The electrochemical stability domains of Li2CO3-Na2CO3 and Li2CO3-K2CO3 are established at different temperatures in the anodic and cathodic conditions generally used in the molten carbonate fuel cell, on the basis of thermochemical calculations. Thermodynamic predictions on the stability of titanium species, according to the nature of the carbonate melt and the acidity level, are systematically developed under both oxidizing (O-2:CO2) and reducing (H-2:CO2:H2O:CO) atmospheres. In all the cases Ti (IV), in an Li2TiO3 form, is the stable species all over the acidity range. A partial transformation of this lithiated compound into other solid or liquid forms is also fully investigated.