Tailoring hydrogen adsorption and desorption properties of Li-doped SV (single vacancy) monolayer h-BN systems using ab initio calculations

Abstract

This study uses density functional theory (DFT) technique to examine the hydrogen molecules (H2) storage on Li-decorated h-BN monolayer. The results of DFT have proven that Li-doped h-BN system can hold up to 9H2 with the adsorption energy lying in between −0.31 eV and −0.24 eV/H2 at ambient condition. However, the calculated average adsorption energy for 9H2 is −0.240 eV/H2 with hydrogen storage capacity of 5.96 wt.%, which is according to the United States Department of Energy. Partial density of state was computed for each configuration to provide additional justifications for the H2 storage on Li-doped h-BN monolayer. The hybridization shows a significant interaction between H2 and Li atom, and most of their hybrid peaks were observed in the energy range from −7.5 to −1 eV. Moreover, the H2 desorption simulations achieved via the ab initio molecular dynamics. The computed desorption temperature TD is 306 °K, which is a suitable operating temperature. Hence, our research demonstrates that Li-doped h-BN is a thermally stable and viable hydrogen storage material for hydrogen storage systems.