A review on solid oxide fuel cell durability : Latest progress, mechanisms, and study tools

The commercial breakthrough of solid oxide fuel cells (SOFCs) is still hampered by degradation related issues. Most SOFCs that perform well do not possess good stability. To achieve a targeted degradation rate of 0.2%/1000 h important to a durable SOFC device, it is vital to identify the sources of degradation. So far, the longest stable performance was given by F1002-97, a short stack from Forschungszentrum Jülich GmbH, which reached 93,000 h of operation at 700 °C under 0.5 A cm⁻² constant current density with a degradation rate of 0.5%/1000 h. In this review, we discuss the most detrimental degradation mechanisms for the core components of the SOFC, mainly poisoning, microstructural deformations, and strains. Electrochemical, chemical, and structural characterization tools for quantifying degradation mechanisms are also presented. The following section addresses the most recent progress in SOFC durability and the associated methods for analyzing degradation. These techniques include different doping techniques (including Mo, Nb, Co, Ce, Ta, Sn, etc.), surface modifications (e.g.infiltration, exsolution techniques, protective coatings), and interface engineering. Finally, the factors that inhibit the enhancement of SOFC durability are briefly discussed, such as inadequate knowledge of the degradation process and limitations in the material choices.