Improved dehydrogenation cycle performance of the 1.1MgH_2-2LiNH_2-0.1LiBH_4 system by addition of La Ni_(4.5)Mn_(0.5) alloy  

作　　者：赵汪 蒋利军 武媛方 叶建华 袁宝龙 李志念 刘晓鹏 王树茂 

机构地区：[1]Energy Materials and Technology Research Institute, General Research Institute for Nonferrous Metals

出　　处：《Journal of Rare Earths》2015年第7期783-790,共8页稀土学报（英文版）

基　　金：Project supported by High-Tech Research and Development Program of China(2012AA051503)

摘　　要：The isothermal desorption kinetics of the 1.1MgH2-2LiNH2-0.1LiBH4 system were improved by addition of LaNi4.5Mn0.5 alloy. The hydrogen desorption peak temperature of the sample containing LaNi4.5Mn0.5 reduced by approximately 5 K and the activation energy reduced by 9%. The results of isothermal dehydrogenation kinetics analysis implied that the isothermal desorption process at initial stage was controlled by the phase boundary mechanism. Moreover, the cycle performance of the materials was extended. The growth and agglomeration of the sample particles caused the deterioration of kinetics during de-/hydrogenation cycles, and then resulted in an incomplete desorption/absorption reaction which were responsible for the capacity fading. The cracking and pulverization of LaNi4.5Mn0.5 alloy had an obvious effect on preventing the composites aggregating, and the fine alloy particles could enhance the catalytic effect of the alloy, thus effectively offsetting part of the deterioration of kinetics caused by particles growth.The isothermal desorption kinetics of the 1.1MgH2-2LiNH2-0.1LiBH4 system were improved by addition of LaNi4.5Mn0.5 alloy. The hydrogen desorption peak temperature of the sample containing LaNi4.5Mn0.5 reduced by approximately 5 K and the activation energy reduced by 9%. The results of isothermal dehydrogenation kinetics analysis implied that the isothermal desorption process at initial stage was controlled by the phase boundary mechanism. Moreover, the cycle performance of the materials was extended. The growth and agglomeration of the sample particles caused the deterioration of kinetics during de-/hydrogenation cycles, and then resulted in an incomplete desorption/absorption reaction which were responsible for the capacity fading. The cracking and pulverization of LaNi4.5Mn0.5 alloy had an obvious effect on preventing the composites aggregating, and the fine alloy particles could enhance the catalytic effect of the alloy, thus effectively offsetting part of the deterioration of kinetics caused by particles growth.

关 键 词：hydrogen storage materials Li-Mg-B-N-H hydride LaNi4.5Mn0.5 cycle performance rare earths 

分 类 号：TB34[一般工业技术—材料科学与工程]