Random-packing model for solid oxide fuel cell electrodes with particle size distributions

Abstract

A percolation theory based model considering particle size and its distribution is proposed for composite electrodes of solid oxide fuel cells (SOFCs). The model calculation agrees excellently with 3D numerical reconstruction results, suggesting great validity of prediction. Moreover, it is also consistent well with experiment for real LSM (lanthanum strontium manganite)–YSZ (yttria-stabilized zirconia) electrodes with different composition, especially in range from 40:60 to 60:40 wt.% LSM:YSZ. The model can explicitly capture the effects of particle size, distribution, and electrode composition on several basic microstructure features and electrochemical properties of composite electrodes, such as coordination numbers and percolation probability, total and active three-phase boundary length, and interfacial polarization resistance. The model is further used to estimate LSM–YSZ electrode performance with the particle size and distribution of the source materials. The estimation generally coincides with the experiment, showing great potential in predicting power density based on the particle parameters of source materials for SOFCs.