This article describes a comparative study of poly(vinylidene fluoride-co-hexafluoropropylene)-polyacrylonitrile-based plain gel polymer blend electrolytes and microporous gel polymer blend electrolytes. Scanning electron microscopy, differential scanning calorimetry, alternating-current impedance, chronoamperometry, and dielectric spectroscopy studies were carried out. The microporous gel polymer blend electrolytes enhanced the ionic conductivity, lithium transference number, and dielectric permittivity, and this could be attributed to a higher uptake of the electrolyte solution (an increase in the number of charge carriers) by the porous structure. The temperature dependence of the ionic conductivity of the polymer electrolyte followed an Arrhenius relationship. An LSV experiment was carried out to investigate the electrochemical stability in the polymer electrolyte. Finally, charge-discharge studies of lithium-ion cells made from the coupling of gel polymer blend electrolytes (plain and microporous) with LiMg0.10Mn1.90O4 as a cathode and carbon as an anode were conducted. (C) 2007 Wiley Periodicals, Inc.