High oxygen transport electrode with long-term stability for high-power and low Pt-loaded proton exchange membrane fuel cells

The reduction of Pt loading in cathode catalyst layers (CCLs) of proton exchange membrane fuel cells (PEMFCs) leads to increased local oxygen transport resistance (R_local) through the ionomer-Pt interface on triple phase boundaries (TPBs), as well as poor durability due to key material degradation. This work introduces a stable and accessible porous carbon featuring a graphitized structure as well as optimized pore size of carbon supports, thereby achieving a comprehensive ionomer/catalyst interface. The results show that the graphitization degree of the carbon surface increased significantly after modification, and the slight thermal corrosion facilitates the conversion of micropores into accessible pores between 4–7 nm on carbon surface. The polarization curves exhibit that the peak power density of catalyst based on modified EC300J is 38% higher than the catalyst with conventional carbon supports EC300J (Pt/porous carbon catalyst) under standard operating conditions, and R_local decreased from 0.35 to 0.08 s·cm⁻¹. It is demonstrated that the positively charged carbon surface and optimized pore size on the Fe graphitized carbon supports provide facile and efficient oxygen transport on TPBs. The higher degree of graphitization also provides improved durability, with less performance loss (8.8%) after degradation compared to the baseline electrode (55.2%).