Investigating the synergistic effect of defect rich V2O5/MWCNTs heterostructure for improved electrochemical performance of supercapacitors†

The synergistic effect of V₂O₅ and multiwall carbon nanotubes (MWCNTs) offers a promising strategy to enhance the redox activity of electrode materials for high-performance supercapacitors. In this study, a simple, scalable, and cost-effective hydrothermal approach is employed to synthesize V₂O₅/MWCNTs heterostructure. The resulting heterostructure exhibits rich oxygen vacancy defects, improved conductivity, favorable structural characteristics, and abundant active sites. DFT study further demonstrate the excellent kinetics of V₂O₅/MWCNTs as compared to pristine V₂O₅ structure. Electrochemical analysis reveals that V₂O₅/MWCNTs electrode achieves good capacitance of 820 F g⁻¹ at 1 A g⁻¹, significantly outperforming pristine V₂O₅ (463 F g⁻¹) in a 1.0 M neutral Na₂SO₄ solution. Moreover, the developed supercapacitor (V₂O₅/MWCNTs//AC) device shows a capacitance of 125 F g⁻¹ at 1 A g⁻¹. The device also delivers an efficient energy density of 39 Wh kg⁻¹ at a power density of 805 W kg⁻¹. Additionally, it exhibits outstanding cycling stability, retaining 93% of its capacity after 8000 cycles at 3 A g⁻¹. These exceptional results highlight the potential of the V₂O₅/MWCNTs heterostructure as a viable electrode material for future energy devices.