Effect of Nanosized Al₂O₃ Dispersion on the Structural and Electrochemical Properties of PMMA/TEGDME-Based Mg-Ion Conducting Polymer Gel Electrolyte

A poly(methylmethacrylate)-based Mg-ion conducting polymer gel electrolyte immobilizing a liquid electrolyte of magnesium perchlorate in tetraethylene glycol dimethyl ether (TEGDME) solvent is presented. In order to enhance the electrolytic properties of the electrolyte, the impact of aluminum oxide (Al₂O₃) nanoparticles on the structural, thermal, and electrochemical properties has been investigated. The optimized composition of the polymer gel electrolyte (PMMA + TEGDME + MgClO₄ + 2.5 wt% Al₂O₃) showed increased ionic conductivity of 4.94 × 10⁻⁵ S cm⁻¹ with a significantly low activation energy of 0.18 eV. Ion dynamics in the polymer gel electrolyte have been quantitatively analyzed by investigating various frequency-dependent parameters such as the real and imaginary components of dielectric permittivity, loss tangent, and the modulus. The possible conformational changes in the electrolyte system on addition of Al₂O₃ nanoparticles have been investigated by x-ray diffraction (XRD), Fourier-transform infrared (FTIR) analysis, and differential scanning calorimetry (DSC). These studies have revealed CH₃-Mg-Al₂O₃ interaction in the electrolyte with significantly affected crystallinity and sufficient gel phase range with variation in temperature.