Behavior of titanium species in molten Li 2CO 3–Na 2CO 3 and Li 2CO 3–K 2CO 3 under anodic and cathodic conditions. I – Thermodynamic predictions at 550–750°C

Abstract

The electrochemical stability domains of Li 2CO 3–Na 2CO 3 and Li 2CO 3–K 2CO 3 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:CO 2) and reducing (H 2:CO 2:H 2O:CO) atmospheres. In all the cases Ti (IV), in an Li 2TiO 3 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.