Advanced study of hydrogen storage by substitutional doping of Mn and Ti in Mg 2 Ni phase

The substitutional doping of Mn and Ti in Mg 2 Ni phase has been investigated by first principles density functional theory calculations. The calculation of enthalpy of formation shows that among the four different lattice sites of Mg(6f), Mg(6i), Ni(3b) and Ni(3d) in Mg 2 Ni unit cell, the most preferable site of substitution of Mn in Mg 2 Ni lattice has been confirmed to be Mg(6i) lattice site. The most preferable site of Ti substitution in Mg 2 Ni lattice is Mg(6i) position and the stability of Ti-doped Mg 2 Ni decreases with the increase of substitution quantity of Ti for Mg.