Density functional theory study of reversible hydrogen storage in monolayer beryllium hydride by decoration with boron and lithium

The hydrogen storage capacity of M-decorated (M = Li and B) 2D beryllium hydride is investigated using first-principles calculations based on density functional theory. The Li and B atoms were calculated to be successfully and chemically decorated on the Surface of the a-BeH2 monolayer with a large binding energy of 2.41 and 4.45eV/atom. The absolute value was higher than the cohesive energy of Li and B bulk (1.68, 5.81eV/atom). Hence, the Li and B atoms are strongly bound on the beryllium hydride monolayer without clustering. Our findings show that the hydrogen molecule interacted weakly with B/a-BeH2(B-decorated beryllium hydride monolayer) with a low adsorption energy of only 0.0226 eV/H2 but was strongly adsorbed on the introduced active site of the Li atom in the decorated BeH2 with an improved adsorption energy of 0.472 eV/H2. Based on density functional theory, the gravimetric density of 28H2/8li/a-BeH2) could reach 14.5 wt.% higher than DOE's target of 6.5 wt. % (the criteria of the United States Department of Energy). Therefore, our research indicates that the Li-decorated beryllium hydride monolayer could be a candidate for further investigation as an alternative material for hydrogen storage.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.