A sol-gel route for ternary lithium fluorides of transition metals (M) is presented allowing the synthesis of Li 3 MF 6 -type and Li 2 MF 5 -type compounds. It is based on a fluorolytic process using transition metal acetylacetonates as precursors. The domain size of the obtained powders can be controlled by modifying the conditions of synthesis. 6 Li and 7 Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is used to study local environments of the Li ions in orthorhombic and monoclinic Li 3 VF 6 as well as Li 2 MnF 5 . The number of magnetically inequivalent Li sites found by MAS NMR is in agreement with the respective crystal structure of the compounds studied. Quantum chemical calculations show that all materials have high de-lithiation energies making them suitable candidates to be used as high-voltage battery cathode materials.

A new synthesis route to Li2NiF4 based on a fluorolytic process using Ni(acac)2 or Ni(OAc)2·4H2O as precursor is presented. Variation of the synthesis conditions allows crystallite size control of the obtained powders. 6Li and 7Li MAS NMR experiments were carried out to study local environments of the lithium ions. Several attempts were made to synthesize Li2CoF4, which are, unfortunately, hitherto not successful. Nevertheless, our studies clearly reveal that solid solutions Li2NiF4–Li2CoF4 are stable up to ca. 30 % cobalt. High‐temperature X‐ray diffraction measurements also show no evidence for the existence of pure Li2CoF4. These findings are supported by quantum chemical calculations.

The nanoscaled ternary transition-metal fluorides Li3MF6 (M = V, Fe, Mn) and Li2NiF4 are promising candidates for cathode materials in high-voltage lithium-ion batteries. The fluorolytic route to these compounds relies on thermal decomposition of a hitherto uncharacterised precursor mixture produced from acetylacetonates and hydrofluoric acid. By addition of pyridine, different cationic, electroneutral and anionic complexes containing the motifs [MFn]((3-n)+) (n = 0-4) have been trapped and characterised by single-crystal X-ray diffraction and IR spectroscopy. Based on the results, a model of successive and incomplete fluorination is proposed for the speciation and formation of the precursor. The decomposition of the latter has been monitored via thermogravimetry (TG) and differential scanning calorimetry (DSC).

Crown ethers and their supramolecular derivatives are well-known chelators and scavengers for a variety of cations, most notably heavier alkali and alkaline-earth ions. Although they are widely used in synthetic chemistry, available crystal structures of uncoordinated and solvent-free crown ethers regularly suffer from disorder. In this study, we present the X-ray crystal structure analysis of well-ordered solvent-free crystals of dibenzo-21-crown-7 (systematic name: dibenzo[b,k]-1,4,7,10,13,16,19-heptaoxacycloheneicosa-2,11-diene, CHO). Because of the quality of the crystal and diffraction data, we have chosen invarioms, in addition to standard independent spherical atoms, for modelling and briefly discuss the different refinement results. The electrostatic potential, which is directly deducible from the invariom model, and the Hirshfeld surface are analysed and complemented with interaction-energy computations to characterize intermolecular contacts. The boat-like molecules stack along the a axis and are arranged as dimers of chains, which assemble as rows to form a three-dimensional structure. Dispersive C-H...H-C and C-H...π interactions dominate, but nonclassical hydrogen bonds are present and reflect the overall rather weak electrostatic influence. A fingerprint plot of the Hirshfeld surface summarizes and visualizes the intermolecular interactions. The insight gained into the crystal structure of dibenzo-21-crown-7 not only demonstrates the power of invariom refinement, Hirshfeld surface analysis and interaction-energy computation, but also hints at favourable conditions for crystallizing solvent-free crown ethers.

In order to meet the goal of 50% renewables in the electrical energy mix till 2030 set by the German government the expansion must be continued. One of the biggest problems with the increasing share of renewable energy are the arising fluctuations. In this study it was investigated how the manageability of the biogas production from waste can be used to create a flexible production strategy in order to improve the reliability of a renewable energy supply. The current misbalances between energy demand and supply of wind turbines and PV systems are the basis for this new strategy. The simulation is based on a stand-alone 100% renewable energy supply of a model town with a population of 1,600 people. In order to investigate the impact of this new biogas management strategy using 100% renewable energy supply (including wind and solar energy) a simulation tool using MATLAB was designed. Furthermore, to receive preliminary real data regarding flexible biogas production tests were done with a plug-flow digester. Lastly, an economic analysis regarding the profitability was carried out. Simulations in this study have shown that using a flexible and demand adapted biogas management can reduce the required battery capacity by up to 60%. Nonetheless, the combination with feed-in management of wind and solar power has to be further investigated.