Design of open-porous materials for high-temperature fuel cells

Microstructure is one of the major factors influencing material properties. It is especially important for open-porous materials dedicated to catalytic applications, where fraction of pores, their size distribution and specific surface influence the diffusion of reactants and the kinetics of catalytic reactions. In these studies the numerical models of the microstructure of open-porous electrodes for molten carbonate fuel cell (MCFC) are presented. The models presented here simulate fabrication routes for real materials, including mixing of powders, tape casting and sintering processes. The substrate powders are represented by spheres with defined size distribution. Mixing and compaction of powders with polymeric binder is simulated by a granular model implemented in LAMMPS code. In the next step the polymeric phase represented by fine particles and larger porogen addition is removed to form pores. The sintering process is simulated by geometry smoothing, which results in sphere aggregation. The models presented here were compared with micro computed tomography (mu CT) 3D images of real MCFC materials. Quantitative analysis of mu CT images was performed and it was demonstrated that algorithms used in these studies make it possible to design materials with the desired porous microstructure.