Phytogenic generation of NiO nanoparticles as green-electrode material for high performance asymmetric supercapacitor applications

Herein, we report a simple, cost-effective, one-step green synthesis of nickel oxide nanoparticles (NiO-NPs) from Opuntia ficus-indica leaves extract for asymmetric supercapacitor application. The plant extract derived NiO-NPs exhibits an exceptional half-cell specific capacitance of 644 Fg(-1) (-89.4 mAhg(-1)) at 0.5 Ag-1. The assembled asymmetric NiO-NPs parallel to activated carbon (AC) supercapacitor cell delivers high specific capacitance of -280 Fg(-1) (-38.8 mAhg(-1)), excellent specific energy of 25 Wh kg(-1). In addition, the NiO-NPs vertical bar AC device works until 1.4 V with 0.1 M KOH as electrolyte delivering an excellent rate capability and high coulombic efficiency of 124% even after 10,000 cycles. Moreover, the biomass derived NiO NPs performs better than the other reported NiO based compounds, due to its presence of nickel-rich natural minerals. Through these findings, the use of plant leaves like Opuntia ficus-indica is hereby shown to be low-cost, environment-friendly alternative for preparing NiO- based composites for energy storage applications.

Automated summary

A simple, cost-effective, one-step green synthesis of nickel oxide nanoparticles from Opuntia ficus-indica leaves extract was reported for asymmetric supercapacitor application. The NiO-NPs exhibited high specific capacitance and excellent energy density, making them a promising alternative for energy storage applications.