Microstructure and Electrochemical Behavior of a Structured Electrolyte/ LSM-Cathode Interface Modified by Flame Spraying for Solid Oxide Fuel Cell Application

摘要

Plasma-sprayed yttria-stabilized zirconia (YSZ) can be potentially employed as electrolyte layers in solid oxide fuel cells (SOFCs). The formation of a structured electrolyte surface characterized by convex micro deposits generated by only partially molten particles at spraying will increase the specific surface area and subsequently improve the output performance of SOFCs. However, using completely molten YSZ particles during plasma spraying leads to the formation of locally flat surface. In this study, flame spraying was employed to deposit YSZ particles on YSZ substrate using surface-melted particles. The deposition was carried out at different spray distances on YSZ substrate preheated to 650°C. The surface and cross-section morphology of YSZ particles were characterized by SEM. The electrochemical behavior of single cell with the structured cathode was characterized by the electrochemical impedance spectroscopy. The results show that spray distance exhibits significant influence on the morphology of deposited YSZ particles. The cathode polarization of a structured cathode was decreased by about 30-43% compared to a flat cathode at different temperatures.