Multi-walled carbon nanotubes (MWNTs) were synthesized by catalytic decomposition of acetylene at 750 degrees C over silica supported cobalt catalysts. The effects of xenon light irradiation on electrochemical storage of lithium into MWNTs were investigated by various electrochemical testing techniques. The as-prepared MWNTs demonstrate a high reversible capacity of 237 mAh g(-1) with good cycling stability at a current density of 30 mA g(-1). Upon illumination, the reversible capacity for the MWNTs reaches about 270 mAh g(-1) at the initial cycle, and remains above 250 mAh g(-1) after 25 cycles. The results from CV and EIS analysis reveal that the light irradiation on the MWNTs may allow easy insertion/extraction of lithium into/from the nanotubes, and therefore leading to higher reversible capacity than that without light irradiation. (c) 2007 Published by Elsevier B.V.