The interaction and diffusion of lithium atoms in a (5,5) carbon nanotube was studied using density-functional theory. The Li-nanotube interaction perpendicular to the tube axis for a single Li inside and outside the tube was calculated and compared with the Li-graphene interaction obtained using the same technique. Both interactions were similar in the repulsive region but exhibit differences in their attractive part. Nevertheless, they can be described using a common parametrization. The Li-Li interaction was calculated as a function of their separation inside the tube. This interaction was similar to a screened repulsive Coulomb potential at small separations. However, at larger separations, the Li-Li interaction does not vanish and exhibited residual oscillations. This repulsive long-ranged interaction favours concerted diffusion of many Li atoms compared to the independent diffusion of individual Li inside the tube.

Interaction and Concerted Diffusion of Lithium in a (5,5) Carbon Nanotube. M.Khantha, N.A.Cordero, J.A.Alonso, M.Cawkwell, L.A.Girifalco: Physical Review B, 2008, 78[11], 115430