Thermodynamic calculations have been made to compare the thermochemical performance of three candidate breeder blanket materials, Li2O, LiAlO2, and Li4SiO4. These calculations were done for the temperature range of 900–1300 K and the oxygen activity range of 10−25 to 10−5. Oxygen activity is an influential variable for these materials and must be considered in the diffusion of tritiated species, determining the chemical form of the released tritium, and retention of tritium in the condensed phase. Surface adsorption may also act as a strong contributor to tritium inventory. In general, LiAlO2 appears better than Li2O and Li2O, in turn, appears better than Li4SiO4.