High-performance chrysanthemum flower-like structure of Ni doped ZnO nanoflowers for pseudo-supercapacitors
R. Dhilip Kumar, Alagarasan Jagadeesh Kumar, S. Balachandran, F. V. Kusmartsev, Amira Ben Gouider Trabelsi, Fatemah H. Alkallas, S. Nagarani, V. Sethuraman, Byeong–Kyu Lee
Abstract
In this study, the chrysanthemum-flower-like structure of Ni-doped ZnO nanoflowers pseudo-capacitance behaviour was synthesized by a conventional hydrothermal method . The X-ray diffraction (XRD) results showed that the prepared materials had formed ZnO and Ni-doped ZnO nanopowder in their hexagonal wurtzite structure. The morphologies of the Ni-doped ZnO have a chrysanthemum-flower-like structure, which was confirmed by SEM and HR-TEM. Galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were used to investigate the pseudo-capacitance behaviour of Ni-doped ZnO. The Ni-doped ZnO nanoflower-modified electrode achieved a maximum specific capacitance value of 1090 F/g at 0.25 A/g, and 3 M KOH was used as the electrolyte. Eight thousand cycles of testing revealed that the Ni-doped ZnO nanoflowers electrode was very stable, far outperforming the stability of undoped ZnO nanoflowers modified electrodes. The fabricated Ni-doped ZnO nanoflower electrode has high capacitance retention and high columbic efficiencies of 101 % and 89 %, respectively. The prepared Ni-doped ZnO nanoflowers are a very effective electrode material and are considerably better suited for supercapacitor applications.