Highly Pseudocapacitive NiO Nanoflakes through Surfactant-Free Facile Microwave-Assisted Route

A facile and rapid surfactant-free microwave-assisted route is developed to synthesize 10 nm sized NiO nanoflakes with high pseudocapacitive performance for supercapacitor cells. The NiO nanoflakes exhibit mesoporous channels and a surface area as high as 206 m(2) g(-1) as revealed under BET study, while the structural identity verified by XRD and IR confirm the phase purity of NiO. NiO nanoflakes maintain similar to 85% of their thermal stability at temperature 900 degrees C which can be related to strong intermolecular forces between the NiO nanoparticles held in the molecular matrix. Electrochemical performance investigated in 6 M KOH solution suggests maximum specific capacitance of 307 F g(-1) for the NiO parallel to NiO cell at 0.5 A g(-1) sustaining about 96% capacitance after being successfully cycled up to 3000 cycles. The NiO nanoflakes reveal high conductivity of 33.87 S cm(-1) at room temperature. Precisely, nanosized NiO bearing "flake" morphology is of particular interest due to the high surface to volume aspect and porosity features-the determining factors for swift ion diffusion into an electrode and improved redox reaction. The illustrated microwave-assisted route unfolds as a direct synthesis method to obtain nanosized NiO flakes with high surface area facilitating excellent device performance characteristics without involving any surface-capping agents.