Reversible hydrogen storage in lithiated boranes: Acumen from molecular dynamics simulation

In this study, we explored the hydrogen adsorption capabilities of lithium-decorated borane clusters (BnHnLi6, n = 5–7) using density functional theory (DFT) calculations. Stability of the hydrogen adsorbed complexes was confirmed through the principles of maximum hardness and minimum electrophilicity. Our findings indicate that hydrogen molecules are adsorbed in a quasi-molecular manner via Niu-Rao-Jena type interactions, with average adsorption energies ranging from 0.10 to 0.11 eV/H2, and Li-H2 bond lengths between 2.436 and 2.550 Å. Molecular dynamics simulations at near room temperature (300 K) confirmed the structural stability and reversibility of these complexes. At storage conditions (100 K and 60 bar), the practical hydrogen storage capacity was found to be a maximum of 26.45 wt%, meeting the targets of U.S. DOE. Therefore, our study suggests that lithium-decorated borane clusters hold great promise for room temperature hydrogen storage.