Anodic behavior of 8Y_2O_3ZrO_2/NiO cermet using an anode-supported electrode

摘要

8Y_2O_3-ZrO_2 (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 Sm_(0.2)Ce_(0.8)O_(19) (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(H_2O)), area specific resistance (ASR), activation energy (E_a), 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 H_2O formation reaction, while the low frequency arc corresponds to the dissociative adsorption and the surface diffusion/gas phase diffusion process. Changes in microstruc-ture by redox and thermal cycling have a significant effect on the electrochemical properties and structural stability of a thick anode-supported cermet structure.