Reversible hydrogen storage for NLi4-Decorated honeycomb borophene oxide

The boron-based two-dimensional (2D) materials decorated with functional groups NLi4 has been numerically investigated for hydrogen storage via first principles calculations method. Strain-energy analysis and molecular dynamics simulations shows the pristine planar honeycomb B2O has strong mechanical and thermal stability. Crystal Orbital Hamiltonian Population analysis confirmed that there exist stronger B–B/B–O covalent bonds within B2O monolayer. In functional material, a local electric field around each lithium atom can be formed and the overall electronic structure is favorably changed for gas adsorptions. Both electrostatic forces and the van der Waals interaction are the dominant hydrogen-attached mechanisms of lithium cation. An anchored functional group NLi4 can adsorb at most 11 hydrogen molecules, and the average adsorption energy per hydrogen molecules is around −0.20 eV, indicating high hydrogen storage capacity and reversible applicability. The highest hydrogen storage capacity can reach to 9.1 wt%. The study shows the investigated material is a good candidate for hydrogen storage.