Theoretical investigation of the V2BX2 (X = S, Se, and Te) monolayers as anode materials for Na-ion batteries

Abstract

The structural, electronic, and electrochemical properties of chalcogen-functionalized V2BX2 (X = S, Se, and Te) monolayers as anode materials for Na-ion batteries (NIBs) were systematically investigated using the first-principles method. It is found that the V2BX2 monolayers exhibit good dynamical stability, thermal stability, and electronic conductivity. Furthermore, the small diffusion barriers (about 0.1 eV) display the fast charge/discharge rate, the low average open-circuit voltages (OCVs) (0.282–0.163 V) are favorable for high-voltage NIBs, and the small lattice changes (less than 5 %) demonstrate good cycling performance. Especially, the V2BS2 and V2BSe2 have high specific capacities of 605.67 and 395.59 mA h g−1 for NIBs, respectively. All of these excellent properties suggest that V2BX2 monolayers could be promising anode materials for NIBs.