First-Principles Study
of Lithium Adsorption and Diffusion
on Graphene with Point Defects
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Abstract
To understand the effect of point defects on the Li adsorption
on graphene, we have studied the adsorption and diffusion of lithium
on graphene with divacancy and Stone–Wales defect using the
first-principles calculations. Our results show that in the presence
of divacancy Li adatom energetically prefers the hollow site above
the center of an octagonal ring rather than the top sites of carbon
atoms next to vacancy site. In the case of Stone–Wales defect,
Li atom is energetically favorable to be adsorbed on the top site
of carbon atom in a pentagonal ring shared with two hexagonal rings,
and such adsorption results in a bucking of graphene sheet. For divacancy
and Stone–Wales defects in graphene, their interactions with
a Li adatom are attractive, suggesting that the presence of point
defects would enhance the Li adsorption on graphene. The difference
charge density and the Bader charge analysis both show that there
is a significant charge transfer from Li adatom to it nearest neighbor
carbon atoms