Synergistic effects of Ni doping in MnO2 nanorods: Structural and electrochemical insights for high-performance supercapacitors
Ritesh Kumar, Diksha Diksha, Prachi Jain, Raj Singh, Achchhe Lal Sharma
Abstract
Supercapacitors are the future of electric vehicles (EVs) because of their high-power density, due to their low energy density, they are not frequently used in EVs, which has pushed researchers towards improving their energy densities. In the present study, the Ni-MnO 2 nanorods have been prepared at different weight percentages of Ni, that is, 2%, 5%, and 7%, using a 1-pot-assisted hydrothermal method. Different techniques were used to characterize the sample, that is, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) to check structural and morphological properties. EDX results confirmed the doping, including different elements (Ni, Mn, O) in the samples. Further, we looked at how well the Ni-MnO 2 electrode worked with 6 M potassium hydroxide (KOH) electrolyte over a wide potential window. The best performance has been observed at 5% weight percentage (NMn-5), exhibiting a specific capacitance of 336 F/g, energy density of 31.7 Wh/kg, and power density of 440 W/kg. Material promises good cyclic stability (capacitance retention 71.8% after 2000 cycles at 1 Ag −1 ) and coulombic efficiency (90.8%). Further, to check the practicality of the material, we fabricated a device to glow the red LED, and the LED glowed for 5 minutes.