Recent advances in the synthesis, doping strategies, and supercapacitor applications of vanadium pentoxide (V2O5) and V2O5-based nanostructures: A review

Vanadium pentoxide (V2O5) is a promising material for next-generation supercapacitor electrodes, thanks to its high theoretical capacitance (2120 F g−1), multivalent redox activity (V5+/V4+/V3+), and layered structure that supports fast ion transport. Its abundance, eco-friendliness, and electrolyte compatibility further enhance its appeal. However, low conductivity, structural instability, volume expansion, and dissolution in electrolytes limit its practical use. To address these challenges, strategies such as nanostructuring, forming composites with conductive materials (e.g., graphene, carbon nanotubes, conductive polymers), and doping with metal cations (Mn, Fe, Co) or anions (N, S, F) have been explored. These approaches enhance conductivity, stabilize phases, and introduce beneficial defects. Co-doping has shown further performance gains. The distribution of dopants and shape can be precisely controlled by synthesis methods such as sol-gel, hydrothermal, chemical vapor deposition, and atomic layer deposition. These developments have made it possible to create high-performance, flexible, binder-free devices, such as hybrid and asymmetric supercapacitors with enhanced energy and power densities. Recent advancements in V2O5-based materials are highlighted in this study, with particular attention paid to synthesis, doping, and device integration. Improving long-term cycle stability, lowering self-discharge rates, avoiding electrolyte-induced degradation, and limiting health and environmental risks during large-scale production are some of the major problems of the future. Additionally, advancing V2O5-based systems toward practical energy storage applications will require enhancing the reproducibility of synthesis techniques, creating standardized testing procedures, and guaranteeing compatibility with cutting-edge green electrolytes.