Impact of sodium salt coating on a graphite negative electrode for lithium-ion batteries

The electrochemical performance of a graphite electrode for rechargeable lithium-ion batteries was successfully enhanced by pretreatment of graphite powders with NaCl and Na2CO3 aqueous solutions. The procedure of the pretreatment is simple and easy, that is, graphite powders are dispersed in the aqueous solutions, and then filtered and dried. Since the surface of the graphite powder was modified with a sodium salt coating, the irreversible capacity at the initial cycle was suppressed by the pretreatment which is capable of modifying the solid electrolyte interface layer formed on the graphite electrode. Further, reversible discharge capacities at 175 mA g(-1) (C/2 rate when 350 mAh g(-1)) increased with better capacity retention in a 1 mol dm(-3) LiClO4 ethylene carbonate-diethyl carbonate electrolyte solution. (c) 2006 The Electrochemical Society.