Modulation of ion dynamics and electrical dielectric characteristics in MC:NaF polymer electrolytes through glycerol incorporation

Polymer electrolytes are essential for advanced applications, particularly in the battery industry, due to their high ionic conductivity and improved material properties. This study enhances the ionic conductivity of a methylcellulose (MC) polymer matrix by incorporating glycerol as a plasticizer at varying concentrations (0, 9, 18, 27, and 36 wt.%). Films were prepared using the casting method with 13% sodium fluoride (NaF), resulting in transparent and flexible films. Characterization was performed using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, and electrochemical impedance spectroscopy (EIS). FTIR analysis showed that increasing glycerol concentrations strengthened hydrogen bonding interactions, which facilitated greater ionic dissociation. XRD results revealed a reduction in bell-shaped peaks, indicating increased segmental freedom of the polymer chains. This structural change created better pathways for cation and anion migration. EIS analysis confirmed a significant improvement in ionic conductivity with glycerol addition. The sample containing 36 wt.% glycerol exhibited the highest conductivity. This enhancement resulted from increased ion dissociation, greater segmental motion of the polymer chains, and reduced polymer rigidity due to glycerol’s plasticizing effect. Dielectric studies further supported these findings. Higher dielectric constants and reduced dielectric loss indicated stronger ionic polarization and enhanced transport mechanisms. These results demonstrate the potential of glycerol-incorporated polymer electrolytes for energy storage applications, contributing to the development of efficient and reliable battery technologies.