Microstructure characterization and hydrogen storage properties study of Mg2Ni0.92M0.08 (M = Ti, V, Fe or Si) alloys

In the present study Mg₂Ni-type compounds alloyed independently with Ti, V, Fe and Si were successfully prepared by wet-milling followed by sintering. Although these alloyed Mg₂Ni compounds exhibited a similar hydrogen storage mechanism as that of pure Mg₂Ni, the dissolution of Ti, V or Fe into the Mg₂NiH₄ lattice had a considerable catalytic effect on hydrogen desorption from additional MgH₂. The further structure investigations clearly indicated that the substitution of Ti for Ni could suppress the formation of the micro-twined low-temperature phase (LT2) and promote the formation of the high-temperature phase (HT), thus resulting in remarkably improved hydrogen desorption kinetics for the Mg₂Ni_0.92Ti_0.08–H system.