Advancing Proton-Exchange Membrane Fuel Cell Catalyst Layers: Ink Processing and Performance Optimization of Novel PtCo and Pt Catalysts

Current PtCo proton-exchange membrane fuel cell (PEMFC) cathode catalysts typically fall short of the durability requirements for long duration applications. Recently developed intermetallic Pt and PtCo catalysts supported on a zeolitic imidazolate framework (ZIF)-derived carbon (Pt/CZIF-8 and PtCo/CZIF-8) shows significantly improved performance and stability under intermittent power demand conditions [1–4]. This presentation will discuss an in-depth investigation using in-situ and ex-situ ultra-small angle X-ray scattering (USAXS) and small-angle X-ray scattering (SAXS) to monitor the structural evolution of cathode catalyst layers as a function of operating conditions and time. The study focuses on how ink formulation variables, including ionomer content and solvent type, influence the breakup of carbon agglomerates during the catalyst-ionomer-solvent preparation process. Comparative studies between Pt and PtCo/CZIF-8 catalysts were conducted to evaluate the effects of ink composition on performance and durability. High-throughput screening using a 25-electrode test fixture enabled the rapid evaluation of catalyst performance in the membrane-electrode assembly environment, including both kinetic activity and high current density performance in air [5]. Operando X-ray absorption spectroscopy were also employed to understand the degradation mechanisms of commercial Pt and PtCo catalysts in comparison with the PtCo/CZIF-8 system. Together, these results offer a pathway to optimize membrane-electrode assembly design for long-duration, demanding applications. [1] C. Wang et al., Current Opinion in Electrochemistry 2021, 28:100715 [2] X. X. Wang et al., Nano Lett, 2018, 18, 4163−4171 [3] Kate Chen et al 2024 Meet. Abstr. MA2024-02 2712 [4] https://www.hydrogen.energy.gov/docs/hydrogenprogramlibraries/pdfs/review24/ fc339_borup_weber_2024_o.pdf [5] J. Park et al., Journal of Power Sources 480 (2020) 228801 Acknowledgments This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the M2FCT Consortium. This work was authored in Argonne National Laboratory, a U.S. Department of Energy (DOE) Office of Science laboratory operated for DOE by UChicago Argonne, LLC under contract no. DE-AC02-06CH11357. This research used the resources of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Los Alamos National Laboratory (Contract 89233218CNA000001)