Comparative performance analysis of nanostructured metal oxides as cathode in solid state magnesium battery

Abstract

Magnesium batteries are considered a promising alternative to lithium-ion batteries due to the abundance, low cost, and high theoretical energy density of magnesium. Metal oxide nanoparticles have shown significant potential in addressing some of these challenges like high charge/discharge rates, low conductivity, and poor cycle life by enhancing the electrochemical performance, stability, and efficiency of magnesium batteries. In this study, nanoparticles of magnesium oxide (MgO), manganese oxide (Mn₂O₃), and magnesium manganese oxide (MgMn₂O₄) are synthesized using the gel-combustion method. These nanoparticles are analyzed through X-ray diffraction (XRD) to determine their crystallite size. Their surface morphology is studied using Scanning Electron Microscopy (SEM), revealing agglomerated and uneven surfaces. The elemental composition is identified by using energy-dispersive X-ray spectrometry (EDX). Electrochemical properties are assessed using Cyclic Voltammetry (CV) and Galvanostatic Charge-Discharge (GCD) analysis. Compared to single metal oxides, the synthesized binary metal oxide demonstrated superior electrochemical performance. GCD results showed that MgMn₂O₄ nanoparticles achieved a maximum specific capacitance of 203 F/g at a current density of 2.1 A/g. Furthermore, after 1000 charge–discharge cycles, the electrode’s power density remains stable, confirming its durability. Using the prepared metal oxides as cathode, three batteries are fabricated and their properties are compared. The electrochemical cell is fabricated using MgMn₂O₄ as a cathode material performs better than the others and the discharge characteristics are also investigated.