title: In Situ Study of Silicon Electrode Lithiation with X-ray Reflectivity.
abstract: 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 (LixSi) 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 LixSi/Si interface.
authors: SSRL Materials Science Division, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.|Department of Materials Science and Engineering, Stanford University , Stanford, California 94305, United States.
authors: Chuntian
authors: C
authors: Cao
authors: SSRL Materials Science Division, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors: Hans-Georg
authors: HG
authors: Steinrück
authors: SSRL Materials Science Division, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors: Badri
authors: B
authors: Shyam
authors: SSRL Materials Science Division, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors: Kevin H
authors: KH
authors: Stone
authors: SSRL Materials Science Division, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
authors: Michael F
authors: MF
authors: Toney
keywords: Li-ion battery; Si anode; X-ray reflectivity; in situ; solid electrolyte interphase