The efficiency and durability of proton exchange membrane fuel cells has come to the forefront of research and development efforts as sustainable transportation applications shift from passenger to heavy duty vehicles. Complementary research expertise and advanced instrumentation are required to accelerate materials discovery and degradation mitigation of fuel cell components, with significant attention on catalysts, ionomers and membranes. The scanning transmission electron microscope (STEM) is among the key characterization techniques for accelerating materials and device development, providing key insights into atomic scale structure. Automating STEM data acquisition and analysis enables large data sets with improved statistical relevance and throughput will expand the impact of this method in the rapid materials and accelerated stress test development.

We will show how the latest instrument developments in automation and high speed detectors enable new insights into catalyst structure and electrode layer degradation. This includes correlative, multimodal STEM techniques, such as aberration-corrected imaging, secondary electron detection, energy dispersive X-ray spectroscopy, cryogenic microscopy and 4D-STEM, to build a more comprehensive view of the effect of particle size and composition on surface strain and durability. These results will be correlated with information obtained from X-ray scattering techniques and fuel cell performance testing to understand the type and degree of degradation occurring during accelerated stress tests under development for heavy duty applications. The prospect of automated electron tomography coupled with identical location (IL)-STEM to provide detailed three-dimensional information on catalyst-support interactions will also be discussed.

This material is based on work performed by the Million Mile Fuel Cell Truck (M2FCT) Consortium, technology managers Greg Kleen and Dimitrios Papageorgopoulus, which is supported by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office. Electron microscopy research was supported by the Center for Nanophase Materials Sciences (CNMS), which is a US Department of Energy, Office of Science User Facility at Oak Ridge National Laboratory. The X-ray scattering experiments were performed at beamline 9-ID-C at the Advanced Photon Source (APS) at Argonne National Laboratory (ANL). Use of the APS, an Office of Science user facility operated by ANL, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AS02-06CH11357