Multilayer Electrodes and Neutrons: A Tool to Study Lithiation Mechanisms

将小金属离子如Li电化学结合和去除到合适的电极中是可再充电电化学能量存储的基本过程。因此，了解实际高容量电极的锂化机理对于基础和应用相关研究具有高度的兴趣。在这个项目中，我们将使用一种新的方法，这是基于多层电极和在操作中子反射法研究这个问题的负电极。这种独特的组合可以轻松识别基本的锂化机制，同时测量电化学锂化过程中的体积变化。该方法的优点是，使用多层布置（同位素或化学调制）将具有众多干涉条纹的复杂中子反射率图案转换为具有单个布拉格峰的简单图案。因此，用于描述图案的相关参数的数量将大幅减少，并且结果的明确解释是可能的。作为多层膜电极模型系统，我们将研究73 Ge/Ge（同位素）和Si/C（化学）薄膜，电极材料将采用离子束溅射沉积。电极过程应在恒电流循环和循环伏安法中通过中子反射法进行研究。结果应该有助于从根本上了解电池改进所需的基本方面

The electrochemical incorporation and removal of small metal Ions like Li into suitable electrodes is a fundamental process for rechargeable electrochemical energy storage. Consequently, an understanding of the lithiation mechanism of actual high capacity electrodes is of high interest for fundamental and application relevant research. Within this project we will investigate this problem for negative electrodes using a novel approach which is based on multilayer electrodes and in-operando neutron reflectometry. This unique combination allows an easy identification of the fundamental lithiation mechanism and simultaneously a measurement of volume modifications during electrochemical lithiation. The advantage of the approach is that the use of a multilayer arrangement (isotope or chemical modulated) transforms complex neutron reflectivity patterns with numerous interference fringes into a simpler pattern with a single Bragg peak. Hereby, the number of relevant parameters for the description of the pattern will be reduced drastically and an unambiguous interpretation of the results is possible. As multilayer electrode model systems thin films of 73Ge/Ge (isotope) and Si/C (chemical) will be investigated.The electrode material will be produced by ion-beam sputter deposition. Electrode processes should be studied in-operando during galvanostatic cycling and cyclic voltammetry by Neutron Reflectometry. The results should help to fundamentally understand the basic aspects, necessary for an improvement of batteries