Design and optimization of CdS-CeO2 composite electrodes for enhanced electrochemical performance for asymmetric supercapacitors.

The advance of high-performance energy storage devices (ESD) is critical for modern semiconductor technology, rechargeable vehicles, and renewable energy integration. In this work, a CdS-CeO2 composite was successfully synthesized via a hydrothermal method and investigated as an electrode material for an asymmetric supercapacitor (ASCs). The CdS-CeO2 composite leverages the high redox activity and structural stability of CeO2 along with the enhanced electrical conductivity and charge transport of CdS. Structural and morphological characterization using XRD, BET surface analysis, SEM, and EDX mapping confirmed the formation of a well-dispersed, hierarchical composite with abundant electro active sites. Electrochemical measurements revealed that the CdS-CeO2 electrode delivers a specific capacitance of 476 F g-1 at 1 A g-1, along with good rate performance and outstanding long-term stability, retaining 95.83% of its initial capacitance after 15 000 charge-discharge cycles. The asymmetric supercapacitor ASC (CdS-CeO2//AC) exhibited a highest energy density of 57.74 Wh kg-1, and power density of 6298 W kg-1, indicating the effectiveness of the CdS incorporation in enhancing the electrochemical performance. These results highlight the potential of oxide-sulfide composite engineering in designing next-generation electrodes for high-performance ASCs.