Chemical Properties of Lithium Cluster (Li-x, x=2-8) on Stone-Wales Defect Graphene Sheet: A DFT Study

摘要

Using the first-principle calculations, we have investigated the chemical properties of small lithium clusters adsorbed on Stone-Wales defected graphene (SW-GN) sheet. The DFT study shows that the Li clusters orient above the defect region in the SW-GN sheet. A single SW defect could accommodate a maximum of four Li atoms. The interaction energy shows that the presence of the SW defect in the graphene sheet enhances the interaction between the SW-GN sheet and Li clusters. As the cluster size increases, the interaction between the defective sheet and Li clusters increases. The interaction energy and cohesive energy per Li atom show a decrease in energy value as the Li cluster size increases, and this result is substantiated with adsorption capacity value. The charge transfer indicates that SW defected graphene acts as an electron acceptor while the clusters behave as donors. The DOS plot indicates that the adsorption of Li clusters has influenced a change in the electronic property of the bare SW graphene sheet, thereby shifting the Fermi level to the conduction band. From all the above results, we infer that SW defected graphene proves to be a prospective anode material by reducing the clustering of Li atoms, thereby hindering dendrite formation. Further improvement in the anodic material could be established through an increase in the defect ratio in the graphene sheet.