First-principles investigations to evaluate Mo2B monolayers as promising two-dimensional anode materials for Mg-ion batteries

Abstract

Magnesium-ion batteries have the potential to replace the current commercial Li-ion batteries due to their eco-friendliness and cost-effectiveness. However, because of the strong polarization of Mg ions, conventional electrode materials find it difficult to capture Mg ions. In order to find an excellent anode material for Mg-ion batteries, we used density functional theory to evaluate the applicability of T-type and H-type Mo2B monolayers as electrode materials for Mg-ion batteries. The simulation results show that the adsorption energies of T-type and H-type Mo2B monolayers for Mg atoms are -1.08 eV and -0.78 eV (-2.16 eV and -2.14 eV with the solvent effect), respectively, which are sufficient to ensure the stability of the procession of magnetization. In addition, the ultra-low diffusion barriers (0.057 eV/0.110 eV) of Mg atoms on their surfaces show a good charge and discharge rate. The theoretical specific capacity (529 mA h g-1) and the theoretical voltages (0.65 V/0.40 V) indicate that T-type and H-type Mo2B monolayers are promising anode materials for Mg-ion batteries.