V2O5 and its Carbon-Based Nanocomposites for Supercapacitor Applications

Vanadium pentoxide (V2O5) is renowned among the highly efficient supercapacitor electrode-materials for high power and energy densities, excellent specific capacitance, prolonged cycle lives, variable oxidation states of V, reversible nature of interconversions, theoretical importance, etc. Various synthetic methodologies and morphologies, formation of composites, and doping for tuning properties are the additional causes of interest. Different synthetic techniques like sol-gel, solvothermal, electro-deposition, electro-spinning, atomic layer deposition, etc. are employed to prepare V2O5-based electrode materials with merits and demerits. High rate of material agglomeration and poor conductivity limit its usage in pristine morphology. Accordingly, the impact on charge storage behavior of V2O5 on blending with various carbon-based systems has been explored for materials like activated carbons, conducting polymers, carbon nanotubes and functionalized graphene systems as binary/ternary composites. The aim has been to optimize the key factors such as reduced nanostructure lumping, minimal interfacial resistance and ultrafast charge diffusion across hollow porous structures which may eventually lead to the theoretically expected high specific capacitance (>1000 Fg(-1)). In this review, we have discussed on the recent progress in the research of V2O5-based materials and highlighted on the correlation between morphology and electrochemical performances. In the course, we have attempted to delineate the advantage-disadvantages of different composite morphologies that may help to outline the present status and future aspects of these materials that the authors believe will be of first-hand assistance especially to the beginners in the field of research.