Li-decorated 2D Irida-graphene as a potential hydrogen storage material: A dispersion-corrected density functional theory calculations

In this research, density functional theory with van der Waals (vdW) dispersion-corrected method is employed to systematically investigate H2 adsorption behaviors on Li-decorated two-dimensional (2D) Irida-graphene (IG). Our results expose that the adsorption performance between H2 and original IG is extremely weak, while Li-decorated IG can significantly promote H2 adsorption capability. Due to a large binding energy, Li atoms strongly bind on the top of octagonal carbon-ring of IG and prevent decorated Li atoms from aggregation. Moreover, single-sided Li decorated IG and double-sided Li decorated IG can adsorb up to 16H2 molecules and 24H2 molecules with the corresponding H2 adsorption energy of −0.230 eV/H2 and −0.276 eV/H2, respectively. Meanwhile, the calculated H2 adsorption energy for each H2-adsorbed Li-decorated IG configuration falls into the range of −0.1 eV/H2 and −0.4 eV/H2 for reversible hydrogen storage. In addition, the obtained hydrogen storage gravimetric density achieves 7.06 wt%, which surpasses the latest standard of 6.5 wt% established by U.S. Department of Energy (DOE). These findings reveals Li-decorated IG can be served as an outstanding hydrogen storage material for on board mobile applications.