First-Principles Study\nof Lithium Adsorption and Diffusion\non Graphene with Point Defects

Abstract

To understand the effect of point defects on the Li adsorption\non graphene, we have studied the adsorption and diffusion of lithium\non graphene with divacancy and Stone–Wales defect using the\nfirst-principles calculations. Our results show that in the presence\nof divacancy Li adatom energetically prefers the hollow site above\nthe center of an octagonal ring rather than the top sites of carbon\natoms next to vacancy site. In the case of Stone–Wales defect,\nLi atom is energetically favorable to be adsorbed on the top site\nof carbon atom in a pentagonal ring shared with two hexagonal rings,\nand such adsorption results in a bucking of graphene sheet. For divacancy\nand Stone–Wales defects in graphene, their interactions with\na Li adatom are attractive, suggesting that the presence of point\ndefects would enhance the Li adsorption on graphene. The difference\ncharge density and the Bader charge analysis both show that there\nis a significant charge transfer from Li adatom to it nearest neighbor\ncarbon atoms.