It is shown that ionic conductivity of polymeric electrolytes based on low molecular weight amorphous polyglycols can be modified by the addition of alpha-Al2O3 fillers containing surface groups of the Lewis acid type. An enhancement of conductivity over pure PEG-LiClO4 electrolyte is observed for PEG-alpha-Al2O3-LiClO4 composite electrolytes containing from 0.5 to 3 mol/kg of the lithium salt. This increase in conductivity is coupled with the lowering of the viscosity of composite electrolytes and increasing chain flexibility when compared to the PEG-LiClO4 system as shown by rheological and DSC experiments. A decrease in the fraction of ionic aggregates is also seen from the FT-LR experiments for composite electrolyte in this salt concentration range. FT-IR studies of the C-O-C stretching mode has shown reduction in the transient cross-link density obtained after the addition of alpha-Al2O3 in the salt concentration range corresponding to the conductivity enhancement. The phenomena observed are explained in view of ion-ion and ion-polymer interactions, involving dispersed filler particles, which are of the Lewis acid-base origin.