Defect chemistry and thermodynamic properties of proton dissolution into BaZr_0.9Y_0.1O_3 − δ

Proton concentration in BaZr_0.9Y_0.1O_3 − δ was measured by highly-accurate thermogravimetry as functions of temperature and p(H₂O), and thermodynamic properties of the proton dissolution were discussed. Apparent Gibbs free energy change of the proton dissolution reaction changes with proton concentration even at a constant temperature. This means the proton dissolution in BaZr_0.9Y_0.1O_3 − δ is not ideal-solution-like. The deviation from the ideal solution became more significant with increasing temperature i.e. decreasing the proton concentration. This indicated the interaction between oxygen vacancies or electron hole, dopant-defect interaction, or lattice deformation may cause the proton dissolution in BaZr_0.9Y_0.1O_3 − δ especially at higher temperature.