Effect of stacking structure on lithium adsorption and diffusion in bilayer black phosphorene

Abstract

Intercalation of lithium in few-layer phosphorene has aroused great concern because of the prospects of few-layer phosphorene as an anode material for high-performance lithium-ion batteries (LIBs). In this paper, we adopt first-principles calculations to explore in detail the effects of stacking structure of bilayer black phosphorene (BBP) on the adsorption and diffusion of lithium in BBP. Our calculated results indicate that Li energetically prefers to intercalate within rather than adsorb outside BBP, and it exists in a cationic state. Moreover, the stacking structure of BBP has very important effects on Li adsorption, the open-circuit voltage, and Li diffusion in BBP. Additionally, Li diffusion in BBP exhibits directional preference, with diffusing along the zigzag direction being easier. The analyses of the potential distribution indicate that the puckered honeycomb structure of monolayer phosphorene and the stacking structure of BBP greatly cause low-potential channels along the zigzag direction, which directly lead to the directional preference in Li diffusion. More interestingly, our results suggest that BBP with AC stacking is the most beneficial for Li adsorption and diffusion. These findings suggest that changing the stacking structure of BBP is one possible way to rationally design the anode material in high charge/discharge rate LIBs based on BBP.