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 Si2BN, 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 Si2BN sheet can be adsorbed to a configuration of Mg8Si16B8N8, which proposes a theoretical capacity of 647.896 mA h g-1 for divalent Mg2+-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 Si2BN one of the most promising anode materials for MIB applications. The porous Si2BN with high structural stability and metallic electronic structures along with the low Mg2+-ion migration barrier energies predict high electron and Mg-ion conductivity, ensuring fast charge/discharge cyclic performance. The above-mentioned findings validate that the Si2BN sheet can work as an excellent high-performance anode material for MIBs.