Exploring the full potential of functional Si2BN nanoribbons as highly reversible anode materials for Mg-Ion battery

Abstract

Efficient energy storage devices like rechargeable batteries have a vital role in the modern society to cater for an ever-increasing demand of energy. In this context, magnesium-ion batteries (MIBs) have emerged as high-capacity energy storage systems. However, the progress in this area is hindered due to the lack of suitable anode materials for efficient Mg2+ ion storage and diffusion. In this study, using state-of-the-art density functional theory (DFT) simulations, we have systematically investigated novel onedimensional Si2BN nanoribbons as anode materials for MIBs applications. Our calculations confirm the structural stability and metallic character of pristine (Si2BN) and hydrogen functionalized (Si2BN-H) nanoribbons upon Mg adsorptions. We find Mg adsorption energies in the ranges of −1.2 to −1.8 (−1.8 to −2.0) eV for 25% (20%) coverages in Si2BN (Si2BN-H), respectively, which are strong enough to mitigate the Mg aggregation. Maximum specific capacities of 661.865 (550.421) mAh g−1 and open-circuit voltages of 0.7−1.1 (0.6−0.8) V are found for Si2BN (Si2BN-H), respectively. Diffusion barrier calculations based on nudge elastic band (NEB) methods reveal a relatively low barrier of 0.14 eV, which guarantees a robust diffusion of Mg ions and faster charge/ discharge capability of Si2BN nanoribbons. These intriguing features confirm the potential of functional Si2BN nanoribbons as promising anode materials for MIBs.