石墨电极中锂离子扩散的原位观测  

In situ observation of lithium ion diffusion in graphite electrode

作　　者：朱建宇[1] 郭战胜[1,2] 冯捷敏 戴文浩[3] 

机构地区：[1]上海市应用数学和力学研究所,上海200072 [2]上海市力学在能源工程中的应用重点实验室,上海200072 [3]上海大学理学院力学系,上海200444

出　　处：《电源技术》2016年第8期1550-1553,1639,共5页Chinese Journal of Power Sources

基　　金：国家自然科学基金(11472165;11332005);上海市自然科学基金(12ZR1410200)

摘　　要：锂离子在电极中的扩散机制是理解和研究锂离子电池各类性能的基础。设计了一个新型实验室模拟电池,实时原位观测了石墨电极充电过程中的颜色变化,研究了锂离子的扩散路径和机理。实验发现,锂离子从石墨电极边缘向中心进行扩散,边缘部分锂离子首先达到饱和状态。充电倍率显著影响锂离子扩散机理。充电倍率增大,LiC_(18)相(对应于深蓝色区域)明显多于LiC_(12)相(对应于红色区域),反映出锂离子浓度梯度增大。通过观测颜色变化,发现大倍率充电时可嵌入的锂离子少于小倍率。通过对石墨负极图像进行原位比色,可以估算出电极的实时充电状态。Diffusion mechanism of lithium ion in the electrode is the basis to understand and research all kinds of lithium ion battery properties, The new experimental device was designed to realize the real time in situ observation of the color change in graphite electrode during charging. The path and mechanism of lithium ion diffusion were researched. It is found that lithium ions diffuse from the edge to the center of graphite electrode. The edge portion lithium ion reaches saturation firstly. Charging rate significantly affects the diffusion mechanism of lithium ion. LiCI~ phase （corresponding to the dark blue region） is more than LiC12 phase （corresponding to the red region） at high charging rate, indicating that lithium ion concentration gradient is greater. By observing color change, It is found that lithium ion enable to inset into electrode at high rate is less than that at low rate. In situ colorimetry of the graphite electrode images can estimate the real time state of charge of the electrode.

关 键 词：锂离子电池 原位观测 锂离子扩散 原位比色 

分 类 号：TM912[电气工程—电力电子与电力传动]