Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Sciences pour l'ingénieur >> Chimie physique et électrochimie
1 proposition(s).

Fracture of porous ceramics: application to the mechanical reliability of Solid Oxide Cells during thermal cycling

Département Thermique Biomasse et Hydrogène (LITEN)

Laboratoire Production d'Hydrogène

01-10-2018

SL-DRT-18-0583

jerome.laurencin@cea.fr

Solid Oxide Fuel Cells (SOFC) and Solid Oxide Electrolysis Cells (SOEC) are promising electrochemical converters operating at high temperatures. Among several advantages, SOFCs and SOECs can reach a very high efficiency without the use of specific electro-catalyst. Thanks to their reversibility, the same device can be alternatively used in fuel cell and steam electrolysis modes. The SOFC/SOEC are made of ceramic materials and they consist in two porous electrodes separated by a dense electrolyte. In planar configuration, the cells are assembled with metallic interconnects to form a stack of high power density. Because of the mismatch in Thermal Expansion Coefficients (TEC) between all the stack components, the cell layers are subjected to significant internal stresses. During the accumulation of start and shutdown of the system, the thermomechanical loading can induce damage in the electrode which leads to a decrease the global system efficiency. The PhD thesis aims to evaluate the mechanical degradation of the SOC electrodes when the stack is submitted to an accumulation of starts and shutdowns of the system. In that objective, it is proposed to validate a local fracture criterion that will be used to compute the density of micro-cracks in the 3D network of the electrodes. The results will be used to estimate the impact of the thermal cycling on the SOC performances.

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