Subbukalai Vijayakumar

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.

Synthesis of Zn3V2O8 nanoplatelets for lithium-ion battery and supercapacitor applications

Zn3V2O8 nanoplatelets were successfully synthesized using a hydrothermal method. The formation of the Zn3V2O8 nanoplatelets was explained via splitting, exfoliation and self-aggregation mechanisms. FESEM revealed the nanoplatelet morphology with a thickness of 27.9 nm. HRTEM imaging confirmed the crystalline nature of the Zn3V2O8 nanoplatelets, and the SAED pattern clearly indicated that the prepared sample was Zn3V2O8. The prepared Zn3V2O8 nanoplatelets were further studied for their potential application in Li-ion batteries and supercapacitors. The discharge capacity in the second cycle was 558 mA h g−1 at 100 mA g−1. The Zn3V2O8 nanoplatelets exhibited a maximum specific capacitance of 302 F g−1 at a scan rate of 5 mV s−1. Furthermore, a Zn3V2O8 electrode retained about 98% of its initial specific capacitance after 2000 cycles. The described Zn3V2O8 nanoplatelets were found to be a highly suitable electrode material for energy storage applications.