Electric properties of passivating films forming on the surface of Li-Sn, Li-Cd and Li-Sn-Cd alloy electrodes in propylene carbonate-based solutions have been investigated using the electrode impedance spectroscopy technique. Within the range of high and medium frequencies, the impedance spectrum has been shown to be described by the equivalent circuit represented by geometric capacitance and ionic resistance of the film, as well as capacitance of ionic space charge in the film and Warburg impedance assigned to lithium cation diffusion. The change of impedance spectra in the course of the electrode storage in the solutions has been discussed.