Cu合金化Mg_2NiH_4储氢体系的组织结构与解氢性能

The Structures and Dehydrogenation Properties of Cu Alloying Mg_2NiH_4 Hydrogen Storage System

基于机械反应球磨技术在氢气气氛下成功合成了Mg2NiH4及Cu掺杂Mg2NiH4储氢体系,并采用XRD、SEM、DSC及TGA检测手段对其组织结构与解氢性能进行表征。结果显示,适当提高氢压、延长球磨时间均有助于2Mg-Ni混合物氢化反应的完全化及产物结构的纳米化;Cu掺杂可进一步加快混合物的氢化反应速率,但其产物结构的团聚现象却因MgCu2相的出现而趋于严重;综合热分析表明Cu掺杂不仅降低了Mg2NiH4的解氢温度,还加快了体系的解氢速率;研究结果很好地证实Cu元素是改善Mg2NiH4储氢体系解氢性能最理想的合金化元素之一。

Using the techonology of mechanical reaction ball-milling, Mg2NiH4 and Cu-doped Mg2 NiH4 hydrogen storage systems were successfully synthesized at hydrogen atmosphere. The structures and dehydrogenation pro- perties of these systems were characterized by XRD, SEM, DSC and TGA. The experimental results show that either enhancing hydrogen pressure or prolonging ball-milling time helps to the sufficiency of hydride reaction for 2Mg-Ni mixture and the nanocrystallization of ball-milled products. The doping of Cu element further accelerates the hydride reaction. However, the agglomeration of hydrided products becomes severe due to the appearance of MgCu2 phase. Further thermal analysis indicates that the doping of Cu element not only decreases the dehydrogenation temperature of Mg2NiH4 hydrogen storage system, but also increases its dehydriding velocity, which forcefully confirms that Cu is one of the promising alloying elements in improving the dehydrogenation properties of Mg2 NiH4 hydrogen storage system.