Lithium polymer electrolytes formed by dissolving a lithium salt LiX in poly(ethylene oxide) PEG, may find useful application as separators in lithium rechargeable polymer batteries. The main problems, which are still to be solved for a complete successful operation of these materials, are the reactivity of their interface with the lithium metal electrode and the decay of their conductivity at temperatures below 70 degrees C. In this paper we demonstrate that a successful approach for overcoming these problems, is the dispersion of selected ceramic powders in the polymer mass, with the aim of developing new types of composite PEO-LiX polymer electrolytes characterized by enhanced interfacial stability, as well as by improved ambient temperature transport properties. (C) 2000 Elsevier Science Ltd. All rights reserved.