Preparation of (PEO)(n)M(SO3Cl)(x) (M = Li, LiAl, Ca, x = 1, 2 and 4) polymer electrolytes is reported. Characterisation of the electrolytes concentrates on the electrical and electrochemical characteristics of the system. Variation of the polymer electrolyte conductivity with temperature is correlated to the corresponding microstructural characteristics (degree of crystallinity and glass transition temperature). Using inert Au electrodes the transport numbers of the positive and negative charge carriers in the polymer electrolyte are determined. The electrical properties of the passive film formed in contact with metallic lithium are studied using impedance spectroscopy. The impedance data is analysed using the well-known general solution for the impedance response of the flat-band case of a system containing two types of mobile charge carrier in the absence of a supporting electrolyte.