电化学膨胀计联用现场X-射线衍射表征螺环季铵盐插嵌石墨负极  

Study on Quaternary Alkyl Ammonium Intercalation into Graphite Negative Electrodes by In-Situ X-ray Diffraction and Electrochemical Dilatometry

作　　者：陈聪聪 李家玉 黄玉豪[1,2] 张磊 王云举[1,2] 王宏宇[1,2] CHEN Cong-Cong;LI Jia-Yu;HUANG Yu-Hao;ZHANG Lei;WANG Yun-Ju;WANG Hong-Yu(State Key Laboratory of Electroanalytical Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院长春应用化学研究所,电分析化学国家重点实验室,长春130022 [2]中国科学技术大学,合肥230026

出　　处：《分析化学》2022年第3期413-423,共11页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(No.21975251)资助。

摘　　要：以活性炭/石墨电容器为平台,通过电化学膨胀计(ECD)和原位X射线衍射(XRD)技术,对螺环季铵盐阳离子(SBP^(+))电化学插嵌不同石墨负极过程中的膨胀现象进行了研究。ECD能准确监测石墨电极的宏观厚度变化,而原位XRD可以实时探测石墨电极微观晶体结构的变化。通过两者数据相互对照,发现微观尺度上因离子插嵌导致的石墨XRD数据非常接近(晶格膨胀程度为56%~59%),但在宏观上却展现出截然不同的膨胀现象,大颗粒片层状石墨电极表现出更大幅度的膨胀(12%),而小粒径的片层状石墨和球状石墨电极的膨胀幅度却很小(5%~6%)。通过扫描电子显微镜观测发现,造成此现象的原因与石墨形貌结构以及其在集流体上的排列密切相关。大颗粒片层状石墨结构和排列上的高度有序性导致电极膨胀相对更大,而小粒径片层石墨杂乱的排列以及天然球状石墨独特的结构会使膨胀向各个方向分散,造成整体膨胀幅度更小。In activated carbon/graphite capacitors,electrochemical dilatometry and in-situ X-ray diffraction(XRD)were used to investigate the expansion of graphite negative electrodes during the storage of spiro-(1,1′)bipyrrolidinium cation(SBP^(+))from both macro and micro perspectives.The electrochemical dilatometry can accurately monitor the changes in the macroscopic thickness of the graphite electrode,while in-situ XRD can detect the changes in the microscopic crystal structure of the graphite electrode in real time.Through the comparison of the two set of data,it was found that the relative lattice expansion of graphite caused by ion intercalation on the microscopic scale was very close(56%-59%),with a completely different expansion phenomenon from a macroscopic point of view.Large graphite flakes exhibited a greater expansion(12%),while graphite flakes with a smaller size and spherical graphite demonstrated a very small expansion(5%-6%).The scanning electron microscope test showed that this tendency was closely related to the morphology of graphite and the arrangement of graphite particles on the current collector.The high orientation of large graphite flakes led to the relatively larger electrode expansion,while the disorderly arrangement of thin graphite flakes and the isotropic structure of natural spherical graphite would cause the expansion to be dispersed in all directions,and then made the overall expansion smaller.

关 键 词：电化学膨胀计 原位X-射线衍射 螺环季铵盐 石墨嵌层化合物 

分 类 号：O657.1[理学—分析化学] TQ127.11[理学—化学] TM53[化学工程—无机化工] TM912[电气工程—电器]