Adsorption of single alkali-metal atoms (Li, Na, K) over the edge-passivated zigzag blue phosphorene nanoribbons

Abstract

In the wake of blue phosphorene’s theoretical prediction and experimental synthesis, it has emerged as an excellent candidate for anode materials in alkali-metal-ion batteries due to its outstanding electrochemical performance. In the work, we have addressed the impact of edge passivation by both hydrogen (H) and oxygen (O) atoms on single adsorption of different alkali-metal atoms (Li, Na, K) over zigzag blue phosphorene nanoribbons (ZBPNRs) using first-principles calculations. Our results unravel that in the presence of edge H-passivation, the nanoribbon binds alkali-metal atoms inferior to the pristine blue phosphorene with binding energies varying from −1.53 to −1.90eV. A complete suppression of binding even occurs at the passivated edge. By contrast, the binding of adatoms is substantially enhanced by passivating the edge of the nanoribbon with O atom. The enhancement in binding not only appears at the edge but also extends across the entire nanoribbon under study. More importantly, the edge of O-passivation binds alkali-metal atoms most strongly amongst all sites, with adsorption energies between −3.93 and −4.83eV. These observations show that the edge O-passivation is highly important to make the adsorption of alkali-metal atoms over ZBPNRs more stable thermodynamically, which can be used to further tailor the nanoribbon’s electronic and magnetic properties. Overall, strengthening of the binding of these alkali-metal atoms to the ZBPNRs of edge O-passivation has clear technological implications for the design and development of electrochemical energy storage devices.