Investigating Ion Conduction Mechanism and Dielectric Characteristics of Sodium-Based PEO + PVDF-HFP Solid Polymer Electrolyte Membranes

Abstract This paper focuses on the preparation, characterization and dielectric studies of the flexible and free-standing solid polymer electrolyte membranes based on PEO + PVDF-HFP complexed with NaPF6 by the solution casting technique. The X-ray diffraction, Differential scanning calorimetry techniques were employed to analyse the structural properties and melting temperatures of the prepared solid polymer electrolyte membranes. In this study, we have explored the impact of polymer blending. The weight percentages of PEO and PVDF-HFP were systematically varied, while keeping the NaPF6 weight percentage constant. The impedance spectra of the prepared solid polymer electrolyte membranes are recorded using the N4L-PSM1735 Impedance Analysis Interface across a frequency range spanning from 1 Hz to 30 MHz. The obtained impedance spectroscopy data facilitated the determination of bulk resistance (R b ) and enabled an in-depth exploration of the dielectric and electrical modulus characteristics of the prepared solid polymer electrolyte membranes. Ionic conductivity values are derived through the analysis of bulk resistance (R b ) measurements. The most notable ionic conductivity value of 5.418x10−7 S/cm at room temperature was achieved with the solid polymer electrolyte membrane 70wt%PEO+30wt%PVDF-HFP+3wt%NaPF6. In this study, the solid polymer electrolyte membrane comprising 70wt%PEO, 30wt%PVDF-HFP, and 3wt%NaPF6 emerged as the optimum conducting composition.