Conductivity and electrochemical stability of composite polymer electrolytes

In this work the synthesis together with the electrical and electrochemical characterization of new composite polymer electrolytes on the basis of poly(ethylene oxide) blend with a perfluorinated polyphosphazene, and gamma-LiAlO2 as a ceramic filler are reported. The effect of the addition of a plasticizer, like propylene carbonate, on the properties of the composite polymer electrolyte has also been analyzed. Ionic conductivity was evaluated by complex impedance analysis, and electrochemical behaviour by cyclic voltammetry. Results indicate that the incorporation of the ceramic filler at low levels decreases the ionic conductivity of the system, while at the higher concentration tested, there is an improvement on the ionic conductivity at high temperatures resulting from the inhibition of the PEO crystallization processes. Cyclic voltammetry results suggest that gamma-LiAlO2 addition has a little effect on polymer electrolyte electrochemical stability. (C) 1998 Elsevier Science B.V. All rights reserved.