TY - JOUR A1 - Grothausmann, R. A1 - Zehl, G. A1 - Manke, I. A1 - Fiechter, S. A1 - Bogdanoff, P. A1 - Dorbandt, I. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Schumacher, G. A1 - Banhart, J. T1 - Dreidimensionale Charakterisierung von Katalysatornanopartikeln N2 - We present transmission electron microscope (TEM) tomography investigations of ruthenium-based fuel cell catalyst materials as employed in direct methanol fuel cells (DMFC). The digital three-dimensional representation of the samples not only enables detailed studies on number, size, and shape but also on the local orientation of the ruthenium particles to their support and their freely accessible surface area. The shape analysis shows the ruthenium particles deviate significantly from spherical symmetry which increases their surface to volume ratio. The morphological studies help to understand the structure formation mechanisms during the fabrication as well as the high effectiveness of these catalysts in the oxygen reduction reaction at the cathode side of fuel cells. KW - Radiography KW - Tomography KW - Neutrons KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Fuel cell stack PY - 2012 SN - 1862-5282 VL - 103 IS - 1 SP - 135 EP - 136 PB - Carl Hanser CY - München AN - OPUS4-25976 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Manke, I. A1 - Kuhn, R. A1 - Arlt, Tobias A1 - Kardjilov, N. A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hartnig, C. A1 - Scholta, J. A1 - Banhart, J. T1 - Neutron tomographic investigations of water distributions in polymer electrolyte membrane fuel cell stacks N2 - Neutron tomography was applied to study the 3D water distribution in full polymer electrolyte membrane fuel cell (PEMFC) stacks. The water distribution after switch-off of the fuel cell was analyzed over a period of 36 h. We found a slowly increasing water amount in the fuel cell, but only few changes within a time period of 5 h, which is about the time necessary for neutron tomography. In this way, the requirement for successful tomography was obtained. It is demonstrated how the quasi in-situ tomography technique enables us to study the water content in individual flow field channels of three-fold stacks. Flow field as well as stack design issues are addressed by this visualization method showing weak points due to a non-uniform water distribution that can be identified by means of neutron imaging. KW - Radiography KW - Tomography KW - Neutron imaging KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Manifold stack KW - Water management PY - 2012 U6 - https://doi.org/10.1016/j.jpowsour.2012.07.043 SN - 0378-7753 VL - 219 SP - 120 EP - 125 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-26317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grothausmann, R. A1 - Zehl, G. A1 - Manke, I. A1 - Fiechter, S. A1 - Bogdanoff, P. A1 - Dorbandt, I. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Schumacher, G. A1 - Banhart, J. T1 - Nanometer-Tomographie: kleinste Katalysatorteilchen erblicken - Mit Elektronen und Computern die mobile Brennstoffzelle erforschen KW - Electron tomography KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Reconstruction algorithm KW - DIRECTT PY - 2012 U6 - https://doi.org/10.1002/maco.201290007 SN - 0947-5117 SN - 1521-4176 VL - 63 IS - 2 SP - 1 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-26348 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Manke, I. A1 - Haußmann, J. A1 - Arlt, Tobias A1 - Klages, M. A1 - Krüger, P. A1 - Hartnig, C. A1 - Scholta, J. A1 - Müller, Bernd R. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Combined synchrotron X-ray radiography and tomography study of water transport in gas diffusion layers N2 - Synchrotron X-ray radiography and tomography investigations of a custom-made polymer electrolyte membrane fuel cell optimised for visualisation purposes are presented. The 3D water distribution and transport pathways in the porous carbon fibre gas diffusion layers (GDLs) were investigated. The authors found that water is not only moving from the GDL into the channel, but can also take the opposite way, that is, from the channel into free pore space of the GDL. Such movement of water into the opposite direction has been subject of speculations but has so far not yet been reported and might bring new insights into the general water transport behaviour, which might give new aspects to the general description of water transport processes and influence modelling assumptions to describe the process taking place in the GDL. KW - Synchrotron radiography KW - Synchrotron tomography KW - Gas diffusion layers KW - Water transport PY - 2012 U6 - https://doi.org/10.1049/mnl.2012.0410 SN - 1750-0443 VL - 7 IS - 7 SP - 689 EP - 692 PB - IET CY - London AN - OPUS4-26282 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Williams, S. H. A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. A1 - Strobl, M. A1 - Douissard, P.A. A1 - Martin, T. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Detection system for microimaging with neutrons N2 - A new high-resolution detector setup for neutron imaging has been developed based on infinity-corrected optics with high light collection, combined with customized mounting hardware. The system can easily be installed, handled and fitted to any existing facility, avoiding the necessity of complex optical systems or further improved electronics (CCD). This is the first time optical magnification higher than 1:1 has been used with scintillator-based neutron detectors, as well as the first implementation of infinity corrected optics for neutron imaging, achieving the smallest yet reported effective pixel size of 3.375 µm. A novel transparent crystal scintillator (GGG crystal) has been implemented with neutrons for the first time to overcome limitations of traditional powder scintillators (Li6/ZnS, Gadox). The standardized procedure for resolution measurements with the Modulation Transfer Function (MTF) is summarized to facilitate comparison between instruments and facilities. Using this new detector setup, a resolution of 14.8 µm with a field of view of 6 mm × 6 mm has been achieved while maintaining reasonable count times. These advances open a wide range of new possible research applications and allow the potential for additional future developments. KW - Instrumentation for neutron sources KW - Neutron radiography KW - Neutron detectors (cold, thermal, fast neutrons) PY - 2012 U6 - https://doi.org/10.1088/1748-0221/7/02/P02014 SN - 1748-0221 VL - 7 IS - P02014 SP - 1 EP - 26 PB - Inst. of Physics Publ. CY - London AN - OPUS4-26433 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Alink, R. A1 - Haußmann, J. A1 - Dittmann, K. A1 - Arlt, Tobias A1 - Wieder, F. A1 - Tötzke, C. A1 - Klages, M. A1 - Reiter, C. A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Gerteisen, D. A1 - Banhart, J. A1 - Manke, I. T1 - Visualization of the water distribution in perforated gas diffusion layers by means of synchrotron X-ray radiography N2 - Perforated gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells (PEMFCs) were investigated by means of in-situ synchrotron X-ray radiography during operation. We found a strong influence of perforations on the water distribution and transport in the investigated Toray TGP-H-090 GDL. The water occurs mainly around the perforations, while the holes themselves show varying water distributions. Some remain dry, while most of them fill up with liquid water after a certain period or might serve as drainage volume for effective water transport. KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Radiography KW - Synchrotron KW - X-ray imaging KW - Perforated gas diffusion layer (GDL) KW - Water transport PY - 2012 U6 - https://doi.org/10.1016/j.ijhydene.2012.01.141 SN - 0360-3199 VL - 37 IS - 9 SP - 7757 EP - 7761 PB - Elsevier CY - Oxford AN - OPUS4-26434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -