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- Lithium (6)
- Corrosion fatigue (3)
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- Laser-induced periodic surface structures (LIPSS) (3)
- Lithium Batterien (3)
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- 1 Analytische Chemie; Referenzmaterialien (18)
- 6 Materialchemie (10)
- 8 Zerstörungsfreie Prüfung (10)
- 1.1 Anorganische Spurenanalytik (9)
- 3 Gefahrgutumschließungen; Energiespeicher (9)
- 3.1 Sicherheit von Gefahrgutverpackungen und Batterien (8)
- 8.5 Röntgenbildgebung (7)
- 1.4 Prozessanalytik (6)
- 1.6 Anorganische Referenzmaterialien (6)
- 5 Werkstofftechnik (6)
Eingeladener Vortrag
- nein (16)
Lithium exists in two stable isotopes, 6Li and 7Li. The ratio of these in every ore varies depending on the geological history of the sample, thus providing a tool for fingerprinting the distinct origin of Li containing samples. Determination of the exact isotope ratio for e.g. designation of provenance today relies on expensive and bulky instrumentation such as multi `collector inductively coupled plasma mass spectrometry` (MC-ICP-MS). These instruments, however, are known to bear pitfalls in the characterization of particular elements including Lithium. BAM recently developed two alternative analytical devices for this task, solely relying on inexpensive optical spectroscopy in combination with state-of-the-art multivariate data analysis such as Machine learning algorithms. Both techniques have been comprehensively studied using certified reference materials and comparing the results to MC-ICP-MS results and could be shown to result in comparable figures of merit, paving the way for a more general accessibility to provenance determination instrumentation. The results also pave the way towards even further simplification of the laboratory infrastructure demands and to further include additional elements into the isotopic fingerprinting methodology.
Das Verhalten von Batteriezellen bei Beschädigung ist von hoher Bedeutung für die Einschätzung der Sicherheit bei Transport, Lagerung sowie Verwendung. Vor allem im Zusammenhang mit dem exponentiell wachsenden Sektor der Lithium-Batterien kam es in der Vergangenheit immer wieder zu kritischen Vorfällen. Hierbei haben Lithium-Metall-Batterien, welche elementares Lithium enthalten, den Ruf besonders gefährlich zu sein. Um dieses Thema bewerten zu können, werden im Vortrag die Unterschiede zwischen Lithium-Ionen- und Lithium-Metall-Batterien erläutert und experimentelle Studien des Verhaltens von aktuellen Systemen bei Schädigung verglichen. Darüber hinaus wird auf die Eigenschaften sowie das Sicherheitsverhalten von zukünftigen Lithium- bzw. Natrium-Batterien eingegangen.
Additive manufacturing (AM) of alkali-activated materials is a promising method for producing ceramic precursors, construction elements and other parts. A recently introduced AM process is laser-induced slip casting of lithium aluminate/microsilica slurries, which yields parts with excellent mechanical strengths. To clarify the underlying mechanisms, μ-Raman spectroscopy was applied to parts produced by the process, and the dissolution and hydration of lithium aluminate was studied inter alia using conventional and in-situ X-ray diffraction. The results show that significant dissolution of lithium aluminate occurs, particularly at increased temperatures during laser interaction, which leads to an increase of pH and precipitation of an akopovaite-like Li-Al-CO3 layered double hydroxide. The increase of the pH is likely to induce dissolution of the microsilica and possibly formation of a hydrous lithium aluminosilicate gel. These observations explain the strength evolution of the studied parts and can also aid the development and improvement of related AM methods.
The application of lithium-sulfur (Li-S) batteries is still limited by their rapid capacity fading. The pulverization of the sulfur positive electrode after the lithiation and the consequence dissolution of long chain polysulfides in organic solvents lead to the shuttle effect. To address these issues, here we report the mechanochemical preparation of ZIF-8 (Zeolitic Imidazole Framework-8)-based composites as sulfur hosts for positive electrodes in Li-S batteries. We studied different methods for the incorporation of conductive carbon. Also, the replacement of Zn2+ metal centers by other bivalent metals (Cu2+, Co2+ and Ni2+), enabled the preparation of other ZIF-8-based materials. The positive electrode ZIF-8/C/S8 showed initial discharges of 772 mA h g−1 while the pristine one, ZIF-8/S8, displayed 502 mA h g−1. The enhanced performance of 54% for ZIF-8/C/S8 indicates that the direct mechanochemical synthesis of ZIF-8 with conductive carbon is beneficial at initials charge/discharge process in comparison to traditional slurry preparation (ZIF-8/S8). Also, the Li2S6 absorption tests shows 87% of discoloration with ZIF-8/C/S8, confirming the better polysulfides absorption.
For the successful use of lithium-ion batteries in automotive applications, reliable availability of high storage capacity and very short recharging times are essential. In order to develop the perfect battery for a certain application, structure–property relationships of each active material must be fully understood. LiFePO4 is of great interest due to its fast-charging capability and high stability regarding its thermal resistance and chemical reactivity. The anisotropic lithium-ion diffusion through the LiFePO4 crystal structure indicates a strong dependence of the electrochemical performance of a nanostructured active material on particle morphology. In this paper, the relationship of the particle morphology and fast-charging capability of LiFePO4/C core/shell nanoparticles in half-cells was studied. For this purpose, a new multistep synthesis strategy was developed. It involves the combination of a solvothermal synthesis followed by an in situ polymer coating and thermal calcination step. Monodisperse rodlike LiFePO4 nanoparticles with comparable elongation along the b-axis (30–50 nm) and a varying aspect ratio c/a (2.4–6.9) were obtained. A strong correlation of the fast-charging capability with the aspect ratio c/a was observed. When using LiFePO4 nanoparticles with the smallest aspect ratio c/a, the best electrochemical performance was received regarding the specific capacity at high C-rates and the cycling stability. A reduction of the aspect ratio c/a by 30% (3.6 to 2.4) was found to enhance the charge capacity at 10 C up to an order of magnitude (7.4–73 mA h·g–1).
The therapeutic dose of lithium (Li) compounds, which are widely used for the treatment of psychiatric and hematologic disorders, is close to its toxic level; therefore, drug monitoring protocols are mandatory. Herein, we propose a fast, simple, and low-cost analytical procedure for the traceable determination of Li concentration in human serum, based on the monitoring of the Li isotope dilution through the partially resolved isotope shift in its electronic transition around 670.80 nm using a commercially available high-resolution continuum source graphite furnace atomic absorption spectrometer. With this technique, serum samples only require acidic digestion before analysis. The procedure requires three measurements—an enriched 6Li spike, a mixture of a certified standard solution and spike, and a mixture of the sample and spike with a nominal 7Li/6Li ratio of 0.82. Lanthanum has been used as an internal spectral standard for wavelength correction. The spectra are described as the linear superposition of the contributions of the respective isotopes, each consisting of a spin-orbit doublet, which can be expressed as Gaussian components with constant spectral position and width and different relative intensity, reflecting the isotope ratio in the sample. Both the spectral constants and the correlation between isotope ratio and relative band intensity have been experimentally obtained using commercially available materials enriched with Li isotopes. The Li characteristic mass (mc) obtained corresponds to 0.6 pg. The procedure has been validated using five human serum certified reference materials. The results are metrologically comparable and compatible to the certified values. The measurement uncertainties are comparable to those obtained by the more complex and expensive technique, isotope dilution mass spectrometry.
Lithium ion batteries (LIBs) are prone to spontaneous and subsequent fire or explosion resulting from thermal runaway. The vented gases are not only toxic and flammable, their emission can also raise the surrounding pressure rapidly. In this study, characteristic variations of explosion pressure rise, rate of explosion pressure rise and 𝐾(sT)-value have been evaluated. The characteristic 𝐾(𝑠𝑇)-values were determined to evaluate the explosive behavior of LIBs during thermal runaway. The estimated values were compared to that of other explosive substances.