Herein, we report the results of density functional theory (DFT) calculations on van der Waals (VdW) heterostructure formed by vertically stacking single-layers of tungsten disulfide and graphene (WS2/graphene) for employing them in Lithium-ion batteries (LIBs) as an anode material. The electronic properties of the heterostructure reveal that the graphene layer helps to improve the electronic conductivity of this hybrid system. Indeed, the charge transfer from Li to WS2/graphene heterostructure further improves their metallic character. Moreover, the Li binding energy in this heterostructure was higher than that of Li-metal's cohesive energy, which indicates the possibility of Li-dendrite formation in this WS2/graphene electrode is low. The effect of heteroatoms such B and N doping on graphene layer of the heterostructure on Li-adsorption ability also explored here. The results revealed that B-doping improves the Li-adsorption energy. Interestingly, the calculated open-circuit voltage (OCV) and Li-diffusion barrier also favor that this heterostructure can act as a potential candidate for LIB anode applications.
WS2-Graphene van der Waals Heterostructure as Promising Anode Material for Lithium-Ion Batteries: First Principles Approach
(1) Ball and stick models of single layer graphene and WS2 (2) Lattice constant optimization of WS2/graphene heterostructure, (3) Inter layer distance vs binding energy diagram for WS2/graphene heterostructure, (4) Band structure of single layer WS2 and graphene sheet, (5) Charge density difference of WS2/graphene heterostructure, (6) Adsorption of Li on various sites of WS2/graphene heterostructure, (7) Various mode of adsorption of Li on WS2/graphene heterostructure, (8) Various adsorption sites in the interface of WS2/graphene heterostructure and corresponding Li-adsorption energy plot, (9) Structural characteristics various lithiated systems, (10) Adsorption of Li on WS2 and graphene (11) Optimized structures of highly lithiated WS2/graphene heterostructure, (12) Local structure showing the formation of W-W bonds, (13) Band structures showing the splitting of Dirac cone in WS2/graphene heterostructure,(14) Energy barrier for the diffusion of Li thorough the interface of WS2/graphene heterostructure,(15) Energy barrier for the diffusion of Li thorough the surface of WS2/graphene heterostructure.