Si/C composites for high capacity lithium storage materials

Thermal pyrolysis of polyvinyl chloride dispersed with nanosized silicon and fine graphite particles at 900 degreesC produces a novel Si/C composite for lithium storage material. Incorporated silicon provides major capacity for lithium insertion, while the introduction of graphite component suppresses the initial irreversibility and hysteresis between charge and discharge caused by pyrolyzed carbon. The first cycle efficiency of the composite is about 85%. The large reversible capacity of ca. 700 mAh/g and good cyclability indicates that such Si/C composite may be a useful alternative to conventional graphite- based anode materials for lithium-ion cells. (C) 2003 The Electrochemical Society.