Nowadays "microplastics" (MPs) is an already well-known term and results of micro-sized particles found in consumer products or environments are regularly reported. However, studies of native MPs smaller than 1 μm, often referred to as nanoplastics (NPs), in analytically challenging environments are rare. In this study, a correlative approach between scanning electron microscopy and Raman microscopy is tested to meet the challenges of finding and identifying NPs in the 100 nm range in various environments, ranging from ideal (distilled water) to challenging (sea salt, human amniotic fluid). To test the viability of this approach in principle, standardized polystyrene beads (Ø 200 nm) are mixed into the various environments in different concentrations. Promising detection limits of 2 10-3 μg/L (distilled water), 20 μg/L (sea salt) and 200 μg/L (human amniotic fluid) are found. To test the approach in practices both sea salt and amniotic fluid are analysed for native NPs as well. Interestingly a nylon-NP was found in the amniotic fluid, maybe originating from the sampling device. However, the practical test reveals limitations, especially with regard to the reliable identification of unknown NPs by Raman microscopy, due to strong background signals from the environments. We conclude from this in combination with the excellent performance in distilled water that a combination of this approach with an advanced sample preparation technique would yield a powerful tool for the analysis of NPs in various environments.

Room temperature operation of Na-S batteries with liquid electrolytes is plagued by fundamental challenges stemming from polysulfide solubility and their shuttle effects. Inorganic solid electrolytes offer a promising solution by acting as barriers to polysulfide migration, mitigating capacity loss. While the sequential formation of cycling products in molten-electrode and liquid electrolytes-based Na-S batteries generally aligns with the expectations from the Na-S phase diagram, their presence, stability, and transitory behavior in systems with inorganic solid electrolytes at room temperature, remain poorly understood. To address this, we employed operando scanning microbeam X-ray diffraction, operando X-ray photoelectron spectroscopy and ex-situ X-ray absorption spectroscopy to investigate the sulfur conversion mechanisms in Na-S cells with Na₃PS₄ and Na₄(B₁₀H₁₀)(B₁₂H₁₂) electrolytes. Our findings reveal the formation of crystalline and amorphous polysulfides, including those predicted by the Na-S phase diagram (e.g., Na₂S₅, Na₂S₄, Na₂S₂, Na₂S), high-order polysulfides observed in liquid-electrolyte systems (e.g., Na₂S_x, where x = 6-8), and phases like Na₂S₃ typically stable only under high-temperature or high-pressure conditions. We demonstrate that these transitions are governed by diffusion-limited kinetics and localized stress concentrations, emphasizing the critical role of pressure, which serves as both a thermodynamic variable, as well as a design parameter, for optimizing solid-state Na-S battery performance necessary for pushing these cells closer to the commercial frontier.

Hybrid electrochemical capacitors have emerged as attractive energy storage option, which perfectly fill the gap between electric double-layer capacitors (EDLCs) and batteries, combining in one device the high power of the former and the high energy of the latter. We show that the charging characteristics of the positive carbon electrode are transformed to behave like a battery operating at nearly constant potential after it is polarized in aqueous iodide electrolyte (1 mol L⁻¹ NaI). Thermogravimetric analysis of the positive carbon electrode confirms the decomposition of iodides trapped inside the carbon pores in a wide temperature range from 190 °C to 425 °C, while Raman spectra of the positive electrode show characteristic peaks of I₃⁻ and I₅⁻ at 110 and 160 cm⁻¹, respectively. After entrapment of polyiodides in the carbon pores by polarization in 1 mol L⁻¹ NaI, the positive electrode retains the battery-like behavior in another cell, where it is coupled with a carbon-based negative electrode in aqueous NaNO₃ electrolyte without any redox species. This new cell (the iodide-ion capacitor) demonstrates the charging characteristics of a hybrid capacitor with capacitance values comparable to the one using 1 mol L⁻¹ NaI. The constant capacitance profile of the new hybrid cell in aqueous NaNO₃ for 5000 galvanostatic charge/discharge cycles at 0.5 A g⁻¹ shows that iodide species are confined to the positive battery-like electrode exhibiting negligible potential decay during self-discharge tests, and their shuttling to the negative electrode is prevented in this system.

Whole sample microscopy mappings are of interest in many cases as they provide analytical information of phases varying in size by orders of magnitude and in composition across the sample. These benefits are amplified if more than one microscopic technique is used for the mappings. However, to take full advantage of correlative whole sample mappings, the data of each technique has to be carefully prepared, treated, correlated and evaluated. With this work, we want to present the key steps of our data treatment approach as well as the results on an exemplary sample, the Chelyabinsk meteorite. The most important step in our data treatment approach is to start by evaluating the spectral maps separately as far as possible (at-% quantification for EDS for example) and then generate pseudo spectral maps from this evaluation in the form of image stacks. This allows us to preserve the advantages of specialized software packages and standard work flows for every spectral mapping, whilst also unifying the data format and compressing the data sufficiently for correlation and the application of machine learning tools. We have performed whole sample mappings using SEM, EDS and Raman on a cross-section of a Chelyabinsk meteorite fragment, roughly 1.0cm × 0.8cm large. Combining these mappings into a single "super" spectral map, we were able to produce a uniquely detailed mapping of the composition of the meteorite fragment, as well as perform a quantitative analysis of the elemental composition of several crystallographic phases. The results of our compositional analysis; olivine (Fo₇₂Fa₂₈), pyroxene (≈ 97 % En₈₀Fs₂₀Wo₀ and 3 % En₅₆Fs₆Wo₃₈), feldspar (albite), troilite, FeNi (taenite and kamacite), merrillite, chromite and hydroxyapatite; agree qualitatively with other reports from literature.

Single atom detection in nanoporous materials is a significant challenge, particularly due to their sensitivity to electron irradiation. Here, natural beryl (Be₃Al₂Si₆O₁₈) is used as a model system to quantitatively analyse the occupancy of its atomic channels. High-angle annular dark-field imaging in a scanning transmission electron microscope is employed, revealing the presence of Cs atoms within the channels. Through statistical analysis of atomic column intensities and comparison with a series of multislice simulations, we successfully pinpoint the three-dimensional positions of individual Cs atoms. Our findings indicate a non-uniform distribution of Cs atoms in the crystal. Importantly, by extracting both the crystal thickness and atomic positions from a single high-resolution micrograph, we effectively minimize the adverse effects of beam damage. This approach offers a promising pathway for accurately determining the three-dimensional distribution of dopant atoms in various porous materials, opening new possibilities for the study and application of these technologically important materials.

The charging of nanoporous carbon via electrodeposition of solid iodine from iodide-based electrolyte is an efficient and ecofriendly method to produce battery cathodes. Here, the interactions at the carbon/iodine interface from first contact with the aqueous electrolyte to the electrochemical polarization conditions in a hybrid cell are investigated by a combination of in situ and ex situ methods. EQCM investigations confirm the flushing out of water from the pores during iodine formation at the positive electrode. XPS of the carbon surface shows irreversible oxidation at the initial electrolyte immersion and to a larger extent during the first few charge/discharge cycles. This leads to the creation of functional groups at the surface while further reactive sites are consumed by iodine, causing a kind of passivation during a stable cycling regime. Two sources of carbon electrode structural modifications during iodine formation in the nanopores have been revealed by in situ Raman spectroscopy, (i) charge transfer and (ii) mechanical strain, both causing reversible changes and thus preventing performance deterioration during the long-term cycling of energy storage devices that use iodine-charged carbon electrodes.