The electrochemical intercalation of lithium has been studied by cyclic voltammetry experiments at single wall carbon nanotubes (SWCNTs) chemically attached at Pt electrodes with 4-aminothiophenol (4ATP). Cyclic voltammetric studies of Li+ at SWCNT/4ATP/Pt electrodes were done evaluate the reversibility of Li intercalation. High-resolution X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and reflection–absorption infrared spectroscopy were done to characterize the structural changes of SWCNTs/4-ATP/Pt electrodes upon electrochemical lithium intercalation. The reversible energy capacity obtained from charge/discharge studies showed a change from 538mAh/g at the first charge/discharge cycle to 703mAh/g, at the fifth cycle. The calculated Li storage capacity for SWCNTs/4-ATP/Pt electrodes almost doubled the theoretical capacity for Li intercalation in graphite electrodes.