TY - JOUR A1 - Qi, Naiyu A1 - Somaskandan, Rachana A1 - Graeber, Gustav T1 - High-Precision Surface Tension Measurements of Sodium, Potassium, and Their Alloys via Du Noüy Ring Tensiometry N2 - The development of post-lithium-ion batteries has sparked significant interest in alkali-metal anodes, particularly sodium (Na), potassium (K), and sodium−potassium (Na−K) alloys. Na−K alloys are promising for partially liquid anodes due to their unique low melting points. A critical factor influencing Na−K-based anode performance is wetting behavior, which governs electrical conductivity, mechanical contact, and long-term stability. At the heart of wetting lies surface tension, a fundamental property of solid−liquid− gas interactions. However, the surface tension of alkali metals and their alloys, particularly Na−K systems, remains poorly understood due to experimental and theoretical challenges. This study bridged these gaps by employing Du Noüy ring tensiometry for the first time in alkali-metal systems to measure the surface tension of Na, K, and Na−K alloys across temperatures from ambient to 180 °C. A key innovation in this work is the development of the push-in Du Noüy method, which provided significantly higher precision and reliability compared to the traditional pull-out technique, without requiring a correction factor. The measured surface tension decreased with increasing temperature for the studied Na−K alloys. For instance, for a eutectic Na−K mixture, the surface tension decreases from 121.7 mN m−1 to 112.2 mN m−1 when increasing the temperature from ambient to 180 °C. Additionally, this study presented the first use of Gibbs free energy minimization to model the surface tension of the Na−K system. The robust method significantly enhanced the predictive accuracy compared to the previous simplified model, reducing deviations from 25% to 2%. Our findings reveal that surface tension increases with sodium mole fraction in the bulk phase, yet the surface monolayer remains potassium-rich, indicating non-ideal surface behavior. This study deepens the understanding of alkali-metal wetting behavior, providing valuable insights for designing optimized interfaces in next-generation semi-solid alkali-metal batteries. KW - Sodium−potassium alloy KW - Liquid-metal anodes KW - Alkali metal KW - Batteries KW - Surface tension PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630102 DO - https://doi.org/10.1021/acsami.5c02183 SN - 1944-8252 VL - 17 IS - 17 SP - 25985 EP - 25995 PB - American Chemical Society (ACS) CY - Washington, DC AN - OPUS4-63010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Batatia, Ilyes A1 - Benner, Philipp A1 - Chiang, Yuan A1 - Elena, Alin M. A1 - Kovács, Dávid P. A1 - Riebesell, Janosh A1 - Advincula, Xavier R. A1 - Asta, Mark A1 - Avaylon, Matthew A1 - Baldwin, William J. A1 - Berger, Fabian A1 - Bernstein, Noam A1 - Bhowmik, Arghya A1 - Bigi, Filippo A1 - Blau, Samuel M. A1 - Cărare, Vlad A1 - Ceriotti, Michele A1 - Chong, Sanggyu A1 - Darby, James P. A1 - De, Sandip A1 - Della Pia, Flaviano A1 - Deringer, Volker L. A1 - Elijošius, Rokas A1 - El-Machachi, Zakariya A1 - Fako, Edvin A1 - Falcioni, Fabio A1 - Ferrari, Andrea C. A1 - Gardner, John L. A. A1 - Gawkowski, Mikołaj J. A1 - Genreith-Schriever, Annalena A1 - George, Janine A1 - Goodall, Rhys E. A. A1 - Grandel, Jonas A1 - Grey, Clare P. A1 - Grigorev, Petr A1 - Han, Shuang A1 - Handley, Will A1 - Heenen, Hendrik H. A1 - Hermansson, Kersti A1 - Ho, Cheuk Hin A1 - Hofmann, Stephan A1 - Holm, Christian A1 - Jaafar, Jad A1 - Jakob, Konstantin S. A1 - Jung, Hyunwook A1 - Kapil, Venkat A1 - Kaplan, Aaron D. A1 - Karimitari, Nima A1 - Naik, Aakash A. A1 - Csányi, Gábor T1 - A foundation model for atomistic materials chemistry N2 - Atomistic simulations of matter, especially those that leverage first-principles (ab initio) electronic structure theory, provide a microscopic view of the world, underpinning much of our understanding of chemistry and materials science. Over the last decade or so, machine-learned force fields have transformed atomistic modeling by enabling simulations of ab initio quality over unprecedented time and length scales. However, early machine-learning (ML) force fields have largely been limited by (i) the substantial computational and human effort required to develop and validate potentials for each particular system of interest and (ii) a general lack of transferability from one chemical system to the next. Here, we show that it is possible to create a general-purpose atomistic ML model, trained on a public dataset of moderate size, that is capable of running stable molecular dynamics for a wide range of molecules and materials. We demonstrate the power of the MACE-MP-0 model—and its qualitative and at times quantitative accuracy—on a diverse set of problems in the physical sciences, including properties of solids, liquids, gases, chemical reactions, interfaces, and even the dynamics of a small protein. The model can be applied out of the box as a starting or “foundation” model for any atomistic system of interest and, when desired, can be fine-tuned on just a handful of application-specific data points to reach ab initio accuracy. Establishing that a stable force-field model can cover almost all materials changes atomistic modeling in a fundamental way: experienced users obtain reliable results much faster, and beginners face a lower barrier to entry. Foundation models thus represent a step toward democratizing the revolution in atomic-scale modeling that has been brought about by ML force fields. KW - Materials Design KW - Thermal Conducitivity KW - Nanoparticles KW - Batteries PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647829 DO - https://doi.org/10.1063/5.0297006 SN - 0021-9606 VL - 163 IS - 18 SP - 1 EP - 89 PB - AIP Publishing AN - OPUS4-64782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müllner, S. A1 - Held, T. A1 - Tichter, Tim A1 - Rank, P. A1 - Leykam, D. A1 - Jiang, W. A1 - Lunkenbein, T. A1 - Gerdes, T. A1 - Roth, C. T1 - Impact of Functional Groups in Reduced Graphene Oxide Matrices for High Energy Anodes in Lithium-Ion Batteries N2 - Most high capacity anode materials for lithium-ion batteries (LiB) require a carbonaceous matrix. In this context one promising material is reduced graphene oxide (rGO). Herein, we present the influence of different reduction degrees of rGO on its physico-chemical properties, such as crystallinity, specific surface area, electrical conductivity and electrochemical lithiation/delithiation behavior. It is found that a heat treatment under inert and reducing atmospheres increases the long-range order of rGO up to a temperature of 700 °C. At temperatures around 1000 °C, the crystallinity decreases. With decreasing oxygen content, a linear decrease in irreversible capacity during cycle 1 can be observed, along with a significant increase in electrical conductivity. This decrease in irreversible capacity can be observed despite an increase in specific surface area indicating the more significant influence of the oxygen content on the capacity loss. Consequently, the reversible capacity increases continuously up to a carbon content of 84.4 at% due to the thermal reduction. Contrary to expectations, the capacity decreases with further reduction. This can be explained by the loss of functional groups that will be lithiated reversibly, and a simultaneous reduction of long-range order, as concluded from dq/dU analysis in combination with XRD analysis. KW - Batteries KW - Functional Materials KW - Graphene Oxide PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606852 DO - https://doi.org/10.1149/1945-7111/ace70a SN - 0013-4651 VL - 170 IS - 7 SP - 1 EP - 12 PB - The Electrochemical Society AN - OPUS4-60685 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharpmann, Philippa T1 - Tracing overdischarge-induced degradation in lithium-ion cells using cyclic voltammetry and differential voltage analysis N2 - Differential voltage analysis (DVA) and cyclic voltammetry (CV) are powerful electroanalytical techniques. While CV can be used to study the kinetics of electron transfer reactions [1], DVA can visualise phase transitions by correlating the opencircuit voltage and exchanged charge [2]. Recently, DVA receives an increasing attention in the battery community for characterising full-cell setups. In contrast, CV is less prominent for batteries, yet the prevalently used technique for ex-situ characterisations of novel electrode materials in half-cell configuration. In this study, we have investigated the overdischarge process of LiFePO4 pouch cells – which is usually presumed to result in a decomposition of the solid electrolyte interphase (SEI) and a corrosion of the copper current collector – in a complementary electrochemical analysis which uses both, CV and DVA in full-cell mode. For this purpose, CV consisting of three low sweep-rate scans and DVA of three low current rate cycles was performed. Degradation was traced by successive CV/DVA sequences during, pre- and post-overdischarge which allowed to pinpoint the features, the limitations, and similarities of both techniques. In this manner, we demonstrate that CV can successfully identify the dynamics of degradation processes, indicating that an irreversible side reaction starts at cell voltages below 0.55 V. For this reason, this study underlines that CV can be effectively used for spotting dynamic degradation mechanisms which are hardy seen in DVA. This may pave the way for further analysis which can be used for fingerprinting characteristic degradation. T2 - 124. Bunsentagung 2025 CY - Leipzig, Germany DA - 17.03.2025 KW - Differential Voltage Analysis KW - Cyclic Voltammetry KW - Batteries PY - 2025 AN - OPUS4-65055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bäßler, Ralph T1 - Review: Electrochemical Energy Storage ‐ Physics and Chemistry of Batteries N2 - Currently, storage of electric energy is becoming more and more interesting in terms of applicability and efficiency. One way is the electrochemical storage by already well‐developed battery‐systems. This textbook provides an introduction into physical and chemical processes necessary for battery application. This book fulfills its intension to serve graduate students of electrical engineering as an introduction into the field of batteries. Even students and interested readers of other faculties might find an introduction in physical and chemical background of batteries. KW - Batteries PY - 2020 DO - https://doi.org/10.1002/maco.202070124 SN - 1521-4176 SN - 0947-5117 VL - 71 IS - 12 SP - 2084 EP - 2085 PB - WILEY‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-51780 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - The role of Critical Raw Materials in Advanced Materials for the Energy Transition N2 - Based on the UBA report “Advanced materials for energy transition” by Xenia Knigge and Jörg Radnik the role of critical raw materials is discussed. Critical raw materials are needed in main fields of the energy transition, like photovoltaic, fuel cells, wind energy, and batteries. For the optimisation of the use of these materials different scenarios are discussed like (i) decreasing the needed amount of raw materials, (ii) searching for alternatives, (iii) using technologies which do not require critical raw materials, (iv) increasing the recycling rates, and (v) expanding the raw material sources. T2 - IRISS policy dialogue CY - Online meeting DA - 12.01.2026 KW - Solar Cells KW - Fuel cells KW - Batteries KW - Multi-use materials PY - 2026 AN - OPUS4-65451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholl, Juliane T1 - Transformation of fluorinated electrolytes from lithium-ion batteries N2 - Lithium-ion battery (LiB) operation remains challenging, particularly in terms of safety, cycling stability, capacity rates and high-voltage applications. Although the electrolytes of LiBs account for 10-15% of the total battery weight, they are still an underestimated part. Data suggest that the composition of electrolytes offers great potential to deal with all these issues. In particular, fluorinated electrolyte solvents or even fluorinated additives offer several advantages due to the strength of the C-F bond, providing chemical and oxidative stability and increased electronegativity, exhibiting flame retardant properties and facilitating anode-mediated degradation, resulting in a LiF-rich and more stable solid electrolyte interphase (SEI), enabling more efficient surface passivation. Therefore, studies suggest that fluorinated equivalents, as well as entirely new compounds, are promising for solving battery-related problems. But what happens to fluorinated organic compounds (FOCs) during usage? And what are the new potential risks associated with their release into the environment? The environmental and application-specific fate of FOCs is investigated by a selection of different fluorinated electrolytes, the application of various simulation methods, including the TOP (Total Oxidizable Precursor) Assay, electrochemistry, photo-induced degradation, and cycling of FOC-prepared self-assembled coin cells. Gas chromatography and liquid chromatography coupled with high resolution mass spectrometry (GC/LC-HRMS) are used to identify transformation products (TP). T2 - Tag der Chemie 2023 CY - Berlin, Germany DA - 05.07.2023 KW - Transformation products KW - Lithium-ion batteries KW - PFAS KW - TP KW - Batteries PY - 2023 AN - OPUS4-58265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scholl, Juliane T1 - Fate of fluorinated electrolytes used in lithium-ion batteries N2 - The use of per- and polyfluorinated alkyl substances (PFAS), which are very persistent and cannot be completely degraded in the environment, is a well-known problem worldwide. In contrast, fluorinated organic compounds used as electrolytes in lithium-based batteries (LiBs) have been less studied. Despite their increasing use in LiBs due to beneficial properties, such as improving safety, cycling performance, or even enabling high-voltage applications, there is little data on their distribution, transformation, and fate in the environment. To fill this gap, fluorine-containing electrolyte components are studied in oxidative and reductive transformation processes. The identified transformation products (TP) will be determined in relevant environmental matrices and LiBs. T2 - ANAKON 2023 CY - Vienna, Austria DA - 11.04.2023 KW - Transformation products KW - Lithium-ion batteries KW - PFAS KW - TP KW - Batteries PY - 2023 AN - OPUS4-57502 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 - Scholl, Juliane T1 - Degradation and Impact of Fluorinated electrolytes from Lithium-Ion Batteries N2 - Lithium-based batteries (LiBs) have become increasingly important in modern society, as cutting-edge portable energy storage systems and as a crucial component in the energy revolution. However, they still face challenges such as safety concerns, capacity degradation, and the ever-growing demand for higher energy density. To address these issues, researchers have turned their attention to fluorinated organic compounds (FOCs) as part of LiBs electrolytes. These substances, closely related to per- and polyfluorinated alkyl substances (PFAS), have shown great potential in optimizing LiBs. Specifically, their strong fluorine-carbon bond offers enhanced oxidative and chemical resistance. Nevertheless, their environmental impact is a cause for concern. Fluorinated organics can persist in the environment or can lead to the formation of persistent end-products, which accumulate and contribute to global health problems. To study the fate of fluorinated organic electrolytes in different environmental and application scenarios, a range of simulation methods are employed, including the TOP (Total Oxidizable Precursor) Assay, electrochemistry, photo-induced degradation, and cycling of self-assembled coin cells prepared with FOCs. Transformation products (TP) are identified using gas chromatography and liquid chromatography coupled with high resolution mass spectrometry (GC/LC-HRMS). T2 - 23. Norddeutsches Doktorandenkolloquium CY - Berlin, Germany DA - 05.10.2023 KW - Transformation products KW - Lithium-ion batteries KW - PFAS KW - TP KW - Batteries KW - Electrolytes PY - 2023 AN - OPUS4-58511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Battistella, Beatrice T1 - Elemental distribution as a key indicator of manufacturing quality and state of health in lithium and sodium ion batteries N2 - Lithium-Ion Batteries (LIBs) dominate the energy storage market due to their high energy density, lightweight, and substantial power output.[1] Since their manufacture involves the usage of critical materials such as lithium, cobalt and copper, Sodium-Ion Batteries (SIBs) are currently emerging as a more sustainable alternative due to the high availability of sodium and other required raw materials on Earth.[2] These two technologies share similar electrochemical principles and currently find different applications in the global market.[3] While LIBs dominate the portable electric devices and electromotive field, SIBs are becoming relevant for stationary energy storage applications, for which energy density plays a less decisive role. The increasing global demand for LIBs, expected to grow by about 27% annually,[4] raises questions about the fate of the millions of tons of exhausted batteries generated. Considering that battery production gigafactories have a scrap rate of about 30% across the entire production chain,[5] it appears evident that improved manufacturing processes and increased battery lifetime are demanded. To meet these requirements, a deeper understanding of the processes that concur with battery degradation is essential. With the aim of gaining further insight into these aspects, this work focuses on the formation, composition, and degradation of the Solid Electrolyte Interphase (SEI). This complex, heterogeneous passivation layer that forms on the negative electrode is essential for the reversible charging of batteries and the understanding of its formation and degradation is essential for producing batteries with superior performances.[6] To gain insight into these intricate phenomena, the distribution of the main elemental components of SEI in LIBs and SIBs electrodes is investigated. Positive electrodes are self made using lithium- and sodium-layered transition metal oxides as active material, while graphite and hard carbon are used to produce the negative electrodes. After their assembly, the cells are formed and artificially aged under different conditions. Post mortem analysis is performed on freshly formed, early failed, and differently aged cells by lateral profile (Laser-Induced Breakdown Spectroscopy LIBS) and in-depth profile (Glow-Discharge Optical Emission Spectroscopy GD-OES and Mass Spectrometry GD-MS) techniques.[7] We present a new GD-OES analytical method where electrodes are sputtered with a neon/argon mixture. This allows for in-depth profiling of fluorine (IE 17.4 eV) due to the higher ionization energy of neon (IE 21.6 eV) compared to argon (IE 15.8 eV). Qualitative analysis of solvents and electrolytes degradation products is performed by GC-MS. Furthermore, Electrochemical Impedance Spectroscopy analysis (EIS), performed on each cell at different stages of life, facilitates the correlation between internal resistance and degradation process. The pool of experimental data is used as feedstock for Machine Learning (ML) methods. By merging data obtained from multiple sources, ML algorithms can unveil correlations between the data sets and, thus, provide insight into the cell’s chemical/physical deterioration. Furthermore, ML tools are employed to correlate chemical degradation of the cells with their electrochemical features, investigated by non-destructive analysis (EIS). Using the acquired experimental data as training set, this work targets the development of a data-driven approach for battery State of Health (SOH) and Remaining Useful Lifetime (RUL) evaluation based on non-destructive analysis results. The method aims to offer a simple way to establish battery RUL, avoiding time consuming and expensive end of life chemical analysis, which offers remarkable implications to the large-scale battery production.[8] T2 - 247th ECS Meeting CY - Montreal, Canada DA - 18.05.2025 KW - Batteries KW - Data Fusion KW - Diagnostic PY - 2025 AN - OPUS4-63298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tichter, Tim A1 - Böttcher, Nils A1 - Schmidt, Anita A1 - Krug von Nidda, Jonas T1 - Exploring the Low-Temperature Threshold for Reactions in Commercial Lithium-Ion Cells N2 - Low-temperature passivation of lithium-ion batteries (LIBs) can reduce the probability of thermal runaway events [1]. In this context, we explore the thermal threshold at which reactions in commercial Li-cells become feasible. It is found that electrochemical reactions take place even below the first phase transition of the electrolyte. Finally, it is concluded that the passivation temperature for all samples in our study does not require cryogenic conditions which is of great relevance for defining the conditions for a safe transportation. T2 - Advanced Battery Power Konferenz CY - Münster, Germany DA - 10.04.2024 KW - Batteries KW - Thermal passivation KW - Arrhenius-law KW - Cyclic voltammetry KW - Chronoamperometry PY - 2024 AN - OPUS4-62307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -