Functionalization of hydrogenated graphene by polylithiated species for efficient hydrogen storage

The hydrogen (H₂) storage capacity of defected graphane (CH) functionalized by polylithiated species CLi₃ and CLi₄ has been investigated by means of first-principles DFT calculations. The stability and electronic structures of these potential H₂ storage materials have also been studied. The binding of these lithium rich species (CLi₃, CLi₄) to the CH sheet has been found to be strong enough to avoid clustering. The nature of bonding in C–Li and C–C has been revealed by Bader charge analysis. It has been found that when both sides of CH sheet are functionalized by polylithiated species, a storage capacity of more than 13 wt% can be achieved with adsorption energies of H₂ in the range of 0.25 eV–0.35 eV, which is suitable for an efficient H₂ storage.