Electrochemical reduction of natural graphite was carried out in 1M LiClO[sub 4] ethylene carbonate (EC)/1,2-dimethoxyethane (DME) solution at 30 C. Natural graphite was reduced stepwise to LiC[sub 6]. The staging phenomenon was observed by X-ray diffraction (XRD). The first stage and the second stage compounds were identified as a commensurate structure in which lithium atoms form a close-packed two-dimensional array. A second-stage compound (LiC[sub 18]) with a different in-plane lithium ordering based on a LiC[sub 9] two-dimensional packing in lithium intercalated sheets also was observed; also third, fourth-stage compounds were identified. The electrochemical oxidation of the first-stage compound (LiC[sub 6]) was examined and shown to reversible over the entire range, i.e., C[sub 6] + xLi [r reversible] Li[sub x]C[sub 6]. The reaction mechanism for the reduction of graphite and the oxidation of the first-stage compound are discussed in relation to the staging phenomenon from the detailed open-circuit voltage and XRD data. The chemical potential of LiC[sub 6] was estimated to be [minus]3.6 kcal mol from the observed reversible potential. The feasibility of using a lithium-graphite intercalation compound in lithium ion (shuttlecock) cells is described, and the innovative secondary systems, C[sub 6]/LiCoO[sub 2] and C[sub 6]/LiNiO[sub 2] fabricated in discharged states,more » are demonstrated.« less