Ionic Interactions and Dielectric Relaxation of PEO/PVDF-Mg[(CF3SO2)2N2)] Blend Electrolytes for Magnesium Ion Rechargeable Batteries

A new series of magnesium-ion conducting solid polymer blend electrolytes based on an optimized blend ratio (90:10) of poly(ethylene oxide) (PEO) and poly(vinylidene fluoride) (PVDF) doped with different concentrations of magnesium bis (trifluoromethane sulfonimide) salt, Mg [(CF3SO2)(2)N-2)] has been prepared by solution casting technique, using dimethylformamide (DMF) as the common solvent. The increase in the amorphous phase with an increase in salt concentration of the prepared blended polymer electrolytes has also been nurtured from the results obtained from X-ray diffraction (XRD) and scanning electron microscopic (SEM) analyses. The electrical transport characteristics were evaluated by means of electrochemical impedance spectroscopy (EIS) and the maximum ionic conductivity obtained at room temperature (298 K) was found to be 1.2x10(-5) S cm(-1) in the case of the blend containing 15 wt% salt. A detailed investigation concerning the mechanism of magnesium ion transport in the optimized polymer blend electrolyte over the frequency range of 1 MHz to 20 Hz has also been carried out in terms of electrical conductivity spectra, dielectric properties and electrical modulus spectra at room temperature.