Estimation of 3D effective properties from 2D cross sections in porous electrodes

The study summarizes the correlations between 2D and 3D microstructural properties of SOFC electrodes within the framework of stereology. 3D geometrical properties, such as the mean particle diameter, the pore size, the specific surface area and the three-phase boundary density are correlated by simple relations to 2D properties evaluated in a cross section, such as the mean diameter of the sectioned particles, the mean chord length, the particle perimeter exposed to the porous phase and the number of three-phase boundary points per unit area, respectively. The strong correlation between 2D and 3D properties predicted by stereological relations is verified by using packing algorithms in a wide range of porosity, particle size and electrode composition. The results provide practical indications that can be easily applied to SEM images of real samples for a short-cut estimation of the effective properties and of the range of confidence of the prediction.