In the environment the weathering of plastic debris is one of the main sources of secondary microplastic (MP). It is distinct from primary MP, as it is not intentionally engineered, and presents a highly heterogeneous analyte composed of plastic fragments in the size range of 1 µm−1 mm. To detect secondary MP, methods must be developed with appropriate reference materials. These should share the characteristics of environmental MP which are a broad size range, multitude of shapes (fragments, spheres, films, fibers), suspensibility in water, and modified particle surfaces through aging (additional OH, C=O, and COOH). To produce such a material, we bring forward a rapid sonication-based fragmentation method for polystyrene (PS), polyethylene terephthalate (PET), and polylactic acid (PLA), which yields up to 10 5 /15 mL dispersible, high purity MP particles in aqueous media. To satisfy the claim of a reference material, the key properties-composition and size distribution to ensure the homogeneity of the samples, as well as shape, suspensibility, and aging -were analyzed in replicates (N = 3) to ensure a robust production procedure. The procedure yields fragments in the range of 100 nm−1 mm (<20 µm, 54.5 ± 11.3% of all particles). Fragments in the size range 10 µm−1 mm were quantitatively characterized via Raman microspectroscopy (particles = 500-1,000) and reflectance micro Fourier transform infrared analysis (particles = 10). Smaller particles 100 nm−20 µm were qualitatively characterized by scanning electron microcopy (SEM). The optical microscopy and SEM analysis showed that fragments are the predominant shape for all polymers, but fibers are also present. Furthermore, the suspensibility and sedimentation in pure MilliQ water was investigated using ultraviolet-visible spectroscopy and revealed that the produced fragments sediment according to their density and that the attachment to glass is avoided. Finally, a comparison of the infrared spectra from the fragments produced through sonication and naturally aged MP shows the addition of polar groups to the surface of the particles in the OH, C=O, and COOH region, making these particles suitable reference materials for secondary MP.

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All-Solid-State-Batteries (ASSBs) are envisioned to be the next-generation lithium-ion batteries (LIBs). Replacing the inflammable organic electrolyte in conventional liquid electrolyte LIBs by a non-inflammable inorganic solid electrolyte (SE) is one of the concepts to increase battery safety. Moreover, ASSBs may offer higher gravimetric and volumetric energy density compared to liquid electrolyte based technology.[1,2] However, their high reactivity with ambient air is a major obstacle which prevents ASSBs from industrial scale processing, as production under inert atmosphere is not possible on this level.[3] Thus, industrial ASSB production would have to take place in dry-rooms, leading to the question whether SE handling in dry-room atmospheres containing O2 and CO2 and ppm-levels of moisture is possible. Therefore, we will examine the reactivity of the commercially available solid electrolyte Li10SnP2S12 (LSPS) with O2 and CO2 as well as with the typical H2O concentration in ambient air, followed by reactivity studies with a mixture of CO2 and H2O vapor. For this purpose, we used Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS), a highly surface sensitive infrared technique.The hermetically sealed DRIFTS cell containing the SE powder was set up such that it could be purged with dry or humidified streams of inert gas (Ar), O2, and CO2, or mixtures thereof while monitoring in situ the chemical changes of the LSPS solid electrolyte and the formed gaseous species by DRIFTS. Figure 1 shows stacked IR spectra of LSPS after exposure to different gasses, stating no reactivity with O2 or CO2 but noticeable changes in the IR spectrum for exposure to moisture and a combination of CO2 and moisture, respectively, indicating decomposition reactions.The spectral analysis of the decomposition process is supported by ex situ X-Ray Diffractometry (XRD) analysis of the LSPS powder after exposure to the different gas streams. Concluding, the impact of exposing LSPS to the above mentioned gas mixtures on the ionic conductivity of the solid electrolyte will be demonstrated. Acknowledgements: This work was carried out as part of the research project ASSB coordinated by ZAE Bayern. The project is funded by the Bavarian Ministry of Economic Affairs, Regional Development and Energy. References: [1] Janek, J. and Zeier, W. G. A solid future for battery development. Nat. Energy 1, 1–4 (2016). [2] Kamaya, N., Homma, K., Yamakawa, Y., Hirayama, M., Kanno, R., Yonemura, Y., Kamiyama, T., Kato, Y., Hama, S., Kawamoto, K. and Mitsui, A. A lithium superionic conductor. Nat. Mater. 10, 682–686 (2011). [3] Muramatsu, H., Hayashi, A., Ohtoma, T., Hama, S. and Tatsumisago, M. Structural change of Li2S – P2S5 sulfide solid electrolytes in the atmosphere. Solid State Ionics 182, 116–119 (2011). Figure 1