Comprehensive elucidation of crystal structures of lithium-intercalated graphite

Graphite is widely used as an anode material in almost all Lithium (Li)-ion batteries. Li is easily absorbed into the layer structure of graphite, forming lithium-carbon intercalation compounds LixC between LiC6 and C. However, although they are simple binary compounds, their structures have been left unelucidated for a long time, especially for the compounds between LiC12 and C. This is probably because the Li concentrations are too low to make a big difference in diffraction pattern between these Li-intercalated graphites and pure graphite. It has been known, however, that they have stacked layer structures, which strongly suggests that they are very likely to form modulated structures. Structural analyses of these compounds based on the modulated structure model were successfully performed, comprehensively elucidating all the LixC structures lying between LiC6 and C.