Pseudocapacitive Characteristics of Vanadium Oxide Deposits with a Three-Dimensional Porous Structure

A three-dimensional porous vanadium oxide was anodically deposited onto graphite substrates (denoted as ) at 0.7 V from an aqueous solution containing 25 mM and 5 mM . Through annealing at temperatures up to , the thermal stability of preserved its porous morphology and excellent capacitive performances in 3 M KCl (pH 2.4). X-ray photoelectron spectroscopic analysis revealed the mixed valence nature of oxy-/hydroxyl-vanadium species in which the amount of species was not significantly affected by varying the annealing temperature. A maximal specific capacitance of ca. measured at was obtained for this porous annealed between 150 and . Only 9–17% loss in specific capacitance was found for these when the scan rate of the cyclic voltammetry was increased from 25 to , demonstrating a typical high power property, which was never found in the -based supercapacitors.