One-pot synthesis of low-cost CuS/Vulcan carbon composites applied as electrode materials for supercapacitors

CuS microflowers composites with Vulcan carbon black (CuS/Vulcan) were synthesized by a low-cost one-pot hydrothermal process and investigated as electrode materials for supercapacitor applications. The phase integrity of pristine CuS and CuS/Vulcan composites was confirmed by XRD measurements. The immobilization of CuS nanoparticles on the Vulcan support prevented their agglomeration and improved the specific surface area, the electric conductivity and the electrochemical response time of CuS-based electrodes. The electrochemical performance of CuS/Vulcan composites was characterized in a three-electrode setup and a two-electrode cell configuration as a function of the CuS/Vulcan weight ratio. The CuS/Vulcan composite electrodes with a mass ratio of 70:30 demonstrated the highest specific capacitance of 285 F g-1 and a capacitance retention of 97% after 2000 galvanostatic charge-discharge cycles at 5 A g-1 in 3M KOH. The assembled CuS/Vulcan (70:30)//CuS/Vulcan (70:30) symmetric cell exhibited an improved specific energy of 12.6 Wh kg-1 at a specific power of 907 W kg-1 (at the discharge current density of 0.25 A g-1). Overall, this study presented a facile, convenient and scalable approach for designing cost-effective and high-performance composite electrodes based on copper sulfide.