Reversible Hydrogen Storage Property and Structural Analysis for Face-Centered Cubic Hydride Mg0.82Zr0.18H2 Prepared by Gigapascal Hydrogen Pressure Method

The face-centered cubic (fcc) type magnesium−zirconium hydride (Mg0.82Zr0.18H x ) was synthesized by means of the ultrahigh pressure (UHP) technique, which could generate 8 GPa of hydrogen pressure. The differential scanning calorimeter (DSC) measurements indicated that the fcc phase exhibited reversible hydrogen releasing and restoring properties under 0.5 MPa of hydrogen pressure. On the pressure−composition isotherms, the released and restored hydrogen capacities were estimated to be 3∼3.5 wt %. The Rietveld analysis for synchrotron X-ray diffraction (XRD) data showed that the fcc phase had around 70 wt % mass fraction and was preserved without decomposition during hydrogen releasing and restoring cycles.