Theoretical prediction of Be2B monolayer as an ultra-high performance anode material for magnesium-ion batteries

Magnesium-ion batteries (MIBs) are expected to be an alternative to lithium-ion batteries due to the lower cost and immanent safety of Mg. Presently, the major difficulty in breaking through MIBs technology is the lack of desirable anode materials. Based on first-principles calculations, we predict a two-dimensional material named the Be2B monolayer as an excellent anode material. The structural stability is confirmed by superior cohesive energy, positive phonon modes, excellent thermal stability, and strong mechanical stability. Afterward, we explore the performance of the Be2B monolayer as the anode material for MIBs. It exhibits stable Mg atom adsorption with an energy of −0.7 eV, low diffusion barrier (0.1 eV), ultra-high specific capacity (7436 mA h g−1), tiny lattice expansion (0.3%), and low average open-circuit voltage (0.29 V). Thereby, the above-mentioned intriguing findings suggest that the Be2B monolayer can act as a promising anode material for high performance MIBs.