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.