Hexagonal Scandium Phosphide Monolayer: A High-Performance Anode for Alkali Metal-Ion Batteries

Two-dimensional (2-D) materials with robust structural stability and high surface activity are promising candidates for advanced alkali metal-ion batteries (AIBs) electrodes. Here, we systematically evaluate the potential of hexagonal scandium phosphide (h-ScP) monolayer as an AIB anode through first-principles calculations. The h-ScP monolayer exhibits good thermal stability and dynamic stability, with a semiconducting bandgap of 1.612 eV that transitions to metallic states upon alkali metal-ion adsorption. Strong interfacial interactions are confirmed by negative adsorption energies and significant charge transfer. Ultralow diffusion barriers (0.216 eV for Li, 0.308 eV for K) and high theoretical capacities (>1200 mA h g^-1 for K) are achieved, along with low average open-circuit voltages (<0.33 V for Na/K). Ab initio molecular dynamics simulations validate structural reversibility and thermal stability under high-temperature operational conditions. These comprehensive properties position h-ScP monolayer as a superior anode candidate for high-performance AIBs.