Multi-length scale imaging of polymer electrolyte fuel cell (PEFC) membrane electrode assembly (MEA) materials is a powerful tool for studying, understanding and furthering improvements in materials engineering, performance and durability. A hot pressed MEA has been imaged using X-ray micro- and nano-computed tomography (CT), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and recently developed helium-ion microscopy (HeIM). X-ray nano-CT captures a volume containing all of the relevant fuel cell interfaces, from the carbon fiber of the gas diffusion layer (GDL) to the Nafion membrane with a field-of-view of 5 µm and a pixel size of 64 nm. Features identified include linear marks on the carbon fiber surface, agglomerates of carbon nanoparticles in the microporous layer (MPL), and intrusion of the catalyst layer material into the Nafion membrane during the hot-pressing process. HeIM has enabled imaging of a large area of MEA from tens of micrometers to sub-nanometers pixel resolution without any sample preparation, and has captured similar features to X-ray micro-CT and nano-CT. Furthermore, at its highest resolution, the platinum and carbon catalyst nanoparticles can be distinguished at the surface of the catalyst layer, overcoming the limitations of SEM and TEM.
Bibliographical noteFunding Information:
The authors would like to acknowledge the EPSRC for supporting the Electrochemical Innovation Lab through (EP/ M009394/1, EP/G030995/1, EP/I037024/1, EP/M014371/1 and EP/M023508/1). PRS acknowledges funding from the Royal Academy of Engineering. We thank Dr. Suguo Huo and the London Centre for Nanotechnology at University College London for the collection of the HeIM data.
© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Copyright 2019 Elsevier B.V., All rights reserved.
- Gas Diffusion Layer
- Helium-ion Microscopy
- Membrane Electrode Assembly
- Transmission Electron Microscopy
- X-ray Computed Tomography
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology