Investigation on Mg-Ion-Conducting Gel Polymer Electrolytes Dispersed with MgS Nanoparticles: Electrochemical and Structural Perspectives

This work investigates the effect of the dispersion of lab-synthesized magnesium sulfide (MgS) nanoparticles on the ion transport behavior within a magnesium-ion-conducting gel polymer electrolyte (GPE) system. Each electrolyte specimen contains poly(methyl methacrylate), i.e., PMMA polymer; magnesium perchlorate, i.e., Mg(ClO4)2 salt; and ethylene carbonate/propylene carbonate, i.e., EC/PC as the binary solvent. Electrochemical impedance spectroscopy revealed a significant enhancement in the ionic conductivity for the optimized GPE composition. The optimized electrolyte membrane, loaded with 3.75 wt % MgS nanoparticles, accomplishes a significantly higher ionic conductivity of 1.5 × 10–3 S cm–1 at 35 °C. The X-ray diffraction investigation reveals decreases in the degree of crystallinity, signifying the improved amorphous nature of the electrolyte, which is favorable for ionic transport. Adding the MgS nanoparticles in an optimized quantity elevates the entropy of the GPE, further promoting the amorphous nature for the fabricated electrolyte. The potential conformational and structural changes on adding MgS nanoparticles in the PMMA/EC-PC/Mg(ClO4)2 matrix have been established using Fourier transform infrared (FTIR) spectroscopy. The reported electrolyte system designed using MgS nanoparticles has the potential to provide good ionic conductivity, an electrochemical stability window, and superior structural properties.