In Operando Quantification of Three-Dimensional Water Distribution in Nanoporous Carbon-Based Layers in Polymer Electrolyte Membrane Fuel Cells
| Autor: | Joachim Scholta, John Banhart, Henning Markötter, Merle Klages, Martin Göbel, Ingo Manke, Saad S. Alrwashdeh, Jan Haußmann |
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| Rok vydání: | 2017 |
| Předmět: |
chemistry.chemical_classification
Materials science Nanoporous 020209 energy Condensation General Engineering Analytical chemistry General Physics and Astronomy chemistry.chemical_element 02 engineering and technology Polymer Electrolyte Microporous material Synchrotron law.invention Membrane chemistry Chemical engineering law 0202 electrical engineering electronic engineering information engineering General Materials Science Carbon |
| Zdroj: | ACS Nano. 11:5944-5949 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/acsnano.7b01720 |
| Popis: | Understanding the function of nanoporous materials employed in polymer electrolyte membrane fuel cells (PEMFCs) is crucial to improve their performance, durability, and cost efficiency. Up to now, the water distribution in the nm-sized pore structures was hardly accessible during operation of the cells. Here we demonstrate that phase contrast synchrotron X-ray tomography allows for an in operando quantification of the three-dimensional water distribution within the nm-sized pores of carbon-based microporous layers (MPLs). For this purpose, a fuel cell design optimized for tomographic phase contrast measurements was realized. Water in the pores of the entire MPL was detected and quantified. We found an inhomogeneous distribution of the local water saturation and a sharp boundary between mostly filled MPL and almost empty areas. We attribute the latter observation to the two-phase boundary created because condensation takes place predominantly on one side of the boundary. Furthermore, high water saturation in large areas hints at gas diffusion or transport along preferred three-dimensional paths through the material, therefore bypassing most of the MPL volume. Our approach may contribute significantly to future investigations of nanoporous fuel cell materials under realistic operating conditions. |
| Databáze: | OpenAIRE |
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