金属卤化物对4MgH_2/TiH_2复合材料储氢性能的影响

Study on the Effect of Metal Halides on Hydrogen Storage Properties of 4MgH_2/TiH_2 Composites

在氢气保护下,采用机械合金化制备4MgH_2/TiH_2以及4MgH_2/TiH_2+5%A(质量分数,A=AlCl_3,LaCl_3,CeCl_3)复合材料,并通过PCT、XRD、SEM以及DTA等手段对复合材料进行表征。结果显示,4MgH_2/TiH_2以及4MgH_2/TiH_2+5A(A=AlCl_3,LaCl_3,CeCl_3)复合材料吸氢量均在4.5%(质量分数)左右,且在150s时间内吸氢即可达到饱和。添加CeCl_3后,复合材料的脱氢反应焓从添加前的72.7kJ/mol下降到65.1kJ/mol,而添加AlCl_3和LaCl_3后,复合材料的脱氢反应焓则分别增加到80.6kJ/mol和82.5kJ/mol。这表明CeCl_3能有效提高4MgH_2/TiH_2复合材料的热力学性能,而AlCl_3和LaCl_3的添加则会导致4MgH_2/TiH_2复合材料的热力学性能下降。

The 4MgH2/TiH2 and 4MgH2/TiH2 ＋5wt. %A（A= AlCl3 , LaCl3, CeCl3 ） composites were prepared by mechanical alloying under the argon atmosphere protection, and the hydrogen performance were investigated by PCT, XRD, SEM and DTA methods. The results showed that the maximum hydrogen capacity of the four samples were all about 4. 5wt%, and the hydrogen capacity could reach to the saturation within 150 seconds in the hydrogen absorption process. The dehydrogenation enthalpy for the 4 MgH2/TiH2 composite was 72. 7 kJ/mol, and it de- creased to 65.1 kJ/mol when adding CeCl3. However, it increased to 80. 6 kJ/mol and to 82. 5 kJ/mol while adding AlCl3 and LaCl3, respectively. It can be inferred that the thermodynamic property of the 4MgH2/TiH2 composite can be improved by adding CeCl3. Unfortunately, its thermodynamic property get worse while adding AlCl3 and LaCl3.