Investigating the oxygen transport law within the Membrane Electrode Assembly at intermediate temperatures (80-120 °C) is crucial for enhancing fuel cell efficiency. This study analyzed the resistance to oxygen transport within the Membrane Electrode Assembly at intermediate temperatures using limiting current density and electrochemical impedance spectroscopy. The study findings reveal that, as temperature progressively increases, the Ostwald ripening effect leads to a 34% rise in the local oxygen transport resistance (Rlocal) in relation to the pressure-independent resistance (Rnp) within the cathode catalytic layer. Concurrently, the total transport resistance (Rtotal) decreases from 27.8% to 37.5% due to an increase in the gas diffusion coefficient and molecular reactivity; additionally, there is a decrease in the amount of liquid water inside the membrane electrode. A three-dimensional multiphysics field steady-state model was also established. The model demonstrates that the decrease in oxygen partial pressure can be mitigated effectively by increasing the back pressure at intermediate temperatures to ensure the cell's performance.
Keywords: PEMFC; intermediate temperature; local transport resistance; numerical simulation; oxygen transport.