Efficient green combustion production of pure nickel oxide (NiO) and silver-doped NiO nanoparticles using Aloe Vera gel extract: Its supercapacitors applications

Abstract

This study employs the synthesis of pure NiO and Ag-doped NiO with varying concentrations (1, 3, 5, 7 and 9 mol%) of Ag₂O nanoparticles by solution combustion method. The Structural and morphology of nanomaterials were elucidated by analytical spectroscopic methods. XRD revealed alterations in physical properties, such as crystallite size and lattice parameters, of NiO nanoparticles due to the presence of Ag₂O. UV-Vis spectroscopy demonstrated a reduction in the bandgap from 3.41 eV (pure NiO) to 3.21 eV for 1, 3, 5, 7 and 9 mol% Ag₂O-doped NiONPs. To assess their viability as active electrode materials in supercapacitors, the synthesized samples were subjected to analysis in a 0.1 M HCl electrolyte. Electrochemical studies done through various tests, including Electrochemical-Impedance, Cyclic-Voltammetry and Galvanic Charge-Discharge. Remarkably, the 5 mol% Ag₂O-doped NiO in a 3-electrode system exhibited a notable capacitance value of 248 Fg⁻¹ at a scan rate of 5 Ag⁻¹. Additionally, it demonstrated robust cycling stability, maintaining over 90% of the original capacitance after 2000 cycles in GCD studies. The potential chemical interaction between nanoscale Ag₂O and NiO could be responsible for the enhanced capacitance. These findings offer valuable insights for researchers exploring the development of novel electrode materials for energy-storage devices.

GRAPHICAL ABSTRACT

Keywords:

• NiO
• Ag₂O
• UV-Vis spectroscopy
• Electrochemical activity
• Specific Capacity