A series of six cathodes Sr0.15La0.85MnO3 (SLM) on yttria-stabilized zirconia with different morphology of the electrode/electrolyte interface were characterized by ac impedance and de polarization measurements. It is found that the electrode kinetics at elevated temperature (945 degrees C) are governed by two serial processes. An activation process can be identified to occur at high cathodic overpotential, whereas a transport process competes with charge-transfer at comparatively low overpotential. Attention is drawn to the profound change in the electrocatalytic properties of Sr0.15La0.85MnO3 upon current passage and its influence in elucidation of the interfacial kinetics.