Influence of transition metals Fe, Co, Ni, Cu and Ti on the dehydrogenation characteristics of LiBH4: A first-principles investigation.

LiBH 4 is among a few chemicals with the highest hydrogen storage capacities. In this paper, the crystal structure, electronic structure and dehydrogenation properties of both pure and transition metal (TM = Fe, Co, Ni, Cu and Ti)-modified LiBH 4 were investigated by using first-principles calculations based on density functional theory. According to the computing results, the occupation energies of TM-doped LiBH 4 suggest that the metal atoms prefer to occupy interstitial sites rather than substitute a Li atom site. Meanwhile, the calculation results show that the TM-modified LiBH 4 could have decreased stability and that all the TM substitutions may kinetically favour H-desorption, due to the decrease in hydrogen removal energy during the H atom release process from the bulk. The electronic structure further proves that the TM modification tends to weaken the B H bonding interaction, and that Ti-doped LiBH 4 has a good dehydrogenation performance, which is also confirmed by the reported experimental results. [ABSTRACT FROM AUTHOR]