Thermo-elastic properties of SOFC/SOEC electrode materials determined from three-dimensional microstructural reconstructions

• Microstructure of SOFC/SOEC electrodes has been characterized by nanotomography.
• Homogenization on high resolution 3D reconstructions has been performed by FEM.
• Original values of elastic constants for thin functional layers have been determined.
• A relation between solid phase connectivity and Young's modulus has been assessed.

Thermo-mechanical properties of SOFC/SOEC electrodes have been computed by homogenization from three-dimensional reconstructions of their microstructure. The support and the functional layer of a Ni/YSZ supported cell and the oxygen electrode made of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) have been studied. Values of the effective Young's modulus obtained for the thick porous Ni/YSZ support are in good agreement with the experimental data (E = 35 GPa). Besides, for thin functional layers, the methodology supplies original values that are difficult to obtain by conventional experimental methods (E = 105 GPa for the Ni/YSZ Functional Layer and E = 55 GPa for the LSCF electrode). Furthermore, it has been shown that the effective elastic parameters are influenced by the following morphological parameters: the porosity and the formation factor that could also be related to the manufacturing process. Theses morphological parameters have however negligible effect on the effective thermal expansion.