The effect of doping NiCl2 on the dehydrogenation properties of LiAlH4

To investigate the effect of NiCl2 dopant and doping processes on the dehydrogenation behavior of LiAlH4, powder mixtures of LiAlH4 and NiCl2 dopant were prepared by designed mixing and milling processes. The microstructures of the powder mixtures were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The onset decomposition temperature and isothermal dehydrogenation kinetics were measured to identify the catalyzing effect of NiCl2 on the dehydrogenation properties of LiAlH4. It has been shown that NiCl2 could greatly reduce the onset decomposition temperature and enhance the dehydriding kinetic performance of LiAlH4. The experimental result showed that milling LiAlH4 and NiCl2 together for 0.5 h can obtain a homogeneous mixture of LiAlH4, which desorbed 4.2 wt% H-2 in 3 h at only 100 degrees C, and the onset decomposition temperature of LiAlH4 is decreased by 50 degrees C. However, higher amount of dopant and unfavorable distribution of NiCl2 in LiAlH4 may cause a reduction of the catalytic efficiency. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.