Preparation and hydriding/dehydriding properties of mechanically milled Mg-30 wt% TiMn1.5 composite

A Mg-30 wt% TiMn1.5 hydrogen storage composite was successfully synthesized by mechanical milling of a mixture of magnesium powder and amorphous TiMn1.5 powder. The absorption/desorption rates and storage capacity under different temperatures were evaluated. The composite possesses high hydrogen storage capacity and exhibits excellent absorption/desorption kinetic properties and is activated in situ due to reaction ball milling (RBM). The hydrogen capacity is over 2.7 wt% at 373 K, and one absorption/desorption hydrogen cycle can be finished in 20 min at 523-573 K. Interestingly, the desorption temperature begins at about 500 K, decreasing about 40 K in contrast to that of the milled pure MgH2. Mechanical milling produces fine powder with nanometer-scaled grains and introduces many imperfections into the Mg matrix, which contribute to the enhanced hydrogen absorption/desorption rates with high capacity catalyzed by TiMn1.5 (amorphous). (C) 2002 Elsevier Science B.V. All rights reserved.