Oxygen-substituted borophene as a potential anode material for Li/Na-ion batteries: a first principles study

Abstract

Two-dimensional graphene-like hexagonal borophene sheets (HBSs) have a thermodynamically unsteady configuration since boron has one electron less than the carbon in graphene. To overcome this problem, we proposed a novel 2D graphene-like HBS oxide (h-B₃O) in theory, which is designed by substituting partial boron atoms in a HBS with oxygen atoms. Molecular dynamics simulations indicate that h-B₃O has good thermal stability. Besides, we also explored the potential of h-B₃O monolayers as anodes for Li-ion batteries (LIBs) and Na-ion batteries (NIBs) by using first-principles calculations. The results indicated that the h-B₃O monolayer has high adsorption energies (−2.33/−1.70 eV for Li/Na), low diffusion barriers (0.67/0.42 eV for Li/Na) and suitable average open-circuit voltages (0.36/0.32 V for LIBs/NIBs). Particularly, h-B₃O has a large theoretical specific capacity of 1161 mA h g⁻¹ for LIBs. Thus, benefiting from these characteristics, the h-B₃O monolayer is considered as a promising candidate for an anode material for LIBs/NIBs.