Li-Jun Jiang

Hydrogen storage properties of mechanically alloyed Mg-8 mol% LaNi0.5 composite

A new nano-ternary Mg–8 mol% LaNi 0.5 was prepared by melted and subsequent mechanical alloying technique for hydrogen storage. It was found from our experiments that, this kind of alloy had superior hydriding/dehydriding characteristics in comparison with conventional materials for hydrogen storage. It possessed large hydrogen capacity at a lower temperature, which could absorb 4.55–7.01 mass% H under 3 MPa hydrogen pressure and desorb 4.40–6.90 mass% H under 0.0133 MPa in 600 s above 423 K without any activation requirement drawn from our pressure-composition isotherm and kinetic experiments. Through the x-ray diffraction and transmission electron microscopy experiments, we further found that these superior characteristics could be attributed to the multiphase structure and a catalytic effect of LaH 3 and Mg 2 Ni that were formed in the material preparation of mechanical alloying process. Finally, based on these data the relationships between equilibrium pressure of hydrogen and temperature were obtained, they were lg p (0.1 MPa) = −3985/ T + 7.188(553 K ⩽ T ⩽ 573K) for hydriding and lg p (0.1 MPa) = −3804/ T + 6.770 (553 K ⩽ T ⩽ 573 K) for dehydriding.