Supercapacitors have attracted significant attention as a promising energy storage technology due to their high power density and rapid charge-discharge capabilities. In this study, we synthesized bismuth vanadate (BiVO4) with varying molar ratios using the sol-gel combustion method and evaluated their effectiveness as supercapacitor electrodes. Crystallographic and morphological analyses confirmed the formation of nanoparticles with different phases. The vanadium-rich BiVO4 compound electrode exhibited a maximum specific capacitance of 893 F<middle dot>g(-1) at a current density of 0.5 A<middle dot>g(-1) and demonstrated superior rate capability. Additionally, an all-solid-state asymmetric supercapacitor, fabricated using vanadium-rich BiVO4 and activated carbon along with a gel electrolyte, achieved an energy density of 6.66 Wh<middle dot>kg(-1) at a power density of 600 W<middle dot>kg(-1) and sustained 86% capacitance retention after 10000 cycles. These results highlight the potential of Bi-V compounds in energy storage applications.