A dielectric relaxation study of nanocomposite polymer electrolytes

► We study the effect of δ-Al2O3 nanofillers on PEO4:LiClO4 polymer electrolytes. ► All polymer electrolytes exhibited VTF behaviour. ► Decreased Tg and fragility indicate non-attractive nature of filler & polymer. ► Up to 4 wt% fillers conct, the ion and segmental polymer dynamics seems to be coupled. ► The γ-relaxation seems to be unaffected by the fillers.