8Y(2)O(3)-ZrO2 (8YSZ)/NiO cermet anode-supported symmetric cell is introduced and fabricated using a tape casting process to analyze the anodic behavior of an anode-supported cell. An anode-supported symmetric cell helps us understand the complex anode structure of cermets. The anodic behavior of 8YSZ/NiO is compared to a MIEC electrode of Sm0.2Ce0.8O1.9 (SDC)/NiO. The anodic behavior of a 8YSZ/NiO cermet electrode is investigated and discussed with respect to the hydrogen partial pressure (p(H-2)), water partial pressure (p(H2O)), area specific resistance (ASR), activation energy (Ea), thermal cycle, and redox process. Based on these studies, an empirical reaction model of 8YSZ/NiO is established, and the related reaction processes are discussed. On impedance spectra diagram, high and medium frequency arcs are associated with the charge transfer process and the H2O formation reaction, while the low frequency arc corresponds to the dissociative adsorption and the surface diffusion/gas phase diffusion process. Changes in microstructure by redox and thermal cycling have a significant effect on the electrochemical properties and structural stability of a thick anode-supported cermet structure. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.