Acta Phys. -Chim. Sin. ›› 2009, Vol. 25 ›› Issue (02): 237-241.doi: 10.3866/PKU.WHXB20090207

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Synthesis of AlH3 by a Ball-Milling Solid-Phase Chemical Reaction and Its Hydrogen Desorption Properties

LUO Yong-Chun; MAO Song-Ke; YAN Ru-Xu; KONG Ling-Bin; KANG Long   

  1. College of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, P. R. China; State Key Laboratory of Gansu Advanced Non-Ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050, P. R. China
  • Received:2008-08-14 Revised:2008-10-23 Published:2009-01-16
  • Contact: LUO Yong-Chun

Abstract: The synthesis of AlH3with LiAlH4 and AlCl3was done by ball-milling solid phase chemical reaction under H2 atmosphere. The effects of different milling times (4-20 h) on the solid state chemical reaction and dehydrogenation properties of the milled mixture were investigated comprehensively using X-ray diffraction (XRD), thermal analysis (TG-DSC), mass spectroscopy (MS), scanning electron microscopy (SEM), and dehydrogenation measurements. The milled reaction was found to proceed as follows: 3LiAlH4+AlCl3→4AlH3+3LiCl. The reaction was almost complete after milling for 20 h and amorphous AlH3 was formed. With an increase in milling time dehydrogenation kinetics was improved resulting in hydrogen desorption at a temperature lower than 100 ℃. The maximum desorbed hydrogen capacities reached 2.6%-3.6% (w), which is close to the theoretical capacity of 4.85% (w) for the reaction. A decrease in the maximum desorbed hydrogen capacity can be attributed to the formation of LiCl·H2O and also to the decomposition of AlH3 during the milling process.

Key words: Metal hydride, Mechanically ball-milling, AlH3, Thermal analysis, Dehydrogenation property


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