Modelling and simulations of carbon corrosion during operation of a Polymer Electrolyte Membrane fuel cell

A two-dimensional model is developed to simulate the carbon corrosion reaction during operation of a Polymer Electrolyte Membrane fuel cell. Specifically, carbon corrosion caused by local fuel starvation and during a startup/shutdown (SUSD) procedure is investigated. The present model considers coupled transport of charged and non-charged species, and multiple electrochemical and chemical reactions. In the simulations, the same set of governing equations is solved for the local fuel starvation case and the SUSD case with appropriate boundary conditions and local properties applied to each case respectively. In the local fuel starvation case, a portion of the gas diffusion layer (GDL) is artificially set to have extremely low gas diffusivity in order to mimic the condition when locally the GDL is flooded by liquid water. For the SUSD case, a portion of the anode channel is filled with air, which simulates the purging/refilling in an SUSD procedure. Several mitigation techniques to reduce carbon corrosion are evaluated and it is found that for the local fuel starvation case, using OER (Oxygen Evolution Reaction)-favorable catalysts and using membranes with low O2 diffusivity are two effective techniques for carbon corrosion mitigation. For the SUSD case, using OER-favorable catalysts appears to be the only effective mitigation technique.