Fig 12. The variation in the potential energy and
temperature of a H2 molecule adsorbed for a) Li
decorated SV silicene and b) Li decorated SW silicene at 300 K.
To get a better understanding of the viability of these systems as
hydrogen storage media, the defective silicene substrates were decorated
with Li atoms both above and below the silicene monolayer and were
allowed to relax. The relaxed configurations seen in Fig. 13. show that
the two Li atoms bind to different Si atoms in the case of SW silicene.
The upper Li atom binds to four Si atoms labelled 11, 12, 14 and 21 in
Fig. 10 with the other Li atom binding to atoms 19, 21, 23 and 35. The
two Li atoms in the SV silicene monolayer bind to three Si atom each.
The average Li binding energies were found to be slightly lower in these
double side decorated systems with the SV silicene system still showing
higher binding energy of -3.14 eV/Li compared to that of SW silicene
which was measured to be -2.57 eV/Li. It was observed that even upon
decorating the Li atoms on both sides of the substrate, the average Li
binding energy remained above the cohesive energy of Li. The average
Si-Li bond lengths were found to be larger than the single side Li
decorated systems measuring to be 2.76 Å and 2.60 Å for the SW silicene
and SV silicene systems, which could relate to the slightly lesser
binding energies in this case.