In situ atomic-scale imaging of electrochemical lithiation in silicon

• Published in: Nature nanotechnology Vol. 7; no. 11; pp. 749 - 756
• Main Authors: Liu, Xiao Hua, Wang, Jiang Wei, Huang, Shan, Fan, Feifei, Huang, Xu, Liu, Yang, Krylyuk, Sergiy, Yoo, Jinkyoung, Dayeh, Shadi A., Davydov, Albert V., Mao, Scott X., Picraux, S. Tom, Zhang, Sulin, Li, Ju, Zhu, Ting, Huang, Jian Yu
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01-11-2012; Nature Publishing Group
• Subjects: 639/301/299/161; 639/925/357; 639/925/930/328/2082; Crystallization; Electric Power Supplies; Electrochemistry; Electrodes; Electrons; Kinetics; Laboratories; Lithium; Lithium - chemistry; Materials Science; Mechanical engineering; Microscopy; Microscopy, Electron, Transmission; Models, Molecular; Nanomaterials; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology; Nanotechnology and Microengineering; Nanowires; Silicon; Silicon - chemistry; Georgia; New Mexico; United States > US; Maryland; Massachusetts; Pennsylvania
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/nnano.2012.170

In lithium-ion batteries, the electrochemical reaction between the electrodes and lithium is a critical process that controls the capacity, cyclability and reliability of the battery. Despite intensive study, the atomistic mechanism of the electrochemical reactions occurring in these solid-state electrodes remains unclear. Here, we show that
in situ
transmission electron microscopy can be used to study the dynamic lithiation process of single-crystal silicon with atomic resolution. We observe a sharp interface (∼1 nm thick) between the crystalline silicon and an amorphous Li
x
Si alloy. The lithiation kinetics are controlled by the migration of the interface, which occurs through a ledge mechanism involving the lateral movement of ledges on the close-packed {111} atomic planes. Such ledge flow processes produce the amorphous Li
x
Si alloy through layer-by-layer peeling of the {111} atomic facets, resulting in the orientation-dependent mobility of the interfaces.
In situ
transmission electron microscopy can be used to study the dynamic lithiation of single-crystal silicon with atomic resolution.