Ab Initio Analysis of Periodic Self-Assembly Phases of Borophene as Anode Material for Na-Ion Batteries

Abstract

In this work, the use of periodic self-assembly phases of borophene as anode material for Na-ion batteries is carefully studied, by employing first-principle calculations. Na atom adsorptions on β₁₂-χ₃-β₁₂ and χ₃-β₁₂-χ₃ were analyzed, by investigating the most stable adsorption locations and the trend of adsorption energies with Na concentration increment. The results demonstrate that the metallic behavior of both phases remains unchanged after the adsorption of Na. Furthermore, the studied phases show acceptable wettability toward different metal salts and solvent molecules in the Na-ion battery systems. For β₁₂-χ₃-β₁₂ and χ₃-β₁₂-χ₃ phases, the calculated minimum energy paths for Na-ion diffusion are 0.22 and 0.24 eV; the theoretical specific capacities are 1264 mAh/g and 1536 mAh/g; and open-circuit voltages are 2.3 and 2.45 V, respectively. The results suggest that periodic self-assembly phases of borophene are promising anode materials with large capacity and high rate capability for Na-ion batteries.