摘要
利用高能球磨方法制备纳米Mg2Ni储氢合金,用于高容量MH/Ni电池氢化物电极电化学性能研究.XRD和TEM测试结果表明,机械合金化方法制备Mg2Ni合金的历程为合金化--非晶化--纳米晶化,球磨时间直接影响Mg2Ni合金的结构.高能球磨20h可以制备非晶态Mg2Ni合金,比普通的机械合金化方法制备非晶态Mg2Ni合金的时间减少了约5倍之多;高能球磨30h可以制备纳米晶态Mg2Ni合金,粒径在10nm以下,有团聚现象.研究了Mg2Ni纳米氢化物电极在不同温度下的电化学性能,并从热力学角度就Mg2Ni纳米氢化物电极的某些高温电化学性能进行了解释和推测.实验结果表明:在30～70℃范围内,随着温度增加,氢化物电极的电化学容量逐渐增加,在70℃时电化学容量可达530.5mAh/g,约为30℃放电容量273.2mAh/g的2倍,Mg2Ni纳米氢化物电极具有较好的高倍率放电性能及大电流充放电性能,这表明机械合金化方法制备的Mg2Ni纳米氢化物电极具备电动车用大型MH/Ni电池负极材料的初步条件,但容量衰减严重.
The electrochemical characteristics of Mg2Ni alloy synthesized by mechanical alloying with SPEX-8000 used as metal hydride electrode in MH-Ni battery of high capacity have been investigated in details at different temperatures and preliminarily explained from thermodynamics. The microstructure of Mg2Ni alloy was examined by XRD and TEM, the results show that there were three steps to synthesis Mg2Ni alloy, that was crystal, amorphous and nanocrystallite. The amorphous of Mg2Ni alloy was synthesized about 20h and the nanocrystallite of Mg2 Ni alloy was synthesized about 30h. For nanocrystallite of Mg2 Ni alloy, the average size of the Mg2Ni alloy was under 10nm deduced from TEM. Mg2Ni metal hydride electrode discharge capacity increases with temperature and the discharge capacity has been reached to 530. 5mAh/g at 70℃, which was about two times of the discharge capacity 273.2mAh/g at 30℃. The high-rate discharge properties of Mg2Ni alloy and the charge/discharge properties with large current density were good at high temperature. It was the preliminary condition for Mg2Ni alloys used for hybrid electric vehicles, but the degradation of the capacity was serious.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2005年第12期1875-1878,共4页
Journal of Functional Materials
基金
国家自然科学基金资助项目(20171042)
关键词
机械合金化
MG2NI
氢化物电极
mechanical alloying
Mg2 Ni alloy
metal hydride electrode
