On the synthesis and electrochemical characterization of ordered hierarchical NiO micro bouquets with trimodal pore size distribution

The present study demonstrates a novel approach by which 'bulk nanostructured' NiO micro bouquets can be processed into a high surface area electrode for supercapacitor applications. A detailed study has been performed to elucidate the impact of porosity and redox reactions on the electrochemical behavior. The spheres were synthesized using a soft template technique. An intrinsic correlation between the surface area, capacitance and the internal resistance has been deduced and explained on the basis of relative contributions from the faradic properties of NiO. These NiO spheres exhibited specific mass capacitance values as high as 1950 F g−1. Further, coin cells employing these rechargeable electrodes were also demonstrated which exhibits energy and power densities of 17 W h kg−1 and 24 kW kg−1. It has been shown that these electrodes based on such bulk nanostructures can allow significant room for high performance supercapacitor devices.