Composite electrolytes based on low molecular weight polyglycols

In the present work ionic conduction is studied in poly(ethylene glycol) (P EG)-LiClO4-alpha -Al2O3 electrolytes over wide salt concentration and tempe rature ranges. Composite electrolytes with alpha -Al2O3 containing inert su rface groups are examined. Conductivity enhancement was observed compared t o PEG-LiClO4, electrolytes in the 0.5-5 mol kg(-1) salt concentration range . Conductivity studies are coupled to viscosity and DSC experiments which h elps us to establish the relation between salt concentration and viscosity (flexibility) of the polymer host. The ion-polymer interactions are studied on the basis of FT-IR spectroscopy and, particularly, changes in the inten sity of the IR modes characteristic of C-O-C vibrations. Finally, the ionic associations are discussed on the basis of the Fuoss-Krauss formalism. The se Studies show the reduction in the ion-pair formation for composite polym eric electrolytes in the entire concentration range studied. (C) 2000 Elsev ier Science B.V. All rights reserved.