Influence of 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl) imide plasticization on zinc-ion conducting PEO/PVdF blend gel polymer electrolyte

Abstract

The influence in terms of plasticizer on zinc-ion conducting polymer blend electrolyte system, [PEO (90 wt%)/PVdF (10 wt%)]-15 wt% Zn (CF3SO3)2] with various concentrations of 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (EMIMTFSI) was investigated. The freshly-prepared thin films of [PEO (90 wt%)/PVdF (10 wt%)]-15 wt% Zn (CF3SO3)2) + x wt% EMIMTFSI, where x = 1, 3, 5, 7, and 10 wt%] were characterized by means of X-ray diffraction (XRD), Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and impedance analysis techniques. The room temperature XRD patterns tend to support the enhanced amorphous phase as a result of deducing the degree of crystallinity of the polymer blend–salt system by the addition of 7 wt% EMIMTFSI. The relevant SEM images of 7 wt% EMIMTFSI incorporated gel polymer electrolyte exhibit a minimised spheurilite structure when compared to that of the polymer blend–salt system. Unusually, the highest ionic conductivity realized in the case of the typical gel polymer electrolyte system, [PEO/PVdF-Zn (CF3SO3)2 + 7 wt% EMIMTFSI] is found to be 1.63 × 10−4 S cm−1 at room temperature. The temperature dependence of conductivity has been examined based on the Vogel–Tammann–Fulcher (VTF) equation, thereby suggesting the segmental chain motion and free volume changes. The occurrence of ion dynamics and dielectric relaxation behaviour in the chosen system has been analysed in a detailed fashion at room temperature using frequency response impedance formalisms involving electric modulus and dielectric permittivity features.