Adsorption and migration of Li-ion in layered SnSe 2 : a first principle study

The properties of Li-ion adsorption and migration in layered SnSe 2 are systematically investigated using the first principle calculations. It is found that the Li atoms are adsorbed strongly on substrate SnSe 2 , and the binding energy (>3eV) is significantly higher than those on graphene, phosphorene, MoS 2 , and some other two-dimensional (2D) layered materials. Bader charge analysis reveals that almost the whole charge of 2s electron of the Li atom transfers to substrate SnSe 2 and Li exists in the cationic state. The Li-ion migration energy barrier for monolayer SnSe 2 is 0.197eV, which is significantly lower than those for graphene, MoS 2 , and other 2D materials. The average open-circuit voltage of 3.05V is predicted in the monolayer SnSe 2 -based Li-ion battery. The Li intercalation also leads to a transition from semiconductor to metallic state and gives rise to a good electrical conductivity. These findings provide insights into the Li-ion adsorption properties and migration mechanism in layered transition-metal dichalcogenide.