Optimizing the Charge Transfer Process by Synthesizing NiO Microspheres on Ni Foam through Microwave-assisted Method

The porous nickel oxide microsphere on Ni foam was adopted to optimize the charge transfer process to improve electrochemical performance by a microwave-assisted method. Microstructure and morphologies of the resulting materials were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope. Results showed that the as-prepared NiO microspheres with nickel sulfate had average diameter of ~2 m. The ultrathin secondary nanoflakes composed of nanowire building blocks were interconnected with each other forming a highly open net-structure. Because of enhanced electron transfer capability, charge transfer resistances of the porous microsphere were reduced and the electrochemical performances were improved, the charge-discharge measurements tested at a discharge current of 0.5 A/g showed higher rate specific capacitance (455 F/g). The impedance characterization illustrated lower electronic and ionic resistance of porous NiO due to its superior surface properties for enhanced electrode electrolyte contact during the faradaic redox reactions.