Structural and ionic conductivity characterization of PEO:MC-NH4I proton-conducting polymer blend electrolytes based films

In the present work, series of proton-conducting polymer electrolyte films based on polyethylene oxide/methylcellulose complexed with different concentrations of ammonium iodide (NH4I) as doping salt were prepared by solution cast technique. The produced films were characterized by X-ray diffraction (XRD), Polarized optical microscope (POM), Fourier transform infrared (FTIR), and electrical impedance spectroscopy (EIS). The XRD and POM results reveal that the sample with 30 wt% NH4I (PBE-30) has the lowest degree of crystallinity. The observed shift in the IR peak position of the N-H stretching band at regions 3000-3300 cm(-1) as a function of NH4I concentration suggested clear evidence of an interaction between host polymers and NH4I. The highest value of electrical conductivity was found to be 7.62 x 10(-5) S. cm(-1) at 303 K for PBE-30. The temperature-dependent of electrical conductivity and ion transport properties was described using both the Arrhenius and Vogel-Tammann-Fulcher (VTF) relations. The activation energy values decrease with increasing DC conductivity and vice-versa.