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Solid polymer electrolyte (SPEs) films based on poly (vinylidene fluoride-co-hexafluoropropylene) P(VDF–
HFP) and sodium thiocyanate (NaSCN) are prepared using the solution casting technique. Ionic liquid (IL; 1−ethyl-3-
methyl−imidazolium tricyanomethanide ([EMIM][TCM]) is incorporated into the prepared polymer-salt complex matrix
to further enhance its ionic conductivity. Polarized optical microscopy (POM) shows a change in the surface morphology
of IL doped polymer electrolyte films. The composite nature of polymer electrolyte films is confirmed using Fourier
transform infrared (FT−IR) spectroscopy via studying ion-ion and ion-polymer interactions. The structural morphology of
ionic liquid doped polymer electrolyte films (ILDPE) confirms the complexation between the ionic liquid
([EMIM][TCM]), salt (NaSCN) and polymer P(VDF–HFP). This is further confirmed using DSC and XRD
measurements. The XRD structural analysis confirms the intensity of crystalline peaks presents in IL doped solid polymer
electrolyte films decreases compared to that of pure polymer as well as polymer salt complex system. XRD clearly
indicates the enhancement in its amorphous nature which is necessary to increase the conductivity. The incorporation of
IL into polymer salt–complex matrix leads to changes in melting of polymer electrolytes, confirmed by DSC
thermograms. Polymer electrolyte films are also characterized using impedance spectroscopy (IS) to check their electrical
properties. The highest ionic conductivity is found to be 7.80×10-4 S cm-1 for 6 wt% IL doped polymer electrolyte film.
The Linear sweep voltammetry (LSV) analysis shows that the optimized polymer gel electrolyte is electrochemically
stable up to 1.5 V. The calculated value of ionic transference number (tion) is found to be 0.985. A laboratory scale
electrical double layer capacitor (EDLC) has been fabricated using this highly conducting polymer electrolyte film. The
specific capacitance value is found to be 1.31 F g-1.
Impact of polymer blending on Ionic Conduction Mechanism and Dielectric Properties of Sodium based PEO-PVdF Solid Polymer Electrolyte Systems
