Porous poly(vinylidene fluoride)-co-hexafluoropropylene/poly(ethylene glycol) (PVDF-HFP/PEG) hybrid-type polymer electrolytes are prepared by partially extracting the PEG molecules during the film-casting process. Thermal, mechanical, swelling, and electrochemical properties of the prepared polymer electrolytes are significantly affected by PEG content, as it changes the structure and size of the pores produced. The ion conductivity is dependent on the amount of electrolyte salt and liquid incorporated. The temperature dependence of ion conductivity is well described by Williams-Lewis-Ferry (WLF) equation. The polymer electrolyte systems are electrochemically stable up to about 5 V (C) 2003 Elsevier B.V. All rights reserved.