The rational design of bifunctional materials capable of treating environmental pollutants, such as toxic dyes, while also serving as efficient electrode materials for supercapacitor applications holds great potential for sustainable energy and environmental solutions. In this study, BiVO4 with varying concentrations of Cashew nut shell-derived carbon composites was developed by a hydrothermal process and used effectively as an electrode and photocatalyst. The electrochemical analysis of BiVO4/100 mg Cashew nut shell-derived carbon composite exhibits a higher specific capacitance of about 326 Fg-1. The energy density and power density of the BiVO4/100 mg Cashew nut shell-derived carbon composite were about 11.12 Whkg−1 and 750 Wkg-1, respectively. The fabricated electrode exhibited retention of about 87.19% after 5000 charge-discharge cycles. BiVO4/100 mg Cashew C degraded the methylene blue dye entirely within 240 min. The proposed materials act as excellent photocatalysts and demonstrate their suitability for high-efficiency supercapacitor applications to meet future demands and needs.