TY - CONF A1 - Theiler, Geraldine T1 - Fretting behavior of elastomer materials in hydrogen N2 - This presentation deals with the fretting wear behavior of elastomer materials (two types of cross-linked hydrogenated acrylonitrile butadiene rubbers) against 316L steel ball in hydrogen environment. Furthermore, aging experiments were conducted for 7 days under static conditions in 100 MPa hydrogen. Fretting tests revealed the wear of the polymer decreases with increasing hydrogen pressure. After high pressure hydrogen exposure, the fretting process is characterized by increased adhesion due to elastic deformation, leading to partial slip. T2 - 63rd German Tribology Conference 2022 CY - Göttingen, Germany DA - 26.09.2022 KW - Fretting KW - Rubbers KW - Hydrogen PY - 2022 AN - OPUS4-62082 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Hydrogen safety - Explosion protection for hydrogen applications N2 - In this lecture the safety related properties of hydrogen and hydrogen mixtures and explosion protection measures are shown and compared with other fuel gases. Measures for primary explosion protection (avoiding flammable mixtures), secondary explosion protection (avoiding ignition sources) and constructive explosion protection (mitigating the consequences of explosions) when handling hydrogen and hydrogen mixtures are presented. The Joint European Summer School JESS 2022 addresses these issues by offering high quality graduate level courses on selected topics of vehicle technology, innovation & business development, safe handling of hydrogen, and modelling. The course content is tailored to the needs of a diverse audience: newcomers to the field, experienced students, and young professionals working at the forefront of fuel cell and hydrogen applications. T2 - Joint European Summer School (JESS) on Fuel Cell, Electrolyser and Battery Technologies CY - Athens, Greece DA - 11.09.2022 KW - Ignition source KW - ATEX KW - Explosion limits KW - Hazardous areas KW - Hydrogen accidents KW - Detonation PY - 2022 AN - OPUS4-57066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - KIC Start 2022 H2 Safety - Explosion Protection N2 - This is a digital lecture on Explosion Protection for Hydrogen Applications. It was designed in context with the project "KICstartH2 Accelerating Sustainable Hydrogen Uptake Through Innovation and Education" and integrated in a teaching module of the University of Birmingham. It is divided in five parts: Introduction, Avoiding Explosive Mixtures, Avoiding Ignition Sources, Mitigation of Consequences and Summary & Comparison. T2 - KICStartH2 Lecture at the University of Birmingham CY - Online meeting DA - 31.10.2022 KW - Safety Related Properties KW - Ignition KW - Hydrogen Safety KW - Explosive Mixtures KW - Fuel Gases PY - 2022 AN - OPUS4-57278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - H2Safety@BAM - Overview of hydrogen research activities N2 - In this presentation the capabilities and different research activities at BAM in the field of hydrogen safety are outlined. A deep dive focussing the transport of hydrogen in pipelines adressing issues on material compatibility, gas quality and test methods is presented. Another deep dive is presented focussing on safety aspects of liquid hydrogen adressing issues of rapid phase transition (RPT) and Boiling liquid expanding vapour explosion (BLEVE). Finally a brief overview on other safety related research activities is given. T2 - Research priorities workshop of IA HySafe 2022 CY - Quebec, Canada DA - 21.11.2022 KW - Hydrogen safety KW - Hydrogen transport in pipelines KW - Liquid hydrogen (LH2) KW - Hydrogen quality KW - Explosion protection PY - 2022 AN - OPUS4-57067 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. A1 - Duffner, Eric T1 - Aspekte der Bauteilprüfung, Bauteilsicherheit und Zulassung im Kompetenzzentrum H2SAFETY@BAM N2 - Der Vortrag zeigt den Weg des Themas Wasserstoff von Adolf Martens bis zum Kompetenzzentrum H2SafetyBAM, die zugehörigen Kompetenzfelder, deren Ziele und verantwortliche Personen. Der Hauptteil reflektiert den Aspekt des Markthochlaufes von Wasserstofftechnologien und zeigt einen Maßnahmenkatalog von der Risikosteuerung über die Konsequenzbegrenzung bis zu probabilistische Ansätzen in der Bewertung von Prüfergebnissen und der Wirkung von Mindestanforderungen. T2 - DVGW-Kongress H2-Sicherheit CY - Online meeting DA - 26.02.2022 KW - Wasserstoffspeicher KW - Markthochlauf KW - Monte-Carlo-Simulation KW - Druck-Volumen-Produkt KW - Alterung PY - 2022 AN - OPUS4-54609 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Sicherheitstechnische Fragestellungen im Zusammenhang mit Elektrolyseanlagen N2 - Im Vortrag werden aktuelle Entwicklungen bei verschiedenen Elektrolysetechnologien kurz vorgestellt. Dann werden für Elektrolyseanlagen spezifische Gefährdungen diskutiert, v.a. die im Zusammenhang mit den Eigenschaften der Gase Wasserstoff und Sauerstoff stehen. Dabei wird auch Bezug auf die Normung- und Regelsetzung genommen und Sicherheitskonzepte werden beispielhaft kurz vorgestellt. Abschließend wird auf Unfallereignisse im Zusammenhang mit der Elektrolyse eingegangen. T2 - BAM/UBA-Behördenerfahrungsaustausch CY - Berlin, Germany DA - 27.06.2022 KW - Explosionsschutz KW - Wasserstofferzeugung KW - Sauerstoff KW - Sicherheit PY - 2022 AN - OPUS4-55220 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orellana Pérez, Teresa T1 - Competence Centre H2Safety@BAM N2 - Presentation of the Competence Centre H2Safety@BAM with all five competence field, representatives as well as its vision, mission, strategic goals and implementation plan. T2 - III. TR Wasserstoff Erfahrungsaustausch, TÜV Rheinland CY - Cologne, Germany DA - 07.12.2022 KW - Hydrogen safety KW - Materials compatibility KW - Component testing KW - Process and plant safety KW - Sensors and analytics KW - Cross-cutting activities PY - 2022 AN - OPUS4-59301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konert, Florian A1 - Nietzke, Jonathan T1 - Application of an in-situ H2Test Method N2 - The degradation effect of hydrogen on the mechanical properties of steels is well known, but still not sufficiently understood. The fast and safe market ramp up of hydrogen technologies makes it evident to evaluate a wider understanding of this topic. In general it is often described as hydrogen embrittlement. Therefore it is desirable to achieve a test method which is able to provide material properties under hydrogen atmosphere in an easy way. Currently mechanical tests under hydrogen atmosphere are executed in autoclaves. For this technique complex hardware is needed, therefore tests are expensive and test capacities are only available in a small scale. The shown test method promises a trendsetting approach for reducing costs and machine time by using hollow specimen. T2 - 4th International Conference on Metals and Hydrogen - Steely & Hydrogen 2022 CY - Ghent, Belgium DA - 11.10.2022 KW - Hydrogen KW - Hollow specimen KW - In-situ KW - Test procedure PY - 2022 AN - OPUS4-56032 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Experimentelle Untersuchung von Zündwahrscheinlichkeiten bei mechanischen Schlagvorgängen in wasserstoffhaltigen Atmosphären N2 - Im Projekt HySpark wird die Wirksamkeit mechanischer Schlagvorgänge beim Aufprall von unterschiedlichen Werkstoffen als Zündquelle für wasserstoffhaltige Atmosphären experimentell untersucht. Zum Einen wird die Zündwirksamkeit bei Wasserstoff/Luft-Gemischen in Abhängigkeit der Werkstoffpaarung untersucht. Dabei konnte v.a. festgestellt werden, dass bei Schlagvorgängen von Nicht-Eisen-Metallen mit verschiedenen Stahlsorten die wirksame Zündung vermieden werden kann. Jedoch können bei Schlagvorgängen mit Estrichbeton hohe Zündwahrscheinlichkeiten beobachtet werden. Zum anderen wird der Einfluss von Wasserstoffbeimischungen im Erdgasnetz auf die Zündwirksamkeit von mechanischen Schlägen untersucht. Bei Anteilen bis 25% Wasserstoff konnte bei den Versuchen kein Erhöhung der Zündwahrscheinlichkeit festgestellt werden. T2 - H2-Kolloquium des Kompetenzzentrums „H2Safety@BAM” CY - Online meeting DA - 04.07.2022 KW - Explosionsschutz KW - Zündquellen KW - Schlagfunken KW - Erdgas PY - 2022 AN - OPUS4-55224 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maiwald, Michael T1 - Competence Centre H2Safety@BAM – Safeguarding the Quality Infrastructure in the Hydrogen Economy N2 - Hydrogen is a central component of the energy transition and the European Green Deal for a climate-neutral Europe. To achieve the goals defined for 2050, the EU and the German government have developed a framework for action and are making long-term investments in research, development, and the rapid implementation of innovative hydrogen technologies. With the Competence Centre "H2Safety@BAM", BAM is creating the safety-related prerequisites for the successful implementation of hydrogen technologies at national as well as European level. To this end, BAM conducts research, testing and consulting in a holistic and inter-disciplinary manner under one roof – in the Competence Centre H2Safety@BAM. The activities of the competence centre focus on ensuring the safety of infra-structures, plants, and processes as well as innovative hydrogen transport and storage systems based on digital quality testing and the experimental testing of components and systems. It thus creates the prerequisites for the implementation and adaptation of legal framework conditions as well as for standardization. Closely related to this are investigations into the properties and compatibility of metallic materials and polymers as well as friction systems for the safe operation of components, plants, processes, and systems. This interdisciplinary and holistic approach is complemented by the development of gas analytics and suitable sensors, online measurements of gas properties in process control, test scenarios under real conditions as well as impact assessments of accidents and risk assessments and risk management systems derived from them. With its portfolio of tasks and competences, BAM builds trust in the safety and reliability of technical system solutions for hydrogen. T2 - 772. WE-Heraeus-Seminar - Metrology and Process Safety for Hydrogen Technologies & Applications CY - Bad Honnef, Germany DA - 10.10.2022 KW - H2Safety@BAM KW - Hydrogen KW - Competence Center KW - Hydrogen Strategy KW - Green Deal KW - Safety KW - Risk Assessment KW - Quality Infrastructure PY - 2022 UR - https://www.we-heraeus-stiftung.de/veranstaltungen/metrology-and-process-safety-for-hydrogen-technologies-and-applications/ AN - OPUS4-55986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg W. T1 - Mit „Knallgas“ in die Zukunft? Sicherheit von Wasserstoff – Von der Herstellung bis zur Nutzung N2 - Der Vortrag gibt eine Antwort auf die Frage: „Ist der Umgang mit Wasserstoff so sicher, dass wir unsere Zukunft darauf aufbauen können?“ Dr. Mair stellt das Kompetenzzentraum H2Safety@BAM vor. Er beginnt mit dem spektakulären Wasserstoff-Unfall auf dem Tempelhofer Feld aus dem Jahr 1894, kommt zur Gründung des Kompetenzzentrums im Kontext der Wasserstoffstrategien Deutschlands und der EU und erläutert deren sicherheitsfokussierte Ausrichtung, um Vertrauen in Wasserstofftechnologien zu schaffen und zu bewahren. Danach werden die physikalischen Eigenschaften von Wasserstoff im Vergleich zu Methan (Erdgas) vorgestellt. Dies leitet über zur Betrachtung des Hindenburg-Unfall sin Lakehurst 1937. Im nächsten Abschnitt werden der weltweite Bedarf an H2, sein Importbedarf aus deutscher Sicht, das weltweite Erzeugungspotential und der Transportaufwand der üblichen H2-Derivate dargelegt. Die zentrale Frage ist die nach der Sicherheit von Wasserstoff als Ergebnis der bisher ergriffenen Maßnahmen. Es werden wenige der immer wieder geschehenden Unfälle im Transport von Energieträgern vorgestellt, was zur Erkenntnis führt, dass, um die Sicherheit objektiv beurteilen zu können, der Risikobegriff herangezogen werden muss. Das Risiko basiert auf der Konsequenz und der Häufigkeit eines Ereignisses. Mit Blick auf den bereits erkennbaren Markhochlauf wird dargelegt, wie eine Risikosteuerung in Abhängigkeit der Produkte im Transport funktionieren kann. Hierzu muss beachtet werden, dass jede Eigenschaft streut. Damit sind auch die Zuverlässigkeit jedes einzelnen Speichers, des gesamten Bestandes an Gasspeichern, im Neuzustand und erst recht mit zunehmendem Alter einer Streuung unterworfen, die aktuell nur über Stichproben abgeschätzt werden kann. Es wird an Beispielen aufgezeigt, welche Prüftechniken und Beurteilungsmethoden die BAM zur Sicherheitsbeurteilung von Transportspeichern und sogar Tankstellen einsetzt und weiterentwickelt. Dies führt zu einem Petitum für probabilistische Betrachtungsweisen von Produktsicherheit mit Blick auf die Qualität der Rechtsvorschriften, der Produktdesigns und der Herstellung von Produkten für die Wasserstoffanwendung. T2 - Tagung Hoffnungsträger Wasserstoff - Chancen, Hürden, Risiken CY - Wittenberg, Germany DA - 20.10.2022 KW - Wasserstoffspeicher KW - Markthochlauf KW - Sicherheit KW - H2Safety@BAM.de KW - Risikosteuerung PY - 2022 AN - OPUS4-56985 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael T1 - Additive manufacturing for components in hydrogen technologies N2 - With the introduction of a hydrogen-based energy and national economy, safety-relevant components for hydrogen technologies are becoming increasingly important. Characteristic of hydrogen technologies are, for example, harsh environmental conditions such as cryogenic or high-pressure storage, corrosion issues in fuel cells and electrolyzers, turbines, and many more. Additive manufacturing of components is becoming increasingly important and irreplaceable for the production of complex technical systems. Using the case studies of burners for gas turbines and electrodes and membranes for polymer (PEMFC) and solid oxide (SOFC) fuel cells, this article shows the potential of additive manufacturing of components. At the same time, however, the challenge of considering divergent mechanical properties depending on the direction of assembly in a "hydrogen-compatible" manner is also highlighted. Finally, the challenges posed by additive manufacturing and hydrogen for materials testing are highlighted under scenarios that are as realistic as possible. T2 - MPA-Workshop Hydrogen CY - Online meeting DA - 10.11.2022 KW - Additive manufacturing KW - Hydrogen KW - Technologies KW - Overview KW - Component PY - 2022 AN - OPUS4-56233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gerrits, Ruben T1 - Fungal biofilms are supported by EPS and protective pigments in their substrate attachment and desiccation tolerance N2 - Rock-inhabiting fungi are known to colonise air-exposed substrates like minerals, photovoltaic panels building facades and monuments, withstanding the various stresses these extreme habitats are known for. Here we show how both colonisation and stress resistance are linked to the properties of the fungal cell surface. By deleting genes involved in the synthesis of melanin and carotenoid pigments of the model rock-inhabiting fungus Knufia petricola via CRISPR-Cas and comparing the behaviour of the gene-deletion mutants with the wild type (WT), we studied the role of these genes in mineral colonisation and stress sensitivity. The extracellular polymeric substances (EPS) of biofilms of the WT and mutants were extracted, quantified and chemically characterised. We observed that the absence of melanin affected the quantity and composition of the produced EPS: melanin-deficient mutants synthesised more EPS containing fewer pullulan-related glycosidic linkages. Moreover, in mineral dissolution experiments, these mutants showed a lower ability to colonise the mineral olivine. We hypothesise that not melanin, but the pullulan-related linkages enabled the melanin-producing strains to attach more strongly to the mineral. Moreover, ICP-OES analysis of the aqueous mineral-derived solutes showed that biofilms of the K. petricola mutants which could attach were able to dissolve the olivine faster than those that could not. The same mutants were also characterised by their sensitivity to desiccation stress: only the mutant deficient in both melanin and carotenoid synthesis was more sensitive to desiccation compared to the WT, indicating that a combination of both pigments is critical to withstand desiccation. Overall, these results show the critical role of the cell surface in the specific capacities of rock-inhabiting fungi. T2 - Biofilms 10 CY - Leipzig, Germany DA - 09.05.2022 KW - Bio-weathering KW - Desiccation KW - Fungal biofilms PY - 2022 AN - OPUS4-56675 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Aristia, Gabriela A1 - Le, Quynh Hoa A1 - Bäßler, Ralph T1 - Integrated Coating System for Corrosion Protection of Carbon Steel in Artificial Geothermal Brine N2 - Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers prefer to use carbon and low alloyed steels, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials. This study investigated a coating system consisting of polyaniline/silicon dioxide based on resources locally available in Indonesia. Protection against corrosion of carbon steel was shown by long-term (28 day) exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to the conditions encountered at a site in Indonesia. Therefore, an integrated coating system is proposed for corrosion protection, combining the electrochemical functionality of polyaniline and the physical advantages of silica. T2 - AMPP International Corrosion Conference CY - Online meeting DA - 06.03.2022 KW - Geothermal KW - Corrosion KW - Coating KW - Polyaniline KW - Silicon dioxide PY - 2022 SP - 1 EP - 11 CY - Houston TX (USA) AN - OPUS4-54451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Electrochemical behaviors of casing steel/mortar interface in CO2 saturated aquifer fluid N2 - To reveal the corrosion resistance of casing steel/mortar interface in CO2 injection condition, sandwich samples were prepared and exposed up to 20 weeks in aquifer fluid under 10 MPa and 60 °C. Cross section analysis revealed the crevice corrosion as main mechanism instead of pitting corrosion despite very high concentration of Cl in NGB. EDS element line scan analysis of the 20-week-exposed metal/mortar coupon showed Chloride distribution, which still not reached the metal/mortar interface, explaining no pitting was observed. It was confirmed that FeCO3 cannot protect the steel surface in CO2 saturated NGB. To verify the protective possibility of passivation happened on casing steel/mortar interface, simulated pore solution was synthesized and used to passivate the steel for 42 days. OCP and EIS confirmed the formation of passive layer. The 42 day passivated layer was broken during the first minute of exposure in CO2 saturated NGB. However, due to high concentration of Ca2+, a new carbonate CaCO3 dense layer was formed, increased the corrosion resistance of steel surface. T2 - EUROCORR 2022 CY - Berlin, Germany DA - 28.08.2022 KW - Corrosion KW - Geothermal KW - CO2 KW - Mortar PY - 2022 AN - OPUS4-55621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Influence of brine components on materials performance in geothermal applications N2 - Significant Cu-deposition and ‑precipitation only occurred in combination with carbon steel. High-alloyed materials prevent the disturbing Cu-agglomeration. Pb-deposition and ‑precipitation only occurred in combination with carbon steel. No negative Pb-effect could be observed in combination with high-alloyed steels. High alloyed corrosion resistant alloys are suitable and shall be chosen for future design of the piping system, either in massive or in cladded form, if formation of crevices with non-metallic materials can be excluded! T2 - EUROCORR 2022 CY - Berlin, Germany DA - 28.08.2022 KW - Corrosion KW - Geothermal KW - Copper PY - 2022 AN - OPUS4-55624 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bäßler, Ralph T1 - Integrated Coating System for Corrosion Protection of Carbon Steel in Artificial Geothermal Brine N2 - Corrosive geothermal brines are a major challenge to geothermal power-plants. For cost reasons, plant designers prefer to use carbon and low alloyed steels, which are susceptible to uniform and localized corrosion when exposed to geothermal brines having acidic and saline properties. To solve such problem, coatings or inhibitors would be a protective solution as an alternative to the use of high alloyed materials. This study investigated a coating system consisting of polyaniline/silicon dioxide based on resources locally available in Indonesia. Protection against corrosion of carbon steel was shown by long-term (28 day) exposure and electrochemical tests of coated carbon steels, performed in an artificial acidic and saline geothermal brine, comparable to the conditions encountered at a site in Indonesia. Therefore, an integrated coating system is proposed for corrosion protection, combining the electrochemical functionality of polyaniline and the physical advantages of silica. T2 - AMPP International Corrosion Conference 2022 CY - San Antonio, TX, USA DA - 08.03.2022 KW - Geothermal KW - Corrosion KW - Coating KW - Polyaniline KW - Silicon dioxide PY - 2022 AN - OPUS4-54452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sestan, A. A1 - Sreekala, L. A1 - Markelj, S. A1 - Kelemen, M. A1 - Zavasnik, J. A1 - Liebscher, C. A1 - Dehm, G. A1 - Hickel, Tilmann A1 - Ceh, M. A1 - Novak, S. A1 - Jenus, P. T1 - Non-uniform He bubble formation in W/W2C composite: Experimental and ab-initio study N2 - Tungsten-tungsten carbide (W/W2C) composites are considered as possible structural materials for future nuclear fusion reactors. Here, we report on the effect of helium (He) implantation on microstructure evolution of polycrystalline W/W2C composite consolidated by field-assisted sintering technique (FAST), homogenously implanted at room temperature with 1 MeV 4He+ ions at the fluence of 8 × 1016 ions cm−2 and annealed at 1873 K for 20 minutes. Samples were analysed by scanning and transmission electron microscopy to study the presence and size of He bubbles. Monomodal He bubbles in W (30-80 nm) are limited to point defects and grain boundaries, with a considerable void denuded zone (150 nm). Bubbles do not form in W2C, but at the W|W2C interface and are considerably larger (200-400 nm). The experimental observations on He behaviour and migration in W and W2C were assessed by density functional theory (DFT) calculations, suggesting He migration and accumulation in the composite are determined by the effective He-He binding in clusters, which will give rise to decohesion. In the presence of He clusters, the decohesion of bulk W into free surfaces is energetically highly favourable but not sufficient in the W2C; hence bubbles are only observed in W grains and interfaces and not within bulk W2C. KW - Density functional theory KW - Tungsten KW - Ditungsten carbide KW - FAST KW - Helium implantation PY - 2022 DO - https://doi.org/10.1016/j.actamat.2021.117608 VL - 226 SP - 1 EP - 11 PB - Elsevier Ltd. AN - OPUS4-54364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sreekala, L. A1 - Dey, P. A1 - Hickel, Tilmann A1 - Neugebauer, J. T1 - Unveiling nonmonotonic chemical trends in the solubility of H in complex Fe-Cr-Mn carbides by means of ab initio based approaches N2 - The microstructure of advanced high-strength steels often shows a sensitive dependence on alloying. For example, adding Cr to improve the corrosion resistance of medium-Mn steels also enhances the precipitation of carbides. The current study focuses on the behavior of H in such complex multicomponent carbides by employing different methodological strategies. We systematically analyze the impact of Cr, Mn, and Fe using density functional theory (DFT) for two prototype precipitate phases, M3C and M23C6, where M represents the metal sublattice. Our results show that the addition of these alloying elements yields strong nonmonotonic chemical trends for the H solubility. We identify magnetovolume effects as the origin for this behavior, which depend on the considered system, the sites occupied by H, and short- vs long-range interactions between H and the alloying elements. We further show that the H solubility is directly correlated with the occupation of its nearest-neighbor shells by Cr and Mn. Based on these insights, DFT data from H containing binary-metal carbides are used to design a ridge regression based model that predicts the solubility of H in the ternary-metal carbides (Fe-Cr-Mn-C). KW - Hydrogen KW - High-strength steel KW - Carbide KW - Ab initio KW - Complexity PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542271 DO - https://doi.org/10.1103/PhysRevMaterials.6.014403 SN - 2475-9953 VL - 6 IS - 1 SP - 1 EP - 14 PB - American Physical Society (APS) CY - College Park, MD AN - OPUS4-54227 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Shu-Han A1 - Appel, Paul Alexander T1 - DialySorb N2 - Lithium-ion batteries (LIBs) have been one of the greatest achievements in the field of energy storage of the last century. However, with the increasing demand for energy storage, battery technologies must be diversified according to their specific requirements in different applications. In terms of stationary energy storage and electric vehicles, sodium-ion batteries (SIBs) are considered to be the most attractive alternative to LIBs due to the uniformly high abundance and cost-effectiveness of raw materials, enabling large-scale and low-cost energy storage. Unlike LIBs where crystalline graphite is commonly used as the anode material, disordered carbons are regarded as more promising for SIBs. However, further advances towards better reversibility and higher specific capacity are still needed to match or exceed that of graphite in LIBs. The main challenge is the complex and unpredictable Na+ storage mechanism in disordered carbons, as they may have different properties depending on the precursors and carbonization conditions. [1] Recently, Matsukawa et al. have reported that the reversibility of (de)sodiation processes of disordered carbons is better for ultramicroporous carbons.[2] These pores are accessible only to Na+ ions and not to solvent molecules. Therefore, the (de)sodiation processes are protected from the side reactions caused by the solvent, which reduces the related irreversible capacity loss. With this idea, the origin of the specific capacity and irreversible losses will be further investigated by tailoring chemical composition (e.g., heteroatom doping) as well as pore structure of hard carbons used as anode materials in SIBs. For the synthesis scalable and industrially relevant processes will be used. The structure and morphology of the materials will be characterized by electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. In addition, different gas sorption techniques will be carried out to analyze the porosity, pore sizes and specific surface areas. The electrochemical performance of the prepared materials will be evaluated based on coin cells, three-electrode Swagelok cells, and pouch cells. Moreover, solid-state nuclear magnetic resonance spectroscopy will be performed to help understand the mechanism of Na+ storage. T2 - Electrochemistry 2022 (GDCh confernece) CY - Berlin, Germany DA - 27.09.2022 KW - Na-ion Battery PY - 2022 AN - OPUS4-62013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koyutürk, B. A1 - Farber, E. A1 - Wagner, F. A1 - Fellinger, Tim-Patrick A1 - Eisenberg, D. T1 - A simple decagram-scale synthesis of an atomically dispersed, hierarchically porous Fe–N–C catalyst for acidic ORR N2 - Carbons doped with iron and nitrogen (Fe–N–Cs) are highly promising electrocatalysts for energy conversion reactions in the oxygen, nitrogen and carbon cycles. Containing no platinum group metals, they nevertheless compete with platinum-based catalysts in crucial fuel cell reactions, such as oxygen reduction in acid. Yet deployment of Fe–N–Cs in fuel cells requires also a flow-enhancing pore structure, and a scalable synthesis procedure – a rarely-met combination of requirements. We now report such a simple synthesis of over 10 g of an Fe–N–C catalyst with high activity towards oxygen reduction in acid. Atomically-dispersed Fe–N4 active sites were designed orthogonally and simultaneously with hierarchical micro-, meso- and macroporosity, by exploiting a dual role of magnesium ions during pyrolysis. Combining the “active site imprinting” and “self-templating” strategies in a single novel magnesium iminodiacetate precursor yielded a catalyst with high specific surface area (SSA > 1600 m2 g−1), a flow-enhancing hierarchical porosity, and high relative abundance of the most desirable D1-type Fe–N4 sites (43%, by Mössbauer spectroscopy at 4.2 K). Despite the relatively low iron contents, the catalysts feature halfwave potentials up to 0.70 V vs. RHE at pH 1 and a mass activity of 1.22 A g−1 at 0.8 V vs. RHE in RDE experiments. Thanks to the simple and scalable synthesis, this active and stable catalyst may serve as a workhorse in academic and industrial research into atomically-dispersed ORR electrocatalysis. KW - Catalysis KW - Fe-N-C catalysts KW - Fuel Cells KW - Electrochemistry PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550113 DO - https://doi.org/10.1039/d2ta00925k SN - 2050-7488 SP - 1 EP - 10 PB - Royal Society of Chemistry AN - OPUS4-55011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Titirici, M. A1 - Baird, S. G. A1 - Sparks, T. D. A1 - Yang, S. M. A1 - Brandt-Talbot, A. A1 - Hosseinaei, O. A1 - Harper, D. P. A1 - Parker, R. M. A1 - Vignolini, S. A1 - Berglund, L. A. A1 - Li, Y. A1 - Gao, H.-L. A1 - Mao, L.-B. A1 - Yu, S.-H. A1 - Díez, N. A1 - Ferrero, G. A. A1 - Sevilla, M. A1 - Szilágyi, P. Á. A1 - Stubbs, C. J. A1 - Worch, J. C. A1 - Huang, Y. A1 - Luscombe, C. K. A1 - Lee, K.-Y. A1 - Luo, H. A1 - Platts, M. J. A1 - Tiwari, D. A1 - Kovalevskiy, D. A1 - Fermin, D. J. A1 - Au, H. A1 - Alptekin, H. A1 - Crespo-Ribadeneyra, M. A1 - Ting, V. P. A1 - Fellinger, Tim-Patrick A1 - Barrio, J. A1 - Westhead, O. A1 - Roy, C. A1 - Stephens, I. E. L. A1 - Nicolae, S. A. A1 - Sarma, S. C. A1 - Oates, R. P. A1 - Wang, C.-G. A1 - Li, Z. A1 - Loh, X. J. A1 - Myers, R. J. A1 - Heeren, N. A1 - Grégoire, A. A1 - Périssé, C. A1 - Zhao, X. A1 - Vodovotz, Y. A1 - Earley, B. A1 - Finnveden, G. A1 - Björklund, A. A1 - Harper, G. D. J. A1 - Walton, A. A1 - Anderson, P. A. T1 - The sustainable materials roadmap N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability. KW - Electrochemistry KW - Fe-N-C catalysts KW - Fuel cells KW - Catalysis PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126 DO - https://doi.org/10.1088/2515-7639/ac4ee5 SN - 2515-7639 VL - 5 IS - 3 SP - 1 EP - 98 PB - IOP Publishing CY - Bristol AN - OPUS4-55012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menga, D. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Wagner, F. A1 - Fellinger, Tim-Patrick T1 - Evaluation of the Specific Activity of MNCs and the Intrinsic Activity of Tetrapyrrolic FeN4 Sites for the Oxygen Reduction Reaction N2 - M−N−C electrocatalysts are considered pivotal to replace expensive precious group metal-based materials in electrocatalytic conversions. However, their development is hampered by the limited availability of methods for the evaluation of the intrinsic activity of different active sites, like pyrrolic FeN4 sites within Fe−N−Cs. Currently, new synthetic procedures based on active-site imprinting followed by an ion exchange reaction, e.g. Zn-to-Fe, are producing single-site M−N−Cs with outstanding activity. Based on the same replacement principle, we employed a conservative iron extraction to partially remove the Fe ions from the N4 cavities in Fe−N−Cs. Having catalysts with the same morphological properties and Fe ligation that differ solely in Fe content allows for the facile determination of the decrease in density of active sites and their turn-over frequency. In this way, insight into the specific activity of M−N−Cs is obtained and for single-site catalysts the intrinsic activity of the site is accessible. This new approach surpasses limitations of methods that rely on probe molecules and, together with those techniques, offers a novel tool to unfold the complexity of Fe−N−C catalyst and M−N−Cs in general. KW - Fe-N-C catalysts KW - M-N-C catalysts KW - Fuel Cells PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567406 DO - https://doi.org/10.1002/anie.202207089 SN - 1433-7851 VL - 61 IS - 50 SP - 1 EP - 6 PB - Wiley-VHC AN - OPUS4-56740 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Metal chloride activation revisited: a sol-gel process to functional carbons N2 - Porous carbon materials are known for their applicability in important areas such as sorption, catalysis and electrochemistry (e.g. fuel cell catalysts, supercapacitor or battery electrodes). It was shown that nitrogen doped carbons (NDCs) act as an inexpensive and highly active non-metal catalyst in the oxygen reduction reaction (ORR), with the potential to reach performances of practical need one day. A key strategy towards improvement for this aim comprises the generation of advantageous porosity, which typically means high surface area and mass transport pores as well as the control over the chemistry of catalytically active sites. My group is developing novel sol-gel type strategies that are using molten salts or molten acids as unconventional reaction medium for the porogenesis in doped carbons, thereby revisiting classic activation techniques.[1,2] Carbon materials with extra high surface area of ~2800 m2 g-1 and pore volumes, up to four times as high as in commercial activated carbons, are obtained.[3] It turns out that the meso- and macrostructure is generated by means of phase separation rather than leaching reactions. However, chemical reactions between the carbon precursor and the melt are also involved. The salt cations Mg2+ and Zn2+ act as template ions, which results in metal coordination sites, embedded into the carbon structure.[4,5] The imprinted structure may be utilized as catalytically active site by performing ion-exchange reactions. The novel preparation strategy towards highly active electrocatalysts will be presented for Mg and Zn and further discussed for lighter elements. T2 - Carbon Chemistry and Materials Conference 2022 CY - Rome, Italy DA - 10.10.2024 KW - Activated carbon KW - Salt templating PY - 2022 AN - OPUS4-61936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - On the structure of doped carbon electrodes N2 - Carbon-based materials are promising electrodes for energy applications. Herein an overview of morphological and chemical features of such carbon materials is given. It is further shown how morphological and chemical features must be devonvoluted to be able to elucidate structure-performance realtionships that are critical to the improvement of the materials for applications such as batteries or fuel cells. T2 - TEC Summer Seminar 2022 CY - Monte Isola, Italy DA - 06.09.2022 KW - Carbon KW - M-N-C KW - Electrocatalysis KW - Energy storage PY - 2022 AN - OPUS4-61935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Sol-gel synthesis of porous boron- and nitrogen-doped carbon N2 - Carbon activation is intensively investigated due to a widespread utilization of activated carbons as sorbents, hosting and support materials owning to its high porosity and surface area. Activated carbons are increasingly considered also for electrochemical applications e.g. supercapacitors and metal-ion hybrid capacitors. Those devices usually employ activated carbon electrodes, where ions are stored by means of adsorption/desorption.[1] Meanwhile, in lithium-sulfur batteries, sulfur is loaded within activated carbon pores to confine insoluble intermediates.[2] The activation is normally proceeded in top-down or bottom-up strategies. Therein pore formation (porogenesis) occurs by reaction with steam, CO2, KOH, or the use of acidic agents. It is generally accepted, that the porogenesis mechanism is chemical leaching of carbon atoms. Recently, the sol-gel type synthesis of nitrogen-doped carbon in molten acids was presented, questioning the general validity of a leaching activation mechanism.[3] The protocol using inorganic salt melts (MgCl2 or ZnCl2) and organic precursors additionally generated N-functionalities. Interestingly, it can be noticed that the imprinting cations play a crucial role towards chemical structure of nitrogen-doped carbon framework. The coordinated geometry is well-known from phthalocyanine, a macrocyclic N-complexes (MN4-sites, where M is metal cation) which are desirable surface complexes, e.g. in electrocatalysis. The analogous phenomenon may be observed when using H3PO4 and H3BO3 agent via sol-gel chemistry.[4] Herein, the carbonization of mixtures of organic compound with H3PO4 and H3BO3 is investigated. Therefore, associated effects regarding the presence of P and B atoms within resulting nitrogen-doped carbons as well as the porogenesis mechanism are discussed. The understanding of moieties probably offers a new perspective of non-leaching carbon activation hence, provides a feasible pathway towards improved performances in electrochemical applications. T2 - Deutsche Zeolith-Tagung 2022 CY - Frankfurt am Main, Germany DA - 24.03.2022 KW - B-N-C KW - Boric acid activation PY - 2022 AN - OPUS4-61957 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Porous Carbon Supported Ni or Co Single Atom Catalysts for Electrochemical Reduction of CO2 N2 - Isomorphous, but chemically unequal Ni-, Co- and Zn-N-C electrocatalysts are investigated for their electrocatalytic properties towards the electrochemical CO2 conversion. It turns out that Ni-N-Cs are clearly most favourable, because of the isomorphism to other catalysts, also clearly due to the NiN4 sites properties. T2 - Deutsche Zeolith-Tagung 2024 CY - Frankfurt am Main, Germany DA - 23.03.2024 KW - M-N-C catalysts KW - CO2 reduction PY - 2022 AN - OPUS4-61953 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mehmood, Asad T1 - Atomically Coordinated Non-Precious Metal Electrocatalysts Using Active Site Imprinted Carbon Matrix N2 - Non-precious metal catalysts generally represented as M-N-C (where M= Fe, Co, Ni etc.) have shown encouraging activity levels for different electrochemical applications involving oxygen reduction reaction (ORR) and carbon dioxide reduction reaction (CO2RR). High activities of these electrocatalysts mainly come from transition metal centres that are atomically dispersed as M-N4 active sites within a nitrogen doped carbon matrix. Because of the required pyrolytic synthesis conditions, it is quite challenging to prepare M-N-Cs that purely consist of M-N4 active sites. Classical synthesis routes often result in the formation of additional side phases such metallic nanoparticles or metal carbides, which limit the density of M-N4 sites and lead to lower catalytic activity.1 Herein, we present our work on M-N-C synthesis using an active site imprinting approach as an alternate synthetic route to address the above-mentioned issue. We show that both Mg and Zn can be used for active site imprinting. The imprinted coordination environment can be coordinated with various transition metal ions, resulting in Fe-N-C, Co-N-C and Ni-N-C catalysts containing M-N4 sites exclusively.2-4 The electrochemical performance of the synthesized catalysts is evaluated for CO2RR and ORR. Ni-N-Cs exhibit an excellent CO2 reduction activity with high CO faradic efficiency value of 95% at U= -0.5 to -0.8 VRHE (vs reversible hydrogen electrode) and a mass activity of 23 A g-1. The performance stability test carried out at -0.65 VRHE demonstrates above 92 % retention of the current density and 97 % retention of the CO selectivity after 100 h of continuous operation, reflecting the structural robustness of the Ni-N-C catalyst in CO2RR test environment. When employed as ORR catalysts, both Fe-N-C and Co-N-C deliver promising activities with half-wave potentials >0.8 VRHE in acidic electrolyte and >0.9 VRHE in alkaline electrolyte. The talk will include greater details of the structural analysis and electrochemical performance evaluation of these catalysts. T2 - 73rd Annual Meeting of the International Society of Electrochemistry CY - Online meeting DA - 12.09.2022 KW - Non-precious metal catalysts KW - Single atom catalysts KW - Electrochemical CO2 conversion PY - 2022 AN - OPUS4-61986 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mehmood, Asad T1 - Ionothermal Template Transformation as a Sustainable Route Towards Carbon Electrodes in Energy Storage and Conversion N2 - Porous carbons with tuneable functionalities and morphologies have extensively been employed as electrode materials in a variety of electrochemical energy conversion and storage systems for instance in fuel cells and electrolysers as active catalysts and catalyst supports, and in secondary batteries as anode materials. Amorphous carbons with well-developed pore structures are of particular interest due to their superior mass-transport characteristics and remarkable charge storage capacities. The salt-templating method with its advantage of combined soft and hard templating effects provides a sustainable way to synthesize nano- and mesoporous carbons with tailored porosities via in-situ ionothermal template transformation [1]. In this work, we utilized a MgCl2-based salt melt to prepare nitrogen doped carbons (N-C) with different morphologies and porosities, which were evaluated as anode materials in sodium ion batteries. Simultaneously, use of MgCl2 salt leads to the formation of Mg-N4 moieties in those carbons by means of a pyrolytic template-ion effect (active site imprinting) [2]. Porous carbon frameworks with imprinted Mg-N4 sites are interesting particularly for electrocatalysis applications as they offer an ideal platform to prepare M-N-C catalysts (where M= Co, Fe, Ni etc.) by ion-exchange reactions at low temperatures. The resultant M-N-C catalysts consist purely of M-N4 active sites and high porosity of carbon framework facilitates efficient mass-transport of reacting species. We utilized Mg-N4 imprinted carbons to synthesize morphologically equivalent Ni-N-Cs and Co-N-Cs, containing phase pure Ni-N4 and Co-N4 sites, for electrochemical reduction of carbon dioxide (CO2RR). In electrochemical tests, Ni-N-Cs exhibited an excellent CO2 reduction activity with considerably higher CO selectivity and mass activity as compared to Co-N-C. The faradic efficiency value of Ni-N-C for CO formation was 95% at U= -0.5 to -0.8 VRHE (vs reversible hydrogen electrode) and a mass activity of 23 A g-1. The performance stability test carried out at -0.65 VRHE demonstrated above 90 % retention of the current density and CO selectivity after 100 h of continuous operation, reflecting the structural robustness of the Ni-N-C catalyst. Finally, these ionothermal carbons with two different morphologies (but without any Ni or Co incorporation) were employed as the anode materials in sodium-ion batteries to evaluate the effects of carbon morphology and functionalization on sodium storage capacities. Compared to the reference carbon material, substantially higher reversible sodium storage capacities were reached with these high porosity carbons that were in the range of 300-500 mAh g-1 [3]. Although the reversible capacity was obtained only after extensive SEI formation, our results reveal the potential for much higher reversible capacities than usually observed using carbons with a tailored porosity in sodium-ion batteries. The talk will include greater details of the structural analysis and sodium storage and CO2 reduction results of these ionothermal carbons. T2 - Materials for Sustainable Development Conference (MAT-SUS) CY - Barcelona, Spain DA - 24.10.2022 KW - Porous carbons KW - Sodium ion batteries KW - Anode materials KW - Single atom catalysts KW - Electrochemical CO2 reduction PY - 2022 AN - OPUS4-61985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Bioinspired atomically dispersed M-N-C catalysts via active-site imprinting into nitrogen doped carbons N2 - Proton-exchange membrane fuel cells are amongst the most promising energy conversion technologies today. Herein non-precious iron-coordinated nitrogen doped carbons (Fe-N-Cs) are very promising alternatives for Pt-based cathode catalysts.[1-3] The early reports on the application of such materials date back to the 1960´s when Jasinski demonstrated that - similar to natural porphyrins - N-coordinated transition metal complexes can be active sites for the ORR.[3] The preparation of these catalysts was strongly optimized over the years; still they typically remain with harsh reaction conditions that complicate the selective formation of active FeN4 sites. The employment of pyrolytic temperatures has been a dogma for the synthesis of MN4 sites, however coming with unfavorable side reactions. We recently introduced a mild procedure, which is conservative toward the carbon support and leads to active-site formation at low temperatures in a wet-chemical step, essentially decoupling the preparation of nitrogen doped carbons (NCs) from the preparation of the active sites.[4, 5] The key concept therein is the so-called active site imprinting into the NC using the less reactive template ions Mg2+ [4] or Zn2+.[5] The presentation will introduce the concept of active site imprinting with a focus on Fe-N-C electrocatalyst development and testing. The broad potential of the synthetic approach will be exemplified by recent results, including the selective synthesis of tetrapyrrolic single site catalysts, the assignment of the role of the transition metal compared to the carbon scaffold and a facile method to evaluate specific activity. T2 - GDCh Electrochemistry 2022 CY - Berlin, Germany DA - 27.09.2022 KW - Bioinspired carbon catalysts PY - 2022 AN - OPUS4-61960 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Effects of Acid Activation via Sol-Gel Chemistry towards Nitrogen-Doped Carbon Structure N2 - Porous carbon materials are known for their applicability in important areas such as sorption, catalysis and electrochemistry (e.g. fuel cell catalysts, supercapacitor or battery electrodes). It was shown that nitrogen doped carbons (NDCs) act as an inexpensive and highly active non-metal catalyst in the oxygen reduction reaction (ORR), with the potential to reach performances of practical need one day. A key strategy towards improvement for this aim comprises the generation of advantageous porosity, which typically means high surface area and mass transport pores as well as the control over the chemistry of catalytically active sites. My group is developing novel sol-gel type strategies that are using molten salts or molten acids as unconventional reaction medium for the porogenesis in doped carbons, thereby revisiting classic activation techniques.[1,2] Carbon materials with extra high surface area of ~2800 m2 g- 1 and pore volumes, up to four times as high as in commercial activated carbons, are obtained.[3] It turns out that the meso- and macrostructure is generated by means of phase separation rather than leaching reactions. However, chemical reactions between the carbon precursor and the melt are also involved. The salt cations Mg2+ and Zn2+ act as template ions, which results in metal coordination sites, embedded into the carbon structure.[4,5] The imprinted structure may be utilized as catalytically active site by performing ion-exchange reactions. The novel preparation strategy towards highly active electrocatalysts will be presented for Mg and Zn and further discussed for lighter elements. T2 - International Sol-Gel Conference 2022 CY - Lyon, France DA - 24.06.2022 KW - Sol-Gel-Carbonization KW - Boron-Nitrogen-Doped Carbon PY - 2022 AN - OPUS4-61958 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wutthiprom, Juthaporn T1 - Sol-Gel Carbonization towards Tailor-Made Boron- and Nitrogen-doped Carbon N2 - The activation of carbon is normally proceeded in top-down or bottom-up strategies. Therein pore formation (porogenesis) occurs by reaction with steam, CO2 , KOH, or the use of acidic agents, in which chemical leaching of carbon atoms occurs. The sol-gel type synthesis of N-doped carbon in excess amounts of molten acids was presented recently, questioning the general validity of a leaching activation mechanism.[1] The protocol using inorganic salt melts (MgCl2 or ZnCl2 ) and organic precursors additionally generated N functionalities. Interestingly, it can be noticed that the imprinting cations play a crucial role towards the chemical structure of N-doped carbon framework. The coordinated geometry is wellknown from phthalocyanine, a macrocyclic Ncomplexes (MN4 -sites, where M is metal cation) which are desirable surface complexes, e.g. in electrocatalysis. The analogous phenomenon may be observed when using H3BO3 agent via sol-gel chemistry. T2 - International Sol-Gel Conference 2022 CY - Lyon, France DA - 24.06.2022 KW - Boron-Nitrogen-Doped-Carbon KW - Sol-Gel-Carbonization PY - 2022 AN - OPUS4-61959 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mehmood, Asad A1 - Fellinger, Tim-Patrick T1 - Porous Carbon Supported Ni and Co Single Atom Catalysts for Electrochemical Reduction of Carbon Dioxide N2 - Non-precious metal single atom catalysts (generally labelled as M/NCs where M= Co, Fe, Ni etc.) consist of active metal centres dispersed on nitrogen doped porous carbon (NC) matrix at atomic level and exhibit promising activities e. g. for electrochemical reduction of CO2, selectively forming CO. We herein use identical Mg/NCs as platform for ion-exchange reactions towards morphologically equivalent Ni/NCs and Co/NCs. The Ni/NC catalyst shows almost double the specific activity and a Faraday efficiency of >80% at a very low overpotential of U= -0.43 V (even 95% at U= -0.5 to -0.8 V) with high stability. T2 - GDCh Electrochemistry 2022 CY - Berlin, Germany DA - 27.09.2022 KW - Electrochemical CO2 conversion KW - Single atom catalysts KW - Porous Carbons PY - 2022 AN - OPUS4-61980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Appel, Paul Alexander T1 - Investigation and Development of Tailor-Made Core-Shell Hard Carbon Materials to be used as Negative Electrodes in Sodium Ion Batteries N2 - The current strong interest in electromotive mobility and the need to transition to an energy grid with sustainable energy storage has led to a renewed interest in sodium ion batteries (SIBs). Hard carbons are promising candidates for high-capacity negative electrode materials in SIBs. Their high capacities, however, are often accompanied with high irreversible capacity losses during the initial cycles.[1] The goal of this project is to use analytical techniques to establish a correlation between the structure and the capacities of hard carbons. This has previously been difficult, in part because the sodium storage mechanism is not stoichiometric and due to the disordered structure of hard carbons. Large irreversible capacities associated with hard carbons are often in contradiction to the experimentally determined low surface area of the sample material.[1] A better understanding of the structure-property relationship should enable quantification and understanding of the potential of hard carbon materials for SIBs. Our approach is to explore whether a core-shell structure can separate sodium storage and solid electrolyte interphase formation so that storage capacity and irreversible losses can be investigated separately. The synthesis of a selection of porous carbon structures serving as the core material, will be attempted. Simultaneously, sodium-conducting shell structures will be developed to allow for separation of sodium ions and electrolyte molecules. Subsequently the combination of core and shell materials will be undertaken. These anodes should enable high capacities accompanied with low irreversible capacity due to optimized solid electrolyte interphase formation. T2 - GDCH Electrochemistry 2022 CY - Berlin, Germany DA - 27.09.2022 KW - Energy Materials PY - 2022 AN - OPUS4-62001 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja T1 - Analysis of O-ring seal failure in the context of radioactive waste containers N2 - At BAM, which is a federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the casks. Besides examining the low-temperature behaviour and irradiation effects of elastomeric seals, it is our goal to estimate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to five years. In order to assess sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings were aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, material properties such as hardness, elastic modulus, glass transition temperature and viscoelastic loss factor as well as relaxation and recovery behaviour are examined in order to understand the underlying ageing mechanisms in each material. For obtaining results closely related to practical conditions, O-rings with a full-scale cord diameter of 10 mm were aged. However, this set-up can lead to heterogeneous aging caused by diffusion-limited oxidation (DLO) effects, resulting in distorted bulk properties such as compression stress relaxation and compression set. However, if DLO-affected data is excluded, extrapolations of CS data are possible using time-temperature shifts and Arrhenius graphs. For selecting an appropriate end-of-lifetime criterion, leakage rate measurements were performed, since leakage rate is the only characteristic directly correlated to the performance of the sealing system. A significant increase in leakage rate was considered as the end of the lifetime. However, the O-rings remained leak tight under static conditions and even exhibited an improved, i.e. decreased leakage rate while other properties already indicated strong deterioration. These tests were extended by seal tests with fast partial decompression. Overall an update will be given on the current investigations and results and the planned activities. T2 - Kautschuk Herbst Kolloquium 2022 CY - Online meeting DA - 08.11.2022 KW - Seal KW - Ageing KW - Compression set PY - 2022 AN - OPUS4-56397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike T1 - Coefficients of Friction in Dependence on Aging State of Elastomers – Experimental Identification and Numerical Simulation of the Experiment N2 - Elastomer seals are mounted as barrier seals in lid systems of containers designed for transport and disposal of negligible heat generating radioactive waste and as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). When the behavior of mounted seals under normal and hypothetical accident conditions of disposal and transport is to be simulated, a comprehensive knowledge of their complex mechanical properties at every state of aging is necessary. In previous works, BAM’s efforts in experimental investigations on specimen artificially aged at different temperatures and times and the implementation of the found results in finite element material models were presented. Additionally, our approaches to reproduce the aging process itself and to extrapolate the results of artificially accelerated aging to longer times were presented. Numerical simulations have shown that the behavior of the seal during mounting and one-sided pressurizing and the resulting performance values such as leakage rate strongly depend on the coefficient of friction (COF) between flange and seal. The friction coefficient, in turn, depends on the aging state of the elastomer material as several publications suggest (see below). Dynamic COF between an exemplary ethylene propylene diene rubber (EPDM) material and a stainless steel ball were determined by using a self-designed linear oscillation tribometer. Unaged and artificially aged EPDM specimen stored for 30 days and 100 days at a temperature of 150 °C were tested. A stainless steel ball (d=10 mm) is brought in contact with the specimen’s surface und loaded by normal forces of 2.5 N, 5 N, 10 N and 20 N. During a reciprocating movement of the EPDM sheet, the horizontal force/friction force is continuously measured, and the COF can be derived. It is well known that friction is a complex phenomenon especially in soft materials. It cannot be excluded that the measured friction force is influenced by additional force components, resulting from the ball’s grooving through the elastomer’s surface. This force depends on the penetration depth of the ball and on the resistance of the elastomer in its different states of aging. The latter results from microstructural changes i.e., chain scission and additional crosslinking that occur during aging which in turn influence the softening or hardening of the material. A finite element (FE) ABAQUS® model was developed to reproduce the measurement process. It should help to better understand the physical mechanisms and to quantify the percentage of measured forces resulting from real friction on the one hand and forces resulting from unintended side effects that could falsify the result on the other hand. The behavior of the elastomer in its different states of aging is reproduced by a FE material model already presented in previous works of BAM. T2 - ASME 2022 Pressure Vessels & Piping Conference (PVP2022) CY - Las Vegas, NV, USA DA - 17.07.2022 KW - Radioactive Waste KW - Elastomers KW - Aging KW - Experiment KW - Seal Behavior KW - Numerical Simulation KW - Leakage Rate KW - Coefficient of Friction PY - 2022 AN - OPUS4-57095 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan T1 - Morpho-Chemical Characterisation of Me-TiO2 Nanoparticles for Enhanced Photocatalytical Activity N2 - The conversion of solar energy into electricity and solar fuels is of crucial importance for a green and sustainable future. Water splitting using semiconductor photo-catalysts is considered a sustainable method to produce clean hydrogen (H2) fuel. Nevertheless, H2 photo-production efficiency remains still low, although extensive research works to understand better the mechanisms of the Hydrogen Evolution Reaction (HER) and the Oxygen Evolution Reaction (OER) are being carried out. In this respect, TiO2 is a key photoactive material, usually employed with a co-catalyst deposited onto the surface to enhance charge carriers’ separation and catalyze surface charge transfer reactions. The deposition of a co-catalyst on the TiO2 nanoparticle surface represents one successful way to enhance the activity of the photocatalyst through a modification of its surface and redox properties. In this context, high-resolution scanning electron microscopy coupled with elemental analysis by energy-dispersive X-ray spectroscopy (EDS) is fundamental for studying and understanding the effect of the nanoparticle morphology on the functional properties of shape-controlled TiO2 crystals (bipyramides, platelets, and elongated particles). Different types of metal-semiconductor combinations, TiO2 shapes and dopant metals (Ag, Pt, etc) and metal concentrations will be discussed. T2 - ECASIA 2022 CY - Limerick, Ireland DA - 29.05.2022 KW - Titania nanoparticles KW - Photocatalysis KW - Scanning electron microscopy KW - Energy dispersive X-ray spectroscopy PY - 2022 AN - OPUS4-54977 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, F. A1 - Wang, C. A1 - Osenberg, M. A1 - Dong, K. A1 - Zhang, S. A1 - Yang, C. A1 - Wang, Y. A1 - Hilger, A. A1 - Zhang, J. A1 - Dong, S. A1 - Markötter, Henning A1 - Manke, I. A1 - Cui, G. T1 - Clarifying the Electro-Chemo-Mechanical Coupling in Li10SnP2S12 based All-Solid-State Batteries N2 - A fundamental clarification of the electro-chemo-mechanical coupling at the solid–solid electrode|electrolyte interface in all-solid-state batteries (ASSBs) is of crucial significance but has proven challenging. Herein, (synchrotron) X-ray tomography, electrochemical impedance spectroscopy (EIS), time-of-flight secondary-ion mass spectrometry (TOF-SIMS), and finite element analysis (FEA) modeling are jointly used to decouple the electro-chemo-mechanical coupling in Li10SnP2S12-based ASSBs. Non-destructive (synchrotron) X-ray tomography results visually disclose unexpected mechanical deformation of the solid electrolyte and electrode as well as an unanticipated evolving behavior of the (electro)chemically generated interphase. The EIS and TOFSIMS probing results provide additional information that links the interphase/electrode properties to the overall battery performance. The modeling results complete the picture by providing the detailed distribution of the mechanical stress/strain and the potential/ionic flux within the electrolyte. Collectively, these results suggest that 1) the interfacial volume changes induced by the (electro)chemical reactions can trigger the mechanical deformation of the solid electrode and electrolyte; 2) the overall electrochemical process can accelerate the interfacial chemical reactions; 3) the reconfigured interfaces in turn influence the electric potential distribution as well as charge transportation within the SE. These fundamental discoveries that remain unreported until now significantly improve the understanding of the complicated electro-chemo-mechanical couplings in ASSBs. KW - All-solid-state batteries KW - Lithium metal batteries KW - Solid electrolytes KW - Sulfide solid electrolytes KW - Synchrotron X-ray tomography PY - 2022 DO - https://doi.org/10.1002/aenm.202103714 SN - 1614-6832 SP - 2103714 PB - Wiley VHC-Verlag AN - OPUS4-54431 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ziesche, R.F. A1 - Hack, J. A1 - Rasha, L. A1 - Maier, M. A1 - Tan, C. A1 - Heenan, T.M.M. A1 - Markötter, Henning A1 - Kardjilov, N. A1 - Manke, I. A1 - Kockelmann, W. A1 - Brett, D.J.L. A1 - Shearing, P.R. T1 - High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells N2 - In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings. This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs. KW - Neutron imaging KW - Tomography KW - Polymer electrolyte membrane fuel cell PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545978 DO - https://doi.org/10.1038/s41467-022-29313-5 VL - 13 IS - 1 SP - 1616 PB - Nature Publishing Group UK CY - London AN - OPUS4-54597 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - John, Sebastian A1 - Auster, Jürgen A1 - Widjaja, Martinus Putra A1 - Duffner, Eric A1 - Mair, Georg W. T1 - NIP II - Forschungsvorhaben „DELFIN“ N2 - Überblick über Projektinhalte und -ergebnisse aus dem Forschungsvorhaben Delfin „Erforschung alternativer Materialien und Fertigungsprozesse für kosten- und gewichtsreduzierte Druckbehälter aus endlosfaserverstärkten Kunststoff“ T2 - SAMPE Kolloquium CY - Online meeting DA - 15.01.2022 KW - Wasserstoff KW - Druckbehälter KW - Impact PY - 2022 AN - OPUS4-58064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liu, Y. T1 - Cooperation in Advanced Technologies Associated with the Back End of Nuclear Fuel Cycle N2 - A Memorandum of Understanding (MOU) between Argonne National Laboratory (Argonne) and the German Bundesanstalt für Materialforschung und -prüfung (BAM) was signed in October 2014. Its objectives are to promote cooperation among scientists and specialists at Argonne and BAM and establish a framework for collaboration in advanced technologies associated with the back end of the nuclear fuel cycle. Collaborative activities involving Argonne and BAM may be implemented through the promotion of joint research activities and scientific workshops and conferences; exchange of technical information; and visits by scientists, specialists, and graduate, postgraduate, and Ph.D. students. The MOU was renewed in January 2020 for another five years. Highlights of the progress and achievements are provided in identified topical areas for collaboration on ageing management guidance, storage, transportation and disposal R&D, joint conference activities, and conclude with the benefits of the MOU in fostering Argonne and BAM collaboration. T2 - 26th International Conference on Structural Mechanics in Reactor Technology - SMiRT 26 CY - Potsdam, Germany DA - 10.07.2022 KW - Nuclear fuel cycle KW - Back end KW - Spent fuel performance KW - Storage KW - Transportation PY - 2022 AN - OPUS4-55862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - ToF-SIMS at advanced materials - from nano to energy N2 - The basic principles of ToF-SIMS will be explained. Examples of the use of ToF-SIMS for the investigation of titania and core-shell nanoplastic will be given. Furhtermore, 3d reconstruction is explained for nanoparticle research and energy-related materials. T2 - BUA Summer School Mass Spectrometry CY - Berlin, Germany DA - 04.10.2022 KW - ToF-SIMS KW - Nanomaterials KW - Imaging PY - 2022 AN - OPUS4-55897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias T1 - Investigations at BAM on Fuel Cladding Integrity and DPC Seal Performance N2 - The presentation provides an update on preliminary results from research projects in the area of long term performance of metal seals and fuel rod integrity as safety relevant components of spent fuel transport and storage casks for spent nuclear fuel. T2 - Extended Storage Collaboration Program (ESCP) winter meeting 2022 CY - Charlotte, NC, USA DA - 07.11.2022 KW - Metal seal KW - Fuel cladding KW - Ring compression test KW - Brittle failure PY - 2022 AN - OPUS4-56400 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sachse, René A1 - Hodoroaba, Vasile-Dan A1 - Kraehnert, R. A1 - Hertwig, Andreas T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing. We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP). KW - Electrochemical catalysts KW - Mixed metal oxide KW - Multi-sample analysis KW - Spectroscopic ellipsometry KW - Thin mesoporous films PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026 DO - https://doi.org/10.1515/aot-2022-0007 SN - 2192-8584 SN - 2192-8576 VL - 11 IS - 3-4 (Topical issue: Ellipsometry) SP - 137 EP - 147 PB - De Gruyter CY - Berlin AN - OPUS4-55102 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Oxidative ageing of elastomers: Experiment and modelling N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125∘C and 150∘C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments. KW - Compression stress relaxation KW - Compression set KW - IRHD microhardness KW - Modelling PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545910 DO - https://doi.org/10.1007/s00161-022-01093-9 SN - 1432-0959 SP - 1 EP - 9 PB - Springer CY - Berlin AN - OPUS4-54591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Z. A1 - Dong, K. A1 - Mazzio, K. A. A1 - Hilger, A. A1 - Markötter, Henning A1 - Wilde, F. A1 - Heinemann, T. A1 - Manke, I. A1 - Adelhelm, P. T1 - Phase transformation and microstructural evolution of CuS electrodes in solid-state batteries probed by in situ 3D X-ray tomography N2 - Copper sulfide shows some unique physico-chemical properties that make it appealing as a cathode active material (CAM) for solid-state batteries (SSBs). The most peculiar feature of the electrode reaction is the reversible formation of μm-sized Cu crystals during cycling, despite its large theoretical volume change (75%). Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X-ray tomography. The formation of μm-sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z-oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z-oriented reversible displacement of the cathode pellet, which is linked to the plating/stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft materials. KW - Copper sulfide KW - Crack evolution KW - Digital volume correlation KW - Phase transformation KW - Solid-state batteries PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564577 DO - https://doi.org/10.1002/aenm.202203143 IS - 2203143 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-56457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Thermoelectric multilayer generators: development from oxide powder to demonstrator N2 - Thermoelectric generators can be used for energy harvesting by directly transforming a temperature gradient into a voltage. Multilayer generators based on ceramic multilayer technology are an interesting alternative to conventional π-type generators. They exhibit several advantages like high filling factor, possibility of texturing, co-firing of all materials in one single-step, and reduction of production costs due to the high possible degree of automation. But, co-firing of promising oxide thermoelectric materials, Ca3Co4O9 (p-type) and CaMnO3 (n-type), is very challenging due to the large difference in sintering temperature (300 K). In this work we show the material development of Ca3Co4O9, CaMnO3, and insulation for multilayer generators co-fired under uniaxial pressure at 900 °C. The materials are tailored regarding their sintering behavior, electrical performance and coefficients of thermal expansion. Tape-casting and pressure assisted sintering are applied to fabricate textured Ca3Co4O9. Compared to conventional sintering, pressure assisted sintering increases the strength by the factor 10 and the power factor by the factor of 20. The combination of sintering additives and uniaxial pressure is used to decrease the sintering temperature of CaMnO3 to 900 °C while maintaining acceptable thermoelectric properties. Different generator designs (unileg and pn-type) were fabricated and analyzed regarding microstructure and thermoelectric performance. A lower level of complexity is beneficial for co-firing and performance. The unileg demonstrators reach 80% of the simulated output power and the power output is highly reproducible between the different demonstrators (99%). T2 - Ceramics in Europe 2022 CY - Krakow, Poland DA - 10.07.2022 KW - Thermoelectrics KW - Multilayer technology KW - Co-firing KW - Texture PY - 2022 AN - OPUS4-55357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stargardt, Patrick T1 - Comparison of design concepts for ceramic oxide thermoelectric multilayer generators N2 - Multilayer thermoelectric generators are a promising perspective to the conventional π-type generators. Ceramic multilayer technology is well established for production of microelectronics and piezo-stacks. Key features of ceramic multilayer technology are full-automation, cost-effectiveness, and the co-firing of all materials in one single step. This requires similar sintering temperatures of all used materials. The development of multilayer thermoelectric generators is a subject of current research due to the advantages of this technology. One of the challenges is the compatibility of the different materials with respect to the specific design. The presented study compares three different designs of multilayer generators based on a given set of material properties. Dualleg, unileg and transverse multilayer generators are compared to conventional π-type generators., the designs are evaluated regarding the expected maximum output power and power density using analytical calculations and FEM simulations. Additionally, the complexity of the production process and material requirements are assessed and design optimizations to simplify production are discussed. Besides the theoretical aspects, unileg multilayer generator prototypes were produced by tape-casting and pressure-assisted sintering. These prototypes are compared to other multilayer generators from literature regarding the power factors of the used material system and the power density. Improvements of the power output by design optimizations are discussed T2 - 18th European Conference on Thermoelectrics CY - Barcelona, Spain DA - 13.09.2022 KW - Thermoelectric oxides KW - Thermoelectric generator design PY - 2022 AN - OPUS4-55820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Grelle, Tobias A1 - Jaunich, Matthias A1 - Goral, Milan A1 - Wolff, Dietmar T1 - Three-dimensional thermal expansion of neat and irradiated (U)HMWPE materials at elevated temperatures N2 - The thermal expansion of polymeric parts can be an issue in many applications where the available space is limited, or exact dimensions of the part are required. For this study, a device was designed and built that allowed measuring the thermal expansion simultaneously in all three spatial directions on cubic samples with real-scale dimensions (78 mm edge length). The results are shown between 25 °C and 125 °C for two PE materials, one HMWPE and one tempered UHMWPE, for non-irradiated samples as well as cubes that have been irradiated with 100 and 400 kGy. The results measured with the new device were very similar to those measured with conventional thermo-mechanical analysis equipment and to literature data of UHMWPE. The HMWPE material shows a much larger thermal expansion coefficient in one direction compared to the other two directions during the first heating due to frozen stresses from the pressing step during material manufacturing. These stresses are mostly released by the expansion during the first heating, so that the expansion during the second heating is more uniform. The overall volumetric expansion is the same for both heating runs. By contrast, the tempered UHMWPE material shows no significant difference between first and second heating run, as the stresses from processing could already relax in the tempering step. The irradiation treatment does not affect the values significantly for the given test set-up. KW - Lupolen KW - Ultra high molecular weight polyethylene KW - GUR KW - Coefficient of thermal expansion KW - High temperature PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563987 DO - https://doi.org/10.1016/j.polymertesting.2022.107841 SN - 0142-9418 VL - 117 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-56398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bresch, Sophie A1 - Mieller, Björn A1 - Moos, R. A1 - Rabe, Torsten T1 - Lowering the sintering temperature of calcium manganate for thermoelectric applications N2 - This study combines three different approaches to lower the sintering temperature of Sm-doped CaMnO3 to save energy in production and facilitate co-firing with other low-firing oxides or metallization. The surface energy of the powder was increased by fine milling, sintering kinetics were enhanced by additives, and uniaxial pressure during sintering was applied. The shrinkage, density, microstructure, and thermoelectric properties were evaluated. Compared to micro-sized powder, the use of finely ground powder allows us to lower the sintering temperature by 150 K without reduction of the power factor. By screening the effect of various common additives on linear shrinkage of CaMnO3 after sintering at 1100 ○C for 2 h, CuO is identified as the most effective additive. Densification at sintering temperatures below 1000 ○C can be significantly increased by pressure-assisted sintering. The power factor at room temperature of CaMnO3 nano-powder sintered at 1250 ○C was 445 μW/(m K2). Sintering at 1100 ○C reduced the power factor to 130 μW/(m K2) for CaMnO3 nano-powder, while addition of 4 wt.% CuO to the same powder led to ∼290 μW/(m K2). The combination of fine milling, CuO addition, and pressureassisted sintering at 950 ○C resulted in a power factor of ∼130 μW/(m K2). These results show that nano-sized powder and CuO addition are successful and recommendable strategies to produce CaMnO3 with competitive properties at significantly reduced temperatures and dwell times. KW - Sintering additive KW - Liquid phase sintering KW - Pressure assisted sintering PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555467 DO - https://doi.org/10.1063/5.0098015 SN - 2158-3226 VL - 12 IS - 8 SP - 1 EP - 9 PB - American Institute of Physics (AIP) CY - New York, NY AN - OPUS4-55546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kardjilov, N. T1 - Quantification of hydrogen in metals applying neutron imaging techniques N2 - Hydrogen interaction with metals is well known to have severe detrimental effects on their mechanical properties. The use of modern high-strength steels, which are attractive to improve fuel economy by reducing weight as well as candidates for H storage cylinders and other components, is currently being severely limited by the fact that the presence of H can cause embrittlement of the material. In addition to steel, several other metals and alloys used in the nuclear industry, like Ti and Zr, are susceptible to H degradation through hydride formation and subsequent cracking. Microstructure-specific H mapping has been recognized as the most important challenge on the pathway towards a better understanding of the nature of H embrittlement in metallic alloys as well as the development of H storage solutions based on metal hydrides. Unfortunately, the characterization of H interactions with metals is an extremely challenging task and neutron-based techniques are of exceptional importance in this matter because – contrary to X-rays and electrons – thermal and cold neutrons interact strongly with the H nuclei, while the neutron beam is only weakly attenuated by the relevant metallic materials. Therefore, hydrogen distributions can be measured and quantified even in 3D by tomographic methods. Here we present several neutron imaging investigations of embrittlement and cracking in Fe and Zr based metal alloys and optimization studies of hydrogen storage systems containing metal hydrides as an active substance. The advantages and the limitations of the experimental methods as well as the attempts for hydrogen quantification will be discussed in detail. T2 - M&M 2022 Annual Meeting (Microscopy & Microanalysis) CY - Portland, Oregon, USA DA - 31.07.2022 KW - Neutron imaging techniques KW - Hydrogen in metals PY - 2022 DO - https://doi.org/10.1017/S1431927622006638 AN - OPUS4-55716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -