Improved dehydrogenation cycle performance of the 1.1MgH_2-2LiNH_2-0.1LiBH_4 system by addition of L

• 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: Energy Materials and Technology Research Institute, General Research Institute for Nonferrous Metals
• 出 处: Journal of Rare Earths
• 发表日期: 2015年07期
• 关键词: kinetics desorption deterioration hydrogenation agglomeration isothermal crackin

The isothermal desorption kinetics of the 1.1Mg H2-2Li NH2-0.1Li BH4 system were improved by addition of La Ni4.5Mn0.5alloy. The hydrogen desorption peak temperature of the sample containing La Ni4.5Mn0.5 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 La Ni4.5Mn0.5 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 1.1Mg H2-2Li NH2-0.1Li BH4 system were improved by addition of La Ni4.5Mn0.5alloy. The hydrogen desorption peak temperature of the sample containing La Ni4.5Mn0.5 reduced by approximately 5 K and the activation of energy is 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 La Ni4.5Mn0.5 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.