2. Crystal growth and electrochemistry of Lithium-based materials: Investigation of model systems for Li-ion batteries
Professor Dr. Rüdiger Klingeler
The project applies a systematic study in order to understand the complex structural and electronic phase diagrams of state-of-the-art cathode materials for Li-ion batteries. We will investigate the crystal growth parameters and synthesize single-crystalline model materials optimized regarding structure, stoichiometry, and size, and we will characterize them regarding their physical and chemical properties. In addition, we will study electrochemical delithiation of the single crystals along their main axes in order to investigate relations between crystal structure, electrochemical properties and kinetics of Li-diffusion along the crystal axis. In particular, we will synthesize LiMPO4, (M = Mn, Fe, Ni, (Mn,Ni), (Mn,Fe)), and LiCoO2 single crystals by means of the high-pressure traveling-solvent floating-zone technique (up to 150 bar). Later on, additional dopants (e.g., Si) will be introduced. The perfection of polycrystalline feed rods as well as single crystals will be analyzed and characterized in detail and the electronic phase diagrams will be investigated by means of magnetic, transport, and thermodynamic measurements. In addition, the crystals will be provided to the priority program where Li-kinetics, ordering phenomena, and structure will be studied, e.g. by NMR, hard x-ray diffraction, and theoretical modelling.Note: The recently granted BMBF-Research group 03SF0340/LIB2015 aiming at the investigation of nanoscaled and single-crystalline cathode materials shall be associated with the SPP. The research group will move to University of Heidelberg. I hence apply for a high-pressure travelingsolvent floating-zone furnace.