(1. 青島大學(xué) 化學(xué)化工與環(huán)境學(xué)院，青島 266071；
2. 西安交通大學(xué) 理學(xué)院，西安 710049)
摘 要: 采用溶體快淬法制備(Mg60Ni25)100-xLax(x=4, 6, 8, 10)的非晶貯氫合金帶，分別采用X射線衍射儀和高分辨透射電鏡對(duì)該合金在充放氫循環(huán)過程中的組織結(jié)構(gòu)進(jìn)行表征。結(jié)果表明：Mg65Ni27La8合金具有最高的放電容量(582 mA？h/g)，充放電(吸釋氫)過程可分為以下4個(gè)階段：1) 氫原子被非晶相吸收，氫原子的分布是無序的；2) 隨著吸氫過程的繼續(xù)，合金中逐漸出現(xiàn)直徑小于4 nm的HT-Mg2NiH4和LT-Mg2NiH4兩種氫化物，且數(shù)量逐漸增加；3) 隨著氫化物開始分解釋氫，分解后局部結(jié)構(gòu)恢復(fù)到無序態(tài)，僅留下一些尺寸較大且較為穩(wěn)定的LT-Mg2NiH4納米晶；4) 剩余的氫原子從非晶相中釋放，表現(xiàn)為非晶相的釋氫，在此過程中合金的結(jié)構(gòu)無顯著變化。
關(guān)鍵字: Mg-Ni-La系貯氫合金；顯微結(jié)構(gòu)；電化學(xué)性能；溶體快淬
（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
