Molecular dynamic investigations of hydrogen storage efficiency of graphene sheets with the bubble structure

In this paper, we designed a new type of 3D graphene bubble structure for hydrogen storage in theory. The graphene-based structures are constructed with different sizes of semi-ellipsoidal graphene bubbles. The hydrogen storage efficiency of the graphene bubble structures at ambient conditions (P = 1.0 bar and T = 300 K) is calculated using molecular dynamic (MD) simulations. The effects of number of graphene layers and density and size of bubbles are systematically investigated in the isothermal-isobaric (NPT) ensemble. The MD results reveal that at ambient conditions, the bubble models can achieve the highest volumetric hydrogen storage efficiency of 45 kg/m(3) and gravimetric hydrogen storage efficiency of 3.75 wt%. The maximum pressures in the bubbles are also evaluated.