Nanostructured transition metal oxide materials for supercapacitor application

Supercapacitors are new generation energy storage devices, which can provide higher energy density (compared with conventional capacitors) and higher power density (compared with batteries). Amorphous ruthenium oxide, applied as an electrode material, yields the best specific capacitance value of 720 F g'^ [1]. However, the high cost of ruthenium oxide limits its extensive use in supercapacitors. Alternative materials, such as activated carbon, transition metal oxides, and conducting polymers, are being comprehensively studied. In this thesis, the transition metal oxides, ViOs/carbon composite, C03O4, and Fe203, were intensively investigated as supercapacitor electrode candidates. Several techniques. X-ray diffraction, scanning and transmission electron microscopy, Brunauer-Emmett-Teller techniques, and thermogravimetric analysis, were applied to characterize the as-prepared materials, while the electrochemical properties were examined by the cychc voltammetry. The maximum specific capacitance was 295 F 281 F 72 F g"^ for ViOs/carbon nanocomposite, C03O4 nanorods, and Fe203 nanorods, respectively, in various electrolj^es at a voltage scan rate of 5 mV The morphology and large specific surface area of the nanomaterials, as well as the presence of pores in the nanostructure, are thought to contribute to the excellent electrochemical performance.