One-Pot Hydrothermal Synthesis of Vanadium Oxide-Decorated Carbon Nanotube Hybrid Composite Electrodes for Superior Supercapacitor Applications

We demonstrate the one-pot hydrothermal synthesis of vanadium oxide (V₂O₅)-multi-walled carbon nanotube (CNT) hybrid composites for advanced energy storage devices with higher efficiency and reliability. The as-obtained composite reveals a unique 3D hierarchical architecture consisting of nanolayered V₂O₅ structures intricately entangled with a conductive CNT network. This configuration with complementary materials enhances the kinetics of charge transfer and ion diffusion rates, leading to superior electrochemical performance. The V₂O₅-CNT hybrid composite electrodes exhibit enhanced specific capacity of 2253.52 C/g (corresponding to specific capacitance of 2816.90 F/g), attributed to the combined contributions of diffusion-controlled processes and surface redox reactions. Furthermore, the electrode also demonstrates excellent cycling stability, retaining 87.74% of its initial capacity after 5000 cycles in a 6 M KOH electrolyte. The symmetric supercapacitor device fabricated by using optimized electrodes demonstrates excellent performance within a wide 1.2 V potential window, achieving an energy density of 22.02 Wh/kg, a power density of 841.67 W/kg, with 93.03% capacity retention over 5000 cycles. These findings highlight the synergistic advantages of the V₂O₅-CNT hybrid, encouraging it as a promising material for superior supercapacitor applications in the pursuit of clean and sustainable energy solutions.