LAUSR

Abstract The synthesis, thermodynamic destabilisation and hydrogen sorption properties of the M0.2Ca0.8MgH4 hydride system, where (M = Na or Li) have been investigated. Samples were mechanically milled under argon for 5, 10 and 15 h; then characterised by X-ray diffraction (in/ex-situ), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) coupled with a mass spectrometer (MS). On Li and Na substitution into Ca–Mg–H ternary hydride, diffraction peaks shifted to higher angles. 2 and 3 endothermic reactions were observed for the Li0.2Ca0.8MgH4 and Na0.2Ca0.8MgH4. The maximum amount of hydrogen release was achieved for the 5 h milled Na0.2Ca0.8MgH4 hydride from 298 °C to 386 °C accounting for 3.5 wt % of H2.