Improve the charge storage efficiency for symmetric supercapacitor applications MoS 2 /Co- BiVO 4 structures

Designing efficient and sustainable energy storage systems is a key scientific priority. Conventional batteries rely on rare metals, making mass production difficult and costly. Metal oxide–sulfide composites have shown strong potential for supercapacitor applications due to their enhanced electrochemical behaviour. In this study, a monoclinic Co-BiVO₄/MoS₂ composite was synthesised via a hydrothermal method, combining cobalt-doped BiVO₄ and MoS₂ nanospheres. Electrodes were fabricated by coating a slurry of active material, acetylene black, and PVDF binder onto nickel foam. Co-BiVO₄/MoS₂ electrodes achieved a specific capacitance of 734 F·g−¹ at 1 A·g−¹, with 87.16% retention after 5,000 cycles at 10 A·g−¹ in a three-electrode setup. A symmetric supercapacitor (SSC) using Co-BiVO₄/MoS₂ as both electrodes delivered 46.4 Wh·kg−¹ energy density and 1053.2 W·kg−¹ power density. The SSC maintained 81.2% capacitance after 16,000 cycles at 10 A·g−¹, confirming its long-term stability. An asymmetric supercapacitor (ASC) was also fabricated using the same active material as the anode and activated carbon as the cathode. The ASC demonstrated a balanced energy–power profile and excellent cycling performance. These results confirm the effectiveness of the synthesis and device assembly protocols in achieving high-performance energy storage.