<p>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·g⁻¹ at a current density of 0.5 A·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·kg⁻¹ at a power density of 600 W·kg⁻¹ and sustained 86% capacitance retention after 10000 cycles. These results highlight the potential of Bi-V compounds in energy storage applications.</p>