Silicon oxycarbide nanospheres were synthesized as an anode for sodium and lithium ion batteries. In the sodium system the material delivers high capacities of up to 200 mA h g−1 at 25 mA g−1.

Addition of a certain amount of Si to state of the art graphite anodes has become the most prominent option to increase the energy density of Li-ion cells. However, the distribution of Si in the depth of Si/C anodes is difficult to measure with established methods. In this paper, we present a semiquantitative depth profiling method based on glow discharge optical emission spectroscopy (GD-OES). The calibration of this method covers 0−100 wt % Si content in the anode and is validated by pilot-line-coated Si/C anodes with known Si contents. The quantified depth profiles with different pristine anodes show a homogeneous distribution of Si before contact with electrolyte. In contrast to that, pilot-line-coated electrodes after formation and long-term cycled cells with Si/C composite anodes from a commercially available 18650-type cell, as control measurement, reveal a peak near the anode surface, which corresponds to a new aging mechanism. This aging mechanism is verified by interrupted GD-OES sputtering. Raman spectroscopy and ICP-OES substantiate the dissolution of Si species in the electrolyte.

Li‐rich layered oxides (LRLO) with specific energies beyond 900 Wh kg−1 are one promising class of high‐energy cathode materials. Their high Mn‐content allows reducing both costs and the environmental footprint. In this work, Co‐free Li1.2Mn0.6Ni0.2O2 was investigated. A simple water and acid treatment step followed by a thermal treatment was applied to the LRLO to reduce surface impurities and to establish an artificial cathode electrolyte interface. Samples treated at 300 °C show an improved cycling behavior with specific first cycle capacities of up to 272 mAh g−1, whereas powders treated at 900 °C were electrochemically deactivated due to major structural changes of the active compounds. Surface sensitive analytical methods were used to characterize the structural and chemical changes compared to the bulk material. Online DEMS measurements were conducted to get a deeper understanding of the effect of the treatment strategy on O2 and CO2 evolution during electrochemical cycling.

The periodontal status of 1688 inhabitants of eastern Germany (former GDR) was investigated between July 1991 and March 1992, using the CPITN. The results show that only 1.4% of those examined have a healthy periodontal apparatus, whereas 40.1% had some signs of severe periodontitis (CPITN 4). This implies a very high therapy requirement in all age-groups, with 93.1% of 15- to 19-year-olds in need of peridontal treatment (CPITN 1 + 2 + 3 + 4). A comparison between educational qualifications and frequency of brushing or routine dental checks reveals a better level of prophylaxis in the more educated classes. As expected, the CPITN code with good oral hygiene and regular dental checks was significantly lower than with poor oral hygiene and infrequent dental checks. The high prevalence of periodontal disease lends urgency to the development of an extensive prevention concept introduced in childhood.

Cu dissolution in Li-ion cells during over-discharge to 0 V was investigated by Post-Mortem analysis. Commercial 18650 type cells with graphite anode and NMC/LMO cathodes as well as pilot-scale pouch full cells with graphite/NMC chemistry with reference electrode were investigated. The effects of discharge time at 0 V in the range of 100 h to 1000 h for fresh cells as well as the effect of cells cycled under Li deposition conditions were considered. For comparison, electrodes from cells discharged to the end-of-discharge voltage (2.0 V) were examined. By extensive Post-mortem analysis using inductively coupled plasma (ICP-OES), scanning electron microscopy (SEM) with BSE and SE detectors, energy dispersive X-ray analysis (EDX), and glow discharge optical emission spectroscopy (GD-OES), we show that Cu compounds are present on the anode surface and on the cathode from cells, which were over-discharged. Cross-sections show that the Cu originates from pitting corrosion of the negative current collector. Combined electrochemical/ICP-OES measurements in commercial cells as well as reference electrode measurements in 3-electrode pouch full cells suggest that Cu is dissolved as Cu+ ions.