Diffusion and condensation of lithium atoms in single-walled carbon nanotubes

We have carried out theoretical investigations to explore the diffusion of lithium on the exteriors and the interiors of single-walled carbon nanotubes (SWNTs). We found that lithium can adsorb on both interior and exterior surfaces with adsorption energy around -2.440.3em0exeV. Lithium has a higher mobility with the diffusion barriers less than 0.20.3em0exeV on both the exteriors and interiors of SWNTs. The diffusion barriers (exo- and endohedral) of lithium depend on the radius and chirality of SWNTs. The lithium capacity trapped inside SWNTs increases with the increasing tube diameter and can be as high as LiC2.6 in a (10,10) SWNT. These lithium atoms tend to form single- or multishelled coaxis nanotubes, together with a linear atomic chain in the axis at low temperature depending on the diameter of SWNTs, suggesting a potential way to synthesize small metal nanotubes and metal nanowires.