Li-decorated graphyne as high-capacity hydrogen storage media: First-principles plane wave calculations

•PBE-GGA and van der Waals corrections are applied for the considered systems.•The Li atom, either at HL site or at HS site, can both adsorb H2 molecules.•The gravimetric density of H2 is 13.0 wt%.•The average adsorption energy of hydrogen molecule is 0.19 eV/H2.

Taking into account the van der Waals correction, the characteristics of the Li-decorated graphyne as the hydrogen storage medium have been explored using first-principles plane wave calculations. We find that Li atom can be adsorbed not only over the center of large hexagon (HL site) but also over the center of small hexagon (HS site). For double-side Li decorations, there are 14H2 molecules can be adsorbed on Li-decorated graphyne primitive cell with the adsorption energy of 0.19 eV/H2. As a result, the hydrogen storage capacity of 13.0 wt% can be obtained. This suggests that the Li-decorated graphyne system can serve as a high-capacity hydrogen storage medium.

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