Prediction of nickel morphological evolution in composite solid oxide fuel cell anode using modified phase field model

The morphological change in nickel (Ni) caused by coarsening during a high temperature operation has been considered one of the main reasons for the performance degradation of conventional composite Ni-yttria stabilized zirconia (Ni-YSZ) solid oxide fuel cell (SOFC) anodes. An improved phase field model is proposed to simulate the Ni coarsening in a Ni-YSZ anode with both the Ni volumetric morphology and multiple crystallographic orientations evolved. Using a three-dimensional (3D) reconstruction of the initial anode microstructure obtained based on focused ion beam-scanning electron microscopy (FIB-SEM), the time dependent evolutions of triple phase boundary (TPB) density, specific Ni surface and Ni-YSZ interface areas, the volume fraction of isolated Ni, and the other factors can be quantitatively analyzed. To validate the model, it was tested based on different initial microstructures from the same anode. Multiple factors that may influence the anode durability during a long-term operation were quantitatively investigated based on the model.