In-situ ATR-FTIR investigation of the solid electrolyte interface (SEI) on single-crystal Si anodes for Li ion batteries

摘要

Silicon has been widely recognized as one of the most promising anode materials because of its high energy density; however, critical drawbacks such as large irreversible capacity and poor reliability and durability have dramatically limited its application. The aforementioned weaknesses are partially due to electrolyte loss by reduction, i.e., the formation of a solid electrolyte interface (SEI), and the instability of SEI with cycling. For a better understanding of the mechanism of Si electrode failure during battery cycling, a novel in-situ ATR-FTIR spectra-electrochemical cell, schematically shown below, was designed and used to carry out in situ studies of the formation of SEI on Si anodes.