This paper describes the preparation and characterization of polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) based nanocomposite polymer electrolyte (NCPE). For the first of its kind lithium fluoroalkylphosphate (LiPF3(CF3CF2)(3)) was incorporated as electrolyte salt in the polymer skeleton. Ethylene carbonate and diethyl carbonate mixture (1:1, wt/wt) was used as a plasticizing agent and SiO2 nanoparticle as filler. The NCPE membranes were characterized by a.c. impedance, Scanning electron microscope, Differential scanning calorimetry, Fourier transform infrared and fluorescence studies. An electrolyte with 2.5wt% SiO2 exhibited a conductivity of 1.16 mS cm(-1) at ambient temperature. It was found that filler contents above 2.5wt% rendered the membranes less conducting. Activation energy and percentage of crystallinity has also been calculated. (C) 2008 Elsevier B.V. All rights reserved.