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 - Geisler, J. T1 - The Influence of Interface Modification on Gassing of Sodium Ion Battery Anodes N2 - This flash talk will briefly introduce the DEMS method[3,4] and highlight a recent piece of our research from the DIALYSORB project. Fitting to the main topic of the conference, interfaces, we will present and the measurement technique to understand the side reactions occurring at this interface and recent data on anode materials with designed interface and interphase. T2 - Humboldt Universität zu Berlin CY - Berlin, Germany DA - 17.09.2024 KW - Gasing of Sodium KW - Ion Battery KW - Anodes PY - 2024 AN - OPUS4-60811 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 - Krug von Nidda, Jonas T1 - Separating Initial Loss from Storage Capacity: Core-Shell Materials as Advanced Anode Materials for Sodium Ion Batteries N2 - The current imperative to shift towards an energy grid equipped with sustainable energy storage solutions has caused a renewed interest in sodium-ion batteries (SIBs). Hard carbons (HCs) are a promising option high-capacity anode materials in SIBs. Nevertheless, their elevated capacities frequently come at the cost of experiencing substantial non-reversible initial capacity losses Commonly, significant losses are associated with irreversible reactions, such as the creation of the solid electrolyte interphase (SEI), that occur during the initial sodium insertion in HC-materials. Intriguingly, high values of irreversible capacity are often found for samples with experimentally determined low specific surface area.[1] A more comprehensive understanding of the structure-property relations is essential for quantifying and grasping the potential of hard carbon materials in sodium-ion batteries (SIBs). Thus, the objective is to employ analytical methods to establish a link between the structure and the electrochemical attributes of HC materials. This has been a challenge, partly due to the non-stoichiometric nature of the sodium storage mechanism and the disordered structure of HCs. To address the challenges mentioned above, our approach is to explore whether a core-shell structure can separate sodium storage and SEI-formation. This way, we can investigate and fine-tune storage capacity and irreversible losses, independently. The strategy involves the synthesis of various porous carbon structures to serve as the core material and their combination with sodium-conductive structures to core-shell materials. Herein, we will present different synthesis routes towards tailor-made carbon core materials. Moreover, different coatings concepts will be introduced, and the electrochemical performance of the core and core-shell materials compared. To elucidate the storage mechanism, the results of advanced analytical methods such as operando NMR and -SAXS will be presented. Generally, these core-shell anodes promise to enable high capacities accompanied with low irreversible losses due to optimized SEI-formation. T2 - Advanced Battery Power Conference 2024 CY - Münster, Germany DA - 10.04.2024 KW - Battery KW - Anode KW - Hard Carbon PY - 2024 AN - OPUS4-61968 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 - Dietzmann, Simon T1 - Synthesis of Atomically Dispersed Electrocatalyst by Imprinting with Different Template Ions throughout Carbonization 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. T2 - GDCh Electrochemistry 2022 CY - Berlin, Germany DA - 27.09.2022 KW - Elechtrochemistry KW - Oxygen reduction reaction KW - Porous carbons PY - 2022 AN - OPUS4-61982 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Appel, Paul Alexander T1 - Developing Tailor-Made Core-Shell Carbon Anode Materials for 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 - ECS Gothenburg CY - Gothenburg, Sweden DA - 08.10.2023 KW - Energy Materials PY - 2023 AN - OPUS4-62003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Appel, Paul Alexander T1 - Development of tailormade core-shell hard carbon materials as anode materials 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 synthesize carbon materials using different zeolite templates to obtain electrode materials that feature a defined and adjustable pore structure. A better understanding of the structure-property relationship by investigating porosity-tailored anode materials, should enable quantification and understanding of the potential of hard carbon materials for SIBs. Furthermore, a goal is to explore whether a core-shell structure can separate sodium storage and solid electrolyte interphase formation allowing the independent investigation of storage capacity and irreversible losses. T T2 - 34. Deutsche Zeolith-Tagung CY - Vienna, Austria DA - 21.02.2023 KW - Energy Materials PY - 2023 AN - OPUS4-62002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Shu-Han T1 - Synthetic Carbon Anodes for SIBs N2 - Hard carbon (HC) is currently one of the most promising anode materials for sodium-ion batteries (SIBs). However, the Na storage mechanism remains controversial, leaving the theoretical limits carbon anodes unclear. To deconvolute the specific capacity from irreversible capacity losses resulting from the formation of solid electrolyte interphase (SEI), core-shell carbon materials with tailored pore structure and defined surface functionalities are synthesized. Meanwhile, these synthetic designer carbons could achieve more competitive capacities for use as better anodes for SIBs. T2 - Adlershofer Forschungsforum (AFF) CY - Berlin, Germany DA - 11.11.2024 KW - Na-ion Battery PY - 2024 AN - OPUS4-61998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Shu-Han T1 - Mole sieving, artificial cathode electrolyte interphase enables stable cycling of room temperature sodium sulfur cells N2 - Porous carbon particles derived from zeolitic imidazolate framework (ZIF-8) were used as a matrix to improve the electrode conductivity and buffer the volume change of sulfur (S). In addition, the porous carbon particles were coated with an additional ion-sieving tailor-made covalent organic framework (COF) shell, which can be regarded as an artificial cathode electrolyte interphase (CEI). The introduced shell can avoid polysulfides from dissolving in the ether-based electrolyte, thus, preventing the shuttling of polysulfides. The as-synthesized sulfur-infiltrated core-shell cathode delivers a reversible capacity of 975 mAh gS–1 (@C/33) and a reasonable rate capability. T2 - 5th International Sodium Battery Symposium, SBS-5 CY - Berlin, Germany DA - 23.09.2024 KW - NaS Battery PY - 2024 AN - OPUS4-61992 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 - Dietzmann, Simon T1 - X-Ray Absorption Spectroscopy to Reveal the „Molecular“ Structure of Metal and Nitrogen doped Carbon Electrocatalysts N2 - High-performance electrocatalysts and sodium-ion (Na+) storage materials for Na-ion batteries anodes are required for energy conversion and storage systems. Metal and nitrogen enriched carbons (M-N-Cs) are promising candidates as they are conductive and can be tuned to the desired properties by appropriate modification. Structural characterization is essential to understand and optimize the active sites at the pseudo-molecular level and the storage of Na+ in the anode T2 - Bessy User Meeting CY - Berlin, Germany DA - 11.12.2024 KW - Single-atom-catalyst KW - Electrochemistry KW - Porous carbons PY - 2024 AN - OPUS4-62074 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 -