Evaluation of Ni-YSZ Anode Degradation during Redox Cycling

Degradation of SOFC anode under redox cycling was evaluated by microstructure change measurements and overpotential calculations using a Lattice Boltzmann method (LBM). Microstructures were obtained by FIB-SEM reconstruction technique. In the overpotential calculation, exchange current density and YSZ ionic conductivity were considered as degradation factors. Numerical simulation reproduced well the decrease of overpotential just after each of the redox treatments. Then, overpotential increased after subsequent discharge process. This is consistent with the experimental result. However, simulation  showed lower overpotential values than the experiment after 10 redox cycles. Decrease of exchange current or YSZ ionic conductivity reduction are considered as the reason for the degradation after redox cycles.