Multiscale Structure Regulation Induced by Fluorine Coordination Enables High-Performance and Durable PEMFC

The stability enhancement of metal–nitrogen–carbon (M–N–C) is often inevitably accompanied by a loss of activity. Additionally, during the long-term operation, the activity frequently declines due to water flooding effects, significantly reducing the lifetime of the membrane electrode assembly (MEA). Herein, fluorine (F)-doping was employed to bypass the activity–stability trade-off of Fe–N–C catalysts. F incorporation increases the metal dissolution energy and lowers the electron density of Fe–N4 sites, improving both stability and catalytic activity. Besides, the hydrophobicity of F can improve water management performance within the MEA, markedly reducing oxygen transport resistance. As a result, the F-doped Fe–N–C cathode enables a high peak power density of 1.1 W cm–2, far exceeding the Fe–N–C counterpart (0.79 W cm–2). More importantly, 90% of the power density can be retained after 30000 cycles of accelerated stress testing, demonstrating huge application potential in fuel cells.