In this work, we have synthesized the carbon microspheres embedded cadmium sulphide nanoflowers (CdS/CMS nanocomposite) using a simple pyrolysis technique. The structural, spectroscopic, morphological, and electrochemical analysis confirms the formation of CdS/CMS nanocomposite with superior supercapacitive performance. The as-prepared CdS/CMS nanocomposite electrode exhibited an excellent specific capacitance of 200 F/g at a current density of 0.5 A/g, achieving a power density of 200 W/kg at an energy density of approximately 18 Wh/kg. A significant 2.86-fold enhancement is observed in specific capacitance compared to CdS nanoflower (70 F/g). The electrochemical performance of CdS/CMS exhibits an increase in capacitance retention rate to 146.5% and a slight decrease in coulombic efficiency to 95.62% after 5000 cycles at a high current density of 5 A/g, demonstrating its excellent cycling stability. A major improvement observed in the CdS/CMS nanocomposite arises from the synergistic interplay between the enhanced surface-active sites of CdS nanoflowers, caused by lattice contraction, charge transfer between CdS and CMS, and the formation of a porous network of CMS that facilitates the reduction of charge transfer resistance and enhances electrolytic ion transport. This reduction in charge transfer resistance even facilitates the deeper penetration of charge carriers through the electrode surface, thereby improving the charge storage capabilities in the as-prepared electrode materials.
Kumari et al. (Thu,) studied this question.