Three electroanalytical techniques have been used to study the solid-state ionic diffusion of lithium into cerium-vanadium mixed oxide thin films, i.e. potentiostatic intermittent titration technique, galvanostatic intermittent titration technique and electrochemical impedance spectroscopy. Diffusion coefficients measured with the above mentioned techniques show a non-monotonic decay between 8 x 10(-12) and g x 10(-14) cm(2) s(-1). In particular, lithium diffusion coefficient drops by mon than one order of magnitude at lithium intercalation degree x = 0.6. This abrupt change seems to be related to a dramatic increase of the material resistance suggesting that the limiting factor in atomic lithium diffusion may be the low electronic conductivity.