Diffusion of the Li+ Ion on C60: A DFT and Molecular Dynamics Study

The interaction of the Li+ ion with fullerene (C-60) surface has been investigated by means of density functional theory (DFT) and direct molecular orbital-molecular dynamics (MO-MD) methods. It was found that the Li+ ion can bind two stable binding sites, hexagonal and pentagonal sites where Li+ binds to six- and five-membered rings composed of carbon atoms, respectively. The saddle points between binding sites were found: activation energies for (5-6) and (6-6) saddle points were calculated to be 2.7 and 3.6 kcal/mol at the B3LYP/6-311G(d,p) level, respectively, where (5-6) means a saddle point between pentagonal and hexagonal sites. The dynamics calculations showed that the Li+ ion diffuses between stable points near the saddle points at 250 K. The electronic states of Li+ ion along the diffusion path on C-60 were discussed on the basis of theoretical results.