Abstract Effect on specific capacity and de-hydrogenation efficiency of MgH2 are studied with sequential doping of La, Ce, Al, Li and Ni using Density Functional Theory. Doping of La and Ce enhance the unit cell volume and thus decrease the volumetric capacity, while, doping of Al, Li and Ni decrease the unit cell volume and subsequently increase the volumetric capacity. Among them, doping of Ni decreases the unit cell volume the most and hence provides highest volumetric capacity. Gravimetric capacities get increased with the following trends of doping; Ce Ce > Al > Li Ni. With co-doping of Ni, MgH2R-Ni is formed, and it exhibit decrement of unit cell volume in comparison to MgH2R. Lesser average bond length of MgH2RNi leads to localization of density of states across Fermi energy enabling easier electron transfer with lesser H2 de-sorption energy.