Phosphine induced anode performance degradation in a planer SOFC: A numerical study

A mathematical model which was validated using button cells is used to predict the phosphine induced performance degradation in relatively large planar cells operating on hydrogen fuel. The empirical model parameters are calibrated using button cell experiments as guide. These parameters are then used to perform simulations to predict fuel contaminant performance degradation of planar cells. The results from the three dimensional model show that the contaminant coverage of Nickel and fuel distribution inside the anode is highly non-uniform. These non-uniform distributions are caused by the geometrical alignment of gas channels and current collectors, as well as the variation of gas concentration along the flow direction. The non uniform deactivation of anode gave raise to altering of current distribution inside the planar cell such that the cell can still produce current even when some regions of the anode are partially inactive. This is in stark contrast with what is observed in button cells where all the distributions are essentially one-dimensional. It is thus observed that the performance degradation rate for planar cells could be slower than that for similar button cells.