TY - CONF A1 - Pedersen, Angus T1 - Coupling Single Atom Electrocatalysts with a Bioreactor for CO2 to C2+ Conversion N2 - To alleviate CO2 emissions impact on climate change, and close the carbon cycle, converting carbon dioxide into valuable products such as multi-carbon organic chemicals is of great importance. Each approach offers distinct merits but also certain challenges in terms of process efficiency, product selectivity and implementation at scale. Developing coupled CO2 conversion systems, for instance bio-electrochemical reactors, can address some of the challenges.[1] Precious-metal free biocompatible single atoms in N-doped C (M-N-C, where M = Fe, Ni, Co) electrocatalysts, based on Mg active site imprinting of bioinspired MN4 sites,[2][3] have shown state-of-the-art activity and selectivity for conversion of CO2 to CO.[4] Pyrolysis of Mg-N-C is carried out in a salt-melt at high temperatures (≥ 800 oC) and followed by an exchange with stoichiometric amounts of Ni or Co at low temperatures. N2-sorption of the materials reveal a micro-mesoporous structure with high surface areas (> 1000 m2 g-1) and a mass-transport enabling pore system. Extended X-ray absorption fine structure reveal the existence of atomically dispersed single atom active sites with defined active site structure. These catalysts were implemented in a home-made bio-electrocatalytic system (BES) consisting of a bioreactor coupled to a CO2 electrolysis cell.[5] Here, CO2 is first electrochemically converted to CO in the electrolysis cell which is then directly fed to bacteria (Clostridium ragsdalei) in the bioreactor which further metabolize it to valuable carbon compounds, such as acetate. An acetate formation rate of 1.8 mg L-1 h-1 was achieved and an acetate concentration of 0.103 g L-1, corresponding to acetate formation rate of 0.73 mmol d-1. We have successfully demonstrated the validity of a coupled bio-electrocatalytic system operating with resource efficient single atom Co- and Ni-N-C electrocatalysts for CO2 conversion. T2 - Electrifying Organic Synthesis CY - Mülheim an der Ruhr, Germany DA - 03.09.2025 KW - Single atom KW - Electrochemical CO2 conversion KW - Bioelectrolysis PY - 2025 AN - OPUS4-64037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mehmood, Asad T1 - ZIF-derived Atomically Dispersed Non-precious Metal Catalysts (M-N-C) for Electrochemical Energy Applications N2 - Zeolitic imidazolate frameworks (ZIFs) which are a subtype of metal organic frameworks (MOFs) have been extensively used to prepare catalyst materials for a variety of electrochemical reactions for energy conversion and storage applications. Most notable examples of ZIFs used for that purpose include ZIF-8 and ZIF-67 etc. Particularly ZIF-8 with its high surface area, defined pore structure and tunable particle size is widely utilized as a platform material to prepare so-called metal- and nitrogen-doped carbon (M-N-C) catalysts with M= Co, Fe, Ni, Zn etc., which are an emerging class of catalyst materials and consist of nitrogen-doped porous carbon matrix hosting atomically distributed active metal sites.[1, 2] The active sites in M-N-Cs ideally have M-N4 coordination resembling to metal centres in macromolecules such as porphyrins and phthalocyanines.[3] Most representative examples of M-N-Cs include Fe-N-Cs, Co-N-Cs and Ni-N-Cs etc. which are showing promising activities for a variety of electrochemical reactions e.g. oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR) and hydrogen evolution reaction (HER). The structures of M-N-C catalysts are quite complex and require a fine balance between morphological, electronic, and chemical properties to reach optimal electrocatalytic activities. In this talk, I will present our activities on (i) preparation of phase-pure M-N-C catalysts derived from ZIF-8 via active-site imprinting [4, 5] and highlight the benefits of our strategy to achieve high density of active sites and enhanced electrochemical performance levels [6] and (ii) feasibility of using gas physisorption techniques as a new approach to quantify active sites in M-N-Cs. The challenges of maximizing active site utilization and eliminating unfavourable mass-transport characteristics faced by ZIF-8 derived M-N-Cs in electrochemical energy devices e.g. fuel cells will also be briefly discussed. T2 - Materials for Sustainable Development Conference (MAT-SUS) CY - Sevilla, Spain DA - 03.03.20225 KW - Electrochemical energy conversion KW - Single atom catalysts KW - Electrochemical CO2 reduction KW - Fuel cells KW - Electrolyzers PY - 2025 DO - https://doi.org/https://doi.org/10.29363/nanoge.matsusspring.2025.251 AN - OPUS4-62927 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 - Appel, Paul Alexander T1 - Connecting Porosity to Storage Capacity: Core-Shell Carbon Material As High-Capacity Negative Electrodes for Sodium Ion Batteries N2 - Due to abundant raw materials, low costs and promising high reversible specific capacities, hard carbons (HCs) are a common choice for commercially manufactured anodes in sodium-ion batteries (SIBs). Despite their potential and extensive use, the storage mechanism is still under debate. The non-stoichiometric adsorption mechanism also means that the search for an upper limit for the reversible capacity is ongoing. There is a strong requirement for synthetic anodes that enable a better understanding of the theoretical capacity associated with HC-anodes. We have developed core-shell carbon anodes consisting of a highly porous carbon core and (almost) non-porous shell. Thus, the reversible capacity can be deconvoluted from irreversible capacity losses, arising from the formation of the solid electrolyte interphase (SEI). Moreover, the porosity of the carbon-core can be linked to the reversible capacities gained. A range of microporous activated carbons were coated via an optimized chemical vapour deposition technique.[1][2] These materials were characterised using a range of techniques including powder x-ray diffraction, small angle x-ray diffraction (SAXS), gas physisorption (N2, CO2) measurements and electrochemical characterisation at coin cell level. After coating, the material showed a significant reduction in detectable surface area (up to a factor of 192x) by N2-physisorption. The tailor-made shell allows the stable cycling of a carbon anode vs metallic Na-electrode in coin cells at room temperature. For the best performing material, the reversible capacity increased from 139 ± 2 mAhg-1 to 396 ± 2 mAhg-1 while irreversible capacity is decreased from 636 ± 3 mAhg-1 to 89 ± 3 mAhg-1 (see Figure 1). After initial stabilization, a CE of 99% was achieved. The coating technique was usefully applied to a range of materials. [3] The successful formation of core-shell structures with high capacities enables separation of the storage mechanism from SEI-formation. In turn a proposed calculation to rank the contributions of surface adsorption and pore filling capacity can be confirmed. The materials also create the opportunity to conduct a range of operando experiments (e.g., SAXS) that can shed further light on the sodium storage mechanism. T2 - ECS Montreal 2025 CY - Montreal, Canada DA - 18.05.2025 KW - Electrochemical Energy Materials KW - Negative Electrodes KW - Sodium Ion Batteries PY - 2025 AN - OPUS4-65115 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 - CONF A1 - Pauw, Paul T1 - Designing Core-Shell Carbon Structures as High- Capacity Negative Electrodes for Sodium Ion Batteries N2 - Due to abundant raw materials, low costs and promising high reversible specific capacities, hard carbons (HCs) are a common choice for commercially manufactured anodes in sodium-ion batteries (SIBs). Despite their potential and extensive use, the storage mechanism is still under debate. The non-stoichiometric adsorption mechanism also means that the search for an upper limit for the reversible capacity is ongoing. There is a strong requirement for synthetic anodes that enable a better understanding of the theoretical capacity associated with HC-anodes. We have developed core-shell carbon anodes consisting of a highly porous carbon core and (almost) non-porous shell. Thus, the reversible capacity can be deconvoluted from irreversible capacity losses, arising from the formation of the solid electrolyte interphase (SEI). Moreover, the porosity of the carbon-core can be linked to the reversible capacities gained. A range of microporous activated carbons were coated via an optimized chemical vapour deposition technique.[1][2] These materials were characterised using a range of techniques including powder x-ray diffraction, small angle x-ray diffraction (SAXS), gas physisorption (N2, CO2) measurements and electrochemical characterisation at coin cell level. After coating, the material showed a significant reduction in detectable surface area (up to a factor of 192x) by N2-physisorption. The tailor-made shell allows the stable cycling of a carbon anode vs metallic Na-electrode in coin cells at room temperature. For the best performing material, the reversible capacity increased from 139 ± 2 mAhg-1 to 396 ± 2 mAhg-1 while irreversible capacity is decreased from 636 ± 3 mAhg-1 to 89 ± 3 mAhg-1 (see Figure 1). After initial stabilization, a CE of 99% was achieved. The coating technique was usefully applied to a range of materials. [3] The successful formation of core-shell structures with high capacities enables separation of the storage mechanism from SEI-formation. In turn a proposed calculation to rank the contributions of surface adsorption and pore filling capacity can be confirmed. The materials also create the opportunity to conduct a range of operando experiments (e.g., SAXS) that can shed further light on the sodium storage mechanism. T2 - MatSUS Conference Sevilla CY - Sevilla, Spain DA - 03.03.2025 KW - Electrochemical Energy Materials KW - Negative Electrodes KW - Sodium Ion Batteries PY - 2025 AN - OPUS4-65113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Low, Jian Liang T1 - Elucidating the Intrinsic CO2RR performance at MN4 sites using Morphologically Comparable M-N-Cs N2 - Metal- and nitrogen-doped carbons (M-N-Cs) are a promising class of low-cost electrocatalysts derived from earth-abundant elements for various electrochemical applications including ORR and CO2RR [1,2]. Traditionally, M-N-Cs containing active metals (M = Fe, Co, and Ni) are synthesized through direct pyrolysis of inorganic and organic precursors. However, this process often leads to the undesired formation of inorganic side phases via carbothermal reduction, hindering both the efficient incorporation of active metal and the intrinsic activity comparison among active sites. To overcome these challenges, we developed an active-site imprinting strategy where active metals are introduced post-pyrolysis through ion-exchange [3-5]. In this work, we applied a Mg imprinting strategy to synthesize Co-N-Cs and Ni-N-Cs with comparable morphology and metal dopant concentrations, enabling a more direct comparison of their intrinsic activities. Notably, Ni-N-Cs produced via this method consistently demonstrated superior activity and selectivity compared to isomorphic Co-N-Cs, achieving CO Faraday efficiencies of up to 95% at relatively low overpotentials. Furthermore, the Ni-N-C catalyst exhibited excellent stability at -0.65 VRHE, retaining 92.5% of its current density and 97.6% of its CO selectivity after 100 hours of continuous operation. A distinct advantage of the imprinting strategy lies in the suppression of inorganic side phases, enabling an accurate local structure characterization of the porphyrin-like tetrapyrrolic MN4 coordination structure using Extended X-ray Absorption Fine Structure (EXAFS). The characterization of the tetrapyrrolic NiN4 site is especially puzzling, as density functional theory (DFT) simulations often predict these sites to be inert to both CO2RR and HER. Drawing on recent studies which highlight the crucial role of cations for CO2RR on noble metal catalysts like Cu, Ag and Au [6-7], we performed mechanistic investigations using DFT to extend the relevance of cations to the CO2RR/HER performance at the MN4 sites, and further illustrate the advantage of the pyrrolic N atoms in anchoring them near the active metals. T2 - 4th Conference of the GDCh Division of Chemistry and Energy CY - Duisburg, Germany DA - 09.04.2025 KW - Electrochemical CO2 reduction KW - Active-site imprinting KW - Metal- and Nitrogen-doped Carbon (M-N-C) KW - Single Atom Catalyst PY - 2025 AN - OPUS4-65145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Low, Jian Liang T1 - Mg-based Imprinting for Assessing Intrinsic Behavior of Co/Ni-N4 sites towards CO2RR N2 - Metal-and nitrogen-doped carbons (MN-Cs) represent a promising class of low cost electrocatalysts derived from nature-abundant elements for various electrochemical processes including CO 2 RR [1, 2]. Traditionally, MN-Cs containing active metals (M= Fe, Co, Ni) are synthesized by direct pyrolysis of inorganic and organic precursors, a process that often results in the undesired formation of inorganic side phases through carbothermal reduction, impeding the effective integration of active metals like Fe, Co and Ni. Furthermore, comparing the intrinsic activities of different MN-Cs can be complicated due to variations in catalyst morphology and active site concentration that arise during the pyrolysis. To address these challenges, we developed an active-site imprinting strategy in which active metals are introduced post-pyrolysis via ion-exchange [3-5]. In this work, we employed the Mg imprinting strategy to produce Co-N-Cs and Ni-N-Cs with comparable morphology and metal dopant concentration. Our approach allows for a more direct comparison of the intrinsic activities that arise from the metal dopant. The Ni-N-Cs derived this way are consistently higher in activity and selectivity than the corresponding Co-N-Cs, exhibiting a CO Faraday efficiency of up to 95% at potentials between-0.5 to-0.8 V RHE. The Ni-NC catalyst maintains high stability at-0.65 V RHE, with 92.5% retention of current density and 97.6% retention of CO selectivity after 100 hours of continuous operation. T2 - The Materials for Sustainable Development Conference (MATSUS) Spring Meeting 2025 CY - Seville, Spain DA - 03.03.2025 KW - Electrochemical CO2 reduction KW - Active-site imprinting KW - Metal- and Nitrogen-doped Carbon (M-N-C) KW - Single Atom Catalyst PY - 2025 AN - OPUS4-65144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Okeke, Joseph T1 - In situ and operando imaging, spectroscopy and tomography of batteries N2 - The development of more powerful and more efficient lithium-ion batteries (LIBs) is a key area in battery research, aiming to support the ever-increasing demand for energy storage systems. To better understand the causes and mechanisms of degradation, and thus the diminishing cycling performance and lifetime often observed in LIBs, in operando techniques are essential, because battery chemistry can be monitored non-invasively, in real time. Moreover, there is increasing interest in developing new battery chemistries. Beyond LIBs, sodium ion batteries (NIBs) have gained increasing interest in recent years, as they are a promising candidate to complement LIBs, owing to their improved sustainability and lower cost, while still maintaining high energy density.[1] Initial phases of NIB commercialisation have occurred in the past year. However, for the widespread commercialisation of NIBs, there are still challenges that need to be overcome in developing optimized electrode materials and electrolytes. For the development of such materials and greater understanding of sodium storage mechanisms, solid electrolyte interface (SEI) formation and stability, and degradation processes, in operando methodologies are crucial. Among the techniques available for in operando analysis, nuclear magnetic resonance spectroscopy (NMR) and imaging (MRI) are becoming increasingly used to characterize the chemical composition of battery materials, study the growth and distribution of dendrites, and investigate battery storage and degradation mechanisms. In situ and in operando 1H, 7Li and 23Na NMR and MRI have recently been used to study LIBs and NIBs, identifying chemical changes in Li and Na species respectively, in metallic, quasimetallic and electrolytic environment as well as directly and indirectly studying dendrite formation in both systems.[2-4] The ability of NMR and MRI to probe battery systems across multiple environments can further be complemented by the enhanced spatial resolution of micro-computed X-ray tomography (μ-CT) which can provide insight into battery material microstructure and defect distribution. Here, we report in operando 1H and 7Li NMR and MRI experiments that investigate LIB performance, and the identification of changes in the Li signal during charge cycling, as well as the observation of signals in both 1H and 7Li NMR spectra that we attribute to diminishing battery performance, capacity loss and degradation. Additionally, recent operando methodology are adapted and implemented to study Sn based anodes in NIBs. 23Na spectroscopy is performed to monitor the formation and evolution of peaks assigned to stages of Na insertion into Sn, while 1H MRI is used to indirectly visualize the volume expansion of Sn anodes during charge cycling. Battery operation and degradation is further explored in these NIBs, using μ-CT, where the anode is directly visualized to a higher resolution and the loss of electrolyte in the cell, during cycling is observed T2 - 17th International Conference on Magnetic Resonance Microscopy CY - Singapore DA - 27.08.2023 KW - Sodium ion battery KW - Lithium ion battery KW - NMR KW - MRI KW - Tomography PY - 2023 AN - OPUS4-58421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sterr, Andrea A1 - Schwarz, Irina T1 - Valorization of Carbon Dioxide by Electrocatalytic Reduction Coupled to Acetogens via Multiple Electron Carriers (Ecat-Acetogens II) N2 - A Bioelectrochemical approach for reducing CO2 to fuels or value-added chemicals allows overcoming the limitations of a pure biochemical or electrochemical approach. A Bioelectrochemical system (BES) for this application has been developed in cooperation with TUM in the first project phase. BAM's contribution to the research focuses on the electrochemical side of the setup, mainly on the development of a suitable CO2RR catalyst for reducing CO2 to CO, which is then consumed by actogenic bacteria to produce further products. Single-metal-atom catalysts in a nitrogen-doped carbon matrix (M-N-Cs) are a promising, sustainable alternative to expensive rare-metal catalysts like Ag and Au. In this work, the first-generation catalyst, a ZIF-8-based Co-N-C is compared to a Mg salt mix templated Ni-N-C. In the new catalysts, the activity for CO2RR as well as the stability during BES operation could be enhanced. T2 - E-Biocat Statusupdate 2025 CY - Karlsruhe, Germany DA - 01.04.2025 KW - CO2RR KW - M-N-Cs KW - Bioelectrochemical System PY - 2025 AN - OPUS4-65143 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -