Electrodeposited endeavour: Concentration-tuned nickel oxide nanostructures for high-performance supercapacitors

Abstract

Herein we focused on synthesis of concentration modulated nickel oxide (NiO) nanosheets by simple and straightforward electrodeposition technique to investigate physicochemical properties and eventually electrochemical performance. Cubic and hydrophilic NiO nanosheets with optimum crystallite size, porosity and mixed Ni²⁺/ Ni³⁺ states show pseudocapacitive nature with excellent performance. It is observed that, 956.22 F/g specific capacitance at 5 mV/s scan rate. The diffusion controlled reaction kinetics during charging and discharging process shows 25.04 Wh/kg and 3.41 kW/kg energy and power density respectively. The optimized sample exhibits lower values for series and charge transfer resistance due to the conducting channel developed through interconnected nanoparticles. Moreover, electrochemical performance of liquid state symmetric supercapacitor device is measured. The overall study reveals electrodeposited NiO nanostructures are an ideal candidate for energy storage applications.