Effect of propylene carbonate and dimethylformamide on ionic conductivity of P(ECH-EO) based polymer electrolyte

Abstract

The new plasticized polymer electrolyte composed of poly(epichlorohydrin-ethyleneoxide) (P(ECH-EO)) as host polymer, mixture of γ-butyrolactone (γ-BL) and propylenecarbonate (PC), γ-butyrolactone (γ-BL) and dimethylformamide (DMF) as plasticizer and lithium perchlorate (LiClO4) as salt were prepared by simple solution casting technique. The structure and the surface morphological characterization were studied by X-ray diffraction (XRD) and polarized optical microscopic (POM) measurements respectively. Differential scanning calorimetry (DSC) analysis was carried out on the plasticized polymer electrolyte to observe the change in transition temperature caused by the addition of two different plasticizers (PC and DMF). The thermal stability of the plasticized polymer electrolyte was studied by TG/DTA and found as the plasticizer content increases the thermal stability of the film decreased. Impedance spectroscopy technique was used to study the mode of ion conduction in the plasticized polymer electrolyte. The highest ionic conductivity is found to be 5.8×10−4Scm−1 at 303K for DMF plasticized polymer electrolyte. The electrochemical stability of the plasticized polymer electrolyte has been studied by cyclic voltammetry using aluminum (Al) as the blocking electrodes. The films were found to be electrochemically stable till 1.2V.