文摘
AlH3 is a promising hydrogen storage material due to its high hydrogen capacity (10?wt % ) and relatively low dehydriding temperature. In this work, ¦Ã-AlH3 was prepared by organometallic synthesis method and the effects of ball milling on dehydriding properties of ¦Ã-AlH3 were investigated systematically. Experimental results shows that as-prepared ¦Ã-AlH3 releases about 8.3?wt % of hydrogen in the temperature range of 130-160?¡ãC at a heating rate of 2?¡ãC/min. Ball milling significantly improves the dehydriding behavior of ¦Ã-AlH3. DSC-MS analysis reveals that the dehydriding temperature of ¦Ã-AlH3 ball-milled for 10?h decreases by around 30?¡ãC. In addition, the dehydriding activation energy of ¦Ã-AlH3 ball-milled for 2?h decreased from 87 to 68?kJ/mol. Isothermal dehydriding measurements demonstrate that duration needed to release 90 % hydrogen for as-prepared ¦Ã-AlH3 is 280?min, but it takes only 82?min after ball milled for 10?h to release the same amount of?hydrogen. Moreover, the dehydriding path of ¦Ã-AlH3 is changed by ball milling. As-prepared ¦Ã-AlH3 transforms to ¦Á-AlH3 before dehydriding, while ball-milled ¦Ã-AlH3 prefers to dehydride directly without firstly transforming to ¦Á-AlH3.