A Scalable Free‐Standing V₂O₅/CNT Film Electrode for Supercapacitors with a Wide Operation Voltage (1.6 V) in an Aqueous Electrolyte

Abstract

While vanadium oxides have many attractive pseudocapacitive features for energy storage, their applications are severely limited by the poor electronic conductivity and low specific surface area. To overcome these limitations, a scalable, free‐standing film electrode composed of intertwined V 2 O 5 nanowires and carbon nanotubes (CNTs) using a blade coating process has been prepared. The unique architecture of this hybrid electrode greatly facilitates electronic transport along CNTs while maintaining rapid ion diffusion within V 2 O 5 nanowires and fast electron transfer across the V 2 O 5 /CNTs interfaces. When tested in a neutral aqueous electrolyte, this hybrid film electrode demonstrates a volumetric capacitance of ≈460 F cm −3 . Moreover, a symmetric capacitor based on two identical film electrodes displays a wide operation voltage window of 1.6 V, delivering a volumetric energy density as high as 41 Wh L −1 .