Studies on structural and electrical properties of NaI doped PEO/CMC blend solid polymer electrolyte

Solid polymer blend electrolyte (SPE) films of Polyethylene oxide(PEO)/Carboxymethyl cellulose (NaCMC) doped with Sodium iodide (NaI), were prepared by solution cast method and their structural, optical and electrical properties were investigated using X-Ray diffraction, Fourier transform infrared spectroscopy, UV–Vis spectrophotometer and Electrical impedance analyser respectively. X-Ray diffraction spectra indicate that, deformation occurred in the structure of the blend followed by doping with NaI salt. The variation in intensity and shifting of characteristic bands in FTIR spectra provides the evidence for formation of complex due to the interaction occurred in the blend with the dopant. Optical energy band gap decreases in the blend samples upon doping and is confirmed by UV–Vis spectrophotometer analysis. Increase of dielectric constant and loss upon doping, exhibits usual behaviour of the polymer electrolytes. An increase in AC conductivity is observed upon doping and maximum conductivity of 9.41 × 10−3 Scm−1 is obtained for 10/90 sample doped with 0.03% Sodium iodide and DC conductivity for the same sample at room temperature is 1.05 × 10–2 Scm−1. In addition, I-T studies confirm the conductivity exhibited by the sample as due to ions and I-V studies show electrochemical stability in the range of good working potential. From the results obtained, it can be inferred that, the prepared sample can be used as polymer electrolytes in the manufacturing of energy storage devices.