First-principles Study on Complex Hydrides for Hydrogen Storage

Abstract

Thermodynamical stabilities of metal borohydrides, M(BH₄)_n, which are potential candidates for hydrogen storage materials due to their high gravimetric hydrogen density, have been investigated using the first-principles calculation based on density functional theory. The results indicate that the charge compensation by Mⁿ⁺ is a key feature for the stability of the internal bonding of [BH₄]− anion. A good correlation between the heats of formation and the Pauling electronegativities of cations is found for M(BH₄)_n. The intermediate phase during the hydrogen desorption reaction is also studied theoretically for LiBH₄.