Numerical simulation of the effect of unidirectional microstructure on the electrochemical performance of solid oxide fuel cell anode

The microstructure of electrodes is closely related to the electrochemical performance of solid oxide fuel cells. Conventional electrode microstructures are almost random, and experimental studies have shown that unidirectional electrode microstructures may have better performance. In this study, four random microstructures and unidirectional microstructures are synthesized, and their electrochemical performances are compared by microscopic simulation. Results show that the three-phase boundary density of the unidirectional microstructures is less than half of that of the random microstructures, and the tortuosity of the random microstructures is 2.5–4 times that of the unidirectional microstructures. A unidirectional microstructure formed using fine particles could improve performance by more than 20%. However, when the particle size exceeds a certain value, the performance improvement is negative. The electrochemical reaction zone of the unidirectional microstructures is thicker and their concentration and activation overpotential distributions are more inhomogeneous than those of the random microstructures.