Publications

In situ atomic-scale imaging of electrochemical lithiation in silicon

Liu, Xiaohua L.; Wang, Jiang W.; Huang, Jian Y.; Fan, Feifei; Huang, Jian Y.; Liu, Yang; Krylyuk, Sergiy; Yoo, Jinkyoung; Dayeh, Shadi A.; Davydov, Albert V.; Mao, Scott X.; Picraux, S.T.; Zhang, Sulin; Li, Ju; Zhu, Ting; Huang, Jian Y.

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 μnm 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. © 2012 Macmillan Publishers Limited. All rights reserved.