A study is made of a polymer electrolyte system composed of poly(vinyl chloride) (PVC) as a host polymer, lithium tetrafluoroborate (LiBF4) and lithium triflate (LiCF3SO3) as salts and a mixture of ethylene carbonate and propylene carbonate as plasticizers. X-ray diffraction (XRD) reveales that the salts and plasticizers disrupt the crystalline nature of PVC-based polymer electrolytes and converts them into an amorphous phase. Differential scanning calorimetry studies suggest that the plasticized samples have lower values of the glass tranisition temperature T g, and thermogravimetric studies show that the thermal stability of the polymer electrolytes decreases with addition of plasticizers. The plasticized PVC electrolyte is used in the fabrication of electrochemical cells. The open-circuit voltage, discharge time for the plateau region, etc. are evaluated.