High-Specific-Capacitance Supercapacitor Based on Vanadium Oxide Nanoribbon

A variety of storage technologies for transmission grid and electric vehicle applications has been gaining importance in the last few years. The supercapacitor is one of the most viable energy storage devices. In this paper, a high-specific-capacitance supercapacitor with vanadium oxide nanoribbon electrode was fabricated. Vanadium oxide nanoribbon was synthesized by a facile and effective hydrothermal treatment with controlling the condensation speeds of precursors in the solution along the 〈010〉, 〈010〉, and 〈010〉 directions. The synthesis involved dissolution of V2O5 into H2O2, and investigation of the precursor weight ratio and the hydrothermal time. The product was characterized by using scanning electron microscopy, transmission electron microscope and X-ray. The electrochemical properties of the material as the electrode of electrochemical capacitor were evaluated by cyclic voltammetry in a three electrode system consisting of a saturated calomel electrode as reference electrode, platinum as a counter electrode and the active material as the working electrode. As far as we know, it is for the first time to report the fabrication of vanadium oxide nanoribbon by using the hydrothermal method. The prepared nanoribbon structure possesses relative short width and significant length. The narrow nanoribbon with ultra-length optimizes the ion diffusion path thereby enhancing the specific capacitance. A high capacitance of 453 F/g was obtained at the scan rate of 2 mV/s in 2 M NaCl electrolyte, and it still maintained a high capacitance of 201 F/g at a higher scan rate of 50 mV/s. And the nanoribbon exhibits faster ion propagation and better conductivity than the nanotube as revealed by the immediate current response to the potentials added on the electrode. The electrochemical performances of the vanadium oxide were found to strongly depend on the nanostructures and electrolytes.