Crystal growth and electrochemistry of Lithium-based materials: Investigation of model systems for Li-ion batteries

该项目进行了系统的研究，以了解最先进的锂离子电池正极材料的复杂结构和电子相图。我们将研究晶体生长参数，合成结构、化学计量比和尺寸优化的单晶模型材料，并从物理和化学性质方面对其进行表征。此外，我们还将研究单晶沿其主轴的电化学脱附，以探讨晶体结构、电化学性质与锂沿晶轴扩散动力学之间的关系。特别是，我们将利用高压流动溶剂浮区技术(高达150bar)合成LiMPO_4(M=Mn，Fe，Ni，(Mn，Ni)，(Mn，Fe))和LiCoO_2单晶。稍后，将引入额外的掺杂剂(例如，硅)。对多晶棒和单晶的完好性进行了详细的分析和表征，并将通过磁、输运和热力学测量来研究电子相图。此外，晶体将被提供给优先计划，在那里将研究锂动力学、有序化现象和结构，例如通过核磁共振、硬X射线衍射和理论建模。注：最近授予的旨在研究纳米级和单晶正极材料的BMBF-研究小组03SF0340/LIB2015应与SPP相关。研究小组将迁往海德堡大学。因此，我申请了一种高压流动溶剂浮区炉。

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.