In situ synchrotron X-ray diffraction study on the rehydrogenation behavior of MgH 2 -LiAlH 4 composites

Rehydrogenation behavior of the discharged MgH 2 -LiAlH 4 composites was investigated by using thermal gravimetric analysis (TGA) and in situ synchrotron X-ray diffraction (XRD) technique. For 4MgH 2 -LiAlH 4 composite, the experimental results showed that at least 3 wt% of hydrogen could be recharged at 170 psi H 2 /400°C to form MgH 2 after its first dehydrogenation reaction. The XRD results indicated that not only Mg but also Mg 17 Al 12 could be rehydrogenated in the hydrogen atmosphere investigated although LiAlH 4 was found irreversible.