TY - CONF A1 - Bäßler, Ralph T1 - Wechselwirkungen in Geothermieanlagen - nicht nur ein Beständigkeitsaspekt N2 - Um Konstrukteuren und Nutzern geothermischer Anlagen grundlegende Informationen über die Korrosionsbeständigkeit zur Verfügung zu stellen, wurden verschiedene metallische Werkstoffe, darunter nichtrostende Duplex- und austenitische Stähle sowie eine Nickellegierung, in künstlichen Geothermalwässern bewertet, die die Bedingungen an verschiedenen Standorten mit geothermischem Potenzial simulieren. Mit Hilfe von elektrochemischen und Langzeittests wurde die Eignung verschiedener metallener Werkstoffe mittels kritischer Potentiale und Korrosionsraten untersucht. In hochsalinaren Umgebungen erwies sich Spaltkorrosion als der entscheidende Mechanismus. Die Nickelbasislegierung zeigt eine ausgezeichnete Beständigkeit gegenüber Lochkorrosion. Abgesehen von ihren hohen Kosten eignet sie sich sehr gut für den Bau von Geothermieanlagen mit stark salzhaltigen Fluiden. Rostfreie Stähle und Duplexstähle weisen eine begrenzte Korrosionsbeständigkeit gegen Loch- und Spaltkorrosion auf. Daher sind sie für stark salzhaltige Fluide nicht geeignet. Der Superaustenit zeigt ein temperaturabhängiges Verhalten. In nichtsalinaren Umgebungen könnten niedrig legierte Stähle (neben den höher legierten Werkstoffen) als Konstruktionsmaterial für Geothermieanlagen eingesetzt werden, sofern eine ausreichende Wandstärke des Materials berücksichtigt wird. Neben Korrosionsaspekten erwies sich auch die Ausfällung von Fluidbestandteilen als interessantes Thema. Beim Betrieb der Forschungsanlage in Groß Schönebeck wurden Kupfer- und Bleieffekte im Bohrloch festgestellt. Die auftretenden Mechanismen und Maßnahmen zur Verhinderung von Ausfällungen und Abscheidungen wurden ebenso untersucht, wie deren mögliche Einflüsse auf die Korrosionsbeständigkeit metallener Werkstoffe für Anlagenkomponenten. Der Vortrag beschreibt die Wechselwirkungen zwischen Geothermalwässern und Ausrüstungs-komponenten. T2 - Geothermiekongress 2024 CY - Potsdam, Germany DA - 22.10.2024 KW - Örtliche Korrosion KW - Edelstahl KW - Geothermie KW - Ni-Legierung KW - Abscheidung PY - 2024 AN - OPUS4-61441 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - You, Zengchao A1 - Hoffmann, V. A1 - Morcillo, Dalia A1 - Agudo Jácome, Leonardo A1 - Leonhardt, Robert A1 - Winckelmann, Alexander A1 - Richter, Silke A1 - Recknagel, Sebastian A1 - Abad Andrade, Carlos Enrique T1 - Investigation of aluminum current collector degradation in lithium-ion batteries using glow discharge optical emission spectrometry N2 - In this work, we employed glow discharge optical emission spectrometry (GD-OES) depth profiling as a fast and semi-quantitative method to investigate the aluminum (Al) current collector degradation in commercial lithium cobalt oxide (LCO) pouch cells with no Al2O3 pretreatment. After battery aging, a heterogeneous deposit was found on the surface of the cathode. Gray hotspot areas within an extensive pale white region were formed. Consistent with energy dispersive X-ray (EDX) analysis of micro-cross sections milled via targeted focused ion beam (FIB), an Al-containing layer of approximately 3 µm can be observed using GD-OES. We attribute one main cause of this layer is the degradation of the Al current collector. The nonuniform growth of this layer was investigated by performing GD-OES depth profiling at different in-plane positions. We found that the gray area has a higher mass concentration of Al, probably in metallic form, whereas the white area was probably covered more homogeneously with Al2O3, resulting from the inhomogeneous distribution of the pitting positions on the current collector. Compared to FIB-EDX, GD-OES enables a faster and more convenient depth profile analysis, which allows the more productive characterization of lithium-ion batteries (LIBs), and consequently benefits the development of preferable battery materials. KW - GD-OES KW - depth profiles KW - Li-ion battery KW - battery aging mechanism KW - current collector corrosion PY - 2023 DO - https://doi.org/10.1016/j.sab.2023.106681 SN - 0584-8547 VL - 205 SP - 106681 PB - Elsevier B.V. CY - Amsterdam, Netherlands AN - OPUS4-57383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Duffner, Eric A1 - el Dsoki, Chalid A1 - John, Sebastian A1 - Schmidt, Anita A1 - Mair, Georg W. A1 - Loechner, Derek A1 - Drousch, Björn T1 - Sicherheitstechnische Bewertung thermischer Betriebsbelastung auf sicherheitskritische Ausrüstung am Beispiel von Composite-Atemluftflaschen und Lithiumbatterien N2 - Ziel des Vorhabens war es, den Einfluss der realen Temperaturbelastung auf Atemschutzflaschen und Lithiumbatterien in Funkgeräten (FG) im Löscheinsatz von Rettungskräften zu ermitteln und deren Auswirkung auf die Alterung und Lebensdauer sowie die potenziellen Gesundheitsgefahren bei deren Nutzung besser beurteilen zu können und Handlungshilfen abzuleiten. Im Rahmen dieses Vorhabens wurden zum einen unterschiedlich thermisch gealterte Composite-Atemluftflaschen systematisch hinsichtlich ihrer Restfestigkeiten untersucht. Zum anderen wurden Lithiumbatterien aus FG hinsichtlich der Einwirkung von kritischen Temperaturen untersucht, ab denen es zu einem thermischen Durchgehen der Batterien kommen kann. Für diese beiden wichtigen Komponenten, Lithiumbatterien und Composite-Atemluftflaschen, wurden kritische Temperatur-Zeit-Profile ermittelt, die Auswirkungen durch geeignete Methodiken untersucht und die sich ergebenden Gefährdungen für den Träger bewertet. Als Methodische Vorgehensweise wurden durch Realversuche die tatsächlichen und zuvor durch Literatur-recherche ermittelten Temperaturprofile verifiziert und auf deren Grundlage die Laborbelastungen abgeleitet. Um den Eigenschaften der aus Faserverbundwerkstoffen hergestellten Composite-Atemluftflaschen Rechnung zu tragen, wurden an zwei repräsentativen Baumustern unterschiedlicher Hersteller Stichprobengruppen unterschiedlicher thermischer Belastung ausgesetzt und hinsichtlich ihrer verbleibenden Restfestigkeitsabnahme geprüft und mit thermisch unbelasteten Baumustern verglichen. Neben den statischen Berstversuchen wurden auch kombinierte Alterungs- und Restfestigkeitsuntersuchungen an zyklisch belasteten Behältern durchgeführt. Die FG wurden thermisch sowohl statischen als auch zyklischen Belastungen ausgesetzt und mit Kapazitätsmessungen begleitet. Die statischen Versuche dienten dem Zweck, die maximale thermische Belastbarkeit der Akkus zu ermitteln, bei der noch kein Versagen auftritt. Bei den zyklischen Versuchen wurde der Temperaturverlauf bei Löscheinsätzen so nah wie möglich im Labor nachgestellt. Hierbei wurden die Akkus wiederholt einem Belastungsprofil mit konstanter Temperatur ausgesetzt und nach einigen Intervallen die Restkapazitäten am Akku gemessen und so die Degradation bestimmt. Als Fazit der im Rahmen dieses Vorhabens durchgeführten Untersuchungen an zwei repräsentativen Baumustern von Atemschutzflaschen kann gefolgert werden, dass die thermischen Belastungen abhängig vom Baumuster einen z.T. deutlichen Einfluss auf die Restfestigkeiten der Atemschutzflaschen haben. Höhere thermische Exposition ist, zumindest an den untersuchten Atemschutzflaschen, deutlich zu erkennen und die Flaschen können durch die zuständigen Gerätewarte leicht ausgesondert und ersetzt werden. Die thermischen Belastungen, wie sie im Rettungseinsatz auftreten, waren für die untersuchten Atemschutzflaschen und die Rettungskräfte nicht kritisch sind. Die langjährige Erfahrung etablierter Hersteller dürfte hier aber nicht ohne Einfluss sein. Es ist somit kein Grund erkennbar, von der Verwendung der leichteren Typ 4 Atemschutzflaschen abzuraten, wenn Atemschutzflaschen, die visuell erkennbare thermische Einwirkungen (Farbänderungen, Materialschmelzungen o.ä.) aufweisen, unmittelbar ersetzt werden. Die Ergebnisse an den FG zeigen, dass trotz hoher Temperaturen keine Selbstentzündung der Lithiumbatterien ausgelöst wird. Der Kapazitätsverlust der Batterien infolge der Belastung führt ebenfalls nicht zu einem Funktionsausfall. Es konnte gezeigt werden, dass die Kapazitätsbestimmung als zuverlässiges und geeignetes Kriterium für die Sicherheitsbewertung der Akkus herangezogen werden kann, wenn die Kapazitätsmessung bei gleichbleibenden Bedingungen (gleiche Raumtemperaturen, gleiche Messgeräte, etc.) stattfindet. Es wird empfohlen, die Akkus ab einer Restkapazität von unter 80% zu tauschen. Als schnelle und sehr einfache Überprüfung kann eine Sichtprüfung an den FG stattfinden. Die im Projekt verwendeten FG zeigten eine Verformung der Kunststoffhülle bei zu hohen Belastungen. N2 - The aim of the project was to determine the influence of the real temperature load on breathing apparatus cylinders and Lithium batteries in radio devices in firefighting operations by rescue services and to be able to better assess their effect on ageing and service life time as well as the potential health hazards and to derive guidelines for action. As part of this project, composite breathing air cylinders that had undergone different thermal ageing processes were systematically analysed with regard to their residual strength. as a second use case, lithium batteries used in radio devices were analysed with regard to the effect of critical temperatures above which thermal runaway of the batteries can occur. Critical temperature-time profiles were determined for these two important components, lithium batteries and composite breathing air cylinders, the effects for the user were analysed using suitable methods and the resulting hazards for the wearer were assessed. As a methodical approach, the actual temperature profiles previously determined by literature research were first verified in real tests and the laboratory loads were derived on this basis. In order to take into account the properties of composite breathing air cylinders made of fibre composites, sample groups were subjected to different thermal loads and examined with regard to their residual strength reduction and in comparison to thermally unloaded samples from two representative samples from different manufacturers. In addition to the static burst tests, combined ageing and residual strength tests were also carried out on cyclic loaded cylinders. The radio devices were subjected to both static and cyclic thermal loads with accompanying capacity measurements. The purpose of the static tests was to determine the maximum thermal load capacity of the batteries at which no failure occurs. In the cyclic tests, practical conditions were simulated as closely as possible in the laboratory. For this purpose, the batteries were repeatedly subjected to a load profile at a constant temperature and the residual capacity of the battery was measured after several intervals to determine the degradation. As a conclusion of the tests carried out on two representative types of breathing apparatus cylinders as part of this project, it can be concluded that the thermal loads have a sometimes significant influence on the residual strength of the breathing apparatus cylinders, depending on the type. Higher thermal exposure is clearly recognizable, at least on the breathing apparatus cylinders tested, and the cylinders can be easily remove and replaced by the responsible equipment maintainers. The thermal loads that occur during rescue operations were not critical for the tested breathing protection cylinders and the rescue teams. However, the many years of experience of established manufacturers should not be without influence here. There is therefore no reason to advise against the use of the lighter Type 4 breathing protection breathing apparatus cylinders if cylinders with visually recognizable thermal effects (color changes, material melting, etc.) are replaced immediately. The results on the radio devices showed that determination of the capacity can serve as a suitable criterion for the safety assessment for the batteries. The loss of capacity of the batteries as a result of the load also does not lead to a functional failure. The capacity determination can be used as a reliable and suitable criterion for the safety assessment of the batteries if the capacity measurement is carried out under constant conditions (same room temperatures, same measuring devices, etc.). It is recommended to replace the batteries when the remaining capacity is below 80%. A visual inspection of the radio devices can be carried out as a quick and very simple check. The radio devices used in the project showed deformation of the plastic casing when subjected to excessive loads. KW - Composite KW - Atemluftflaschen KW - Litiumbatterien KW - Funkgeräte KW - Thermische Belastung KW - Rettungskräfte KW - Feuerwehr KW - PSA KW - DGUV PY - 2024 UR - https://www.dguv.de/ifa/forschung/projektverzeichnis/ff-fp0462.jsp N1 - Abschlussbericht zum Vorhaben mit der Projekt-Nr. FF-FP 0462 (CoLiBri), Laufzeit 01.03.2021–29.02.2024, Bericht vom 15.04.2024 SP - 1 EP - 66 PB - Deutsche Gesetzliche Unfallversicherung (DGUV) CY - Berlin AN - OPUS4-59877 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Naumann, Kathrin A1 - Tichter, Tim A1 - Nielsen, Rasmus S. A1 - Seger, Brian A1 - Hansen, Ole A1 - Chorkendorff, Ib A1 - Vesborg, Peter C. K. T1 - Protection Materials on III–V Semiconductors for Photoelectrochemical CO Reduction N2 - Tantalum oxide (TaOx) and amorphous titanium dioxide (TiO2) are employed as protection materials for commercial GaInP/GaAs/Ge triple-junction solar cells to facilitate the unbiased photoelectrochemical reduction of carbon monoxide on nanostructured copper particles. It has been found that a photoelectrode protected by a 150 nm-thick layer of TiO2, capped with 8 nm TaOx, and decorated with copper nanocubes in the size of 150 nm can successfully drive the photoelectrochemical conversion of carbon monoxide to ethylene. Implemented into a photoelectrochemical flow reactor, which continuously supplies the active interface with CO-saturated electrolyte, the device achieves a faradaic efficiency of 24% under AM1.5G conditions. Direct attachment of the copper nanocubes to a protection layer of TiO2 in the absence of TaOx results in a strong hydrogen evolution reaction (HER) and no CO reduction products are found. This unexpected loss in selectivity is studied via post-operando X-ray photoemission spectroscopy and ion-scattering spectroscopy. No modifications in the redox state of TiO2 orsigns of H intercalation are found, while the preferential redeposition of small Cu nanoparticles is considered possible. This increasein HER appears specific for TiO2, as additional, purely electroanalytical experiments using tantalum oxide or carbon as a support layer for Cu nanocubes can produce ethylene effectively. KW - Photoelectrochemistry KW - Carbon Monoxide Reduction KW - Protection Material KW - Multi‐junction KW - Copper Catalyst PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618712 DO - https://doi.org/10.1021/acs.jpcc.4c04782 SP - 1 EP - 10 PB - American Chemical Society (ACS) AN - OPUS4-61871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prenner, Stefanie A1 - Part, Florian A1 - Jandric, Aleksander A1 - Bordes, Arnaud A1 - Leonhardt, Robert A1 - Jung-Waclik, Sabine A1 - Huber-Humer, Marion ED - Djebali, Ridha T1 - Enabling Circular Business Models: Preconditions and Key Performance Indicators for the Market Launch of Repurposed Second‐Life Lithium‐Ion Batteries From Electric Vehicles N2 - With the rise of electric vehicles (EVs) and thus lithium‐ion batteries (LIBs), the number of end‐of‐life (EoL) LIBs after their first life in EVs is about to increase significantly. These end‐of‐first‐life (EoFL) EV LIBs still have sufficient energy density for less‐demanding second‐life applications like stationary battery energy storage systems (BESSs) or mobile applications (e.g., forklifts, tools). Repurposing EoFL EV LIBs extends their lifespan, offering sustainability benefits and supporting several United Nations (UN) Sustainable Development Goals (SDGs). However, prevailing market entry barriers, such as high repurposing costs, little information on battery history and aging, or lacking performance indicators, hinder the widespread implementation of second‐life applications. Thus, this study aims to identify preconditions for considering and selecting useful EoFL LIBs and to determine key performance indicators (KPIs) to minimize economic risks for a successful second‐life market launch. KPIs were rated according to importance using a Likert scale, and reference values were introduced. A mixed‐methods approach, using expert interviews, an exploratory workshop, and an online survey, was applied. Twelve important preconditions were identified, with the “availability of information on battery specification” and “compliance with standards and regulations” considered very important. In addition, 12 KPIs were derived, covering six economic, three environmental, and three technical and safety‐related indicators. The KPIs “state of safety (SoS)” and “resource savings (Rsav)” were rated as highly important. Overall, the findings provide performance measurement guidance for repurposing companies, facilitating the market launch and adoption of second‐life applications. Future research can build on these results and investigate variations among different battery types, ultimately promoting a circular economy. KW - Lithium-Ion battery KW - Key performance indicators KW - Circular economy KW - Electric vehicle KW - Sustainability PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-619167 DO - https://doi.org/10.1155/er/8331870 SP - 1 EP - 19 PB - Wiley AN - OPUS4-61916 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Rechtliche Grundlagen und Entwicklungen im Bereich des Transports von Lithiumbatterien N2 - Als zuständige Behörde im Bereich des Transports von Lithiumbatterien und Ressortforschungsanstalt ist die BAM sowohl an der Rechtsfortentwicklung beteiligt als auch an der hierfür benötigten Forschung. Aktuelle Themen, Forschungsprojekte und deren Ergebnisse werden vorgestellt. T2 - 1. Fachkonferenz Transport von Lithiumbatterien CY - Munich, Germany DA - 12.07.2024 KW - LIthiumbatterien PY - 2024 AN - OPUS4-62329 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Transport von defekten Lithiumbatterien: Umsetzungspraxis der neuen Rechtsvorschriften, Wo besteht Forschungsbedarf? N2 - Transport von defekten Lithiumbatterien - die BAM setzt die Vorschriften des internationalen Gefahrguttransportrechts für defekte Lithiumbatterien um. Um die Kompetenz hierfür sicherzustellen, bedarf es eigener Forschungstätigkeit. Auch im zuständigen UN Gremium werden Untersuchungen durchgeführt, an denen die BAM beteiligt ist. T2 - Fachkonferenz Lithiumbatterien CY - Göttingen, Germany DA - 22.01.2020 KW - Lithiumbatterien KW - Gefahrguttransport KW - ADR PY - 2020 AN - OPUS4-50806 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prenner, Stefanie A1 - Part, Florian A1 - Jung-Waclik, Sabine A1 - Bordes, Arnaud A1 - Leonhardt, Robert A1 - Jandric, Aleksander A1 - Schmidt, Anita A1 - Huber-Humer, Marion T1 - Barriers and framework conditions for the market entry of second-life lithium-ion batteries from electric vehicles N2 - Transition to circular economy for lithium-ion batteries used in electric vehicles requires integrating multiple stages of the value cycle. However, strategies aimed at extending the lifetime of batteries are not yet sufficiently considered within the European battery industry, particularly regarding repurposing. Using second-life lithium-ion batteries (SLBs) before subsequent recycling can offer several advantages, such as the development of sustainable business models, the reduction of emissions, and alignment with UN Sustainable Development Goals 7, 12, and 13. Using expert and problem-centred interviews along with an exploratory workshop, this study guides stakeholders in the battery sector by illustrating the necessary changes for a more holistic circular economy. Moreover, an extended political, economic, social, technological, environmental, legal, and additionally safety-related (PESSTEL) analysis approach is carried out, which has not yet been used in this context. In this process, barriers, as well as necessary institutional framework conditions and organisational requirements for a successful market entry of SLB applications are investigated. Among others, key barriers relate to the competition with first-life applications and safety concerns. SLBs require high manual labour costs for repurposing, along with expenses for expired warranties and re-certifications. Ownership structures in traditional business models often result in SLBs and their corresponding usage data staying under the control of the manufacturers. Market viability, however, requires a level playing field for both first-life and second-life operators as well as circular battery and data-sharing business models. Gathering data on the ageing performance and performing improved safety testing according to test protocols facilitates the reliable assessment of SLBs. KW - Electric vehicle KW - Circular economy KW - Market entry barrier KW - Repurposing KW - Second-life lithium-ion battery KW - Second-life battery energy storage system PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614543 DO - https://doi.org/10.1016/j.heliyon.2024.e37423 VL - 10 IS - 18 SP - 1 EP - 15 PB - Elsevier Ltd. AN - OPUS4-61454 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 - JOUR A1 - Caianiello, Carlo A1 - Tichter, Tim A1 - Arenas, Luis F. A1 - Wilhelm, René T1 - Toward Symmetric Organic Aqueous Flow Batteries: Triarylamine‐Based Bipolar Molecules and Their Characterization via an Extended Koutecký–Levich Analysis N2 - Symmetric organic flow batteries (SOFBs) can potentially address membrane crossover problems by employing bipolar redox‐active organic molecules (BROMs). Herein, a triarylamine (TAA) skeleton was chosen as a posolyte moiety for a new class of bipolar molecules for pH‐neutral aqueous flow batteries (FBs). Pyridinium and viologen derivatives were tethered to the posolyte moiety, and the new compounds were characterized. Cyclic voltammetry revealed that only viologen with a highly hydrophilic substituent, connected to the TAA moiety via a Zincke reaction, could be reversibly reduced. Varying the supporting electrolyte concentration on the selected derivative revealed water solubility as a challenge for further development. The selected derivative, MeO‐TPA‐Vi‐DMAE, was subjected to hydrodynamic voltammetry, and a modified Koutecký–Levich analysis was developed to investigate the observed potential‐dependent currents at the hydrodynamically dominated region, which are often seen with redox‐active organic molecules. This model discarded a purely Ohmic effect, showing a useful Levich slope at a certain overpotential before the onset of a secondary reaction. TAA‐based BROMs hold promise for pH‐neutral aqueous SOFBs, and the results will guide the design of new derivatives. The three‐term Koutecký–Levich relation here introduced will be useful not only to develop BROM‐based FBs but will most likely appeal to a much broader audience. KW - Redox Flow Batteries KW - Koutecký-Levich Analysis KW - Rotating Disc Electrode KW - Redox-active Bipolar Molecules KW - Electrode Kinetics PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631476 DO - https://doi.org/10.1002/chem.202500815 SN - 1521-3765 SP - 1 EP - 15 PB - Wiley VHC-Verlag AN - OPUS4-63147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Umgang mit defekten Lithiumbatterien - Transport und Lagerung N2 - Während es umfangreiche Transportvorschriften für Lithiumbatterien und auch defekte Lithiumbatterien gibt, gibt es aktuell keine Lagervorschriften. Jedoch sind hier einige Aktivitäten und Ansätze zu verzeichnen, die ebenfalls vorgestellt werden. Ein Schwerpunkt liegt dabei auf e-bike Akkus. T2 - VdS-Fachtagung "Lithium-Batterien: Brand- und Arbeitsschutz" CY - Collogne, Germany DA - 17.09.21 KW - Lithium Batterien KW - Transport KW - Lagerung KW - E-bike Akkus PY - 2021 AN - OPUS4-54180 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tichter, Tim T1 - Thermal Investigations on Battery Safety N2 - The transportation and storage of lithium-ion batteries (LIB) — damaged or in an undefined state — is a major safety concern for regulatory institutions. Damaged LIBs pose the risk of a so-called thermal runaway (TR), a strongly exothermic reaction with the formation of gases, flames or even an explosion of the battery. The relevance of this issue is underlined by the number of fires that have occurred at recycling centers in the recent past. One solution to circumvent a TR is given by thermal passivation (i.e. deep-freezing) of batteries. Practically, this method is already used and temperatures below -60 °C are considered safe. In this talk, the parameter battery safety is revisited under the premise of heat-transfer and activation energies. At first, mechanically initiated TRs are compared for different cell chemistries, cell sizes, and temperatures, revealing that the threshold of thermal passivation is vastly system specific. Combining these results with differential scanning calorimetry underlines that the hazard potential of a battery is not necessarily eliminated by freezing the electrolyte. Instead, the potential for a TR needs to be regarded as a multivariant function of energy content, cell-voltage, chemical stability, and electrokinetic performance. Since the latter parameter is known to be vastly temperature-dependent, it is addressed in detail by a low-temperature electrokinetic study of different types of LIB. In this context, it is demonstrated that batteries are kinetically active even at temperatures well below the freezing point of the electrolyte and that their instantaneous power output is resembled sufficiently via Arrhenius´ law. To get a detailed understanding of cell-specific heat release during and prior to a TR, data from accelerated rate calorimetry will be discussed for various cell types at different state of charge and state of health. This will eventually provide a conclusive picture how a cell-internal TR-propagation takes place and which parameters need to be deliberately tuned under the premise of battery safety. T2 - 26. Kalorimetrietge CY - Leipzig, Germany DA - 11.06.2025 KW - Thermal passivation of batteries KW - Critically defective batteries KW - Differential scanning calorimetry KW - High-speed nail penetration KW - Accelerated rate calorimetry PY - 2025 AN - OPUS4-65058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tichter, Tim T1 - Analytical solutions for the impedance of symmetrically distributed relaxation processes N2 - Distribution of relaxation times (DRT) analysis of impedance data is a powerful tool for unravelling entangled relaxation processes. However, reconstructing the DRT function from experimental data is an ill-posed inversion problem which suffers from noisy input and, hence, assigns a pseudo-signal to any kind of noise. To circumvent the resulting overfitting, different methods have been proposed, which are usually based on regularization. Alternatively, carefully selected distributed basis functions (e.g. Gauss-type, Cauchy-type, Matern-type) can be included in the algorithm of DRT reconstruction. This concept originates from the work of Cuicci and coworkers and has been implemented in their great software package DRT-tools. While this works exceptionally well for minimizing the demand on regularization, it must be kept in mind that the impedance of real-world relaxation processes of the constant phase element type is not represented by any of the resulting DRT functions. Bridging this gap was therefore the motivation for the present study. We derived analytical solutions for the impedance of several different types of distribution functions. The resulting impedances are compared with classical relaxation models and special features are pinpointed. The choice of an optimized basis function for reconstructing the DRT from experimentally acquired impedance data will improve electrochemical analysis in future work. Additionally, analytical solutions may be used for assigning a physical origin to the distributed behaviour in the impedance of certain types of electrodes. T2 - Bunsentagung CY - Leipzig, Germany DA - 17.03.2025 KW - Electrochemical Impedance Spectroscopy KW - Distribution of Relaxation Times KW - Cauchy Distribution KW - Gaussian Distribution KW - Cole-Cole Relaxation PY - 2025 AN - OPUS4-62894 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 - JOUR A1 - Tichter, Tim A1 - Tichter, Alex A1 - Andrae, Dirk A1 - Roth, Christina T1 - Simulating cyclic voltammetry at rough electrodes by the digital-simulation–deconvolution–convolution algorithm N2 - The influence of electrode roughness on diffusional cyclic voltammetry (CV) is investigated from a theoretical perspective. For this purpose, the digital-simulation–deconvolution–convolution (DSDC) algorithm, initially developed for the simulation of CV at porous electrodes, is subjected to three substantial modifications. First, by employing adaptive numerical resolution and sample volumina, the computational demand of the digital simulation (DS) step is reduced significantly. Second, by modifying the Douglas–Gunn algorithm of the DS-step to operate on an arbitrarily incremented spatial grid perpendicular to the macroscopically planar electrode surface, the bulk of the fluid can be treated with an exponentially increasing spatial discretization which uses computational power even more efficiently. The third modification is an optimization of the computationally demanding deconvolution step which is used to extract the mass-transfer function from the data computed in the DS-step. This, initially recursive procedure, is replaced by a three-step sequence consisting of (I) a numerical Laplace transformation (NLT) on an exponentially expanding time-grid, (II) a Laplace-domain integration (LDI) and finally (III) a numerical inversion of Laplace transformation (NILT) using the Gaver–Stehfest (GS) inversion formula. Based on this novel strategy for CV simulation, the effects of electrode roughness are thoroughly investigated. It is demonstrated that for an ideally reversible reaction the effects of electrode roughness on the CV response are insignificant at common experimental timescales. In contrast, for scenarios with electrochemically quasi-reversible (or irreversible) kinetics, the apparent rate constants are allegedly upscaled by the area ratio 𝜓 = 𝐴rough∕𝐴planar . This manifests in a lower peak-to-peak separation without a distortion of the shape of the voltammetric profile. This behavior is finally explained in a quantitative manner in terms of convolution-sums and mass-transfer functions which ultimately puts the parameter electrode roughness into the semianalytical framework of convolutive modeling. KW - Rough electrodes KW - Electrode kinetics and Peak-to-Peak separation KW - Vanadium redox-flow batteries KW - Convolutive modeling KW - Digital-simulation KW - Numerical inversion of Laplace transformation KW - Gaver–Stehfest inversion formula PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614620 DO - https://doi.org/10.1016/j.electacta.2024.145175 VL - 508 SP - 1 EP - 17 PB - Elsevier B.V. AN - OPUS4-61462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharpmann, Philippa T1 - Exploring the effects of accelerated ageing on lithium- and sodium-ion cells N2 - Lithium-iron-phosphate (LFP) and sodium-ion batteries (SIBs) offer safe and cost-effective options for energy storage. In this study, the effects of continuous electrical stress, including high current loads and overdischarge, during cyclic ageing are investigated by tracing capacity loss and Coulombic efficiency during cycling of both cell types. Additionally, differential voltage analysis of pseudo open-circuit voltage discharges is utilised for degradation mode analysis. The results show that electrical stress accelerates degradation in both LFPs and SIBs, with high current rates potentially triggering plating or even cell failure in SIBs. Overdischarging primarily intensifies ageing by promoting accelerated solid electrolyte interphase growth. T2 - Doktorandenseminar der Technischen Universität Berlin CY - Berlin, Germany DA - 29.09.2025 KW - Lithium-ion -batteries KW - Sodium-ion-batteries KW - Electrical stress KW - Differential voltage analysis KW - Plating PY - 2025 AN - OPUS4-65057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scharpmann, Philippa T1 - Electrochemical characterisation of degradation mechanisms in lithium- and sodium-ion batteries during overdischarge N2 - Lithium-iron-phosphate (LFP) and sodium-ion batteries (SIBs) are promising technologies for energy storage systems due to their safe handling and cost-effectiveness. SIBs can be discharged to 0V without the safety concerns associated with lithium-ion batteries' copper current collector oxidation. However, overdischarging both types of batteries may decompose and subsequently rebuild the solid electrolyte interphase (SEI), leading to irreversible capacity loss and degradation. This study performs an in-situ analysis of the overdischarge process of LiFePO4 pouch and Na-ion cylindrical cells. Therefore, the cells are characterised for three low C-rate constant current or three slow-scan voltage cycles. While the voltage range of the manufacturer’s specifications is chosen for the first and third cycle, for the second cycle the minimum voltage is modified to 0.5V (LFP) and 0V (SIB), respectively. This enables tracing the degradation during the overdischarge, as well as through a comparison of the results pre- and post-overdischarging. For this purpose, the study employs two electrochemical characterisation techniques: differential voltage analysis (DVA) and cyclic voltammetry (CV). While cyclic voltammetry allows for the study of the kinetics of electron transfers [1], DVA enables the assessment of lithium distribution homogeneity and capacity degradation [2]. In both cells, the characterisation shows significant differences before and after overdischarging, indicating lasting changes through the decomposition and rebuilding of the SEI. This comparative study elucidates the overdischarge-induced degradation in sodium- and lithium-ion batteries, highlighting the utility of CV and DVA in analysing degradation mechanisms. T2 - Advanced Battery Power CY - Aachen, Germany DA - 02.04.2025 KW - Battery degradation KW - Overdischarge KW - Solid electrolyte interphase PY - 2025 AN - OPUS4-65056 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Lithiumbatterien - Transport und Sicherheit N2 - Regularien und Anforderungen (zum Transport) von Lithiumbatterien. T2 - 6. Photovoltaik-Betriebs- und Sicherheitstagung CY - Berlin, Germany DA - 24.11.2022 KW - Lithiumbatterien KW - Regularien KW - Energiespeicher KW - Transport PY - 2022 AN - OPUS4-56744 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Neue Regeln - Klassifizierungsregeln: Was tut sich auf UN-Ebene? - TRGS 520: Es tut sich etwas auf nationaler Ebene N2 - Die Entwicklungen der Regelwerke auf nationaler und internationaler Ebene werden vorgestellt. Die BAM ist hier beteiligt und trägt mit zahlreichen Versuchsergebnissen bei, die hier erläutert werden. T2 - Fachkonferenz Lithiumbatterien CY - Göttingen, Germany DA - 23.01.2023 KW - Lithiumbatterien KW - Prüfung KW - Regelwerksentwicklung PY - 2023 AN - OPUS4-59275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmidt, Anita T1 - Safety in transport of Li-ion batteries N2 - Safety in transport is the pre-requisite for bringing Lithium-ion batteries on the market. In order to consider the different types and degree of hazards, UN has set out to define a new classification system based on testing. BAM has participated in the test rounds and presents here the results. T2 - Technical Workshop on Advanced Materials Challenges and Standardisation Needs for Net Zero Technologies (AMCSNZT-2023) CY - New Delhi, India DA - 09.10.2023 KW - Lithium-ion batteries KW - Propagation testing KW - Safety PY - 2023 AN - OPUS4-59274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -