The results of the electrochemical intercalation of lithium into raw carbon nanotubes in 1M LiClO4 EC/DEC (50:50) are presented here. We have examined the correlation between structure and charge-discharge characteristics of the raw carbon nanotubes produced by are discharge method; it was found that the carbon nanotubes with closed ends possess a reversible capacity of 125 mA h g(-1). Surface film formation occurred during the first discharge at 0.8 V vs. Li+/Li. Taking into account the difficulty of lithium intercalation into the layers or hollows of the end-closed tubes, we propose a surface mechanism in which the naked surfaces of the carbon nanotubes and carbon nanoparticles are capable of storing lithium species.