The reduction of 1,3-propane sultone (PS) on graphite and the performance of Li-ion batteries with PS as an additive in the electrolyte were studied by cyclic voltammetry, energy dispersive spectroscopy, quantum chemical calculation, and battery discharge experiments. The reduction of PS on graphite takes place at the potential 0.2 V more positive than that of other compositions of electrolytes, resulting in the formation of a stable solid electrolyte interphase film on graphite. With the application of PS in the electrolyte of graphite/LiCoO2 battery, the discharge capacity of the battery is significantly improved even after the battery is stored at -20 degrees C or at 80 degrees. (c) 2006 The Electrochemical Society.