Hydrogen storage in magnesium based-composite hydride through hydriding combustion synthesis

Mg and Zr-based AB₂ hydride composite was prepared by hydriding combustion synthesis (HCS) and the hydriding–dehydriding properties of HCS Mg–(20, 40 wt%)AB₂ products were extensively examined. The dehydriding onset temperatures of the HCS Mg–20AB₂ and Mg–40AB₂ composites were 533 K and 493 K, respectively, which were lower than that of the MgH₂. It is suggested that the well-dispersed Zr-based AB₂ phase in a Mg composite prepared by HCS plays a crucial role in significantly improving its kinetic properties. Especially, the HCS Mg–20AB₂ composite showed fully activated hydrogenation within the 8th cycle and reached a saturated H₂ absorption capacity of 5.7 wt.% at 573 K in 10 min. In addition, the hydrogen capacity did not show any significant decrease even after 86 cycles. These results display a potential excellence of HCS processing in preparing Mg-based hydrogen storage materials.