to have a perfect microstructure, high specific capacitance, and good rate performance. To further improve the electrochemical performance of this electrode, it was combined with polyaniline (PANI) to obtain a CuS/C-120@PANI electrode via the cyclic voltammetric electrodeposition method. The CuS/C-120@PANI electrode exhibits a specific capacitance of 425.53 Fg−1 at a current density of 1 Ag−1 and a good cycling stability of 89.86% after 3000 cycles. The perfect architecture of CuS/C-120@PANI maximizes the synergistic effect between its different components and provides abundant electrochemically reactive sites, promoting the diffusion and transfer of electrolyte ions during the electrochemical reaction processes. Detailed analysis shows that the CuS/C-120@PANI electrode has great potential for use in high-performance energy storage devices.