Studies on the morphology and conductivity of PEO/LiClO4

Abstract

Polymer based ion conducting materials have potential applications as an electrolyte and separator in the field of lithium batteries. The present work is aimed at the optimization of LiClO4 loading in PEO/LiClO4 films for solid polymer electrolyte (SPE) applications. PEO was complexed at different wt% ratios (95:5), (92.5:7.5), (90:10), (87.5:12.5) and (85:15) and then made into films by solution casting. The PEO/LiClO4 films thus fabricated are characterized by X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The above studies have indicated enhancement in amorphous phase of polymer with increase of salt concentration. Further, a reduction in melting temperature (Tm) of PEO was observed from DSC results indicating increase in the flexibility of the polymer chains. Ionic conductivity studies were carried out as a function of frequency and temperature using Hioki LCR Hitester. The PEO/LiClO4 films with maximum salt concentration (85:15) have exhibited an enhancement in conductivity of about four orders of magnitude compared to host polymer electrolyte.