Linking of Model and Commercial Active Materials for Lithium Ion Batteries by In-situ Determination of Thermodynamic and Kinetic Data

开发高性能锂离子电池的基本要求包括动力学限制和热力学稳定性的知识。这里设想的系统研究是基于一种新的技术，以确定作为活性材料的组合物的函数的相变的温度和焓，同时锂含量被原位控制。因此，将使用沉积在压电换能器上的薄膜，这使得能够同时应用进一步的方法，例如X射线衍射和阻抗谱。将采用微重量分析法和稳定示踪剂以及随后的质谱法来研究动力学和运输途径。 感兴趣的材料包括系统Li（Co，Ni，M）O2（M = Mn，Al）的常规氧化物和新的TiO 2/Si和MoS 2化合物，其由于诸如阳极氧化的制备工艺而显示出不同的微结构。基于对锂离子的极限传输步骤的识别，打算通过定制微结构来修改活性表面或减少扩散长度。此外，将研究离子液体作为电解质与上述电极材料组合的适用性。重点将主要放在弱配位阴离子的系统上。这些数据，特别是电极的微观结构，将成为发展输运、缺陷化学和热力学模型的基础。同时，数据将提供给进行热力学计算的合作者。

Essential requirements for the development of high-performance lithium ion batteries include the knowledge of kinetic limitations and of the thermodynamic stability. The systematic studies envisaged here are based on a new technique to determine temperature and enthalpy of phase transformations as function of composition of the active materials while the lithium content is controlled in-situ. Thereby, thin films deposited on piezoelectric transducers will be used which enables the simultaneous application of further methods such as X-ray diffraction and impedance spectroscopy. Microgravimetry and stable tracers with subsequent mass spectrometry will be applied to investigate the kinetics and the routes of the transport. Materials of interest include conventional oxides of the system Li(Co,Ni,M)O2 (M = Mn, Al) and new TiO2/Si and MoS2 compounds showing distinct microstructures due to preparation processes such as anodic oxidation. Based on the identification of the limiting transport step for lithium ions, modifications of the active surfaces or reduction of the diffusion lengths by tailoring the microstructure are intended. Further, the applicability of ionic liquids as electrolytes in combination with the above electrode materials will be investigated. The focus shall be mainly on systems with weakly coordinating anions.Those data and, in particular, the microstructure of the electrodes will form the basis to develop transport, defect chemical and thermodynamic models. Simultaneously, the data will be provided to the collaborators performing thermodynamic calculations.