Defect-Induced Properties and Thermodynamics of La 0.5 Ba 0.5 CoO 3– δ

Abstract

The defect structure model of La 0.5 Ba 0.5 CoO 3– 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 p O 2 simultaneously with the total conductivity, and chemical strain of this oxide. The partial molar enthalpy of oxygen in La 0.5 Ba 0.5 CoO 3– 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, La 0.5 Ba 0.5 CoO 2.99 , from the drop calorimetric measurement results in air. The standard enthalpies of formation of cubic La 0.5 Ba 0.5 CoO 2.95 and double LaBaCo 2 O 5.90 perovskites, and the enthalpy of cation ordering in A-sublattice of La 0.5 Ba 0.5 CoO 2.95 , were found using the results of solution calorimetry at 298.15 K. With the data obtained, we predicted the chemical compatibility of La 0.5 Ba 0.5 CoO 3– δ with solid oxide fuel cell (SOFC) electrolyte materials.