Improved reversible hydrogen storage of LiAlH4 by nano-sized TiH2

Abstract Transition metal halides are mostly used as dopants to improve the hydrogen storage properties of LiAlH 4 , but they will cause hydrogen capacity loss because of their relatively high molecular weights and reactions with LiAlH 4 . To overcome these drawbacks, active nano-sized TiH 2 (TiH 2 nano ) prepared by reactive ball milling is used to dope LiAlH 4 . It shows superior catalytic effect on the dehydrogenation of LiAlH 4 compared to commercial TiH 2 . TiH 2 nano -doped LiAlH 4 starts to release hydrogen at 75 °C, which is 80 °C lower than the onset dehydrogenation temperature of commercial LiAlH 4 . About 6.3 wt.% H 2 can be released isothermally at 100 °C (800 min) or at 120 °C (150 min). The apparent activation energies of the first two dehydrogenation reactions of LiAlH 4 are reduced by about 20 and 24 kJ mol −1 , respectively. Meanwhile, the regeneration of LiAlH 4 is realized through extracting the solvent from LiAlH 4 ·4THF, which is obtained by ball milling the dehydrogenated products of TiH 2 nano -doped LiAlH 4 in the presence of THF and 5 MPa H 2 . This suggests that TiH 2 is also an effective catalyst for the formation of LiAlH 4 ·4THF.