We study the passivation of a metal immersed in an oxidizing solvent and propose a simulation model based on reaction and diffusion processes. A poisoning mechanism of the moving reactive interface between the layer and the solvent is introduced. The blocking effect induced by chemical species initially added to the solvent or produced by the growth reaction itself is studied. The model accounts for the formation of a thin compact primary layer at the beginning of the growth process. Applying the model to the lithium anode passivation during the storage of a Li/SOCl2 cell, we analyse the influence of the simulation parameters on the compact layer properties. An optimization of the lithium battery performance is discussed.