NiO nanoparticles and their nanohybrid with flat rGO sheets: As an ideal electroactive material for hybrid capacitor applications

Extensive research on electrode materials has revealed that the nature, structure, surface area, and conductivity of the electrode material largely control the overall performance of the electrochemical capacitor (ECC). Herein, we prepared homogeneous sized NiO nanoparticles (NPs) via a surfactant-assisted wet-chemical technique and ultrasonically mixed with 2% and 4% rGO for ECC applications. The surface area, conductivity, and specific capacity of the NiO@rGO nanohybrid had been improved by graphene nanosheets, making the nanohybrid appropriate for ECC applications. Our NiO@rGO nanohybrid electrode with 4% graphene content demonstrated a high specific capacity of 883 Cg(-1) at 05 mVs(-1) and a superior rate capability of 72.64% at 100 mVs(-1) . Furthermore, following 3500 cycle testing at 100 mVs(-1) , the NiO@rGO nanohybrid (with 4% rGO) based electrode shows a minimum capacity loss of 7.3%, confirming its outstanding cyclic stability. In the light of impedance studies, the charge transfer, equivalent series, and diffusion resistance values were at their lowest for a nanohybrid sample with 4% rGO, indicating a fast redox reaction at the NiO@rGO/electrolyte interface. The exceptional electrochemical presentation of the NiO@rGO sample is ascribed to its good conductivity, a large number of active sites at the surfaces, and facile electrolyte diffusion into the structure due to the well-organized nanostructured constituents. Our surfactant-assisted and ultrasonically manufactured synthesized NiO@rGO nanohybrid sample offers a broad application promise in hybrid capacitors because of its beneficial integrated properties.

Automated summary

Extensive research has shown that the performance of electrochemical capacitors (ECC) is largely controlled by the nature, structure, surface area, and conductivity of the electrode material. In this study, NiO nanoparticles were prepared using a surfactant-assisted wet-chemical technique and mixed with 2% and 4% rGO for ECC applications. The NiO@rGO nanohybrid exhibited improved surface area, conductivity, and specific capacity, making it suitable for ECC applications. The nanohybrid electrode with 4% graphene content showed high specific capacity and superior rate capability, as well as outstanding cyclic stability. The excellent electrochemical performance was attributed to the good conductivity, large number of active sites, and facile electrolyte diffusion enabled by the well-organized nanostructured constituents.