Diffusion dynamics of lithium ion and atom on graphene surfaces

Recent theoretical studies of the diffusion dynamics of lithium ions and atoms (Li+ and Li) in carbon materials have been reviewed. Graphene, graphene flakes, and fullerene (C60) were examined as the carbon materials. The direct ab initio molecular dynamics (MD) method, used in the present study, is a hybrid technique composed of ab initio molecular orbital and MD methods. The diffusion of Li+ ions (atoms) and their interaction with the carbon materials are treated at the quantum mechanical level. The diffusion path and reaction mechanism obtained by the direct ab initio MD method were significantly different from those of a usual classical MD calculation. Details of the diffusion dynamics of the lithium were discussed on the basis of theoretical results.