Halohydrin dehalogenases (HHDHs) are of biotechnological interest due to their promiscuous epoxide ring-opening activity with a set of negatively charged nucleophiles, enabling the formation of C−C, C−N, or C−O bonds. The recent discovery of HHDH-specific sequence motifs aided the identification of a large number of halohydrin dehalogenases from public sequence databases, enlarging the biocatalytic toolbox substantially. During the characterization of 17 representatives of these phylogenetically diverse enzymes, one HHDH, namely HheG from Ilumatobacter coccineus, was identified to convert cyclic epoxide substrates. The enzyme exhibits significant activity in the azidolysis of cyclohexene oxide and limonene oxide with turnover numbers of 7.8 and 44 s −1 , respectively. As observed for other HHDHs, the cyanide-mediated epoxide ring-opening proceeded with lower rates. Wild-type HheG displays modest enantioselectivity, as the resulting azido-and cyanoalcohols of cyclohexene oxide ring-opening were obtained in 40% enantiomeric excess. These biocatalytic findings were further complemented by the crystal structure of the enzyme refined to 2.3 Å. Analysis of HheG's structure revealed a large open cleft harboring the active site. This is in sharp contrast to other known HHDH structures and aids in explaining the special substrate scope of HheG.

The influence of the dispersion process and the carbon black (CB) particle size on the resulting structure and, hence, on the properties of lithium‐ion battery cathodes is investigated. N‐methyl‐2‐pyrrolidone‐based cathode slurries with 95.5 wt% LiNi 0.6   Co 0.2   Mn 0.2   normalO 2 (NCM622) and a high mass content (82.5 wt%) are processed in a planetary mixer PMH10 from NETZSCH with varying high‐speed stirrer tip speeds. Particle size analyses are carried out to measure the CB particle size at different time steps of the dispersion process. The resulting cathodes are characterized to determine mechanical and electrical properties. The microstructure of chosen electrodes is reconstructed and quantified by focused ion beam/scanning electron microscopy tomography and correlated with experimental data. In addition, discrete element method simulations are used for a deeper understanding of the dispersion process and breakage of CB aggregates. Correlations between process, structure, and properties of lithium‐ion battery cathodes are revealed.

As moisture presents a critical contamination in lithium-ion batteries (LIBs), electrodes and separators need to be post-dried before cell assembly. The moisture adsorption, desorption and re-adsorption of electrodes during processing is strongly dependent on their material system, manufacturing route and microstructure. The microstructure, in turn, is significantly defined by the coating density, which is adjusted by calendering. As a consequence, the calendering step is expected to directly influence the moisture sorption behavior of electrodes. This is why the influence of different coating densities and structural properties on the moisture content of NCM622 cathodes was investigated in this study. For increasing density, an increasing moisture content was detected by Karl Fischer Titration and sorption measurements. SEM and BET analyses showed an increasing amount of NCM622 particle breakage, accompanied by a rising surface area. Hence, the increased moisture uptake of cathodes with higher density is mainly caused by a higher surface area, which results from particle cracking and breakage during calendering. Electrochemical analysis showed that the increased active surface area of cathodes with higher densities leads to a good performance during formation and at low C-rates. However, the reduced porosity impairs the ionic conductivity and causes capacity loss at higher C-rates.

Low-cost and high-performance lithium ion batteries (LIBs) are a key technology in these days. One promising candidate for cathodes is the layered nickel (Ni)-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) active material due to its high energy density, high specific capacity and lower material costs as well as social aspects concerning mining due to the diminished cobalt content. However, the lower thermal stability and higher sensitivity to H2O and CO2 result in a potential stronger performance degradation and lower safety. Therefore, process adaptions are inevitable. In this paper the current status and challenges of the entire cathode production process with NCM811 as active material are reviewed taking quality, cost and environmental aspects into account. General important aspects within the process are presented which are specially extended to NCM811 cathode production. Process recommendations are highlighted and innovative approaches like a water-based or solvent-free processing are discussed in comparison to conventional production technologies.

In order to reduce the residual moisture in lithium‐ion batteries, electrodes and separators need to be post‐dried prior to cell assembly. On an industrial scale, this is often conducted batch‐wise in vacuum ovens for larger electrode and separator coils. Especially for electrodes, the corresponding post‐drying parameters have to be carefully chosen to sufficiently reduce the moisture without damaging the sensitive microstructure. This requires a fundamental understanding of structural limitations as well as heat transfer and water mass transport in coils. The aim of this study is to establish a general understanding of the vacuum post‐drying process of coils. Moreover, the targeted design of efficient, well‐adjusted and application‐oriented vacuum post‐drying procedures for electrode coils on the basis of modelling is employed, while keeping the post‐drying intensity as low as possible, in order to maintain the sensitive microstructure and to save time and costs. In this way, a comparatively short and moderate 2‐phase vacuum post‐drying procedure is successfully designed and practically applied. The results show that the designed procedure is able to significantly reduce the residual moisture of anode and cathode coils, even with greater electrode lengths and coating widths, without deteriorating the sensitive microstructure of the electrodes.