Highly reversible crystal transformation of anodized porous V2O5 nanostructures for wide potential window high-performance supercapacitors

Abstract The advancement of efficient pseudocapacitive electrodes is a formidable challenge. In this study, we fabricated a binder-free porous network of vertically aligned V2O5 nanochannels via the simple and economical electrochemical anodization of vanadium foil. Reversible charge storage and the structural transformation of V2O5 during successive reduction and oxidation cycles was confirmed through X-ray diffraction analysis. We used several electrochemical techniques to study pseudocapacitive charge storage within the active sites of the porous network and rapid charge transfer through the vertical V2O5 channels in a 1 M LiClO4–propylene carbonate electrolyte. The as-prepared V2O5 electrode was studied over a wide potential window of 1.5 V, and it exhibited a specific capacitance of 840 F g−1 at 4 A g−1. A rate capability of 48% was observed with an eight-fold increase in the current density, and the electrode retained 90% of its capacitance after 5500 CV cycles. This performance indicated that the porous structure was highly retained, as confirmed through microstructural analysis after cycling. The V2O5 electrode presented herein may provide new options for replacing electrodes in next-generation supercapacitors.