Modeling Chemical Degradation of a Polymer Electrolyte Membrane and its Impact on Fuel Cell Performance

We present here an elementary kinetic model of the electrochemical phenomena occurring in a polymer electrolyte membrane fuel cell (PEFC). Chemical degradation of the Nafion (R) membrane is described through a combination of OH radical formation via Fenton's reaction and a radical mechanism of side chain decomposition. At the electrodes, the model is coupled to a description of the hydrogen oxidation reaction, the oxygen reduction reaction, and the hydrogen peroxide formation reaction at the anodic side. We establish a first feedback between the evolution of structural properties of the membrane and its transport parameters (i.e., proton conductivity) for a fully humidified fuel cell. We assess the influence of the chemical membrane degradation on the cell performance and on macroscopic properties of the membrane (i.e., sulfonate site concentration).