Hydrogen storage in Li-doped charged single-walled carbon nanotubes

Density functional calculations have been carried out to investigate the interaction of hydrogen molecules with Li-doped charged single-walled carbon nanotubes (SWNTs). The results show that binding of H2 on positively charged Li-doped SWNTs is enhanced compared with that on uncharged systems. As the charge of the Li-doped SWNTs increases, the binding energy of H2 increases with the largest binding energy of 0.26 eV. The reason for the increase in H2 binding energy is that the positively charged tube improves the charge transfer from Li atom to the tube and make the Li atom more ionized, which strengthens the polarization interaction between H2 and Li atom.