The alkaline operating environment of anion-exchange membrane (AEM) fuel cells (AEMFCs) makes it possible to employ a wide variety of catalysts, including platinum group metals (PGMs) as well as PGM-free materials. However, little is understood about radical formation during AEMFC operation with different catalysts and their implications. In this investigation, we utilized spin-trapping and electron-paramagnetic resonance measurements to measure and identify the radicals produced on selected PGM and PGM-free oxygen-reduction reaction catalysts. To the best of our knowledge, this is an original study exploring radical formation on different classes of catalysts in operando AEMFCs. This work highlights an unexplored radical degradation mechanism in AEMFCs and calls for innovative strategies in designing radical attack-resistant AEMs.
