Solid electrolyte interphase(SEI)on the electrode surface of lithium-ion batteries plays a crucial role in determining the electrochemical performance such as specific capacity,rate capability,cycle life,as well as chemical and physical stability,which is regarded as one of most hot and challenge topics that the world is facing today.The single Si microtube battery was fabricated by rolled-up method,and will be applied to the study of the SEI formation and its properties [1-2].The in-situ micro Raman spectroscopic and electric transportation analyses of a single Si microtube electrode will be performed at a fixed charge/discharge sate [3-4].Through a combination of various characterization methods such as Auger Electron Spectroscopy(AES),Electrochemical Impedance Spectroscopy(EIS),and Transmission Electron Microscopy(TEM),the formation voltage,interface composition and depth profile,Li-ion intercalation and de-intercalation interface reaction,and properties of SEI layers will be explored,and the effect on the performance of lithium ion battery will be discussed as well.The exploration of the formed metastable state Si/Li alloys formed at different lithiation conditions and the variation of micro Raman spectroscopy will be symmetrically performed.The systematic investigation of the properties of SEI layers and intrinsic reason of capacity decay will be performed based on quantum chemical calculation.The research in this project is expected to provide helpful reference for the future design of lithium ion batteries,which can be a guidance to improve the properties of SEI layers,reduce the irreversible capacity at the first cycle,and improve the cycling performance.