Room temperature gaseous hydrogen storage properties of Mg-based metallic glasses with ultrahigh Mg contents

► Mg-Ce-Ni metallic glasses with record high Mg content of 90 at.%. ► Reversibly absorb and desorb about 0.2-0.4 wt.%-H at room temperature without activation. ► Hydrogenation capacity shows close connection with the glassy structure of the alloys. ► The higher Mg content amorphous structure can store more hydrogen.