Mechanistic investigations on significantly improved hydrogen storage performance of the Ca(BH4)2-added 2LiNH2/MgH2 system

► Hydrogen storage properties of 2LiNH2-MgH2 are improved by doping Ca(BH4)2. ► Hydrogen desorption from the 0.3Ca(BH4)2-doped sample starts at 80 °C. ► Ca(BH4)2 reacts with LiNH2 to form Ca(NH2)2 and LiBH4 during ball milling. ► The newly formed Ca(NH2)2 and LiBH4 provide the synergetic effects.