First-principles hydrogen adsorption properties of Li-decorated ThMoB 4 -type graphene

The hydrogen storage (1–10H 2 ) properties of single- and double-side lithium decorated ThMoB 4 -type graphene (Li/ThMoB 4 C) are systematically investigated by density functional first-principles calculations within Dmol 3 package. After well-converged geometry optimizations, it is found that the binding energy of Li adatom is higher enough, and there is no adatom clustering. The average adsorption energies of 1–6 H 2 deviate in 0.20–0.27 eV/H 2 range, which is providing a convenient physical adsorption-desorption cycle. A detailed examination of the binding mechanism between the constituents of the H 2 adsorbed Li-decorated systems is presented by density of states, Mulliken charge analysis, electron density and density difference calculations. For further decoration and adsorption with 12Li adatom and 72H 2 molecules, the computation yields a high gravimetric density of 14.5 wt % with the acceptable adsorption energy. In this way, it is concluded that Li/ThMoB 4 system can be considered as a promising hydrogen storage medium.