LaNi5-xAlx合金的Al含量对吸氢量和平衡氢压的影响

在研究LaNi5-xAlx合金系的结构特性、储氢性能及热力学性能的基础上，分析讨论了Al的加入使LaNi5-xAlx合金系晶胞体积增大的同时，引起了晶格的各向异性膨胀，以及这种非平衡的空间增长对吸氢量和平衡氢压的影响。结果表明，添加Al的合金化影响了原子间的相互作用，导致了原子间距的重新调整，从而导致了储氢性能的变化。根据实验数据导出了LaNi5-xAlx金属间化合物中的Al含量x与平台压力间的对应关系。晶格的各向异性膨胀与吸氢量之间呈很好的线性关系；Seitz半径随Al的加入而增大，有利于平衡氢压的降低；同时吸氢量可能由于晶格畸变增大而减少。

Effect of Al Content on Hydrogen Storage Capacity and Plateau Pressure of LaNi5- xAlx-H System

On the basis of investigating the structural, thermodynamic and hydrogen storage properties of LaNi5- x Al x hydrides, the expansion of the crystal cell volumes and the anisotropic expansion along the a axis and c axis as a function of the Al concentration and their effects on the hydrogen content and the plateau pressure were discussed. The results show that aluminum substitution influences the interaction of the atoms and leads to readjustment of distances between atoms in the crystal cell. There is a linear relation between the Al content and the logarithm of the plateau pressure at a given temperature. The relationship between x in LaNi 5- x Al x and the plateau pressure is deduced from the experimental data. The hydrogen content decreases linearly with decreasing the a/c ratio. Wigner Seitz radii increasing are proportious to reduce the equilibrium hydrogen pressure. The Al increasing may tend to increase crystal lattice distortion so that the hydrogen storage capacity decreases.