Impedance spectroscopy of perovskite air electrodes for SOFC prepared by laser ablation method

Abstract

Perovskite thin film electrode for SOFC was prepared on a YSZ single crystal by laser ablation method. The deposited film appeared in pore-free and dense polycrystals oriented in a specific direction. The crystal orientation was controlled by the surface structure of the single crystal substrate. The electrochemical impedance spectroscopy was used to disintegrate the electrode reaction into the constituting basic several processes. For each process, the pO 2 and temperature dependence was discussed. In the surface reactions, the dissociative adsorption of oxygen molecules on La 0.8Sr 0.2CoO 3 (LSC) is rate limiting, while the charge transfer process becomes a limiting step on La 0.8Sr 0.2MnO 3 (LSM). The kinetics of these processes shows dependence on the kind of electrode material and the crystal plane of perovskite surface.