Graphene-like SbP3 monolayer as a potential anode material for Na/K ion batteries: First-principles calculations

Abstract

Progress in rechargeable alkali metal ion batteries (AMIBs) mainly depends on the improvement of high-performance anode materials. To evaluate the feasibility of using SbP₃ monolayer as an anode material for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs), comprehensive first-principles calculations were performed. Validation of the dynamic stability of the SbP₃ monolayer is ensured by the analysis of the phonon dispersion spectrum, which reveals no imaginary frequencies throughout the entire Brillouin zone. Our study reveals that the adsorption of Na and K ions can lead to a phase transition from semiconductor to metal in the SbP₃ monolayer, highlighting a significant finding. After absorbing six layers of sodium and potassium ions on both sides of the SbP₃ monolayer, the average open-circuit voltages measured were 1.44 V for each ion. Through the multilayer adsorption of sodium and potassium ions on both surfaces of the SbP₃ monolayer, an impressive specific storage capacity of 749 mAhg⁻¹ was achieved. The SbP₃ monolayer exhibits high mobilities due to its low diffusion barriers, measuring 0.28 eV for Na ions and 0.19 eV for K ions. These characteristics suggest that the SbP₃ monolayer is a promising candidate for high-performance anode materials in sodium-ion and potassium-ion batteries.