(1. 青岛大学 化学化工与环境学院，青岛 266071；
2. 西安交通大学 理学院，西安 710049)
摘 要: 采用溶体快淬法制备(Mg60Ni25)100-xLax(x=4, 6, 8, 10)的非晶贮氢合金带，分别采用X射线衍射仪和高分辨透射电镜对该合金在充放氢循环过程中的组织结构进行表征。结果表明：Mg65Ni27La8合金具有最高的放电容量(582 mA？h/g)，充放电(吸释氢)过程可分为以下4个阶段：1) 氢原子被非晶相吸收，氢原子的分布是无序的；2) 随着吸氢过程的继续，合金中逐渐出现直径小于4 nm的HT-Mg2NiH4和LT-Mg2NiH4两种氢化物，且数量逐渐增加；3) 随着氢化物开始分解释氢，分解后局部结构恢复到无序态，仅留下一些尺寸较大且较为稳定的LT-Mg2NiH4纳米晶；4) 剩余的氢原子从非晶相中释放，表现为非晶相的释氢，在此过程中合金的结构无显著变化。
关键字: Mg-Ni-La系贮氢合金；显微结构；电化学性能；溶体快淬
（1. College of Chemistry, Chemical and Environmental Engineering, Qingdao University, Qingdao 266071, China;
2. School of Science, Xi’an Jiaotong University, Xi’an 710049, China）
Abstract:(Mg60Ni25)100-xLax(x=4, 6, 8, 10) amorphous alloys were prepared by melt-spinning. The phase structures of the ribbons before and after charge/discharge cycling were characterized by X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HRTEM), respectively. The results show that Mg65Ni27La8 has the maximum discharge capacity of 582 mA？h/g, and its absorption/desorption process can be divided into the following four stages: 1) the hydrogen atoms are absorbed by the amorphous phase, and the distribution of the hydrogen atoms is disordered; 2) with further hydrogen-absorbing, two hydrides of HT-Mg2NiH4 and LT-Mg2NiH4 with a diameter of less than 4 nm form gradually and their numbers increase; 3) beginning with the release of hydrogen, the local structure the decomposition after returns to the disorderly state, leaving only some of the large size and relatively stable LT-Mg2NiH4 nanocrystals; and 4) the remaining hydrogen atoms release from the amorphous phase, and the structure of the alloy in the process has no significant change.
Key words: Mg-Ni-La hydrogen-storage alloy; microstructure; electrochemical property; melt-spinning
