Metallic MoScP2Se6 monolayer with ultrafast ion diffusion for high-performance sodium and potassium-ion batteries

The increasing demand for advanced energy-storage systems beyond lithium-ion batteries has stimulated intensive interest in sodium-ion and potassium-ion batteries owing to the abundance and low cost of sodium and potassium. However, identifying anode materials that simultaneously exhibit high capacity, fast ion diffusion, and robust structural stability remains a major challenge. Herein, the anodic performance of a MoScP 2 Se 6 monolayer for Na + and K + ion batteries is systematically investigated using first-principles density functional theory calculations. The polyanion-bridged chalcogenide framework provides intrinsic structural robustness and wide diffusion channels for alkali-ion transport. Ab initio molecular dynamics simulations at 300 K and phonon dispersion analysis confirm excellent thermal and dynamical stability. Electronic structure calculations reveal intrinsic metallicity dominated by Mo 4d and Se 4p states, enabling efficient electron transport. Theoretical specific capacities of 713 mAh g −1 (Na + ) and 687 mAh g −1 (K + ) are achieved, exceeding those of many reported two-dimensional anodes. In addition, low migration barriers of 0.18–0.22 eV for Na + and 0.11–0.14 eV for K + indicate rapid ion diffusion and favorable rate capability. These results highlight MoScP 2 Se 6 as a promising high-rate anode candidate for next-generation alkali-ion batteries.