Publication

Abstract : In pursuit of developing a suitable sodium‐ion conducting solid polymer electrolyte (SPE) with enhanced ionic conductivity at room temperature (RT), poly(vinylidene fluoride) (PVDF) is blended with poly(ethylene oxide) (PEO) of varying molecular weights and sodium nitrate (NaNO 3 ) at different loadings, via the solution blending technique. The impact of the molecular weight of PEO on the ionic conductivity, dielectric properties, and structural evolution of PVDF‐50 wt% PEO blend incorporated with y wt% NaNO 3 ( y  = 0,1,3,5,7,9,10,12,15), is studied in detail. Fourier transform infrared (FTIR) spectroscopy analysis confirms PEO–Na + interaction in SPEs, while X‐ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses reveal suppressed PEO crystallinity, crucial for enhanced ion conduction. The highest ionic conductivity of 6.98 × 10 −4  S cm −1 at RT is achieved for PVDF‐50 wt% PEO‐9 wt% NaNO 3 with high molecular weight (HMW) PEO due to the availability of more coordinating sites. The mobility of mobile ions dominates the ionic conductivity in both HMW and low molecular weight (LMW) PEO‐incorporated SPEs. The temperature‐dependent conductivity studies reveal that both HMW and LMW PEO‐incorporated SPEs follow Arrhenius behavior. The ion transference number, evaluated from the DC Wagner polarization method, is greater than or equal to 0.95 for selected SPEs.