Li-decorated B2O as potential candidates for hydrogen storage: A DFT simulations study

Abstract

Two-dimensional (2D) B2O monolayer is considered as a potential hydrogen storage material owing to its lower mass density and high surface-to-volume ratio. The binding between H2 molecules and B2O monolayer proceeds through physisorption and the interaction is very weak, it is important to improve it through appropriate materials design. In this work, based on density functional theory (DFT) calculations, we have investigated the hydrogen storage properties of Lithium (Li) functionalized B2O monolayer. The B2O monolayer decorated by Li atoms can effectively improve the hydrogen storage capacity. It is found that each Li atom on B2O monolayer can adsorb up to four H2 molecules with a desirable average adsorption energy (Eave) of 0.18 eV/H2. In the case of fully loaded, forming B32O16Li9H72 compound, the hydrogen storage density is up to 9.8 wt%. Additionally, ab initio molecular dynamics (AIMD) calculations results show that Li-decorated B2O monolayer has good reversible adsorption performance for H2 molecules. Furthermore, the Bader charge and density of states (DOS) analysis demonstrate H2 molecules are physically absorbed on the Li atoms via the electrostatic interactions. This study suggests that Li-decorated B2O monolayer can be a promising hydrogen storage material.