Durability Study of Anode-Supported SOFC with Large-Area Fabricated By 4-Layer Sequential Co-Lamination and GDC Co-Firing Process

Abstract

Electrolyte-Cathode interfaces are life-threatening regions of solid oxide fuel cells where degradation phenomena occur due to chemical interdiffusion. The Buffer layer is inserted between the electrolyte-cathode to limit the cation exchange across the interface. However, state of the art buffer layer coated by screen printing does not fully prevent cation migration which results in the formation of insulating phases such as La2ZrO7 and SrZrO3. Herein, a reliable four-layered (NiO-YSZ, NiO-CeScSZ, CeScSZ, and GDC) thin film-based anode-supported SOFCs with a large-area (12 cm × 12 cm) were fabricated by sequential co-lamination, in which all cell components perform a distinct role to enhance the interfacial connectivity and packing density of electrolytes. This enhanced connectivity with a highly dense electrolyte (5-6 µm) and buffer layer (2-3 µm) was accomplished on the porous anode support without any structural defects. The single cell (144 cm2) showed a power output of 38 W at a total current of 50 A (700 °C). The Post-tested cell had exceptional micro-structural characteristics and excellent interfacial adhesion and retained its structural integrity during steady and unsteady state operation. Also, the formation of insulating phases and decomposition of the cathode were completely prevented, resulting in a remarkable improvement in durability. The cell with a four-layered structure exhibits an extreme low degradation rate of 0.2% kh-1 under 25 A current and 21 dynamic load cycling conditions, which satisfies the strict benchmark of durability for technology commercialization.