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 - Markötter, H. A1 - Manke, I. A1 - Krüger, P. A1 - Arlt, Tobias A1 - Huassmann, J. A1 - Klages, M. A1 - Riesemeier, Heinrich A1 - Hartnig, C. A1 - Scholta, J. A1 - Banhart, J. T1 - Investigation of 3D water transport paths in gas diffusion layers by combined in-situ synchrotron X-ray radiography and tomography N2 - The three-dimensional water distribution and water transport paths in the gas diffusion layer (GDL) and the adjacent micro-porous layer (MPL) of a polymer electrolyte membrane fuel cell (PEMFC) were analyzed during cell operation. The technique of quasi in-situ X-ray tomography was used for a 3D visualization of the water distribution and the structure of the GDL at different operating conditions. Based on findings from in-situ radiographic measurements water transport paths were detected and subsequently examined by tomography. The combination of these 2D and 3D techniques allows for a fully three-dimensionally resolved visualization of transport paths through the GDL. KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Radiography KW - Tomography KW - Synchrotron X-ray imaging KW - Gas diffusion layer (GDL) KW - Water transport paths PY - 2011 U6 - https://doi.org/10.1016/j.elecom.2011.06.023 SN - 1388-2481 VL - 13 IS - 9 SP - 1001 EP - 1004 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-25244 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 - TY - JOUR A1 - Markötter, H. A1 - Haußmann, J. A1 - Alink, R. A1 - Tötzke, C. A1 - Arlt, Tobias A1 - Klages, M. A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Gerteisen, D. A1 - Banhart, J. A1 - Manke, I. T1 - Influence of cracks in the microporous layer on the water distribution in a PEM fuel cell investigated by synchrotron radiography N2 - Water evolution in the gas diffusion layer of a polymer electrolyte membrane fuel cell was visualized in situ by means of synchrotron X-ray radiography. Cracks in the microporous layer were identified as start points of efficient liquid water transfer paths through the gas diffusion layer. Quantitative analysis of the water flow rate through those arbitrarily distributed cracks into the gas channel revealed that they have a strong influence on the overall liquid water transport. This could find entry into future material design and simulation. KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Radiography KW - Synchrotron X-ray imaging KW - Microporous layer (MPL) KW - Water transport KW - Liquid water flow rate PY - 2013 U6 - https://doi.org/10.1016/j.elecom.2013.04.006 SN - 1388-2481 VL - 34 SP - 22 EP - 24 PB - Elsevier CY - Amsterdam AN - OPUS4-30548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zabler, S. A1 - Rueda, A. A1 - Rack, A. A1 - Riesemeier, Heinrich A1 - Zaslansky, P. A1 - Manke, I. A1 - Garcia-Moreno, F. A1 - Banhart, J. T1 - Coarsening of grain-refined semi-solid Al-Ge32 alloy: X-ray microtomography and in situ radiography KW - Microtomography KW - Radiography KW - 2D/3D imageanalysis KW - Technical binary alloys KW - LSW PY - 2007 U6 - https://doi.org/10.1016/j.actamat.2007.05.028 SN - 1359-6454 SN - 1873-2453 VL - 55 IS - 15 SP - 5045 EP - 5055 PB - Elsevier Science CY - Kidlington AN - OPUS4-20583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Risse, S. A1 - Juhl, A. A1 - Mascotto, S. A1 - Arlt, T. A1 - Markötter, Henning A1 - Hilger, A. A1 - Manke, I. A1 - Fröba, M. T1 - Detailed and Direct Observation of Sulfur Crystal Evolution During Operando Analysis of a Li-S Cell with Synchrotron Imaging N2 - Herein, we present a detailed investigation of the electrochemically triggered formation and dissolution processes of α- and β-sulfur crystals on a monolithic carbon cathode using operando high-resolution synchrotron radiography (438 nm/pixel). The combination of visual monitoring with the electrical current response during cyclic voltammetry provides valuable insights into the sulfur formation and dissolution mechanism. Our observations show that the crystal growth process is mainly dictated by a rapid equilibrium between long-chain polysulfides on one side and solid sulfur/short-chain polysulfides on the other side, which is consistent with previous studies in this field. The high temporal and spatial resolution of synchrotron imaging enables the observation of different regimes during the sulfur formation and dissolution process. The appearance of short-chain polysulfides after the first anodic CV peak initiates a rapid dissolution process of α-sulfur crystals on the cathode. The increase in the long-chain lithium polysulfide concentration at the cathode surface during charge results in an increased crystal growth rate, which in turn produces imperfections in α- and β-sulfur crystals. There are strong indications that these defects are fluid inclusions, which may trap dissolved polysulfides and therefore reduce the electrochemical cell capacity. KW - LiS battery KW - Radiography KW - Synchrotron Imaging PY - 2020 U6 - https://doi.org/10.1021/acs.jpclett.0c01284 VL - 11 IS - 14 SP - 5674 EP - 5679 AN - OPUS4-51100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alrwashdeh, S. S. A1 - Markötter, H. A1 - Haußmann, J. A1 - Hilger, A. A1 - Klages, M. A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Manke, I. T1 - Investigation of water transport in newly developed micro porous layers for polymer electrolyte membrane fuel cells N2 - In this investigation, synchrotron X-ray imaging was used to investigate the water distribution inside newly developed gas diffusion media in polymer electrolyte membrane fuel cells. In-situ radiography was used to reveal the relationship between the structure of the microporous layer (MPL) and the water flow in a newly developed MPL equipped with randomly arranged holes. A strong influence of these holes on the overall water transport was found. This contribution provides a brief overview to some of our recent activities on this research field. KW - Polymer electrolyte membrane fuel cell KW - Microporous layer KW - Water distribution KW - Radiography KW - Synchrotron X-ray imaging PY - 2017 U6 - https://doi.org/10.9729/AM.2017.47.3.101 SN - 2287-4445 SN - 2287-5123 VL - 47 IS - 3 SP - 101 EP - 104 AN - OPUS4-43356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -