A first-principles research of two-dimensional Sc2N monolayer as an anode material for Na, K, Mg, and Ca ion batteries

Abstract

With the continuous growth in global energy demand and the challenges posed by the intermittent nature of renewable energy, the development of efficient energy storage systems has become increasingly critical. This has spurred significant interest in non‑lithium metal-ion batteries and their high-performance anode materials. Based on first-principles calculations, this study systematically investigates the potential of Sc₂N monolayers as anode materials for Na, K, Mg, and Ca ion batteries. The results demonstrate that Sc₂N monolayers exhibit excellent mechanical, thermodynamic, and kinetic stability, along with outstanding electrical conductivity, making them good candidates for the next-generation anode materials. The theoretical capacities and open-circuit voltages of Sc₂N monolayers for metal ions are as follows: Na (1547.4 mAh/g, 0.321 V), K (343.9 mAh/g, 0.401 V), Mg (2063.2 mAh/g, 0.211 V), and Ca (458.5 mAh/g, 0.292 V). Sc₂N monolayers also exhibit low ion diffusion barriers of 10.1, 9.7, 32.3, and 38.3 meV for Na, K, Mg, and Ca, respectively. Ab Initio molecular dynamics (AIMD) simulations conducted at 300, 500, and 700 K under fully loaded Na and Mg conditions further confirm the excellent thermal stability of Sc₂N monolayers. Therefore, Sc₂N monolayers demonstrate high theoretical capacities, low diffusion barriers, and ideal open-circuit voltages for Na and Mg ion batteries, with superior safety features, underscoring their significant potential for applications in energy storage technologies.