In Situ Study of Silicon Electrode Lithiation with X-ray Reflectivity

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• 作者：Chuntian Cao ; Hans-Georg Steinrück ; Badri Shyam ; Kevin H. Stone ; Michael F. Toney
• 刊名：Nano Letters
• 出版年：2016
• 出版时间：December 14, 2016
• 年：2016
• 卷：16
• 期：12
• 页码：7394-7401
• 全文大小：475K
• ISSN：1530-6992

文摘

Surface sensitive X-ray reflectivity (XRR) measurements were performed to investigate the electrochemical lithiation of a native oxide terminated single crystalline silicon (100) electrode in real time during the first galvanostatic discharge cycle. This allows us to gain nanoscale, mechanistic insight into the lithiation of Si and the formation of the solid electrolyte interphase (SEI). We describe an electrochemistry cell specifically designed for in situ XRR studies and have determined the evolution of the electron density profile of the lithiated Si layer (Li<sub>xsub>Si) and the SEI layer with subnanometer resolution. We propose a three-stage lithiation mechanism with a reaction limited, layer-by-layer lithiation of the Si at the Li<sub>xsub>Si/Si interface.