Evaluating Hydrogen Storage Potential and Sorption Characteristics of Li-Mg Alloy

This study aimed to examine the hydrogen sorption characteristics of a Li-Mg ribbon under 100 bar H2 using reactive milling, ex/in-situ X-ray diffraction (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). Direct hydrogenation was achieved after 1 hour of milling, forming a powder containing LiH, MgH2 and Li-Mg phases. Hydrogenation of the as-received ribbon occurred within ~5 hours under 3 bar H2 at 200 ˚C. In-situ XRD confirmed MgH2 decomposition to Mg and H2 at ~150 ˚C. DSC analysis revealed diverse thermal events for as received and milled samples, with the milled sample showing a single endothermic peak at ~193 ˚C associated with hydride desorption. TGA demonstrated a hydrogen release of 0.19 wt. %, improving upon previous reports by achieving higher efficiency at lower temperatures (250 ˚C vs 450 ˚C). No ternary Li-Mg-H phases were identified. Rietveld refinement showed thermal expansion trends and potential Li substitution in the Mg phase. This study highlights the potential of Li-Mg alloys for lower temperature hydrogen storage, revealing promising hydrogenation pathways. However, further optimization is necessary to enhance hydrogen storage capacity for practical applications.