Exploring the Full Potential of Functional Si2BN Nanoribbons As Highly Reversible Anode Materials for Mg-Ion Battery

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 one-dimensional 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.