A thorough study on the F-decoration of χ3 borophene and enhancement of anodic performance of Lithium-ion batteries

Abstract

χ3 borophene is a promising 2D anode material in Lithium-ion batteries, but its pristine structure needs to be improved for increasing its specific capacity and Li diffusivity. For this purpose, the decoration of χ3 with the Fluorine atom was investigated using the density functional theory. Two F-decorated χ3 configurations (Fχ3-A and Fχ3-B) with very close energy and good kinetic stability were identified for the Li storage. Li atoms were gradually loaded on both configurations and the results showed a maximum specific capacity of 1396 mAh/g for the Fχ3-B structure which thermodynamically is a slightly lower stable configuration. The interaction of the Li atom with the surface is stronger in this configuration and resulting in −1.75 eV adsorption energy. The PDOS and band structure analysis showed a good metallic characteristic of the surface during lithiation process. The Li diffusion barrier in this structure is extremely low, 0.21 eV, which enables very fast Li diffusion on the surface. Also, this study demonstrated the importance of considering the different configurations resulting from decorating a structure, with proper thermodynamic and kinetic stability, in the computational investigation. As in this study, for F-decorated χ3 borophene, the configuration with lower stability and symmetry showed better results in all storage parameters of Li atoms.