New cathode materials for ITSOFC: Phase stability, oxygen exchange and cathode properties of La2 − xNiO4 + δ

La2 − xNiO4 + δ (x = 0 ; 0.05) has been prepared by modified Pechini method and characterized by XRD, TGA, SIMS and Electrochemical Impedance Spectroscopy. La2 − xNiO4 + δ phases show no reaction with YSZ at 900 °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 °C) and small applied d.c. potential, whereas at high temperature (T > 700 °C) and large d.c. potential, it is the interface diffusion process which becomes limiting.