Preparation and capacitive properties of sheet V6O13 for electrochemical supercapacitor

V6O13 with sheet morphology and mixed valence of V(V) and V(IV) for supercapacitors has been prepared by a thermal decomposing and quenching method with NH4VO3 as the starting material. The samples were characterized by thermogravimetry analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and scanning electron microscope (SEM). The products exhibited the sheet morphology with an average size of 2 mu m and a thickness of about 200 nm. its electrochemical properties were determined by cyclic voltammetry and charge-discharge tests in various aqueous electrolytes. The results showed that the species of aqueous electrolyte, potential range, scan rate and current density have great effects on the capacitive properties of V6O13. In the voltage range of -0.2 to 0.8 V (vs. SCE) in 1 mol L-1 NaNO3 electrolyte, V6O13 electrode exhibited obvious capacitance performance. At the current density of 50 mA g(-1), the material delivered a specific capacitance value of 285 F g(-1). At the current of 200 mA g(-1), the electrode exhibited an initial specific capacitance of 215 and 208 F g(-1) after 300 cycles. (C) 2008 Elsevier B.V. All rights reserved.