Graphene-like BGe monolayer as anode material for metal-ions batteries: Computational predictions

Magnesium-, calcium- and potassium-ion batteries (MIBs, CIBs and PIBs) have attracted extraordinary attention as alternative batteries of lithium-ion batteries, due to their due to their abundancies, the low cost, safety. Herein, we investigated the suitability of BGe monolayer as anode material for MIBs, CIBs, and PIBs by using firstprinciples calculations in framework of density functional theory (DFT). The energy adsorption calculations and the charge transfer analysis show that the hollow site is the most favorable site for Mg, Ca, and K atoms adsorption on the BGe monolayer. In addition, the BGe monolayer has remained the same, preserving its metallic behavior after Mg, Ca and K atoms adsorption, which is suitable for batteries applications. The open circuit voltage ranges from 1.03 V to 1.02, 1.86 V to 1.67 V, and 2.85 V to 2.28 V for Mg, Ca, and K, respectively. Especially, the BGe monolayer exhibits a high theoretical specific capacity, up to 1284.63 mAhg(-1) for Mg and Ca, and 642.31 mAhg(-1) for K, which are higher than other monolayers. In addition, the BGe monolayer can provide a good charging-discharging processes with a low diffusion barrier of 0.80, 0.52, and 0.17 eV for Mg, Ca, and K-ion, respectively. All these properties indicate that the BGe monolayer is promising anode material for Mg/Ca/K ion batteries.