First principles predictions of Na and K storage in layered SnSe2

Recent years have witnessed a flow of research in two-dimensional (2D) materials for the development of new rechargeable metal-ion battery systems due to their large surface areas and plenty accommodating sites for the adsorption of metal ions. Inspired from the experimental synthesis of 2D SnSe2 for Na ion batteries, we speculate the adsorption and diffusion mechanism of Na and K on SnSe2 by means of computational approach. Our results disclose strong adsorption strength with Na and K loading, confirming the favorable electrochemical reactions between adsorbates (Na/K) and the host SnSe2. The electronic structure of the host material is displaying the conductive behavior with Na and K loading. Additionally, the low average voltages for Na (0.68 V) and K (0.48 V), and the high theoretical capacity (387.5 mAhg(-1)) captivate SnSe2 monolayer for Na- and K- ion batteries. Finally, the activation barriers and the energy pathways for Na and K are calculated. The simulated activation barriers for Na and K are as low as 0.104 eV and 0.113 eV, respectively. The current study endows that Na and K storage for SnSe2 sheet could be industrious and productive for the commercialization of Na- and K- ion batteries.