Remarkable hydrogen storage capacity in Li-decorated graphyne: Theoretical predication

On the basis of first-principles density functional calculations, we predict that Li-decorated graphyne can serve as a promising candidate for hydrogen storage, with a largest storage capacity of 18.6 wt %. The average adsorption energy of hydrogen is about -0.27 eV/H ₂, indicating that the doped system is an ideal hydrogen storage material at ambient conditions. It is proposed that the polarization mechanism, which stems from the electric field induced by the ionic Li coated on the graphyne, plays a key role in the adsorption of H ₂ molecules. Furthermore, the formation of the hydrogen-hydrogen complex also stabilizes the adopted hydrogen molecules.