Density Functional Theory Studies of Si₂BN Nanosheets as Anode Materials for Magnesium-Ion Batteries

The unique structural characteristics make the 2D materials potential candidates for designing negative electrodes for rechargeable energy storage devices. Here, by employing density functional theory (DFT) calculations, we study the precise viability of using Si 2 BN, a graphene-like 2D material, as a high-capacity anode material for Mg-ion battery (MIB) application. The favorable Mg-adsorption sites with maximum possible coverage effect are explored in detail. It is found that the Si 2 BN sheet can be adsorbed to a configuration of Mg 8 Si 16 B 8 N 8, which proposes a theoretical capacity of 647.896 mA h g –1 for divalent Mg 2+ -ion battery applications. The average open-circuit voltage of 0.6–0.7 V and intercalation migration energy barrier in the range of 0.08–0.35 eV make Si 2 BN one of the most promising anode materials for MIB applications. The porous Si 2 BN with high structural stability and metallic electronic structures along with the low Mg 2+ -ion migration barrier energies predict high electron and Mg-ion conductivity, ensuring fast charge/discharge cyclic performance. The above-mentioned findings validate that the Si 2 BN sheet can work as an excellent high-performance anode material for MIBs.