Enhanced electrochemical activity of MgO nanoparticles for high-performance supercapacitors

Abstract

To support various forms of energy storage systems for high power requirements, supercapacitors are essential as an additional type of energy storage device. In this study, magnesium oxide nanoparticles (MgONPs) were synthesized using a co-precipitation method and systematically evaluated as active electrode materials. FESEM images revealed a porous and aggregated surface morphology, which may facilitate ion transport by providing accessible diffusion pathways while Raman spectroscopy confirmed the presence of characteristic vibrational modes, including features associated with structural defects, which are commonly observed in nanostructured oxides. The electrochemical behavior of the MgONPs electrode material was evaluated using the three-electrode technique in a 2 M KOH aqueous electrolyte. At a current rate of 1 A g⁻¹, a MgONPs electrode material exhibited a specific capacity of 11 F g⁻¹. The CV behavior demonstrates the strong reversibility of the electrode material revealed a maximum specific capacitance of 99 F g⁻¹ at 10 mV s⁻¹ and good rate capability, underscoring the potential of MgONPs in energy storage devices. To complement the experimental observations, a density functional theory (DFT) study was conducted to examine the structural stability and electronic properties of MgONPs at the molecular level. The DFT-optimized geometry closely matched experimental lattice parameters, while a low HOMO–LUMO energy gap (ΔE = −6.571 eV) indicated high reactivity and efficient charge transfer. Additional descriptors such as dipole moment, softness, and electrophilicity supported the electrochemical behavior observed experimentally. This integrated computational–experimental approach provides comprehensive insights into the fundamental properties of MgONPs, establishing them as promising, cost-effective, and high-performance electrode materials for next-generation supercapacitor systems.