The aim of this work is to determine whether the dispersion of dedoped (insulating) polyaniline (PAni) nanofibers affect the ion transport properties of [P(VdF-HFP)] based composite polymer electrolytes. By analysis of SEM, XRD, impedance spectroscopy and FTIR results it has been demonstrated that the incorporation of dedoped PAni nanofibers up to a moderate concentration to P(VdF-HFP)-PC-DEC-LiClO4 gel polymer electrolyte system significantly enhance the ionic conductivity and interfacial stability of the electrolyte system. At higher concentration dedoped nanofibers appear to get phase separated and form insulating clusters which impede ionic transport. The pores in the polymer matrix are greatly widened by the nanofibers due to their high aspect ratio (> 50) and the ions get extra free volume for movement. Thus, up to a moderate concentration of dedoped nanofibers the P(VdF-HFP) based gel polymers can be used as electrolyte membranes for rechargeable lithium batteries. (c) 2008 Elsevier B.V. All rights reserved.