A special type of polyacrylonitrile (PAN)based microporous polymer electrolyte was prepared by the dissolution of poly(vinyl chloride) (PVC) with a novel preferential polymer dissolution process from cast polymer films containing various amounts of PAN and PVC. PVC, dissolved from a 50: 50 (w/w) PAN/PVC blended polymer film, had a high ionic conductivity of 5.01 X 10(-3) S/cm at the ambient temperature when soaked in a 1M solution of LiClO4, in ethylene carbonate and diethyl carbonate. The amorphosity, surface morphology, and thermal stability of the microporous gel polymer electrolyte were characterized by X-ray diffraction, scanning electron microscopy, and differential scanning calorimetry studies. Chronoamperometry and linear-sweep voltammetry studies were performed to determine the lithium transference number and stability of the microporous polymer electrolyte membrane, respectively. Finally, a Li-ion polymer cell was assembled with the prepared inicroporous gel polymer electrolyte, and its compatibility with electrode materials was studied by cyclic voltarnmetry. (c) 2005 Wiley Periodicals, Inc.