Simulating Microstructure Evolution in Ni-YSZ Electrodes of Solid Oxide Cells Under Operating Conditions

A model for simulating microstructure evolution in Ni-YSZ electrodes of solid oxide cells under fuel cell, electrolysis, and reversible mode has been developed by coupling our recently developed phase field model, multi-physics model, and microstructure analyzing tools. The mechanisms of Ni(OH)(2) diffusion and Ni-YSZ wettability change have been considered. The model has been used to investigate the effect of temperature, current density, and gas compositions on the degradation of Ni-YSZ electrode. Both Ni coarsening and redistribution are found to be affected by gas composition and temperature, while current density only affects the Ni redistribution. The results are compared to available experiments. It shows both mechanisms cannot fully explain the Ni redistribution observed experimentally.