Lithium-decorated oxidized porous graphene for hydrogen storage by first principles study

The first-principles calculations are performed to investigate the geometric stability and the hydrogen storage capacity of lithium-decorated oxidized porous graphene (PG). Due to strong interaction between Li and O atom, two stable Li decorated structures have relatively high Li binding energies of 3.84 and 3.04 eV, which could eliminate the clustering problem for Li atoms on PG surface. One doped Li atom could hold five H-2 molecules and the binding energy of each H-2 is above 0.2 eV. The interaction of H-2 molecules with Li atom results from charge exchange between H-2's sigma orbital and Li's 2s orbital. In the final structure with two Li-O groups in one carbon pore, a hydrogen storage capacity of 9.43wt. % could be achieved. By the combination of the advantage of Li decoration and oxidized porous graphene, Li-OPG possesses remarkable geometric stability and high hydrogen storage capacity. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770482]