Turning bulk V2O5 into an active capacitive material by thermally driven nanostructuring and surface activation

Abstract

Despite many new advances in supercapacitor material design, few have been adopted for industrial use because of a lack of consideration for industrial requirements. This fact has long been overlooked in academia, but the potential impact of the technical gap between laboratory-scale demonstrations and large-scale applications is considerable. To this end, we performed a proof-of-concept study using vanadium pentoxide (V2O5), one of the most promising supercapacitor electrode materials, to narrow this technical gap. We demonstrated a facile thermal approach in which electrochemically poor bulk V2O5 can be transformed into a highly active electrode material, which can be potentially developed for an economical large-scale production process. Two subsequent thermal treatments of bulk V2O5 under NH3 and H2S gas flow yielded a pseudocapacitive nanocomposite composed of vanadium oxynitride and vanadium sulfide. Superior capacitive performance of the bulk V2O5 in terms of capacitance and stability was achieved by this novel electrode material. In-depth characterization and electrochemical analysis revealed that the underlying reason for this enhancement resulted from a synergistic effect induced by the two-step thermal process. We believe that this successful demonstration of our conceptual approach will be an important stepping stone toward the development of practical material design processes that can meet the rigorous demands of the industry.