Monolayer, Bilayer, and Heterostructure Arsenene as Potential Anode Materials for Magnesium-Ion Batteries: A First-Principles Study
Abstract
Magnesium-ion batteries (MIBs) have emerged as an attractive candidate for high-performance energy storage devices because of the low-cost and dendrite-free Mg metal anodes. However, the passivation layers formed on Mg anodes result in the sluggish kinetics of Mg2+ ion diffusion. Herein, we report Mg insertion materials based on arsenene as alternative anodes to Mg metal. Our first-principles calculations reveal the following findings: (1) Mg can be adsorbed on monolayer (bilayer) arsenene and arsenene/graphene heterostructure with adsorption energies in the range of 0.82–2.48 eV, suggesting Mg-adsorbed arsenene systems with good energetic stability. (2) Monolayer arsenene has a ∼3 times higher specific capacity (1429.41 mA h g–1) than the arsenene bilayer and arsenene/graphene heterostructure. Among them, the arsenene monolayer possesses the lowest average open-circuit voltage. (3) In comparison with bilayer arsenene, the arsenene monolayer and heterostructure exhibit low barriers (0.08–0.33 eV) for Mg diffusion, corresponding to a fast charge/discharge capability. (4) During the magnesiation process, the small volume changes (<16%) of arsenene-based materials suggest a good cycling reversibility. Therefore, the combination of ultrahigh capacity, good Mg mobility, low average open-circuit voltage, and high structural stability renders the arsenene monolayer a promising anode material in MIBs.