Oxygen nonstoichiometry and defect chemistry of the mixed conductor La0.9Ca0.1FeO3−δ at low oxygen partial pressure

Abstract

Abstract The equilibrium oxygen nonstoichiometry, δ, for the mixed ionic and electronic conducting perovskite La 0.9 Ca 0.1 FeO 3 − δ (LCF91) was measured for oxygen partial pressures, p O2 , between 10 − 3 and 10 − 21 atm and temperatures of 750 to 900 °C using a tubular, two-probe Pt|YSZ|LCF coulometric titration cell. XRD experiments confirmed that LCF91 remains a single phase perovskite under the reducing conditions of a fuel electrode, and reveal no evidence of reaction with the zirconia electrolyte. The p O2 -nonstoichiometry relationship can be interpreted using a dilute-solution point-defect model involving oxygen vacancies, electrons, and electron holes.