Abstract:The hydrogen storage properties of four LaNi_5−xAl_x (x = 0.25, 0.50, 0.75, 1.00) pseudobinary alloys were systematically studied. The characteristics of microstructure before and after hydrogenation, activation, kinetics and thermodynamics properties, as well the anti-combustibility properties of the four pseudobinary alloys were investigated. The results reveal that the alloys have excellent activation properties and kinetics properties. X-ray diffraction analysis of crystal lattice of the alloys show that the crystal structures of alloys do not change with the addition of Al in the range of 0≤x≤1, but the lattice constants slightly increase. It is found by measuring thermodynamic properties of the alloy-H₂ systems that with increasing x value the equilibrium pressure, hydrogen-absorbing ability and hysteresis decrease, whereas the absolute value of the enthalpy increases. It is also found that the hydrogen absorbing velocity of the alloys decreases with increasing x value.

Key words: hydrogen storage; LaNi_5−xAl_x alloy; kinetics property; thermodynamics property; crystal lattice parameter