Mg3Mm compound based hydrogen storage materials

Hydrogen storage properties, composition and phase structures of the Mg–Mm (Mm is abbreviated for misch metal) and Mg–Mm–Ni alloys prepared by induction melting were investigated by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX) and pressure–composition-isotherms (PCIs) measurement. It has been found that the Mg3Mm compound with the D03 structure can absorb hydrogen at room temperature with rapid hydriding kinetics. The desorption of hydrogen of Mg3Mm and Mg3MmNi0.1 alloys takes place at 281 and 250 °C and the reversible hydrogen storage capacities reach 2.91 and 2.51 wt.%, respectively. The enthalpy (ΔH) and entropy (ΔS) of Mg3Mm–H dehydriding reaction were determined by using van’t Hoff plot. Hydrogen absorption kinetics of the Mg3Mm alloy at room temperature was also measured and the experimental curves can be well fitted by using Avrami–Erofeev equation.