Li containing endohedral SWCNT: DFT study of the structural and electronic properties

Abstract We investigate the geometrical structures, relative stabilities, and electronic properties of lithium-doped endohedrally to the single-walled carbon nanotubes (5,0), (6,0), (7,0), (8,0), Contreras-Torres et al. (2008) [7], and (Matsubara et al., 2013 [8]), through DFT calculations. The obtained optimized geometries reveal that Li atoms insertion dramatically modifies the nanotube structures. Averaged binding energies, fragmentation energies, second-order energy differences, and Mulliken population analysis are expressed as Li concentration functions. Results reveal Fermi level displacement towards the conduction band due to the Li atoms' charge transfer to the nanotube walls. Stability analysis identifies the complexes with superior relative stability. In particular, nanotubes (7.7) and (8.8) show storage capacities that exceed the graphite's intercalation limit.