Interface-regulated charge transport in V2O5-CNT-hydroxylated graphene nanocomposite for high-performance aqueous supercapacitors

The practical application of V 2 O 5 electrodes in supercapacitors is limited by their low electronic conductivity, structural changes during ion insertion and extraction, and aggregation, which can restrict electrolyte access to redox-active sites. This study investigated the integration of V 2 O 5 nanorods with carbon nanotubes (CNTs) and hydroxylated graphene (G-ol) to produce a more conductive, accessible, and structurally stable electrode architecture. V 2 O 5 , V 2 O 5 -CNT and V 2 O 5 -CNT-G-ol nanomaterials were prepared using hydrothermal and wet-chemical methods and characterized by structural, spectroscopic, microscopic, surface-area, and electrochemical techniques. Microscopy revealed V 2 O 5 nanorods with apparent widths of approximately 72.4 nm and their integration within the carbon framework. Raman and XPS analyses confirmed the presence of the constituent materials and indicated interfacial interactions between V 2 O 5 and the carbon components. Nitrogen adsorption-desorption measurements showed mesoporous characteristics while the BET surface area increased from 4.65 m 2 g − 1 for pristine V 2 O 5 to 10.15 m 2 g − 1 for V 2 O 5 -CNT-G-ol. Electrochemical measurements in 1 M KOH showed specific capacities of 481.7, 901.9, and 1314.6 C g − 1 at 5 mV s − 1 for V 2 O 5 , V 2 O 5 -CNT, and V 2 O 5 -CNT-G-ol, respectively. The enhanced response of the ternary composite was attributed to the combined contributions of the V 2 O 5 redox-active phase and the interconnected carbon framework. An asymmetric AC//V 2 O 5 -CNT-G-ol device delivered a specific capacitance of 66.4 F g − 1 at 1 A g − 1 , with a specific energy of 21.9 Wh kg − 1 , a specific power of 6608.9 W kg − 1 , and 97.6% capacitance retention after 5000 cycles. These findings demonstrate that integrating CNTs and G-ol with V 2 O 5 is a promising strategy for improving the charge-storage performance and cycling stability of V₂O₅-based asymmetric supercapacitors.