A computational study of LiBH4 clusters and enhancement of their hydrogen storage by excess electrons

The electronic structures and energies of neutral and anionic (LiBH₄)_x clusters (x = 1 – 5) have been systematically studied by using density functional theory with the B3LYP/6‐311++G(d, p) level. For investigating the importance of excess electrons on hydrogen storage capacity, the interactions between hydrogen atoms and the anionic (LiBH₄)_x clusters are also examined. The calculated formation energies of the anionic clusters show that the anionic clusters have a high thermal stability. It is found that hydrogen atoms are adsorbed on the anionic (LiBH₄)_x clusters chemically with adsorption energies in the range of ?69.13 – ?153.73 kcal/mol. The hydrogen storage capacity can be improved from 18.51% to 19.26 – 22.12% in weight percent depending on the size of various anionic (LiBH₄)_x clusters. Our calculation results show that the existence of excess electrons on the (LiBH₄)_x clusters can enhance the hydrogen storage capacity. The Mulliken charge analysis was performed to illustrate the interactions between H atoms and the anionic (LiBH₄)_x clusters. Copyright © 2016 John Wiley & Sons, Ltd.