基于多尺度图像重建的硅负极结构演化定量分析  

Quantitative analysis of the structural evolution in Si anode via multi-scale image reconstruction

作　　者：朱晨 陈诗名 李珂 尹祖伟 肖荫果 林海 潘锋 杨卢奕 Chen Zhu;Shiming Chen;Ke Li;Zu-Wei Yin;Yinguo Xiao;Hai Lin;Feng Pan;Luyi Yang(School of Advanced Materials,Peking University Shenzhen Graduate School,Shenzhen 518055,China;College of Energy,Xiamen University,Xiamen 361005,China)

机构地区：[1]School of Advanced Materials,Peking University Shenzhen Graduate School,Shenzhen 518055,China [2]College of Energy,Xiamen University,Xiamen 361005,China

出　　处：《Science Bulletin》2023年第4期408-416,M0004,共10页科学通报（英文版）

基　　金：supported by Soft Science Research Project of Guangdong Province(2017B030301013);China Postdoctoral Science Foundation(2019M660317)。

摘　　要：为了深入了解硅基负极在循环过程中的结构演化,本文首次应用电极和颗粒水平多尺度的三维图像重建技术,对微米硅负极在电循环过程中的结构进行了可视化的定量表征;通过分析电解液中氟代碳酸乙烯酯(FEC)添加剂的影响,生动展示了硅负极的结构/成分演变与电化学性能之间的联系.利用聚焦离子束和扫描电子显微镜(FIB-SEM)技术,对电极中的三种组分(硅活性颗粒,非活性组分和孔隙)的体积和形状变化进行了定量的分析,并统计了循环过程中硅颗粒的平均尺寸.结合电化学分析结果表明,电解液FEC添加剂可以在硅负极的循环早期形成稳定的固态电解质界面(SEI),从而有效抑制硅颗粒的巨大体积膨胀和粉化现象,提高电极的循环稳定性.本文提出的方法为具有类似体积膨胀问题的电极体系提供了新的研究视角.Despite the high theoretical capacity,silicon(Si)anode suffers from dramatical capacity loss,due to its massive volume swings(up to 300%)during cycling.Hence,thorough understanding of the structural evolution mechanism is necessary and essential for performance optimization of Si anode.Herein,a multi-scale three-dimensional(3D)image reconstruction technique is firstly applied to visualize the structural evolution process of Si anodes.Three key components(Si particles,inactive components,and voids)in the electrode are quantitatively analyzed by the focused ion beam and scanning electron microscope(FIB-SEM)technology.Furthermore,the average sizes of Si particles were run statistics during the cycling.By combining the componential observation within the electrode(macroscopic information)and the 3D models of the particle with solid electrolyte interphase(SEI)layer(microscopic information),the failure mechanism of Si anode is vividly demonstrated.This work establishes a new methodology to quantitatively analyze the structural and compositional evolution of Si anode,which could be further applied for the studies of many other electrode materials with similar issues.

关 键 词：Li-ion battery Si anode Structural evolution Three-dimensional image reconstruction 

分 类 号：TM912[电气工程—电力电子与电力传动]