To investigate the effects of salt concentration, LiBF4 was incorporated into a PVdF-PVC based polymer blend and thin electrolytes were prepared by solution casting technique. The obtained thin films were subjected to various characterizations such as FTIR, XRD and TG/DTA analysis to study their complex behaviour, amorphicity and thermal stability, respectively. The ionic conductivities of the electrolytes were measured by AC impedance. A PVdF (80)-PVC (20)-LiBF4 (8 wt%) polymer electrolyte was found to have high conductivity compared to other complexes. Similar investigations were also repeated with a LiClO4 salt in the above blend and the electrical conductivity was found to be higher in the polymer complex having 8 wt% of salt concentration. (c) 2006 Published by Elsevier B.V.