Ab-initio structural and electronic properties of the intermetallic compound TiFeH2

Using the first principles “full-potential linearized augmented plane-wave method” based on density functional theory, structural and electronic properties of the dihydride TiFeH2 was investigated. This intermetallic hydride −65 Cmmm space group-with moderate hydrogen storage (1.8-1.9%Wt.) has an orthorhombic structure. The stability analysis and total energy were calculated using the general gradient approximation (GGA). We have investigated in the ground state the lattice parameters, bulk modulus, electronic structure and formation energy of TiFeH2 hydride. Total and partial DOS analysis show that the TiFeH2 hydride has a metallic character. Iron below the Fermi level is the main contributor to bonding manifold whereas anti-bonding titanium states dominate above. The hybridization between iron 3d and hydrogen 1s states appear to be the strongest. Electron density reveals that a relatively high electron density extends from the hydrogen atom site to the iron atom site, but not to the titanium atom site. Formation energy values indicate that the TiFeH2 system is more hydrogen reversible compared with TiFeH.