Supercapacitor studies on NiO nanoflakes synthesized through a microwave route.

NiO nanomaterial was synthesized at different calcination temperatures using cetyltrimethyl ammonium bromide (CTAB) as surfactant via microwave method. Thermogravimetric studies revealed the decomposition details of Ni(OH)2 precursor. The structure and morphology of the NiO was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). NiO calcined at 300 °C shows a nanoflake-like structure. A possible formation mechanism has been discussed with time evolution study. Electrochemical studies indicate that the sample calcined at 300 °C exhibits better charge storage. The NiO nanoflakes exhibit maximum specific capacitance of 401 F g(-1) at a current density of 0.5 mA cm(-2). The energy generated and hence the charges collected from wind and solar panels are slow but in many applications the power delivery has to be at a faster rate. Considering this aspect, slow-charge and fast-discharge tests have been performed and reported. The NiO nanoflakes appear to be a promising electrode material for supercapacitor application.