Initially
single H2 adsorption was modelled onto these Li
decorated monolayers by placing one H2 at a distance of
2 Å from the bound Li atoms and allowing the systems to relax. These
relaxed configurations can be seen in Fig. 15. H2molecules were seen to adsorb more strongly in these double-sided
decorated systems with the highest average H2 binding
energy seen in the Li decorated SV system of -0.388
eV/H2. In order to measure the gravimetric densities for
the lithium decorated systems, equal number of H2molecules were placed in the vicinity of both the Li atoms and the
systems were allowed to relax. It was seen that, the average
H2 adsorption energies remained negative until 28
H2 molecules were adsorbed on both the substrates with
the Li decorated SV silicene showing the highest gravimetric density of
5.97 wt% out of the two systems. The average distance between the Li
atoms and the H2 molecules was measured in both cases
and was found to be below 2.6 Å with the farthest H2molecule in each case being less than 2.8 Å away, indicating that all
the H2 molecules were sufficiently adsorbed. The relaxed
structures of the 28 H2 adsorbed Li decorated SV and SW
silicene can be seen in Fig. 16.