Influence of Fe Doping on the Electrochemical Performance of a ZnO-Nanostructure-Based Electrode for Supercapacitors

Shalendra Kumar; Faheem Ahmed; Nagih M Shaalan; Nishat Arshi; Saurabh Dalela; Keun Hwa Chae

doi:10.3390/nano13152222

Influence of Fe Doping on the Electrochemical Performance of a ZnO-Nanostructure-Based Electrode for Supercapacitors

Nanomaterials (Basel). 2023 Jul 31;13(15):2222. doi: 10.3390/nano13152222.

Authors

Shalendra Kumar^{1

2}, Faheem Ahmed¹, Nagih M Shaalan^{1

3}, Nishat Arshi⁴, Saurabh Dalela⁵, Keun Hwa Chae⁶

Affiliations

¹ Department of Physics, College of Science, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia.
² Department of Physics, University of Petroleum & Energy Studies, Dehradun 248007, India.
³ Physics Department, Faculty of Science, Assiut University, Assiut 71516, Egypt.
⁴ Department of Basic Sciences, Preparatory Year Deanship, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia.
⁵ Department of Pure & Applied Physics, University of Kota, Kota 324005, India.
⁶ Advanced Analysis & Data Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea.

Abstract

ZnO is a potential candidate for providing an economic and environmentally friendly substitute for energy storage materials. Therefore, in this work, Fe-doped ZnO nanostructures prepared using the microwave irradiation procedure were investigated for structural, morphological, magnetic, electronic structural, specific surface area and electrochemical properties to be used as electrodes for supercapacitors. The X-ray diffraction, high-resolution transmission electron microscopy images, and selective-area electron diffraction pattern indicated that the nanocrystalline structures of Fe-doped ZnO were found to possess a hexagonal wurtzite structure. The effect of Fe doping in the ZnO matrix was observed on the lattice parameters, which were found to increase with the dopant concentration. Rods and a nanosheet-like morphology were observed via FESEM images. The ferromagnetic nature of samples is associated with the presence of bound magnetic polarons. The enhancement of saturation magnetization was observed due to Fe doping up to 3% in correspondence with the increase in the number of bound magnetic polarons with an Fe content of up to 3%. This behavior is observed as a result of the change in the oxidation state from +2 to +3, which was a consequence of Fe doping ranging from 3% to 5%. The electrode performance of Fe-doped ZnO nanostructures was studied using electrochemical measurements. The cyclic voltammetry (CV) results inferred that the specific capacitance increased with Fe doping and displayed a high specific capacitance of 286 F·g^-1 at 10 mV/s for 3% Fe-doped ZnO nanostructures and decreased beyond that. Furthermore, the stability of the Zn_0.97Fe_0.03O electrode, which was examined by performing 2000 cycles, showed excellent cyclic stability (85.0% of value retained up to 2000 cycles) with the highest specific capacitance of 276.4 F·g^-1, signifying its appropriateness as an electrode for energy storage applications.

Keywords: Fe-doped ZnO nanostructure; bound magnetic polaron; electrochemical; ferromagnetic; specific capacitance.

Grants and funding

INSTR002/Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this research work.