Effects of in-situ formed Mg2Si phase on the hydrogen storage properties of Mg Li solid solution alloys

Mg--Li solid solution alloys, Mg90Li10- x Si x (x =0,2,4,6), were synthesized via sintering and ball-milling. Analysis of the samples, via X-ray diffraction (XRD), revealed that the Mg2Si phase formed with the addition of Si. Moreover, measurements of the pressure composition isotherms (PCT) revealed reversible hydrogen storage capacities of 6.47wt.%, 5.69wt.%, 5.56wt.%, and 5.28wt.%, respectively, at 623K, for the Mg90Li10- x Si x (x =0,2,4,6) alloys. The Mg2Si acted as a catalyst that reduced the apparent activation energy (Ea), enhanced the reversible hydrogenation reaction, and improved the kinetic and thermodynamic performance of the hydrogenation/dehydrogenation process of the Mg--Li solid solution.