TY - CONF A1 - Mehmood, Asad A1 - Fellinger, Tim-Patrick 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. T2 - Nano-Pak 2023, 2nd International Conference on Emerging Trends & Innovations in Nanotechnology CY - Lahore, Pakistan DA - 17.06.2023 KW - Ionothermal Template Transformation KW - Sustainable Route KW - Carbon Electrodes PY - 2023 AN - OPUS4-58897 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 - Structure-Performance Relations of PGM-free Electrocatalysts for PEM Fuel Cells 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) as well as metal-free nitrogen-doped carbons (NDCs) are very promising alternatives for Pt-based cathode catalysts. 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.1 The preparation of Fe-N-Cs was strongly optimized over the years; still they typically remain with harsh reaction conditions that complicate the selective formation of active FeN4 sites. Until recently, the employment of pyrolytic temperatures was a dogma for the synthesis of FeN4 sites, however coming with unfavorable side reactions. To avoid those harmful side reaction a limit of maximum ≈3 wt.% of Fe (depending on the precursor) was reached, which was also limiting the progress in catalyst performance for this class of materials.2, 3 Since 2006 it was shown that nitrogen doped carbons (NDCs) act as an inexpensive and highly active non-metal catalyst in the oxygen reduction reaction (ORR).4 Both, NDCs and Fe-N-Cs nowadays show the potential to reach performances of practical need, where NDC seem to be promising only for alkaline conditions, while Fe-N-Cs show promise independent of the pH.5, 6 For both PGM-free catalysts, high performance requires advantageous porosity, which typically means high surface area and mass transport pores as well as the control over the chemistry of catalytically active sites. Results and Discussion My group is developing novel synthetic strategies e.g. using molten salts or molten acids as unconventional reaction medium for the preparation of carbons materials.7, 8 Carbon materials with tunable very high surface area of ~2800 m2 g-1 and pore volumes, up to four times as high as in commercial activated carbons, are obtained. Fig. 1: Scheme of the porogenesis mechanism for NDCs by phase separation in of molten salt carbonization (a) to obtain tunable high surface area and porous carbon materials with varying nitrogen content (b). It turned out that such NDCs synthesized in presence of Mg2+ or Zn2+ give rise to a high degree of pyridinic and pyrrolic sites and outstanding ORR activity in alkaline conditions. The salt cations Mg2+ or Zn2+ act as template ions, which results in tetrapyrrolic functional groups embedded into the carbon structure. Based on this, we recently introduced a mild procedure to synthesize Fe-N-C, which leads to active-site formation at low temperatures due to coordination of Fe ions to the tetrapyrrolic functional groups of NDCs.2, 3 Figure 2: Scheme of the Active-Site Imprinting Strategy. A pyrolytic template-ion reaction forms a tetrapyrrolic functional group within the carbon framework (first step). Exchange of the template ion T (with T=Mg2+ or Zn2+) with Fe results in tetrapyrrolic Fe-N-C. The synthesis strategy of active-site imprinting and transmetalation is decoupling the preparation of NDCs from the preparation of the active sites and therefore breaks with the dogma of Fe-N-Cs preparation, circumventing the limitation to 3 wt.% of Fe.9 After a thermal activation step the Fe-N-Cs derived from active site imprinting show very good performance of ORR in acidic conditions, both on the half-cell (rotating disc electrode) and full-cell (5cm2 PEM single cell) level. Figure 3: a) Rotating disk electrode measurements show the large increase in ORR activity and low amount of peroxide formed by exchange of Zn to Fe coordinated to tetrapyrrolic NDC, especially when followed by a second heat treatment. b) Single cell PEMFC H2-O2 tests show a peak power density above 0.4 W cm-2 at a catalyst loading of 2 mg cm-2. Active-site imprinting is currently used by many groups worldwide, successfully pushing the performance of Fe-N-Cs forward, with higher Fe loadings and improved porosities.10-12 Challenges are the moderate turnover frequency (0.24 e- s-1 at 0.8 VRHE) of tetrapyrrolic Fe-N4 sites, 13 and a moderate shelf-life of tetrapyrrolic Fe-N-Cs in atmospheric conditions.14 Besides improvements of electrode engineering and optimization of fuel cell management, an improved synthetic control, leading to more active and stable catalytic environments are needed to tackle the need of sustainable electrocatalysts for future energy conversion technology.15 T2 - International Conference on Materials and Systems for Sustainability (ICMaSS2023) CY - Nagoya, Japan DA - 01.12.2023 KW - PGM-free catalysts PY - 2023 AN - OPUS4-61937 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 - Valorization of carbon dioxide by the electrocatalytic reduction coupled to acetogens via multiple electron carriers N2 - A summary of the DFG project "Ecat-Acetogens" within the SPP priority programm Ebiotech (2240) was given. The successful developmante of a bioelectrocataltic reactor system based on standard 2l stirred tank bioreactors and common 5cm2 singel cell electrolysis reactors was presnted and first results discussed based on the catlytic properties of a specifically designed cathode catalyst for CO2 reduction. T2 - DFG SPP Statusmeeting Ebiotech 2024 CY - Jena, Germany DA - 22.04.2024 KW - CO2 conversion KW - Bioelectrocatalytic reactor PY - 2024 AN - OPUS4-61939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schwarz, I. A1 - Rieck, Arielle A1 - Fellinger, Tim-Patrick A1 - Weuster-Botz, Dirk T1 - Bio-electrochemical CO2 conversion into organic products using precious-metal free electrocatalysts N2 - For the realization of a sustainable economy, it is of great importance to make use of CO2 for the production of multi-carbon organic chemicals used as feedstock in the chemical industry as well as carbon-neutral fuels (Varela et al. 2019). A promising approach is the electrochemical CO2 reduction followed by microbial conversion of the reduced products. KW - Bio-electrochemical KW - Organic products KW - Electrocatalysts PY - 2024 SP - 1 EP - 2 AN - OPUS4-59572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Overview of Battery Research Activities at BAM N2 - An overview on battery research activities of BAM was given using a seletion of activities of all work packages within the field of activity EES and selected activities of divsion 3.6. T2 - Boot Camp of the BAccara Graduate School on Batteries CY - Bad Sassendorf, Germany DA - 24.04.2024 KW - State of Safety KW - Compositional traceability KW - Sustainable energy materials KW - Sodium Ion Batteries PY - 2024 AN - OPUS4-61940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Chemie der Energiewende N2 - Es wurde ein Überblick über die BAM-Aktivitäten im Bereich Chemie der Energiewende gegeben. Dabei wurde ein Fokus auf Aktivitäten in Aktivitätsfeld EES und im Fachbereich 3.6 gelegt. T2 - 30 Jahre Naturwissenschaftliches Studium in Zittau CY - Zittau, Germany DA - 13.04.2024 KW - Chemie KW - Energiewende PY - 2024 AN - OPUS4-61941 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Sodium-Ion Battery Research and Testing at BAM N2 - An overview of activities at BAM on the topic of sodium ion batteries was given. Examples of the internal SIB-links project were given and a focus on novel synthetic anodes. T2 - Sodium Battery Sympoium-5 (2024) CY - Berlin, Germany DA - 23.09.2024 KW - Sodium ion batteries KW - Synthetic carbon anodes PY - 2024 AN - OPUS4-61944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick A1 - Krug von Nidda, Jonas T1 - Porous „Ionophoric“ Carbon Materials: Synthesis Routes and Electrochemical Applications N2 - Porous carbon materials play an important role for energy storage and conversion, e.g., as fuel cell catalysts, supercapacitor or battery electrodes. Tuning porosity features such as pore connectivity, specific surface area, maximum pore size and pore volume is one of the key strategies to improve the performance of those materials.[1] Moreover, the alteration of the chemistry allows further enhancement in performance, even leading to the applicability in new fields. In this context, nitrogen doped carbons (NDCs) are a very promising material class. Highly porous NDCs for example show interesting Na-storage features.[2] Moreover, the integration of iron ions in an NDC, forming FeN4-sites, can results in materials with very promising properties as fuel cell cathode catalysts.[3] However, to relate certain sites to specific performance indicators is still challenging as the variation of the present N-sites is very large in typically obtained NDCs. In the past, we were able to develop an ionothermal synthesis strategy which results in highly porous materials with specific, i.e., tetrapyrrolic, N4-sites.[4] Such N4 sites and there metal complexes are reminiscent of biomolecules like the heme molecule, which originally inspired the research on such materials.[5] The N4-sites are mainly occupied by Zn2+ as the synthesis is performed in a ZnCl2-containing salt melt. Moreover, the electrochemical performance of those materials can be rather easily altered upon removing/exchanging the Zn2+. Moreover, again looking at biomolecules, those kind of materials can be regarded as ionophoric carbons as they possess distinct, metal-binding N4-sites embedded in a carbon matrix. Herein, we will focus on the synthesis of zeolitic imidazolate framework (ZIF) based NDCs with high porosity. We will discuss different strategies to remove and/or exchange Zn2+ in the obtained ZnN4-containing materials. Different analytical methods, e.g., physisorption (N2, Ar, CO2), XPS, XAS, and NMR, will be used to understand the alteration of morphological and chemical features upon ion exchange (see Figure 1). Figure 1: A) Schematic illustration of the partial Zn-removal in a ZnN4-containing, ionophoric carbon. B) High resolution N 1s XPS-results of a ZIF-derived ionophoric carbon before and after metal leaching. Due to the ion exchange/removal, the chemistry of the NDCs is altered, however, typically preserving the porosity features as well as the general structure of the N-motifs. Thus, the influence of the occupancy of the N4-sites on the electrochemical performance can be studied in detail. Finally, structure-property-relations of the different ZIF-derived ionophoric NDCs regarding the performance as anodes in sodium ion batteries will be discussed. T2 - Deutsche Zeolith-Tagung 2024 CY - Jena, Germany DA - 28.02.2024 KW - Ionophoric carbon KW - Sodium ion battery KW - PGM-free catalysts PY - 2024 AN - OPUS4-61955 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 - DialySorb und Eigenschaften kommerzieller Zellen N2 - In dem Vortrag wurden zunächst die Eigenschaften erster kommerzieller Natrium-Ionen-Batterien vorgestellt, die an der BAM elektrotechnisch untersucht wurden und auf ihre Bestandteile hin analysiert wurden. Weiterhin wurden die aktuellen Projektergebnisse des BMBF-geförderten Verbundprojekts Dialysorb vorgestellt. T2 - KLiB-Gesprächsrunde zu Natrium-Ionen-Batterien und Festkörperbatterien CY - Frankfurt am Main, Germany DA - 09.07.2024 KW - Natrium-Ionen-Batterien PY - 2024 AN - OPUS4-61942 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Leveraging the Potential of Na-Ion-Batteries with Tailormade Anodes N2 - The concept of sodium-ion-batteries and their expected impact for the energy change is introduced, by explaining differences to lithium-ion-batteries. The challenge as well as the potential may be illustrated on the example of novel carbon anodes.While the general suitability is proven since the recent commercialization, limitations and detailed structure-performance relations remain topic to research. The progress in activities of BAM division 3.6 are illustrated further supporting the future impact of the technology. T2 - TechConnect Adlershof 2024: Sustainable Energy Future CY - Berlin, Germany DA - 09.11.2024 KW - Synthetic Carbon Anodes PY - 2024 AN - OPUS4-61947 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 - Fellinger, Tim-Patrick T1 - Research on Synthetic Anodes for Na-Ion-Batteries N2 - Carbons with an amorphous structure are currently revisited as candidates for Li- and Na-ion batteries. High irreversible capacities (due to SEI formation) were considered an intrinsic problem of such hard carbons, rendering them irrelevant for practical use. Amorphous carbon anodes would present safety-related advantages such as lower heat dissipation throughout lithiation per mol of lithium, mechanical stability throughout cycling and a larger set of optional electrolytes. T2 - Advanced Automotive Battery Conference Europe 2024 CY - Strasbourg, France DA - 13.05.2024 KW - Synthetic Carbon Anodes PY - 2024 AN - OPUS4-61956 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 - 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 - JOUR A1 - Appel, Paul Alexander A1 - Prinz, Carsten A1 - Low, Jian Liang A1 - Asres, Nahom Enkubahri A1 - Wu, Shu-Han A1 - Freytag, Annica A1 - Krug von Nidda, Jonas A1 - de Sousa Amadeu, Nader A1 - Fellinger, Tim-Patrick T1 - Kern–Schale: Versiegelung nanoporöser Partikel mit semipermeablen Kohlenstoffschichten befreit Hartkohlenstoffanoden von ihrem Dilemma N2 - In der vorliegenden Arbeit wird eine Kern-Schale-Strategie vorgestellt, die das grundlegende Problem gängiger nichtgraphitischer Hartkohlenstoff-Anoden adressiert: Hohe reversible Kapazitäten gehen bislang typischerweise mit erheblichen irreversiblen Verlusten in den ersten Zyklen einher. Analog zu Graphit, das sowohl Lithiumspeicherung als auch die Abtrennung von Elektrolytlösungsmitteln in einer homogenen Struktur vereint, zeigen wir, dass sich diese beiden Funktionen auch in nichtgraphitischen Kohlenstoffen gezielt in einer heterogenen Architektur kombinieren lassen. Hochporöse Aktivkohlen werden durch kinetisch kontrollierte Gasphasenabscheidung mit einer dünnen Schicht nichtgraphitischen Kohlenstoffs überzogen, sodass eine funktionale Kern-Schale-Struktur entsteht. Gasadsorptionsmessungen an Kern-, Schalen-, Kern-Schale- und mechanisch beschädigte Kern-Schale-Partikeln, bestätigen, dass die Porosität des Kerns erhalten bleibt und die Schale semipermeabel ist. Die Sorption von Diethylcarbonat wird als geeignetere Methode im Vergleich zu N2- oder CO2-Sorptionsmessungen eingeführt, um die irreversiblen Verluste des ersten Zyklus mit der tatsächlichen Flüssig-Fest-Grenzfläche von Kohlenstoffanoden zu verknüpfen. Die funktionalen Kern-Schale-Partikel zeigen eine stark reduzierte Aufnahme von Diethylcarbonat, was hohe reversible Kapazitäten bei deutlich geringeren Erstzyklusverlusten ermöglicht. Bei einer reversiblen Kapazität von 400 ± 24 mAh g−1 und einer initialen Coulombeffizienz von 82 ± 2% zeigt sich, dass die dreistufige Natriumspeicherung in der gezielt entwickelten Kern-Schale-Architektur den größeren Ionenradius von Natrium gegenüber Lithium (372 mAh g−1 in Graphit) kompensieren kann. Die entwickelten Kern-Schale-Anoden erreichen damit ein Leistungsniveau, das für eine kommerzielle Anwendung vielversprechend ist. KW - Kern-Schale-Struktur KW - Natriumionenbatterie KW - Hartkohlenstoffanode KW - Diethylcarbonatdampfsorption KW - Aktivkohle PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655354 DO - https://doi.org/10.1002/ange.202519457 SN - 1521-3757 N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-65535 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Appel, Paul Alexander A1 - Prinz, Carsten A1 - Low, Jian Liang A1 - Asres, Nahom Enkubahri A1 - Wu, Shu-Han A1 - Freytag, Annica A1 - Krug von Nidda, Jonas A1 - de Sousa Amadeu, Nader A1 - Fellinger, Tim-Patrick T1 - Core‐Shell: Resolving the Dilemma of Hard Carbon Anodes by Sealing Nanoporous Particles With Semi‐Permeable Coatings N2 - A core-shell strategy is introduced to overcome the dilemma of common non-graphitic hard carbon anodes, linking high reversible storage capacity to practically unacceptable irreversible losses in the first cycle(s). Just as Graphite homogeneously combines effective lithium storage with an electrolyte solvent-sieving function, we show that both of these functions could be strategically integrated into non-graphitic carbons in a heterogeneous structure. Highly porous activated carbons are sealed by kinetically tuned gas-phase deposition of non-graphitic carbon to form a functional core-shell structure. Gas sorption porosimetry on core, shell, core–shell, and cracked core-shell particles confirms preserved core porosity and a semi-permeable shell. Diethyl carbonate sorption analysis is introduced as a more suitable probe than N2 or CO2 sorption, linking first-cycle losses to the liquid–solid interface of carbon anodes. The functional core-shell particles with much reduced diethyl carbonate uptake allow for high storage capacity and reduced first cycle losses. Delivering 400 ± 24 mAh g−1 with 82 ± 2% first-cycle reversibility, it is shown that three-stage Na storage in designed core-shell anodes can compensate for the larger size of sodium compared to lithium stored in graphite anodes (372 mAh g−1). The designed core-shell anodes show state-of-the-art performance with commercial promise. KW - Sodium-ion battery KW - Activated carbon KW - Core-shell KW - Hard carbon anode KW - Diethyl carbonate vapor sorption PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655346 DO - https://doi.org/10.1002/anie.202519457 SN - 1433-7851 N1 - Es gibt eine parallele Sprachausgabe (deutsch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (German), a link is in the field related identifier SP - 1 EP - 9 PB - Wiley-VCH CY - Weinheim AN - OPUS4-65534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Batteries: Basics, Challenges and Trends N2 - In this lecture the fundamental principles of batteries are briefly introduced aligned by the historical development of the technology. The introduction is continued with an overview on current challenges regarding performance, durability, sustainability, cost and safety. Lastly, research trend on approaches to tackle the challenges are discussed by selected examples. T2 - 2025 Scientific and Technological Training Course "Design and Evaluation Methods of Fire Safety Engineered Materials" CY - Hefei, China DA - 20.10.2025 KW - Fundamentals of Batteries KW - Safety KW - Active Materials KW - Research Topics PY - 2025 AN - OPUS4-64917 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fellinger, Tim-Patrick T1 - Sicherheit von NIB und das Potenzial synthetischer Kohlenstoff-Anoden N2 - Nach einer kurzen Einleitung zu kommerziellen Natrium-Ionen-Batterien, deren Zusammensetzung und Sicherheitstest die auch an der BAM untersucht wurden, folgt eine Vorstellung der Forschungsarbeiten des Fachbereich 3.6 im Rahmen des Verbundprojekts Dialysorb. Die Forschungsergebnisse stellen u.a. das Potenzial von synthetischen Anodenmaterialien dar. T2 - Deutsches Batterieforum 2025 CY - Berlin, Germany DA - 21.01.2025 KW - Natrium-Ionen-Batterien KW - Zusammensetzung KW - Potenzial KW - Sicherheit KW - Synthetische Anoden PY - 2025 AN - OPUS4-64904 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hickel, Tilmann A1 - Waske, Anja A1 - Tehranchi, Ali A1 - Bhattacharya, Biswajit A1 - Stawski, Tomasz M. A1 - Fellinger, Tim-Patrick A1 - Mehmood, Asad A1 - Witt, Julia A1 - Ozcan, Ozlem A1 - Guilherme Buzanich, Ana A1 - Kumar, Sourabh A1 - Mishra, Rajesh Kumar A1 - Holzer, Marco A1 - Stucchi de Camargo, Andrea Simone A1 - Agudo Jácome, Leonardo A1 - Manzoni, Anna A1 - Fantin, Andrea A1 - John, Elisabeth A1 - Hodoroaba, Vasile-Dan A1 - Bührig, Sophia A1 - Murugan, Jegatheesan A1 - Marschall, Niklas A1 - George, Janine A1 - Darvishi Kamachali, Reza A1 - Maaß, Robert A1 - Emmerling, Franziska T1 - Chemically complex materials enable sustainable high-performance materials N2 - Chemically complex materials (CCMats) 􀀀 including high-entropy alloys, oxides, and related multi-principal element systems 􀀀 offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility. Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and environmental demands. KW - Chemically complex materials KW - Structural stability KW - Functional performance KW - Design strategies KW - Sustainability PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655598 UR - https://www.sciencedirect.com/science/article/pii/S1359028626000033?via%3Dihub DO - https://doi.org/10.1016/j.cossms.2026.101256 SN - 1359-0286 VL - 42 SP - 1 EP - 26 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-65559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dietzmann, Simon A1 - Mehmood, Asad A1 - de Oliveira Guilherme Buzanich, Ana A1 - Emmerling, Franziska A1 - Fellinger, Tim-Patrick A1 - Thomas, A. T1 - Characterization of Solid-State Complexes by XAS N2 - Atomically dispersed metal-nitrogen doped carbons (M-N-C) are promising catalysts for the activation of small molecules such as O2 and CO2. These single atom catalysts (SAC) operate at the interface between homogenous and heterogenous catalysts. Currently, many examples of M-N-C are known with good oxygen reduction reaction activity but lacking a controlled synthesis of the specific active sites of the precatalyst. Recently, our group facilitated the synthesis of pure pyrrolic M-N4 sites using Zn ions as imprinters.[1] These amorphous materials obtained by active site imprinting method are characterized at the BAMline (Bessy II) by X-ray absorption spectroscopy (XAS). In-situ/operando measurements will be crucial in future work for a better understanding of the dynamic changes of the active site. T2 - InSynX Workshop 2023 CY - Sao Paulo, Brazil DA - 06.03.2023 KW - Solid-State Complexes PY - 2023 AN - OPUS4-58933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pedersen, Angus A1 - Zhu, Jinjie A1 - Barrio, Jesús A1 - Parker, Joseph A1 - Hunter, Robert D. A1 - Haigh, Sarah J. A1 - Fellinger, Tim-Patrick A1 - Stephens, Ifan E. L. A1 - Titirici, Maria-Magdalena T1 - Contribution of Mg-templated porosity to activity and durability in Fe–N–C O 2 reduction catalysts N2 - Atomically dispersed Fe in N-doped carbon (Fe–N–C) catalysts are leading platinum-group-metal-free candidates for the O2 reduction reaction in proton exchange membrane fuel cells (PEMFCs). Zeolitic imidazolate framework (ZIF-8) derived Fe–N–C present the most promising performance; however, they possess a narrow distribution of small micropores, which limits active site accessibility. Here, to induce hierarchical porosity in Fe–N–C, we report a systematic study on MgCl2·6H2O-templated ZIF-8-derived Fe–N–C catalysts for the O2 reduction reaction. MgCl2·6H2O addition induced complete Zn removal, collapse of the ZIF-8 framework, and formation of large micro- and mesopores, with graphene-like structures. N content was markedly reduced, with conversion from pyridinic to pyrrolic N species. Rotating disc electrode tests showed a progressive increase in O2 reduction activity with MgCl2·6H2O, which is strongly correlated (R2 = 0.98) to the formation of large micropores and small mesopores (1–4 nm). This introduces an indirect structure–activity design principle for Fe–N–Cs. The enhanced Fe–N–C porosity also leads to increased degradation rates under accelerated stress test conditions, which we attributed to the oxidation of disordered carbon domains and active Fe loss. This study highlights a key trade-off between porosity-driven O2 reduction activity and durability in Fe–N–C catalysts. KW - Porosity KW - Single atom KW - Oxygen reduction PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657549 DO - https://doi.org/10.1039/d5ma01488c SN - 2633-5409 SP - 1 EP - 8 PB - Royal Society of Chemistry (RSC) AN - OPUS4-65754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -