Enhanced dehydrogenation of LiBH4 with Ti or/and F additives: Insight from first-principles calculations

The present work gives the hydrogen dissociation energies and electronic structures of Li8_xTixB8FyH32_y (x, y = 0 or/and 1) compounds by first-principles density functional theory calculations, with the aim of providing new insights into the enhanced dehydrogenation of LiBH4 with Ti or/and F additives. The results indicate that substituting more electronegative elements Ti for Li or/and F for H helps to destabilize LiBH4, resulting in decreased hydrogen dissociation energies for favorable H-desorption. This is particularly obvious for LiBH4 sample with Ti + F co-substitution, and associated with the decrease of Li-B, Li-H and B-H bonding interactions, the formation of Ti-B, Ti-H and Li-F bonds, as well as the presence of metallic character. Our work suggests that combined metal cation and nonmetal anion co-doping could effectively modify the properties of LiBH4, which is useful for hydrogen storage applications.(c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.