Experimental Study on the Hydrogen Storage Properties of LaNi5 Alloy in Repeated Hydriding/Dehydriding Cycles

LaNi5 alloy is one of the promising materials for hydrogen storage. It has good activation property, fast reaction rate and moderate plateau pressure. However, some of its hydrogen storage properties will change after repeated hydriding/dehydriding cycles, which limits its practical application. Therefore, this paper investigated the cycling properties of LaNi5 alloy by volumetric method. The results showed that the reaction rate increased with cycling. The hydriding/dehydriding hydrogen content decreased with cycling. For hydriding reaction, the equilibrium pressure increased with cycling, while it decreased for dehydriding at 40°C and 60°C. After 100 cycles, the LaNi5 alloy has been severely pulverized and oxygenated. The oxidation products include LaNiO2, La2NiO4, La2NiO4.18 and LaNiO3. The JMA model was found to fit the kinetic data well, suggesting a nucleation and growth controlling mechanism. The intrinsic reaction rate constant ka increases from 21.87 s-1to 24.81 s-1, while the activation energy decreases from the initial value of 19459 to 19373 J/mol after 100 cycles.

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Elastic stress in composite FeTi hydrogen storage materials

Journal of Materials Research ◽

10.1557/jmr.1998.0214 ◽

1998 ◽

Vol 13 (6) ◽

pp. 1538-1547 ◽

Cited By ~ 11

Author(s):

P. Tessier ◽

R. Schulz ◽

J. O. Ström-Olsen

Keyword(s):

Hydrogen Storage ◽

Elastic Stress ◽

Plateau Pressure ◽

Miscibility Gap ◽

Second Phase ◽

Storage Site ◽

Intergranular Phase ◽

Hydrogen Storage Properties ◽

Absorbing Material ◽

Storage Properties

A simple model of the elastic stress in a composite hydrogen absorbing material is developed to account for the hydrogen storage properties of nanocrystalline FeTi with a network of intergranular phase having a wide storage site energy distribution. The model accounts for the equilibrium properties of nanocrystalline FeTi hydrogen absorbers made by ball-milling such as the narrowing of the miscibility gap and changes in plateau pressure. A second model is proposed for disconnected inclusions of the second phase. The effect of chemical disorder is also briefly examined.

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Hydrogen storage properties of mechanically alloyedMg–8 mol% LaNi0.5 composite

Journal of Materials Research ◽

10.1557/jmr.2004.0396 ◽

2004 ◽

Vol 19 (10) ◽

pp. 2871-2876 ◽

Cited By ~ 14

Author(s):

Qian Li ◽

Qin Lin ◽

Kuo-Chih Chou ◽

Li-Jun Jiang ◽

Feng Zhan

Keyword(s):

Hydrogen Storage ◽

Mechanical Alloying ◽

X Ray Diffraction ◽

Equilibrium Pressure ◽

Hydrogen Storage Properties ◽

X Ray ◽

Transmission Electron ◽

Lower Temperature ◽

Material Preparation ◽

Storage Properties

A new nano-ternary Mg–8 mol% LaNi0.5 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 LaH3 and Mg2Ni 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 lgp(0.1 MPa) = −3985/T + 7.188(553 K ⩽ T ⩽ 573K) for hydriding and lgp(0.1 MPa) = −3804/T + 6.770 (553 K ⩽ T ⩽ 573 K) for dehydriding.

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