Hexagonal <scp> Be <i>X</i> </scp> ( <i>X</i> : S, Te) Monolayer as Potential Electrode Material for Alkali Metal‐Ion Batteries: A <scp>DFT</scp> Perspective

ABSTRACT Metal‐ion batteries (MIBs) are essential for transitioning to a cleaner and more sustainable energy future. By employing the density functional formalism, we have investigated the hexagonal ( h ) monolayer of BeS and BeTe as electrode materials for alkali (Li and Na) MIBs. The structural and thermodynamic stability, adsorption of Li/Na atoms, density of states, diffusion, and migration of atoms, as well as capacity, are investigated. The structures of h ‐BeS and h ‐BeTe remain stable upon adsorption of the adatoms, with improved electronic conductivity of these monolayers. The climbing image‐nudged elastic band calculations estimate a low diffusion barrier of 0.16 eV (0.01 eV) for Li (Na) in h‐ BeS and 0.20 eV (0.16 eV) for Li (Na) in h‐ BeTe. Additionally, a maximum storage capacity of 580 mAh g −1 for Li‐ions and 1305 mAh g −1 for Na‐ions in h‐ BeS as well as 174 mAh g −1 for both metal ions in h ‐BeTe, is estimated.