Oxygen nonstoichiometry and transport properties of LaNi0.6Co0.4O3−δ

• Oxygen nonstoichiometry is independent of p(O2) in the range of 10− 4 bar > p(O2).
• Lattice parameter showed same tendency of p(O2) with oxygen nonstoichiometry.
• The Dv estimated from the D* were close to those reported for other perovskite oxide.

The oxygen nonstoichiometry of the perovskite-type oxide, LaNi0.6Co0.4O3−δ, was measured at various temperatures and oxygen partial pressures (p(O2)) by high temperature gravimetry and coulometric titration. The oxygen nonstoichiometry appeared independent of p(O2) in the range of 10− 4 bar > p(O2), 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 δ determined in this work.