Defect-Induced Properties and Thermodynamics of La_0.5Ba_0.5CoO_3–δ

Abstract

The defect structure model of La0.5Ba0.5CoO3–δ was successfully verified using a combined set of coulometric and thermogravimetric data. The results were used to model the dependences of Seebeck coefficient, measured vs T and pO2 simultaneously with the total conductivity, and chemical strain of this oxide. The partial molar enthalpy of oxygen in La0.5Ba0.5CoO3–δ was calculated from the defect structure model and used to evaluate the enthalpy increments and high-temperature heat capacity of an oxide with constant chemical composition, La0.5Ba0.5CoO2.99, from the drop calorimetric measurement results in air. The standard enthalpies of formation of cubic La0.5Ba0.5CoO2.95 and double LaBaCo2O5.90 perovskites, and the enthalpy of cation ordering in A-sublattice of La0.5Ba0.5CoO2.95, were found using the results of solution calorimetry at 298.15 K. With the data obtained, we predicted the chemical compatibility of La0.5Ba0.5CoO3–δ with solid oxide fuel cell (SOFC) electrolyte materials.

Energetics of formation and stability in high pressure steam of barium lanthanide cobaltite double perovskites

“…3b, shows the combined effect of the lattice volume, the Co oxidation state, and oxygen vacancies on the energetics of barium lanthanide cobaltites. The of BLC with δ = 0.1 obtained by Malyshkin et al using room temperature solution calorimetry was −184.9 ± 14.7 kJ mol −1 , 27 which is slightly less exothermic than the for BLC with δ = 0.37 (−221.98 ± 3.73 kJ mol −1 ) in this study. As for BGC, the results obtained by Ivanov et al show that as the oxygen nonstoichiometry ( δ ) increases, the becomes less exothermic, e.g.…”