The effect of four different plasticizers on the thermal properties, lithium ion conduction and electrochemical stability of polymer electrolytes based on blends of poly(ethylene oxide), poly(propylene oxide) and a fluorinated polyphosphazene has been investigated using DSC, impedance spectroscopy and cyclic voltammetry techniques. The addition of 80 wt% of plasticizer increases the conductivity various orders of magnitude, depending on the chemical nature of the plasticizers; lowering the glass transition and melting temperatures of the complexes, maintaining good electrochemical (stable up to 4 V) and cyclability properties after 10 cycles.