Model for investigation of oxygen transport limitation in a polymer electrolyte fuel cell

► Oxygen dissolution process from gas phase into the ionomer was included in the model. ► Dissolution kinetics were assessed using thin ionomer films on a Pt electrode. ► Agglomerate sizes were determined based on diffusion-limited currents. ► The estimated agglomerate size is close to that observed in the catalyst layer. ► Slow dissolution is the main hindrance to oxygen transport.