Robust Dynamic Operation of High Temperature Electrolysis Solid Oxide Cells: Article No. 239770

This study evaluates the durability of Ni/YSZ-supported SOECs under dynamic operating conditions relevant to real-world applications. Systematic tests were conducted to assess cell performance under steam cycling (3 to 75% humidified H2), mode cycling between SOFC and SOEC operation, thermal cycling (150 to 750 degrees C at OCV, and 600 to 800 degrees C at 1.3V), and redox cycling (between 50% humidified H2 and 50% humidified N2). Steam cycling, mode cycling, and thermal cycling at OCV do not significantly accelerate performance degradation. Thermal cycling at 1.3V caused minimal damage within 600 to 800 degrees C. Full redox cycling (multi-hour oxidation holds) induced cell structural failure, while partial redox cycling (0.5 h holds) was tolerated. Extensive characterization revealed some material evolution, namely Sr and Co secondary phase formation, within the oxygen electrode due to La0.6Sr0.4Co0.2Fe0.8O3-..delta.. instability, especially for steam cycling and mode cycling. Minimal changes were identified within the Ni-YSZ fuel electrodes. These findings provide critical insights into SOEC reliability under dynamic conditions, supporting their application in dynamic or intermittent energy systems.