Performance degradation prediction of direct internal reforming solid oxide fuel cell due to Ni-particle coarsening in composite anode

Long-term stability and durability of solid oxide fuel cell (SOFC) are the major challenges for fuel flexibility and commercialization. In this study, a fully coupled multi-field model is developed by coupling a modified Ni-particle coarsening model and a microstructure model for predicting the performance degradation of methane direct reforming (DIR) SOFC due to Ni-particle coarsening. The effect of Ni-particle coarsening on percolation probability of Ni-particle, effective TPB area, effective electron-conductivity, maximum power density, and the degradation rate of DIR-SOFC are quantitatively investigated under different operating conditions. The results indicate that to enhance the electrical performance and to reduce the degradation rate, the optima of the operating conditions and anode microstructure for the long-term DIR-SOFC are as follows: 750 °C for the cell operating temperature, 1.0 for anode inlet steam to carbon ratio (S/C), 0.3 A/cm2 for the operating current density, and corresponding to Ni-particle with an initial diameter of 0.6 μm, the optimal YSZ-particle diameter is 1.0 μm.