A full series of variously lithiated graphite anodes material Li_xC₆ (0<x<1) corresponding to a different state‐of‐charge (SOC) between 0 % and 100 % was collected from 18650‐type cylinder Li‐ion batteries, and the thermal structural behavior of these electrodes was mapped using ex situ high‐resolution X‐ray and neutron diffraction. Their structural behavior was analyzed over a broad temperature range. At high temperatures, a non‐reversible decomposition of the lithiated graphite anodes takes place, accompanied by a loss of intercalated lithium ions, forming novel phases such as LiF and Li₂O strongly coupled to the degradation of the solid electrolyte interface (SEI). Complementary calorimetric measurements showed the strongly exothermic chemical reactions during the decomposition matching well to the collected diffraction data. Post mortem analysis applying scanning electron microscopy revealed various morphological features supplementing the treatment of battery anodes and highlighted the importance of the SEI layer during the cycling of the cell and its thermal degradation.

Structural and spatial aspects of cell degradation are studied using a combination of diffraction-and imaging-based tools applying laboratory X-rays, neutron scattering and synchrotron radiation with electrochemical and thermal characterization. Experimental characterization is carried out on cylindrical cells of 21700-type, where four regimes of cell degradation are identified, which are supplemented by an increased cell resistance and surface temperature during cell operation. The amount of intercalated lithium in the fully charged anodes in the fresh and aged states is determined by ex situ X-ray diffraction radiography and in situ X-ray diffraction computed tomography. The qualitatively similar character of the results revealed a loss of active lithium along with the development of a complex heterogeneous distribution over the electrode stripe.

The dissolution of nano-sized Ni3Al-based γ′ precipitates was investigated in the newly developed polycrystalline nickel-based VDM^® Alloy 780 at the surface and in the bulk region with in-situ lab-source and synchrotron X-ray diffraction. These studies are important in obtaining a deeper understanding of the strengthening mechanism responsible for the stability and long service lives of such superalloys. We found that the dissolution behavior of the γ′ phase is very similar at the surface and in the bulk region, but small deviations were detected. The dissolution of γ′ starts at around 800 °C and no γ′ was found at temperatures exceeding 970 °C. As a result, the elements Al and Nb, which were bound in the γ′ phase, dissolved into the γ matrix and strongly increased the γ lattice parameter, as their atomic size is larger than the γ-forming elements Ni, Co, and Cr. However, this effect was suppressed in the surface area. A second matrix γ phase was detected at the same temperature range as that of the dissolution of the γ′ phase in the lab-source XRD measurements. The newly formed γ-2 phase had a smaller lattice parameter than that of the initial γ matrix. We propose that the γ-2 matrix phase is a result of high-temperature surface oxidation, which consumes, among other elements, Al and Nb and, therefore, leads to the smaller γ lattice parameter.

Residual lignocellulosic biomass represents a major resource to be incorporated into the circular economy, with up to 1400 Mt/y in EU27. Due to its complex composition of three biopolymers (cellulose, hemicellulose and lignin) combined with its seasonal and regional variability and high water content, its valorization involves manifold challenging aspects. Herein a three-step procedure is presented to transform this type of biomass into solid composite panels: hydrothermal carbonization (HTC), dry thermal treatment and curing a phenolic resin. HTC triggers chemical dehydration of the polysaccharide part of the lignocellulose and breaks up the cell structure of the plants. This facilitates the diffusion of the water and its separation by filtration, which is more energy efficient than evaporation. HTC and thermal treatment induce chemical changes that concentrate the carbon content and make the material suitable for crosslinking with a phenolic resin, achieving a 90% renewable content. The composite panels are competitive with products of the particle and fiberboard sector with respect to tensile strength and screw withdrawal resistance. Hence, the products can be employed for construction or in the furniture industry.