Investigation of phase formation and phase constitution in the systems Li-Mg-Al-O and Li-Al-Mn-O with special focus on spinel solid solutions

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The objective of this project is the detailed investigation of the phase formation in the two quaternary subsystems Li-Mg-Al-O and Li-Al-Mn-O, which are part of the complex oxide slag system (Li, Mg, Al, Si, Ca, Mn)-O, relevant for Li-ion battery recycling. A special focus will be on spinel solid solutions as concurring processes to the formation of LiAlO2 as early crystallization. The investigation of the subsystems will be conducted using combinatorial deposition of thin film materials libraries, accompanied by compositional and crystallographic high-throughput characterization as well as mineralogical investigation and characterization. In the system with Mn a special focus will be on the influence of the speciation (MnII – MnIV) on the phase reactions. Annealing of the materials libraries will be carried out at relevant temperatures to gain information about the phase formation and kinetic behavior of the systems. The result will be existence diagrams of the two multinary oxide systems. This approach aims on specifying “regions of interest” for solidification experiments. The compounds and the morphology of selected solidified melts in the system Li, Mg, Al, Mn, O will be analyzed with PXRD and EPMA. Li contents in the samples will be analyzed using XPS and SIMS and for selected samples with atom probe tomography,. These results in combination with the material libraries will be used for mineralogical characterization including a comparison of the reactions on the micro-scale (thin film material library) and the macro-scale (melt experiments) with pico-liter printing experiments as intermediate step on demand to gather additional information on the kinetics of these systems.