A new type dual-phase polymer electrolyte (DPE) based on poly(MMA-g-NBR) and poly(methyl methacrylate) (PMMA) was prepared by film-casting method. In the DPE, PMM A phase is selectively impregnated with the lithium salt solution, forming an ion-conducting network, while poly(MMA-g-NBR) phase maintains mechanical strength in the system. With grafting effect, the compatibility of two phases (PMMA/poly(MMA-g-NBR)) can be enhanced obviously. The chemical and physical characteristics, morphology and ionic conductivity behavior of DPEs, and their interfacial stability between lithium metal electrode were characterized by using of FTIR, (HMNR)-H-1, DSC, SEM, optical microscopic images, AC impedance, and linear sweep voltammetry. A new type DPE with good mechanics and high electrochemistry properties is obtained at an optimum proportion of two blending polymers. (c) 2007 Wiley Periodicals, Inc.