High-performance ionomerless cathode anion-exchange membrane fuel cells with ultra-low-loading Ag–Pd alloy electrocatalysts

Rapid translation of catalysts from fundamental studies to high-performance devices could facilitate the development and commercialization of anion-exchange membrane fuel cells (AEMFCs). Traditionally, translation from material screening in three-electrode rotating disk electrode cells to AEMFCs is complicated by differences in microenvironments, for example, solid ionomer/membrane vs liquid electrolyte. Here we introduce a platform for translation to devices that utilizes ionomerless ultra-low-loading Ag–Pd alloy electrocatalyst cathodes synthesized by co-physical vapour deposition. Our ionomerless cathodes allow for systematic H 2 –O 2 AEMFC experiments while demonstrating comparable activity trends to those in three-electrode cells. Furthermore, we show that our Ag 10 Pd 90 -based AEMFC reaches a peak power density of ∼1 W cm geo − 2 (geometric area basis) and ∼10 W mg PGM Cathode − 1 , satisfying the US Department of Energy’s platinum group metal (PGM) loading and cost targets. Our approach shows promise in facilitating the rapid translation between three-electrode studies and AEMFCs, offering a simple and effective design for decreasing PGM loadings. Highly performing fuel cell catalysts tested at the fundamental level rarely translate well to full devices, in part due complicated ionomer-catalyst interfaces at the heart of devices, where the electrochemical reactions occur. Here the authors demonstrate ionomerless-thin-film-deposited cathodes that have comparable activity trends across fundamental tests and fuel cells.