The effect of vinylene carbonate (VC) as an electrolyte additive on the electrochemical performance of Si film anode is reported in this paper. The cycle performance and efficiency of Si film anode were enhanced significantly with the presence of VC in electrolyte. It was found that the SEI layer formed in VC-containing electrolyte was impermeable to electrolyte and its impedance remained almost invariant upon cycling. Moreover, silicon oxide was formed in solid electrolyte interface layer of Si film anode due to the reaction of lithiated silicon with permeated electrolyte in both VC-free and VC-containing electrolytes. (c) 2006 The Electrochemical Society.