Hexagonal BeX (X: S, Te) monolayer as potential electrode material for alkali metal-ion batteries: A DFT perspective

TL;DR

This study uses density functional theory to explore hexagonal BeS and BeTe monolayers as promising electrode materials for alkali metal-ion batteries, highlighting their stability, conductivity, and capacity.

Contribution

It provides the first systematic DFT analysis of BeS and BeTe monolayers for alkali metal-ion battery electrodes, including stability, diffusion, and capacity assessments.

Findings

h-BeS and h-BeTe remain structurally stable after adatom adsorption

Low diffusion barriers for Li and Na in both monolayers

High storage capacities for Li and Na in h-BeS, moderate in h-BeTe

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 systematically investigated. The structures of h-BeS and h-BeTe remain stable upon the adsorption of adatoms, resulting in 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 and 1305 mAh g-1 for Na in h-BeS, as well as 174 mAh g-1 for h-BeTe, is estimated for both metal ions.