Topology optimization of microstructure of solid-oxide fuel cell anode to minimize thermal mismatch

Thermomechanical reliability and lifetime of solid-oxide fuel cells are significantly influenced by thermal mismatch between anode and electrolyte layers. This study presents a numerical analysis of topology optimization of the microstructure of Ni–8YSZ anode to minimize the thermal mismatch of the components. We obtain two 2D microstructures by taking minimum thermal mismatch as object function. The 3D microstructures become fibrous and orthogonal by stretching the 2D microstructures. Results show that the coefficients of thermal expansion of microstructures in the plane parallel to the electrolyte layer are almost equal to those of electrolytes from room temperature to 800°C, which almost completely removes the thermal mismatch. Both microstructures have high three-phase boundary density, which is almost twice or five times that of a typical anode. Compared with the typical anodes, the microstructures have higher Ni–pore interfacial areas and ion conductivities. Optimization results are helpful in the design of future electrodes.