Multi-scale electrochemical reaction anode model for solid oxide fuel cells

A 2D axial-symmetrical model is developed for a button cell test system, integrating the detailed electrochemical elementary reactions with multiple transport processes. The model is validated using experimental polarization curves of the cell under different temperature conditions. Extensive simulations are performed to elucidate the complicated interactions between fuel/gas species, adsorbed/desorbed surface ions, elementary reactions, and their effects on the cell performance. Results indicate that the concentrations of surface adsorbed species of O(s), OH(s) and H2O(s) ions presented at the anode/electrolyte interface are relatively high, while that of H(s) ion is relatively uniform within the entire anode. With increasing the operating temperature, the concentrations of surface adsorbed O(s), OH(s) and H2O(s) ions at the anode/electrolyte interface are significantly improved, while the H(s) ion is slightly influenced. The adsorbed surface species O(s), OH(s) and H2O(s) ions are very sensitive to the fuel compositions and cell voltage.

► Elementary reactions are linked to multi-transport processes in a button cell model.
► The model considers fuel/gas supply subsystem.
► The model is validated using experimental polarization curves.
► Gas species, surface ions, and their effects on cell performance are systematically studied.