Degradation studies of ceria-based solid oxide fuel cells at intermediate temperature under various load conditions

Chemical lattice strain in nonstoichiometric oxides: an overview

“…9c demonstrates the pinhole and crack formation in the ceria-based SOFC electrolyte, caused by the reduction-induced chemical expansion of ceria. 24 In the latter case, dynamic load conditions, resulting in varying oxygen partial pressure gradients, were found to exacerbate the SOFC degradation. 24…”

“…24 In the latter case, dynamic load conditions, resulting in varying oxygen partial pressure gradients, were found to exacerbate the SOFC degradation. 24…”

“…to account for the fact that for real, distorted perovskites the values of a calculated directly with the rst and second expressions in eqn (23) would differ from each other. By tting eqn (24) to experimentally determined a data for 77 stoichiometric ABO 3 oxides, the following values were obtained: A ¼ 0.816, B ¼ 1.437 and C ¼ À0.609. 32 The fact that B > A indicates that r B inuences a (hence, chemical expansion) to a greater degree than r A , which was also observed in experiments.…”

“…22 However fascinating the ever-increasing magnification of modern analytical methods, more “conventional” ones, such as thermogravimetric analysis, dilatometry, and X-ray and neutron diffraction, despite having been with us for many decades, are still indispensable when it comes to the properties of bulk materials. 23 Imaging techniques such as scanning electron microscopy 24,25 or even X-ray tomography 7 are useful for assessment of the consequences of chemical expansion, e.g. , the damage caused to electrochemical devices.…”

“…22 However fascinating the ever-increasing magnication of modern analytical methods, more "conventional" ones, such as thermogravimetric analysis, dilatometry, and X-ray and neutron diffraction, despite having been with us for many decades, are still indispensable when it comes to the properties of bulk materials. 23 Imaging techniques such as scanning electron microscopy 24,25 or even X-ray tomography 7 are useful for assessment of the consequences of chemical expansion, e.g., the damage caused to electrochemical devices. In turn, the more complex, in terms of the experimental setups and the interpretation of the results, and more recently developed methods-transmission electron microscopy, 26 scanning probe microscopy, 27,28 X-ray absorption ne structure (EXAFS), 29 etc.are well-suited for studying thin lms and interfaces.…”