Microporous fibrous membranes were prepared from poly(vinylidenefluoride-co-hexafluoropropylene) P(VdF-HFP) solutions in an acetone/N,N-dimethylacetamide mixture using the electrospinning method. Varying the P(VdF-HFP) polymer concentration in electrospinning can easily control the pore size and the porosity of the electrospun fibrous membranes (ES-FMs). The usefulness of the ES-FMs as a matrix of polymer electrolyte for a lithium-ion polymer battery with high performance was evaluated. Electrospun fibrous polymer electrolyte membranes (ES-FPEMs) showed excellent electrochemical properties of ionic conductivity, higher than 1 x 10(-3) S/cm at room temperature, and the electrochemical stability window, up to 4.5 V vs. Li+/Li. At a C/2 rate, the prototype cell using the ES-FPEM showed a good charge/discharge property, with little capacity fade under constant current and constant voltage conditions at 20 and 60degreesC. (C) 2004 The Electrochemical Society. All rights reserved.