La2-xNiO4+delta (x=0 : 0.05) has been prepared by modified Pechini method and characterized by XRD, TGA, SIMS and Electrochemical Impedance Spectroscopy. La2-xNiO4+delta phases show no reaction with YSZ at 900 degrees C for 4 h. The materials have promising high oxygen diffusion coefficient and surface exchange coefficient. The electrode reaction process is identified to be the reaction rate limiting step at low temperature (T<700 degrees C) and small applied d.c. potential, whereas at high temperature (T>700 degrees C) and large d.c. potential, it is the interface diffusion process which becomes limiting. (C) 2008 Elsevier B.V. All rights reserved.