Molecular Design of High Performance Molecular Devices Based on Direct Ab-initio Molecular Dynamics Method: Diffusion of Lithium Ion on Fluorinated Amorphous Carbon

摘要

Hybrid density functional theory (DFT) calculations have been carried out for the lithium adsorbed on a fluorinated graphene surface (F-graphene, C_(96)F_(24)) to elucidate the effect of fluorination of amorphous carbon on the diffusion mechanism of lithium ion. Also, direct molecular orbital-molecular dynamics (MO-MD) calculation [H. Tachikawa and A. Shimizu: J. Phys. Chem. B 109 (2005) 13255] was applied to diffusion processes of the Li~+ ion on F-graphene. The B3LYP/LANL2MB calculation showed that the Li~+ ion is most stabilized around central position of F-graphene, and the energy was gradually instabilized for the edge region. The direct MO-MD calculations showed that the Li~+ ion diffuses on the bulk surface region of F-graphite at 300 K. The nature of the interaction between Li~+ and F-graphene was discussed on the basis of theoretical results.