Magnesium-Ion Conducting Pullulan-Based Solid Polymer Electrolytes: Structural and Electrochemical Insights

This study investigates the microstructure of solid polymer electrolyte (SPE) films designed for magnesium-ion conduction, utilizing pullulan as the polymer matrix. The traditional solution casting method was used for developing the electrolyte films, which were then thoroughly characterized. Examining the electrolyte systems using FTIR and XRD takes into account the complexation of the polymer matrix and the enhancement of its amorphous character. The examination of the electrolyte systems indicates that the electrical characteristics are enhanced by the addition of salt to the matrix. The maximal ionic conductivity at room temperature in an electrolyte system containing 20 wt.% salt is found to be in the range of 10⁻⁵ S/cm. With an activation energy of 1.143 eV/mol, the film containing 20 wt.% magnesium nitrate salt, the highest conducting electrolyte system, exhibits Arrhenius behavior. The electrolyte system with the highest conductivity exhibits an ion transference number of 0.993, indicating that ionic transport dominates the conduction mechanism. A primary battery utilizing this highly conductive electrolyte film demonstrates outstanding discharge performance.