Linker Group Directed High Mass Activity Fe-N-C Cathode in Proton Exchange Membrane Fuel Cells.
basic_science · Level V
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- Record sourced from PubMed, PMID 41504527.
- Also identified by DOI 10.1002/adma.202518053.
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Abstract
Atomically dispersed Fe-N-C catalysts are regarded as promising alternatives to platinum-group-metal (PGM) catalysts for proton exchange membrane fuel cells (PEMFCs). However, their further development is hindered by inadequate utilization of active sites in membrane electrode assembly (MEA). Herein, we developed a high mass activity O-FeNC catalyst with high site density and enhanced site utilization. C═O groups function as hard base linkers, promoting the densification of FeN<sub>4</sub> sites through Lewis acid-base interactions. Moreover, they also direct interfacial alignment within triple-phase boundaries, leading to concentrated hydronium ions and accelerated oxygen permeation via regulated ionomer nanophase segregation. As a result, the obtained O-FeNC cathode delivered a current density of 66.45 mA cm<sup>-2</sup> at 0.90 V<sub>iR-free</sub>, surpassing the US Department of Energy 2025 target (44 mA cm<sup>-2</sup> at 0.9 V<sub>iR-free</sub>), with a mass activity that is 59% higher than commercial Pt/C. The peak power densities reached 1.8 W cm<sup>-2</sup> under H<sub>2</sub>-O<sub>2</sub> and 0.93 W cm<sup>-2</sup> under H<sub>2</sub>-air, alongside demonstrated industrial scalability through gram-scale synthesis and a 500 W PGM-free cathode stack prototype.