Porous structured vanadium oxide electrode material for electrochemical capacitors

A nano porous vanadium oxide (V2O5) was prepared by sol–gel method. The preparation involved elutriation of aqueous sodium meta vanadate over a cation exchange resin. The product was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, surface area analysis and thermogravimetric analysis. Electrochemical characterization was done using cyclic voltammetry in a three electrode system consisting of a saturated calomel electrode as reference electrode, platinum mesh as a counter electrode, and V2O5 mounted on Ti mesh as the working electrode. Two molars of aqueous KCl, NaCl and LiCl were used as electrolytes. A maximum capacitance of 214 F g−1 was obtained at a scan rate of 5 mV s−1 in 2 M KCl. The effect of different electrolytes and the effect of concentration of KCl on the specific capacitance of V2O5 were studied. Specific capacitance faded rapidly over 100 cycles in 2 M KCl at a 5 mV s−1 scan rate.