Solid State Ionics, Vol.292, 52-58, 2016
Oxygen nonstoichiometry and transport properties of LaNi0.6Co0.4O3-delta
The oxygen nonstoichiometry of the perovskite-type oxide, LaNi0.6Co0.4O3-delta, was measured at various temperatures and oxygen partial pressures (p(O-2)) by high temperature gravimetry and coulometric titration. The oxygen nonstoichiometry appeared independent of p(O-2) in the range of 10(-4) bar > p(O-2), which was in good agreement with the tendency of lattice parameter determined by the high-temperature X-ray diffraction (HT-XRD). The oxygen nonstoichiometry behavior was analyzed using the defect equilibrium model assuming delocalized electron. In addition, the diffusion coefficient, D*, and the surface reaction rate constant, k*, were obtained by the isotope exchange and secondary ion mass spectrometry. The Dv estimated from the D* showed similarity with those reported for other perovskite oxides which supported the reliability of delta determined in this work. (C) 2016 Elsevier B.V. All rights reserved.