Compare Investigation of Lithiation, Sodiation, and Magnesiation Ion Adsorptions and Diffusions on Monolayer MoS2 for Energy Storages Using First-Principles

Abstract

Effective energy storage and conversion technologies have attracted extensive attention for developing advanced rechargeable batteries. The high-energy capacity of molybdenum disulfide (MoS2) monolayer for Li-ion battery was recently introduced. Compared with Li-ion battery, the growing interests have been concentrated on the Na-ion batteries and Mg-ion batteries based on two-dimensional nanomaterials. Though the Li- and Mg-ion batteries based on MoS2 nano-tubes have been theoretically studied, knowledge about the Na, Mg- ion batteries with MoS2 monolayer is lack. To look insight into the capability of energy storage, herein, we performed the first-principles calculations to investigate the Li, Na, and Mg ions adsorption on and diffusion through the MoS2 monolayer. The binding energies of these ions at different sites, including top of S atom, top of Mo atom, and hole site (centre of hexagonal lattice), were measured. It was found that the binding energy at the top of Mo atom is the largest, which indicates the possibly stable absorption configuration. Energy barriers of ions passing through and diffusing over the MoS2 monolayer were also calculated. Results show that the Mg-ion has a largest energy barrier to pass through the MoS2 layer and a smallest energy barrier to diffuse above the MoS2 layer. The band structures and density of states of MoS2 before and after ion absorption were also calculated and discussed.