Hydrogen storage in the TiCo and TiNi alloys

Abstract

This is an ab initio study based on the density functional theory that uses GGA-PBE as the exchange–correlation potential. The energetic, electronic, magnetic properties, and optical conductivity of the cubic [Formula: see text] of TiCo and TiNi alloys with and without the hydrogen atom are performed. The present alloys are found to be thermodynamically stable and can be created. It can be deduced that the octahedral site has higher energetic stability absorption for the hydrogen atoms compared to the bridge and tetrahedral sites in the TiCo and TiNi alloys. The absorption energy at octahedral site is found to be 2.37[Formula: see text]eV for TiCo and 2.32[Formula: see text]eV for TiNi. Hydrogen absorption expands and brittles the host alloy. Hydrogen storage in more than one site in the host alloy is found to be energetically stable and can be formed. The chemical bonding between the constituent atoms of the present alloys is mainly ionic with some covalent bonding. The hydrogen absorption has a clear effect on the magnetic, and electrical conductivity relative to the relaxation time and optical conductivity of the present alloys. Beneficial optical applications can be assumed for the present alloys due to their high optical conductivity.