ZSM-5 molecular sieves, usually known as shape-selective catalyst in a great deal of catalysis fields, due to its special pore size and two-dimensional interconnect channels. In this work, a novel PEO-based composite polymer electrolyte by using ZSM-5 as the filler has been developed. The interactions between ZSM-5 and PEO matrix are studied by DSC and SEM techniques. The effects of ZSM-5 on the electrochemical properties of the PEO-based electrolyte, such as ionic conductivity, lithium ion transference number, and interfacial stability with lithium electrode are studied by electrochemical impedance spectroscopy and steady-state current method. The experiment results show that ZSM-5 can enhance the ionic conductivity and increase the lithium ion transference number of PEO-based electrolyte more effectively comparing with traditional ceramic fillers such as SiO2 and Al2O3, resulting from its special framework topology structure. The excellent performances such as high ionic conductivity, good compatibility with lithium metal electrode, and broad electrochemical stability window suggesting that PEO-LiClO4/ZSM-5 composite polymer electrolyte can be used as candidate electrolyte materials for lithium polymer batteries. (c) 2005 Elsevier B.V. All rights reserved.