Hybrid, solid polymer electrolyte films consisting of poly (vinyl chloride) (PVC), poly (acrylonitrile) (PAN) and, propylene carbonate (PC) with different concentrations of LiClO4 are prepared by means of a using solvent-casting technique. The structure and complex formation are studied by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The temperature dependence of the ionic conductivities of the polymer films is explained in terms of a free volume model. The conductivities of PVC–PAN–LiClO4–PC complexes are determined at different salt concentrations. The highest ionic conductivity (8.35×10−5 Scm−1) is obtained for 8wt.% LiClO4 in the polymer complex at 304K. The thermal stability of the electrolyte is examined by thermogravimetric/differential thermal analysis (TG/DTA).