TY - JOUR
A1 - Gong, Mengjun
A1 - Mehmood, Asad
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Fellinger, Tim-Patrick
A1 - Jackson, Colleen
A1 - Cui, Junyi
A1 - Drazic, Goran
A1 - Kucernak, Anthony
T1 - Designing Co–N/C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC Performance
N2 - Metal-nitrogen/carbon (M-N/C) catalysts, particularly those incorporating Fe,Co, or Mn, are among the most promising non-platinum group catalysts forthe acidic oxygen reduction reaction (ORR) in fuel cells. This study reports aCo-N/C catalyst featuring high (3 wt%) cobalt content exclusively present asatomic sites. Extended X-ray absorption fine structure analysis confirms atetrapyridinic Co-N4 coordination environment in the optimized (3.0)Co-N/C𝚫catalyst. The high cobalt loading leads to a significant density ofelectrochemically accessible active sites, 3.58 × 10 19 sites g−1 , quantified viathe nitrite stripping method. The catalyst demonstrates excellent ORR activityin a rotating ring-disk electrode setup, achieving a half-wave potential (E 1/2 ) of0.76 V at a low loading of 0.2 mg cm−2 and a mass activity of 3.5 A g−1 at 0.80VRHE . Single-cell hydrogen-oxygen PEMFC tests achieve a peak power densityexceeding 1.3 W cm−2 (iR-corrected). Under hydrogen-air condition, thecatalyst delivers 0.54 A cm−2 at 0.60 V (0.39 W cm−2 ). Despite the intrinsicallyhigher turnover frequency of Fe-based sites, the optimized(3.0)Co-N/C𝚫 catalyst achieves similar fuel cell performance to that of Fe-N/C,highlighting the critical role of site density in overall activity.
KW - Fuel cells
KW - Single atom catalysts
KW - Oxygen reduction reaction
KW - Non-precious catalysts
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644276
DO - https://doi.org/10.1002/advs.202516060
SN - 2198-3844
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-64427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - INPR
A1 - Rieck, Arielle
A1 - Low, Jian Liang
A1 - Dietzmann, Simon
A1 - Radnik, Jörg
A1 - Teimouri, Zahra
A1 - Higgins, Drew
A1 - Hodoroaba, Vasile-Dan
A1 - Mehmood, Asad
A1 - Fellinger, Tim-Patrick
T1 - Understanding the Activity Trade-Off between Tetrapyrrolic Fe-NCs and Co-NCs in the Alkaline Oxygen Reduction Reaction
N2 - A water-free ionothermal synthesis of porous magnesium-imprinted nitrogen-doped carbon (Mg–NC) materials is introduced to prepare a platform material to investigate electrocatalytic structure-performance relations. Atomically dispersed Co- and Fe-NCs isomorphic to the pristine Mg-NCs are prepared by ion-exchange reactions. The current Mg-templating strategy enables relatively high pyrolysis product yields of up to 50 wt% and resultant Fe-NC and Co-NC catalysts contain high and comparable active metal loading of up to 2.52 wt% Fe and 2.29 wt% Co, respectively. A combination of X-ray spectroscopies with DFT studies reveals a tetrapyrrolic structure of the coordination sites, originating from a pyrolytic magnesium template ion reaction within the ionothermal synthesis. Two sets of highly active isomorphic tetrapyrrolic Fe-NCs and Co-NCs are utilized to understand the differences in intrinsic electrocatalytic performance of Co-NCs and Fe-NCs towards the alkaline oxygen reduction reaction (ORR). Despite their superior valence electronic properties to facilitate the initial outer-sphere electron transfer to O2, Co-NCs show significantly lower performance than Fe-NC with comparable loading. Although the generally discussed weaker binding of peroxide intermediates to CoN4 sites compared to FeN4 sites is evident, experimental and theoretical investigation reveal that it is the underlying peroxide oxidation activity that suppresses the oxygen reduction activity of M-NCs. The high peroxide oxidation activity of Co-NCs explains their reduced alkaline ORR relative to Fe-NCs, shedding light on the understated significance of controlling peroxide chemistry for the optimizing cathodic performance.
KW - Magnesium Imprinting
KW - Tetrapyrrolic Sites
KW - Metal- and nitrogen-doped carbon (M-N-C)
KW - Oxygen Reduction Reaction (ORR)
KW - Nitrogen doped Carbon
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651487
DO - https://doi.org/10.26434/chemrxiv-2025-s59s5
SP - 1
EP - 24
AN - OPUS4-65148
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Nils
A1 - Sander, Luise
A1 - Ulbricht, Alexander
A1 - Widjaja, Martinus Putra
A1 - Fellinger, Tim-Patrick
A1 - Schmidt, Anita
A1 - Krug von Nidda, Jonas
T1 - Sodium-ion battery research @ BAM (I): investigating the thermal runaway behaviour of commercial sodium-ion battery cells
N2 - Commercially available sodium-ion battery (SIB) cells, with energy densities comparable to lithium-ion battery (LIB) cells based on LiFePO4, were investigated regarding their safety behaviour under thermal abuse conditions. Tests were carried out in an inert atmosphere. The SIB-cells went into thermal runaway (TR), intriguingly, even at a rather low state of charge of 30%. The TR-event was coupled with a pronounced jelly roll ejection, challenging the interpretation of the TR-diagrams. These findings highlight the necessity of incorporating SIB-cells into the ongoing safety classification discussions for LIB-cells.
KW - Sodium Ion Batteries
KW - Thermal Runaway
KW - Battery safety
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647652
DO - https://doi.org/10.1039/d5se00687b
SN - 2398-4902
VL - 9
IS - 21
SP - 5832
EP - 5838
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Basics, Challenges and Trends in Electrochemical Energy Storage
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 - Basics, Challenges and Trends in Electrochemical Energy Storage
CY - Cottbus, Germany
DA - 15.09.2025
KW - Batteries
KW - Electrochemistry
KW - Energy Materials
PY - 2025
AN - OPUS4-64919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Core-shell type carbon anodes for na-ion batteries
N2 - Increasing prices of the material basis for lithium-ion batteries caused by limited production capacities or resource abundance has led to a renewed interest in sodium ion batteries (SIBs). Therein, amorphous disordered carbons such as hard carbons (HCs) 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] while low initial losses are mostly accompanied with moderate capacities.[2] In our research we are aiming at morphologically improved carbons to reduce irreversible losses using a core-shell concept, leading to spacial separation of the reversible storage and unfavorable side reactions.[3]
We investigated different methods to obtain core-shell structures with improved interfaces to restrict SEI formation to the external particle surface, while leveraging the Na storage potential of porous carbon core materials. With a simple and scalable chemical vapour deposition we obtained a 190-fold decrease in surface roughness, resulting in drastically reduced first cycle losses. Interestingly, the sodiation capacity at the same time increased to 400 mAh/g revealing the interference of excessive SEI formation with the storage process within the particles.
T2 - Research Seminar of the Dahn Labs at Dalhousie University
CY - Halifax, Canada
DA - 27.05.2025
KW - Natrium-Ionen-Batterien
KW - Synthetische Anoden
KW - Kohlenstoff
PY - 2025
AN - OPUS4-64912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Commercial State-of-the-Art Sodium-Ion Batteries and Perspectives for the Negative Electrode (Anode)
N2 - The current strong interest in electromotive mobility and the need to transition to an energy grid with sustainable storage devices has led to a renewed interest in sodium ion batteries (SIBs). Chinese battery manufacturers marketed the first cells, which are commercially available now. We have purchased and investigated two of these early cells to understand their composition and be able to compare to the state-of-the-art in the scientific community. According to our results and the current literature, all commercial cells utilize carbon-based anodes, with the characteristic sloping charge-discharge profile. In the presentation the results will be discussed in context with safety aspect and space for improvement. The latter aspect will be focused on hard carbon anodes. Amorphous disordered carbons such as hard carbons (HCs) 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] while low initial losses are accompanied with moderate capacities.[2] In our research we are aiming at morphologically improved carbons to reduce irreversible losses using a core-shell concept.[3, 4]
T2 - Eco-Mat Conference 2025
CY - Istanbul, Türkiye
DA - 29.07.2025
KW - Natrium-Ionen-Batterien
KW - Synthetische Anoden
KW - Kohlenstoff
PY - 2025
AN - OPUS4-64908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Improved Hard Carbon Anodes for Na-ion Batteries by Interface Modification
N2 - The current strong interest in electromotive mobility and the need to transition to an energy grid with sustainable storage devices has led to a renewed interest in sodium ion batteries (SIBs). Amorphous disordered carbons such as hard carbons (HCs) 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] while low initial losses are accompanied with moderate capacities.[2] In our research we are aiming at morphologically improved carbons to reduce irreversible losses using a core-shell concept.[3]
We investigated different methods to obtain core-shell structures with improved interfaces to restrict SEI formation to the external particle surface, while leveraging the Na storage potential of porous carbon core materials. With a simple and scalable chemical vapour deposition we obtained a 190-fold decrease in surface roughness, resulting in drastically reduced first cycle losses. Interestingly, the sodiation capacity at the same time increased revealing the interference of excessive SEI formation with the storage process within the particles.
T2 - ECS Spring Meeting 2025
CY - Montreal, Canada
DA - 18.05.2025
KW - Natrium-Ionen-Batterien
KW - Synthetische Anoden
KW - Kohlenstoff
PY - 2025
AN - OPUS4-64911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Designing Core-Shell Carbon Materials for High-Performance Sodium-Ion Battery Anode
N2 - Increasing prices of the material basis for lithium-ion batteries caused by limited production capacities or resource abundance has led to a renewed interest in sodium ion batteries (SIBs). Therein, amorphous disordered carbons such as hard carbons (HCs) 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] while low initial losses are mostly accompanied with moderate capacities.[2] In our research we are aiming at morphologically improved carbons to reduce irreversible losses using a core-shell concept, leading to spacial separation of the reversible storage and unfavorable side reactions.[3]
We investigated different methods to obtain core-shell structures with improved interfaces to restrict SEI formation to the external particle surface, while leveraging the Na storage potential of porous carbon core materials. With a simple and scalable chemical vapour deposition we obtained a 190-fold decrease in surface roughness, resulting in drastically reduced first cycle losses. Interestingly, the sodiation capacity at the same time increased to 400 mAh/g revealing the interference of excessive SEI formation with the storage process within the particles.
T2 - International Carbon Conference 2025
CY - Saint Malo, France
DA - 29.06.2025
KW - Sodium-Ion-Batteries
KW - Hard Carbons
KW - Synthetic Anodes
KW - Carbon
PY - 2025
AN - OPUS4-64907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Sustainable energy materials and circularity
N2 - Li-ion batteries (LIB) are the dominant energy storage technology and present in electrified transportation, electronic devices as well as robotics. This is due to their high energy density (300 watt-hours per kilogram), low self-discharge (1.5-2% per month), long storage life (10 years) and cyclability (500-2000 cycles). Unfortunately, these batteries require the use of scarce, toxic and unethically resourced materials for their fabrication. Furthermore, it is expected an increase of 26 million units of LIB on electric vehicles by 2030 generating a large amount of waste in a very near future. However, those end-of-life batteries can be considered an important source of metals and materials (electrolytes, binders, anodes) to be reused in other applications or incorporated in the battery supply chain. This also pushes the need to redesign the LIB components and other sustainable technologies using low-cost materials. The focus of this symposium is to bring together experts from around the world to discuss the latest advancements in sustainability of battery technologies and their impact on the future landscape of our society and environment. During the symposium, speakers will present recent research and developments in solving future and present problems derived from the exponential demand of LIB manufacturing
T2 - Mat-Sus Spring Meeting 2025
CY - Sevilla, Spain
DA - 03.03.2025
KW - CRM-free
KW - Sustainability
KW - Energy Materials
PY - 2025
AN - OPUS4-64915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Molekularsiebende Kohlenstoffe als hochkapazitive und stabile Anoden in Natrium-Ionen-Batterien
N2 - In dem Vortrag wird ein Fortschrittsbericht über die laufenden Arbeiten im BMBF-geförderten Verbundprojekt „Dialysorb“ gegeben. Nach einer kurzen Schilderung der Arbeitspaketstruktur und den Arbeitspaketinhalten werden einzelne wissenschaftliche Ergebnisse genannt und kurz diskutiert.
So gelang es hier u.a. hochporöse Materialien mittels Gasphasenabscheidung von Kohlenstoffverbindungen derart zu modifizieren, dass nur noch ein Bruchteil der Porosität mittels Gassorption messbar ist. Elektrochemische Sodiierungs-/Dessodiierungsergebnisse deuten darauf hin, dass die Porosität im Kern der Materialien erhalten ist, da die reversible Sodiierungskapazität deutlich erhöht ist. Abschließend werden folgende Arbeitschritte erläutert und der Vortrag zur Diskussion gestellt.
T2 - BMBF-Statusmeeting B@TS 2025
CY - Cologne, Germany
DA - 07.04.2025
KW - Natrium-Ionen-Batterien
KW - Synthetische Anoden
KW - Kohlenstoff
PY - 2025
AN - OPUS4-64906
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 - Research progress on synthetic hard carbon anodes was suggested as key technology to leverage the potential of sodium ion batteries. The background, progress and market size of sodium ion batteries was presented and the relevance of producing such materials in terms of a business case was suggested.
T2 - HWR Entrepreneural Workshop 2025
CY - Berlin, Germany
DA - 18.10.2025
KW - Natrium-Ionen-Batterien
KW - Synthetische Anoden
KW - Kohlenstoff
PY - 2025
AN - OPUS4-64909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Bioinspired Electrode Materials
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 developed 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. 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. Hierarchical pore systems, like used in nature (leaves, lungs, etc.) facilitate some of the electrochemical performances. Moreover, because of the elements also defining organic matter, also binding motifs can be realized that are reminiscent of proteins/enzymes. We established the pyrolytic template-ion reaction using cations like Mg2+ and Zn2+ to imprint tetrapyrrolic N4 sites (like in the heme molecule), embedded into the carbon structure. The imprinted structure may be utilized as catalytically active site by performing ion-exchange reactions. This way catalytic activity can be tuned for different societal important reactions, but also the defined catalysts structure allows the assignment of structure-performance relations. Other “tricks” that nature uses, are to influence the passage of ions through cell walls, or to expel water molecules from catalytically active sites. I will show some recent work on carbon electrodes used as battery active materials that utilizes similar pathways.
T2 - Kolloquium des Instituts für Anorganische und Allgemeine Chermie der Universität Freiburg
CY - Freiburg, Germany
DA - 04.12.2025
KW - Carbon
KW - M-N-C
KW - Fuel cell
KW - Core-shell
KW - Sodium ion battery
PY - 2025
AN - OPUS4-65021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Design, Structure and Performance of Fe-N-C Catalysts Based on Active-Site Imprinting
N2 - Atomically dispersed M-N-C catalysts such as Fe-N-Cs are most promising alternatives for precious metal-based catalysts for several energy conversion reactions. Early reports on such materials date back to the 1960´s, when Jasinski pioneered the research based on tetrapyrrolic phthalocyanine macrocycles which were inspired by natural transition metal porphyrin complexes present in enzyme active sites. For decades, the selective synthesis of these catalysts was complicated by the formation of side phases due to the harsh reaction conditions facilitating side phase formation. In 2018, we introduced a mild procedure, which is conservative toward the carbon support and leads to atomically dispersed Fe-N4 site formation at temperatures as low as 80 °C in a wet-chemical step, essentially decoupling the preparation of the N-C backbone from the preparation of the active sites. The key concept therein is the so-called active-site imprinting into the N-C backbone using pyrolytic template ion reactions, allowing for high concentrations of N4 sites resulting in more than 3 at.% of Fe in atomically dispersed phase. Using the same precursor that is used for the preparation of phthalocyanines, we were able to produce atomically-dispersed single-site Fe-N-Cs that consist of tetrapyrrolic FeN4 complexes. The tetrapyrrolic Fe-N-C derivatives are highly active and extraordinary selective electrocatalysts for the oxygen reduction reaction. The well-defined and homogeneous active site structure allows to quantify the intrinsic catalytic activity of the materials in acid and base, reveal insights into the electrocatalytic mechanism and to reveal distinct degradation mechanism upon storage and electrochemical cycling. Herein, the general synthetic strategy of active-site imprinted catalysts will be discussed mainly based on both Mg-ion and Zn-ion templating towards “designed” Fe-N-C catalysts. The tetrapyrrolic active sites will be discussed regarding structure, activity, selectivity and durability. This hopefully stimulates a fruitful discussion of the perspectives in the field.
T2 - Chemical Engineering Research Seminar of Higgins Group of McMaster University
CY - Hamilton, Canada
DA - 29.05.2025
KW - Carbon
KW - M-N-C
KW - Electrocatalysis
KW - Fuel cells
PY - 2025
AN - OPUS4-64913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Low, J. L.
A1 - Li, Y.-S.
A1 - Arcon, I.
A1 - Koyutürk, B.
A1 - Wagner, F.
A1 - Ruiz-Zepeda, F.
A1 - Gaberscek, M.
A1 - Paulus, B.
A1 - Fellinger, Tim-Patrick
T1 - Resolving the Dilemma of Fe-N-C Catalysts by the Selective Synthesis of Tetrapyrrolic Active Sites via an Imprinting Strategy
N2 - Combining the abundance and inexpensiveness of their constituent elements with their atomic dispersion, atomically dispersed Fe−N−C catalysts represent the most promising alternative to precious-metal-based materials in proton Exchange membrane (PEM) fuel cells. Due to the high temperatures involved in their synthesis and the sensitivity of Fe ions toward carbothermal reduction, current synthetic methods are intrinsically limited in type and amount of the desired, catalytically active Fe−N4 sites, and high active site densities have been out of reach (dilemma of Fe−N−C catalysts). We herein identify a paradigm change in the synthesis of Fe−N−C catalysts arising from the developments of other M−N−C single-atom catalysts. Supported by DFT calculations we propose fundamental principles for the synthesis of M−N−C materials. We further exploit the proposed principles in a novel synthetic strategy to surpass the dilemma of Fe−N−C catalysts. The selective formation of tetrapyrrolic Zn−N4 sites in a tailor-made Zn−N−C material is utilized as an active-site imprint for the preparation of a corresponding Fe−N−C catalyst.
By successive low- and high-temperature ion exchange reactions, we obtain a phase-pure Fe−N−C catalyst, with a high loading of atomically dispersed Fe (>3 wt %). Moreover, the catalyst is entirely composed of tetrapyrrolic Fe−N4 sites. The density of tetrapyrrolic Fe−N4 sites is more than six times as high as for previously reported tetrapyrrolic single-site Fe−N−C fuel cell catalysts.
KW - Fe-N-C catalyst
KW - Precious-group metal-free catalyst
KW - Tetrapyrrolic active-site
KW - Single-site catalyst
KW - Fuel cell
KW - Carbon materials
PY - 2021
DO - https://doi.org/10.1021/jacs.1c04884
SN - 1520-5126
VL - 143
IS - 43
SP - 18010
EP - 18019
PB - American Chemical Society
AN - OPUS4-53657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Deciphering Structure-Performance Relations of PGM-Free Fe-N-C Electrocatalysts Based on Synthetic Materials Design
N2 - Fe-N-C electrocatalysts are very promising alternatives for precious metal-based catalysts for energy conversion reactions.[1-3] Early reports on such materials date back to the 1960´s, when Jasinski pioneered the research based on tetrapyrrolic phthalocyanine macrocycles which were inspired by natural transition metal porphyrin complexes present in enzyme active sites.[3] For decades, the synthesis of these catalysts with a high iron loading was complicated by the formation of side phases due to the harsh reaction conditions facilitating side phase formation. In 2018, we 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 the N-C backbone from the preparation of the active sites.[4, 5] The key concept therein is the so-called active-site imprinting into the N-C backbone using pyrolytic template ion reactions.[4][5] Using the same precursor that is used for the preparation of phthalocyanines, we were able not only to produce atomically-dispersed single-phase Fe-N-Cs with a high iron loading, but were also able to selectively form tetrapyrrolic Fe-N4 complexes.[6] The tetrapyrrolic Fe-N-C derivatives are highly active and extraordinary selective electrocatalysts for the oxygen reduction reaction. Deconvolution of morphological effects on the performance allowed to quantify the intrinsic catalytic activity of the materials in acidic and alkaline conditions and gives new insights into the reaction mechanism in alkaline.[7, 8] A distinct degradation mechanism upon storage was found for the tetrapyrrolic sites and new insights on degradation upon fuel cell operation could be obtained.[9, 10] Herein, the general synthetic material design strategy for atomically dispersed catalysts will be discussed based on tetrapyrrolic Fe-N-C catalysts, which will be analyzed for their potential as PGM-free fuel cell catalysts.
T2 - Research Seminar of National Institute of Chemical Physics and Biophysics
CY - Tallinn, Estonia
DA - 29.09.2025
KW - Carbon
KW - M-N-C
KW - Electrocatalysis
KW - Fuel cells
PY - 2025
AN - OPUS4-64916
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Negative Electrode Ionophoric Core-Shell Carbon for Sodium-Ion Batteries
N2 - The current strong interest in electromotive mobility and the need to transition to an energy grid with sustainable storage devices has led to a renewed interest in sodium ion batteries (SIBs). Amorphous disordered carbons such as hard carbons (HCs) 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] while low initial losses are accompanied with moderate capacities.[2] In our research we are aiming morphologically and chemically functional carbons. Morphologically, our target is a local separation of reversible sodium storage and irreversible losses in novel synthetic carbon anodes, using a core-shell concept. On chemical side, we aim at ion-binding functional groups.
We investigated different methods to obtain core-shell structures to restrict SEI formation to the external particle surface, while leveraging the Na storage potential of porous carbon core materials. Moreover, we apply active-site imprinting to realise disting ion-binding features into the core carbons. The electrochemical performance of those materials can be rather easily altered upon removing/exchanging the ions bound to the functional group. Herein, we will focus on the synthesis of zeolitic imidazolate framework (ZIF) based NDCs. 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.
T2 - Mat-Sus Spring Meeting 2024
CY - Barcelona, Spain
DA - 04.03.2024
KW - Ionophoric carbon
PY - 2024
AN - OPUS4-61938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fellinger, Tim-Patrick
T1 - Design Structure and Performance of FeNC Catalysts
N2 - Atomically dispersed M-N-C catalysts such as Fe-N-Cs are most promising alternatives for precious metal-based catalysts for energy conversion reactions.[1-3] Early reports on such materials date back to the 1960´s, when Jasinski pioneered the research based on tetrapyrrolic phthalocyanine macrocycles which were inspired by natural transition metal porphyrin complexes present in enzyme active sites.[3] For decades, the selective synthesis of these catalysts was complicated by the formation of side phases due to the harsh reaction conditions facilitating side phase formation. In 2018, we introduced a mild procedure, which is conservative toward the carbon support and leads to atomically dispersed Fe-N4 site formation at temperatures as low as 80 °C in a wet-chemical step, essentially decoupling the preparation of the N-C backbone from the preparation of the active sites.[4, 5] The key concept therein is the so-called active-site imprinting into the N-C backbone using pyrolytic template ion reactions, allowing for high concentrations of N4 sites resulting in more than 3 at.% of Fe in atomically dispersed phase.[4-6] Using the same precursor that is used for the preparation of phthalocyanines, we were able to produce atomically-dispersed single-site Fe-N-Cs that consist of tetrapyrrolic FeN4 complexes.[6] The tetrapyrrolic Fe-N-C derivatives are highly active and extraordinary selective electrocatalysts for the oxygen reduction reaction. The well-defined and homogeneous active site structure allows to quantify the intrinsic catalytic activity of the materials in acid and base,[7, 8] reveal insights into the electrocatalytic mechanism and to reveal distinct degradation mechanism upon storage and electrochemical cycling.[9, 10] Herein, the general synthetic strategy of active-site imprinted catalysts will be discussed mainly based on Zn-ion templating towards tetrapyrrolic Fe-N-C catalysts. The catalytic active sites will be discussed regarding structure, activity, selectivity and durability, hence the potential as fuel cell catalyst.
T2 - ECS Spring Meeting 2025
CY - Montreal, Canada
DA - 18.05.2025
KW - Fuel Cell
KW - ELectrocatalyst
KW - Fe-N-C
KW - Carbon
PY - 2025
AN - OPUS4-64910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koyutürk, B.
A1 - Farber, E.
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
A1 - Eisenberg, D.
T1 - A simple decagram-scale synthesis of an atomically dispersed, hierarchically porous Fe–N–C catalyst for acidic ORR
N2 - Carbons doped with iron and nitrogen (Fe–N–Cs) are highly promising electrocatalysts for energy conversion reactions in the oxygen, nitrogen and carbon cycles. Containing no platinum group metals, they nevertheless compete with platinum-based catalysts in crucial fuel cell reactions, such as oxygen reduction in acid. Yet deployment of Fe–N–Cs in fuel cells requires also a flow-enhancing pore structure, and a scalable synthesis procedure – a rarely-met combination of requirements. We now report such a simple synthesis of over 10 g of an Fe–N–C catalyst with high activity towards oxygen reduction in acid. Atomically-dispersed Fe–N4 active sites were designed orthogonally and simultaneously with hierarchical micro-, meso- and macroporosity, by exploiting a dual role of magnesium ions during pyrolysis. Combining the “active site imprinting” and “self-templating” strategies in a single novel magnesium iminodiacetate precursor yielded a catalyst with high specific surface area (SSA > 1600 m2 g−1), a flow-enhancing hierarchical porosity, and high relative abundance of the most desirable D1-type Fe–N4 sites (43%, by Mössbauer spectroscopy at 4.2 K). Despite the relatively low iron contents, the catalysts feature halfwave potentials up to 0.70 V vs. RHE at pH 1 and a mass activity of 1.22 A g−1 at 0.8 V vs. RHE in RDE experiments. Thanks to the simple and scalable synthesis, this active and stable catalyst may serve as a workhorse in academic and industrial research into atomically-dispersed ORR electrocatalysis.
KW - Catalysis
KW - Fe-N-C catalysts
KW - Fuel Cells
KW - Electrochemistry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550113
DO - https://doi.org/10.1039/d2ta00925k
SN - 2050-7488
SP - 1
EP - 10
PB - Royal Society of Chemistry
AN - OPUS4-55011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Titirici, M.
A1 - Baird, S. G.
A1 - Sparks, T. D.
A1 - Yang, S. M.
A1 - Brandt-Talbot, A.
A1 - Hosseinaei, O.
A1 - Harper, D. P.
A1 - Parker, R. M.
A1 - Vignolini, S.
A1 - Berglund, L. A.
A1 - Li, Y.
A1 - Gao, H.-L.
A1 - Mao, L.-B.
A1 - Yu, S.-H.
A1 - Díez, N.
A1 - Ferrero, G. A.
A1 - Sevilla, M.
A1 - Szilágyi, P. Á.
A1 - Stubbs, C. J.
A1 - Worch, J. C.
A1 - Huang, Y.
A1 - Luscombe, C. K.
A1 - Lee, K.-Y.
A1 - Luo, H.
A1 - Platts, M. J.
A1 - Tiwari, D.
A1 - Kovalevskiy, D.
A1 - Fermin, D. J.
A1 - Au, H.
A1 - Alptekin, H.
A1 - Crespo-Ribadeneyra, M.
A1 - Ting, V. P.
A1 - Fellinger, Tim-Patrick
A1 - Barrio, J.
A1 - Westhead, O.
A1 - Roy, C.
A1 - Stephens, I. E. L.
A1 - Nicolae, S. A.
A1 - Sarma, S. C.
A1 - Oates, R. P.
A1 - Wang, C.-G.
A1 - Li, Z.
A1 - Loh, X. J.
A1 - Myers, R. J.
A1 - Heeren, N.
A1 - Grégoire, A.
A1 - Périssé, C.
A1 - Zhao, X.
A1 - Vodovotz, Y.
A1 - Earley, B.
A1 - Finnveden, G.
A1 - Björklund, A.
A1 - Harper, G. D. J.
A1 - Walton, A.
A1 - Anderson, P. A.
T1 - The sustainable materials roadmap
N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability.
KW - Electrochemistry
KW - Fe-N-C catalysts
KW - Fuel cells
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126
DO - https://doi.org/10.1088/2515-7639/ac4ee5
SN - 2515-7639
VL - 5
IS - 3
SP - 1
EP - 98
PB - IOP Publishing
CY - Bristol
AN - OPUS4-55012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, Davide
A1 - Li, Yan‐Sheng
A1 - Damjanović, Ana Marija
A1 - Proux, Olivier
A1 - Wagner, Friedrich E.
A1 - Fellinger, Tim-Patrick
A1 - Gasteiger, Hubert A.
A1 - Piana, Michele
T1 - On the Stability of an Atomically‐Dispersed Fe−N−C ORR Catalyst: An In Situ XAS Study in a PEMFC
N2 - The stability of Fe−N−C oxygen reduction reaction (ORR) electrocatalysts has been considered a primary challenge for their practical application in proton exchange membrane fuel cells (PEMFCs). While several studies have attempted to reveal the possible degradation mechanism of Fe−N−C ORR catalysts, there are few research results reporting on their stability as well as the possible Fe species formed under different voltages in real PEMFC operation. In this work, we employ in‐situ X‐ray absorption near‐edge structure (XANES) to monitor the active‐site degradation byproducts of an atomically dispersed Fe−N−C ORR catalyst under a H2/O2‐operating PEMFC at 90 % relative humidity and 80 °C. For this, stability tests were carried out at two constant cell voltages, namely 0.4 and at 0.8 V. Even though the ORR activity of the Fe−N−C catalyst decreased significantly and was almost identical at the end of the tests for the two voltages employed, the analysis of the XANES recorded under H2/N2 configuration at 0.6 and 0.9 V within the stability test suggests that two different degradation mechanisms occur. They are demetalation of iron cations followed by their precipitation into Fe oxides upon operation at 0.8 V, versus a chemical carbon oxidation close to the active sites, likely triggered by reactive oxygen species (ROS) originated from the H2O2 formation, during the operation at 0.4 V.
KW - PGM-free catalysts
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638981
DO - https://doi.org/10.1002/celc.202400228
SN - 2196-0216
VL - 11
IS - 18
SP - 1
EP - 16
PB - Wiley VHC-Verlag
AN - OPUS4-63898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rappsilber, Tim
A1 - Yusfi, Nawar
A1 - Krüger, Simone
A1 - Hahn, S.-K.
A1 - Fellinger, Tim-Patrick
A1 - Krug von Nidda, Jonas
A1 - Tschirschwitz, Rico
T1 - Meta-analysis of heat release and smoke gas emission during thermal runaway of lithium-ion batteries
N2 - Herein a meta-analysis of 76 experimental research papers from 2000 to 2021 is given about possible effects on the thermal runaway of lithium-ion battery cells. Data on the hazards of gas emissions and released heat are related to each other and differentiated by cell properties such as, cell geometry, cathode type or state of charge. Quantitative information on the total heat release in the range of 2.0–112.0 kJ Wh−1, the peak heat release rate in the range of 0.006–2.8 kW Wh−1and the smoke gas emission were extracted, normalized in terms of cell energy (Wh), combined in a data library and compared graphically. The total amount of gas emitted (3–48 mmol Wh−1) as well as the released amount of carbon monoxide (1–161 mg Wh−1) and hydrogen fluoride (2–197 mg Wh−1) were investigated as a function of the state of charge and cell geometry. The analysis reveals that the measured values are significantly influenced by the types of calorimeters and smoke gas analyzers used as well as by the type of thermal runaway trigger. This meta-analysis can serve as an important basis for any risk assessment of lithium-ion batteries.
KW - Lithium-ion battery
KW - Thermal runaway
KW - Cathode active material
KW - Heat release
KW - Smoke gas emission
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568071
DO - https://doi.org/10.1016/j.est.2022.106579
SN - 2352-152X
VL - 60
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Low, Jian Liang
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Paulus, B.
A1 - Fellinger, Tim-Patrick
T1 - The Tetrapyrollic Motif in Nitrogen Doped Carbons and M-N-C Electrocatalysts as Active Site in the Outer-Sphere Mechanism of the Alkaline Oxygen Reduction Reaction
N2 - Development and fundamental understanding of precious-group-metal-free electrocatalysts is hampered by limitations in the quantification of the intrinsic activity of different catalytic sites and understanding the different reaction mechanisms. Comparing isomorphic nitrogen-doped carbons, Zn-N-Cs and Fe-N-Cs with the common tetrapyrrolic motif, a catalyst-independent outer-sphere rate-determining step in the alkaline oxygen reduction reaction is observed. Density functional theory (DFT) simulations on tetrapyrrolic model structures indicate the highest occupied molecular orbital (HOMO) level as a good descriptor for the catalytic activity. Contour plots suggest that the electron transfer occurs directly from the tetrapyrrolic coordination site, rather than from the metal center. Metal-free tetrapyrrolic N4 sites are discovered to be highly active oxygen reduction reaction (ORR) active sites in alkaline that reach turnover frequencies (TOF) of 0.33 and 1.84 s−1 at 0.80 and 0.75 VRHE in the order of magnitude of tetrapyrrolic Fe–N4 sites in the acidic ORR. While Zn-coordination lowers the HOMO level and therefore the catalytic activity, Fe-coordination lifts the HOMO level resulting in TOF values of 0.4 and 4 s−1 for tetrapyrrolic Fe–N4 sites at 0.90 and 0.85 VRHE, respectively. At higher mass activities, the peroxide reduction becomes rate-limiting, where highest peroxide production rates are observed for the nitrogen-doped carbon.
KW - Tetrapyrollic
KW - Motif
KW - Nitrogen
KW - Carbons
KW - Alkaline Oxygen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606239
DO - https://doi.org/https://doi.org/10.1002/aenm.202400482
SN - 1614-6832
VL - 2024
SP - 1
EP - 8
PB - Wiley-VCH
AN - OPUS4-60623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, I.
A1 - Rieck, Arielle
A1 - Mehmood, Asad
A1 - Bublitz, R.
A1 - Bongers, L.
A1 - Weuster-Botz, D.
A1 - Fellinger, Tim-Patrick
T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons
N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of −2.4 to −3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however required. Atomically-dispersed M−N−C catalysts show promise, if degradation throughout autoclaving can be omitted. The development of selective and autoclavable catalysts resistant to contamination and electrode design for the complex electrolyte will enable efficient bioelectrocatalytic power-to-X systems based on the introduced BES.
KW - Energy Conversion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594766
DO - https://doi.org/10.1002/celc.202300344
SN - 2196-0216
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, I.
A1 - Rieck, Arielle
A1 - Mehmood, Asad
A1 - Bublitz, R.
A1 - Bongers, L.
A1 - Weuster-Botz, D.
A1 - Fellinger, Tim-Patrick
T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons
N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of 2.4 to 3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however requ
KW - PEM
KW - Stirred-Tank Bioreactor
KW - Clostridium ragsdalei
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615239
UR - http://www.chemelectrochem.org/
DO - https://doi.org/10.1002/celc.202300344
VL - 11
IS - 6
SP - 1
EP - 9
PB - Chemistry Europe and Wiley-VCH GmbH
AN - OPUS4-61523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
T1 - Evaluation of the Specific Activity of MNCs and the Intrinsic Activity of Tetrapyrrolic FeN4 Sites for the Oxygen Reduction Reaction
N2 - M−N−C electrocatalysts are considered pivotal to replace expensive precious group metal-based materials in electrocatalytic conversions. However, their development is hampered by the limited availability of methods for the evaluation of the intrinsic activity of different active sites, like pyrrolic FeN4 sites within Fe−N−Cs. Currently, new synthetic procedures based on active-site imprinting followed by an ion exchange reaction, e.g. Zn-to-Fe, are producing single-site M−N−Cs with outstanding activity. Based on the same replacement principle, we employed a conservative iron extraction to partially remove the Fe ions from the N4 cavities in Fe−N−Cs. Having catalysts with the same morphological properties and Fe ligation that differ solely in Fe content allows for the facile determination of the decrease in density of active sites and their turn-over frequency. In this way, insight into the specific activity of M−N−Cs is obtained and for single-site catalysts the intrinsic activity of the site is accessible. This new approach surpasses limitations of methods that rely on probe molecules and, together with those techniques, offers a novel tool to unfold the complexity of Fe−N−C catalyst and M−N−Cs in general.
KW - Fe-N-C catalysts
KW - M-N-C catalysts
KW - Fuel Cells
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567406
DO - https://doi.org/10.1002/anie.202207089
SN - 1433-7851
VL - 61
IS - 50
SP - 1
EP - 6
PB - Wiley-VHC
AN - OPUS4-56740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Wagner, F. E.
A1 - Fellinger, Tim-Patrick
T1 - Life cycle of single atom catalysts: a Mo¨ssbauer study on degradation and reactivation of tetrapyrrolic Fe–N–C powders
N2 - The degradation of a single-site atomically dispersed, model Fe–N–C powder catalyst with high activity is investigated using cryo-Mössbauer spectroscopy. The results indicate a degradation initiated by an Fe2+ to Fe3+ oxidation due to coordination of oxygen to tetrapyrrolic Fe–N4 sites at atmospheric conditions (change between characteristic doublets) before iron(III) oxide is formed (sextet). Thermal reactivation can be used to restore substantial catalytic activity of aged Fe–N–C powders.
KW - Life cycle
KW - Atom catalysts
KW - Tetrapyrrolic Fe–N–C powders
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586007
DO - https://doi.org/10.1039/d3mh00308f
SN - 2051-6347
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Wagner, F. E.
A1 - Fellinger, Tim-Patrick
T1 - Life cycle of single atom catalysts: a Mössbauer study on degradation and reactivation of tetrapyrrolic Fe–N–C powders
N2 - The degradation of a single-site atomically dispersed, model Fe–N–C powder catalyst with high activity is investigated using cryo-Mössbauer spectroscopy. The results indicate a degradation initiated by an Fe2+ to Fe3+ oxidation due to coordination of oxygen to tetrapyrrolic Fe–N4 sites at atmospheric conditions (change between characteristic doublets) before iron(III) oxide is formed (sextet). Thermal reactivation can be used to restore substantial catalytic activity of aged Fe–N–C powders.
KW - Single atom catalysts
KW - Mössbauer study
KW - Tetrapyrrolic Fe–N–C powders
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589352
DO - https://doi.org/10.1039/d3mh00308f
VL - 10
SP - 5577
EP - 5583
PB - Royal Society of Chemistry
AN - OPUS4-58935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mieller, Björn
A1 - Fellinger, Tim-Patrick
T1 - Berlin Battery Lab - Vom Material zur Zelle - Batterieinnovation aus Berlin
N2 - Das Berlin Battery Lab (BBL) vereint exzellente Materialforschung, modernste Analytik und gezielten Technologietransfer. Als gemeinsames Labor von BAM, HZB und der Humboldt Universität zu Berlin entwickeln wir zukunftsfähige Natrium-Ionen- und Metall-Schwefel-Batterien – von der Materialidee bis zur funktionsfähigen Zelle.
T2 - Batteriaforum Deutschland
CY - Berlin, Germany
DA - 20.01.2026
KW - Batterie
KW - Kooperation
KW - Natrium-Ionen
KW - BBL
PY - 2026
AN - OPUS4-65410
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bates, J. S.
A1 - Martinez, J. J.
A1 - Hall, M. N.
A1 - Al-Omari, A. A.
A1 - Murphy, E.
A1 - Zeng, Y.
A1 - Luo, F.
A1 - Primbs, M.
A1 - Menga, D.
A1 - Bibent, N.
A1 - Sougrati, M. T.
A1 - Wagner, F. E.
A1 - Atanassov, P.
A1 - Wu, G.
A1 - Strasser, P.
A1 - Fellinger, Tim-Patrick
A1 - Jaouen, F.
A1 - Root, T. W.
A1 - Stahl, S. S.
T1 - Chemical Kinetic Method for Active-Site Quantification in Fe-N‑C Catalysts and Correlation with Molecular Probe and Spectroscopic Site-Counting Methods
N2 - Mononuclear Fe ions ligated by nitrogen (FeNx) dispersed on nitrogen-doped carbon (Fe-N-C) serve as active centers for electrocatalytic O2 reduction and thermocatalytic aerobic oxidations. Despite their promise as replacements for precious metals in a variety of practical applications, such as fuel cells, the discovery of new Fe-N-C catalysts has relied primarily on empirical approaches. In this context, the development of quantitative structure−reactivity relationships and benchmarking of catalysts prepared by different synthetic routes and by different laboratories would be facilitated by the broader adoption of methods to quantify atomically dispersed FeNx active centers. In this study, we develop a kinetic probe reaction method that uses the aerobic oxidation of a model hydroquinone substrate to quantify
the density of FeNx centers in Fe-N-C catalysts. The kinetic method is compared with low-temperature Mössbauer spectroscopy, CO pulse chemisorption, and electrochemical reductive stripping of NO derived from NO2 − on a suite of Fe-N-C catalysts prepared by diverse routes and featuring either the exclusive presence of Fe as FeNx sites or the coexistence of aggregated Fe species in addition to FeNx. The FeNx site densities derived from the kinetic method correlate well with those obtained from CO pulse chemisorption and Mössbauer spectroscopy. The broad survey of Fe-N-C materials also reveals the presence of outliers and challenges associated with each site quantification approach. The kinetic method developed here does not require pretreatments that may alter active-site distributions or specialized equipment beyond reaction vessels and standard analytical instrumentation.
KW - Active-Site Quantification
PY - 2023
DO - https://doi.org/10.1021/jacs.3c08790
SP - 1
EP - 16
PB - ACS Publications
AN - OPUS4-58889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krug von Nidda, Jonas
A1 - Fellinger, Tim-Patrick
T1 - Current State of Research of Environmentally Friendly, Alternative Materials - Sodium-Ion-Batteries as an Example
N2 - In order meet the anticipated future need for battery-based energy storage, it is essential to explore alternative systems beyond lithium-ion batteries. Sodium-ion batteries emerge as a promising option due to the abundance of readily available materials and the potential for reduced costs.
T2 - 32. Sitzung Beraterkreis Technologie (BKT)
CY - Cologne, Germany
DA - 19.10.2023
KW - Sodium-ion-batteries
PY - 2023
AN - OPUS4-58886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
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 -