The prospects of phosphorene as an anode material for high-performance lithium-ion batteries: a fundamental study

Abstract

To completely understand lithium adsorption, diffusion, and capacity on the surface of phosphorene and, therefore, the prospects of phosphorene as an anode material for high-performance lithium-ion batteries (LIBs), we carried out density-functional-theory calculations and studied the lithium adsorption energy landscape, the lithium diffusion mobility, the lithium intercalation, and the lithium capacity of phosphorene. We also carried out, for the very first time, experimental measurement of the lithium capacity of phosphorene. Our calculations show that the lithium diffusion mobility along the zigzag direction in the valley of phosphorene was about 7 to 11 orders of magnitude faster than that along the other directions, indicating its ultrafast and anisotropic diffusivity. The lithium intercalation in phosphorene was studied by considering various Li P configurations (n = 1-16) including single-side and double-side adsorptions. We found that phosphorene could accommodate up to a ratio of one Li per P atom (i.e. LiP). In particular, we found that, even at a high Li concentration (e.g. x = 1 in Li P), there was no lithium clustering, and the structure of phosphorene (when fractured) is reversible during lithium intercalation. The theoretical value of the lithium capacity for a monolayer phosphorene is predicted to be above 433 mAh g, depending on whether Li atoms are adsorbed on the single side or the double side of phosphorene. Our experimental measurement of the lithium capacity for few-layer phosphorene networks shows a reversible stable value of ∼453 mAh g even after 50 cycles. Our results clearly show that phosphorene, compared to graphene and other two-dimensional materials, has great promise as a novel anode material for high-performance LIBs.

Emerging Applications of Elemental 2D Materials

“…Data from refs. . The inset shows energy profiles of Li diffusion along the armchair and zigzag directions on phosphorene surface.…”

“…c) Charge–discharge voltage versus Li‐ion capacity curves tested at C/10 rate for phosphorene battery anodes. Reproduced with permission . Copyright 2017, IOP Publishing.…”

“…This kind of difference in Li ion diffusion is also present in the puckered structure of phosphorene, where theoretical calculations reveal ultrahigh diffusivity of Li ions along the armchair direction, compared to the zigzag direction. This results in a relatively high Li‐ion capacity of 865 mAh g −1 . While Li‐ion batteries based on borophene have yet to be experimentally realized, multi‐layer phosphorene sheets have already demonstrated potential as battery anodes (Figure c), although issues such as capacity fading and irreversible loss after the first cycle must be solved for their large‐scale applicability.…”

2D Black Phosphorus for Energy Storage and Thermoelectric Applications

“…In addition, the ultrafast diffusion of Li ions along the zigzag directions of phosphorene due to the low shallow energy barrier (0.08 eV) is almost 10 4 and 10 2 times faster than that in graphene and MoS 2 , respectively, indicating that phosphorene possesses potentially excellent Li storage properties . Good reversibility has been also reported due to the self‐recovery of phosphorene monolayer when it is distorted during the intercalation of Li ions at high Li/P ratio . Therefore, favorable features of phosphorene as anodes of LIBs including ultrafast diffusivity, good reversibility, and high open circuit voltage have been demonstrated theoretically as a promising candidate as anodes toward high‐performance LIBs.…”

“…The puckered layer structure of BP provides 2D interstitial space for Li insertion and extraction. Owing to the unique properties of phosphorene, numbers of theoretical calculations have been carried out related to the diffusion of Li ions in phosphorene . It is found that stronger interaction between Li and phosphorene than that in graphene could potentially provide high open circuit voltage and enhance the electrochemical performance accordingly .…”