Where E(WS 2 /graphene_xLi) is the total energy of lithiated WS 2 /graphene, E(WS 2 /graphene) is the total energy of non-lithiated WS 2 /graphene heterostructure and E(Li) is the atomic energy of Li-atom and x denotes to the total number of added Li to the heterostructure. The E ad values for the addition of first Li was found to be -1.88, -2.43 and -2.01 eV for case (i), (ii) and (iii), respectively. Hence it is clear that energetically Li prefers to occupy at the interface of the The calculated E ad is the range of -2.33 to -1.99 eV for x = 2 -6. Interestingly, in all these cases, the E ad is higher than that of the cohesive energy of bulk Li-metal (= 1.70 eV), which implies that the intercalated Li atoms will not cluster on the electrode surface. By preventing clustering of Li ions on the WS 2 /graphene electrode, it is possible to suppress the formation of Li-dendrites, and thus ensure the safety of LIBs. Moreover, the lattice expansion during the Li-intercalation was found to less and we could not observer any significant changes on local atomic structure of the heterostructure as well. This persuaded us to study the effect of enhanced Liconcentration on WS 2 /graphene heterostructure. Thus more Li atoms have been deposited on the active sites. Note that for considering higher Li concentration we also considered top graphene sites for Li-adsorption. The relaxed structure of more Li added WS 2 /graphene heterostructures is shown in Figure (refer Supporting Information). Despite the concentration of Li has been increased significantly (x= 18 -27), it is important to observe that in all these cases the E ad values (-1.88 and -1.70 eV), which are still higher than that of Li-metal's cohesive energy. Moreover, we could not find any abnormal changes in the lattice constants of the heterostructure while lithiation. The maximum expansion was measured to be only heterostructure reveals that they are strongly polarized after adsorbing on the WS 2 /graphene heterostructure. It is worth mentioning that C, W, and S receive charge from the Li in this heterostructure. For a better understand, we have resolved the Bader charge of lithiated heterostructure into two components, i.e., Bader charge of graphene and Bader charge of WS 2 , as depicted in Figure . For obtaining the latter, we have summed up the Bader charges of W and S. As seen from Figure (d) that the Bader charge of WS 2 is larger than that of graphene in all the cases. Here, the Li interacting S atoms receive majority of the charges followed by C and W. The higher charge transfer from Li to S is attributed to the greater electronegativity of S than C and W. Furthermore to understand the effect of lithiation of WS 2 /graphene heterostructure on the electronic properties, we deduced electronic DOS and DOS we understood that the addition of Li to WS 2 /graphene heterostructure increases its electronic conductivity. Also, the shifting of DOS to lower energy region enhances the electronic stability of the heterostructure.