Li Transport in Nano-sized Silicon Electrode Materials for Li-Ion Batteries

锂离子电池纳米硅电极材料中的锂传输

• 批准号: 253211366
• 负责人: Dr. Erwin Hüger
• 金额: --
• 依托单位: Institut für Metallurgie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/253211366?language=en
• 关键词: Li; Transport; Nano; sized; Silicon

Aim of the present proposal is to establish a new methodology for measuring Li transport through only nanometer sized thin amorphous silicon layers, which are used as a promising negative electrode material in Li-ion batteries and also interesting as selective membranes. Lithium diffusion in electrodes is a key parameter for the performance of Li-ion batteries, important for charging and discharging rates, power density, self-discharge and practical capacity. In order to overcome structural degradation, nanoscaled electrodes are advantageous. The selective filtering of Li by thin silicon membranes is especially important for lithium-air batteries, Li-ion selective electrodes, and sensors. A methodology will be established that allows measuring Li transport through nanometer thin amorphous silicon layers from adjacent solid-state Li reservoirs. The modification of the relative 6Li/7Li isotope fraction in [6LiNbO3/Si/natLiNbO3/Si] multilayers during isothermal annealing at low temperatures (room-temperature - 400°C) will be detected by neutron reflectometry and secondary ion mass spectrometry. The experiments will allow to determine the rate determining step (diffusion controlled or interface controlled) of the overall transport process and to quantify Li diffusivity and permeability for the first time in nanometer sized electrode materials. Characteristic activation energies will be extracted from temperature dependent measurements. In order to also address additional important open questions in the field of Li-ion battery research, the experiments will be extended to study exemplarily Li transport in Li containing Li2Si layers and in Si layers under mechanical stress during the third year of funding,The fundamental concept of the proposed method in combination with its flexibility to adopt it to various materials systems makes it applicable for a broad field of interest.

本文的目的是建立一种新的方法来测量Li通过纳米尺寸的薄非晶硅层的输运，这种非晶硅层被用作锂离子电池中有前途的负极材料，也被用作选择性膜。锂在电极中的扩散是锂离子电池性能的关键参数，对充放电速率、功率密度、自放电和实际容量都有重要影响。为了克服结构退化，纳米级电极是有利的。硅薄膜对锂离子的选择性过滤对于锂空气电池、锂离子选择性电极和传感器尤为重要。将建立一种方法，允许测量从相邻的固态锂储层通过纳米薄非晶硅层的锂传输。采用中子反射法和二次离子质谱法检测[6LiNbO3/Si/natLiNbO3/Si]多层材料在低温（室温- 400℃）等温退火过程中相对6Li/7Li同位素分数的变化。该实验将允许确定整个传输过程的速率决定步骤（扩散控制或界面控制），并首次量化纳米尺寸电极材料中的Li扩散率和渗透率。特征活化能将从温度相关测量中提取出来。为了解决锂离子电池研究领域中其他重要的开放性问题，实验将在资助的第三年扩展到典型地研究Li在含Li2Si层和机械应力下的Si层中的输运。所提出方法的基本概念及其采用各种材料系统的灵活性使其适用于广泛的兴趣领域。