Adsorption and diffusion of Li/Na atom on blue phosphorene with defects by first-principles calculations

Abstract

Two-dimensional materials such as blue phosphorene (BlueP) as a substitute for conventional anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) have garnered significant attention recently because of their large surface areas, ultrafast intrinsic carrier mobilities, and shorter ion diffusion paths. In this study, the adsorption and diffusion properties of Li and Na ions on BlueP with defects are investigated through first-principles calculations. The calculations show that the adsorption energy increased from −0.64 to −1.50 eV for Li and from −0.72 to −1.61 eV for Na because of defects. Moreover, the defects resulted in middle bands in the density of states of BlueP, indicating enhanced electron localization. This may contribute to an increase in binding energies. However, it is discovered that Li and Na ion diffusion on the surface of BlueP with defects involves a larger migration energy barrier than Li and Na on pristine BlueP, which is disadvantageous to BlueP as a battery anode.