Assistance of rearrangement of active sites in Fe/N/C catalyst for harvesting ultra-high power density PEMFCs

The infeasible cost of PEMFCs can be effectively lowered by replacing Pt-based catalysts with PGM-free catalysts. Although promising advancements have been achieved recently, the practical availability of PGM-free catalysts in PEMFCs remains apprehensive, typically, owing to their low output power density. Herein, a huge breakthrough has been made for high power density PGM-free PEMFCs with a peak power density of 1.36 W cm-2 in H2–O2 and 0.65 W cm-2 in H2–air PEMFCs. Moreover, after iR-corrected, it delivers an affirmative current density of 62 mA cm-2 at 0.9 V in H2-O2 fuel cells, a breakthrough on the US Department of Energy 2025 target for PGM-free catalysts. The tremendous progress can be attributed to the rearrangement of active sites by recrystallization which significantly increases the active site density and mesoporosity of the Fe/N/C catalyst. Consequently, it cost-effectively enhances the catalytic activity and boosts its power density output.