The effects of Co and Ni addition on the hydrogen storage properties of Mg3Mm

The effects of Ni and Co addition on the hydrogen storage properties of Mg3Mm alloy was studied by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX) and pressure-composition isotherm (PCI) measurement. The hydrogen absorption kinetics and the thermodynamic parameters (apparent ΔH, ΔS) for Mg3Mm dehydrogenation reactions in Mg3Mm, Mg3MmNi0.1 and Mg3MmNi0.1Co0.1 alloys have been also investigated. The maximum hydrogen storage content of Mg3Mm, Mg3MmNi0.1 and Mg3MmNi0.1Co0.1 alloys was improved due to that the addition of Ni and/or Co further spurred the MmH3 phase transforming to MmH2 phase. On the other side, the kinetics curves show the addition of Co could enhance hydrogen absorption rate while the addition of Ni change the hydrogenation reaction mechanism.