TY - GEN A1 - Langner, Thomas A1 - Sieber, Tim A1 - Rietig, Anja A1 - Merk, Virginia A1 - Pfeiffer, Lutz A1 - Acker, Jörg T1 - A Phenomenological and Quantitative View on the Degradation of Positive Electrodes from Spent Lithium-ion Batteries in Humid Atmosphere T2 - Scientific Reports N2 - The present study deals with the phenomenological observation of the corrosion of the positive electrode foil of lithium-ion batteries containing LiNi0.6Co0.2Mn0.2O2 (NMC) as cathode material. Due to the presence of moisture, localized water accumulation is formed on the NMC surface. The water absorbed by the electrolyte reacts with the NMC under Li+/H+ exchange and the resulting pH increase leads to dissolution of the carrier foil and characteristic salt-like blooms on the NMC surface. With the increase in the relative area occupied by the holes in the aluminum foil per time, a sufficiently suitable parameter was found with which to quantitatively determine the extent of corrosion. The degree of degradation depends on time and ambient humidity. It was shown that functional recycling with the water jet method is no longer applicable for degraded foils, since the mechanical stability of the foils decreases as corrosion progresses. Lithium, aluminum, sulfur and oxygen were detected in the blooms using SEM–EDX and Laser-Induced-Breakdown-Spectroscopy (LIBS). The underlying NMC layer was found to contain mainly aluminum and significantly lower lithium content than the non-degraded material. SEM and Raman microscopy analyses also showed that the active material is also locally degraded and therefore no longer suitable for functional recycling. KW - Analytical chemistry KW - lithium KW - cathode KW - materials KW - LIBS KW - Raman KW - SEM-EDX KW - degradation Y1 - 2023 U6 - https://doi.org/10.1038/s41598-023-32688-0 SN - 2045-2322 VL - 13 ER - TY - GEN A1 - Rietig, Anja A1 - Langner, Thomas A1 - Acker, Jörg T1 - About determining reliable etching rates and the role of temperature in kinetic experiments on acidic wet chemical etching of silicon T2 - Physical Chemistry Chemical Physics Y1 - 2023 UR - https://pubs.rsc.org/en/content/articlelanding/2023/cp/d2cp05837e U6 - https://doi.org/10.1039/D2CP05837E SN - 1463-9084 VL - 25 IS - 16 SP - 11387 EP - 11397 ER - TY - GEN A1 - Rietig, Anja A1 - Acker, Jörg T1 - Kinetic studies on acidic wet chemical etching of silicon in binary and ternary mixtures of HF, HNO3 and H2SiF6 T2 - Physical Chemistry Chemical Physics Y1 - 2023 U6 - https://doi.org/10.1039/d3cp03188h SN - 1463-9084 SN - 1463-9076 VL - 25 IS - 38 SP - 26245 EP - 26257 ER -