Influence of Ti super-stoichiometry on the hydrogen storage properties of Ti1+xCr1.2Mn0.2Fe0.6 (x = 0–0.1) alloys for hybrid hydrogen storage application

Abstract Ti 1+ x Cr 1.2 Mn 0.2 Fe 0.6 ( x  = 0, 0.02, 0.05, 0.1) alloys with high hydrogen desorption plateau pressures for hybrid hydrogen storage vessel application were prepared by induction levitation melting, as well as the effect of Ti super-stoichiometry on the crystallographic characteristics and hydrogen storage properties were systematically investigated. The results show that all of the alloys were determined as a single phase of C14-type Laves structure, the unit cell volume expands with increasing Ti content. Compared with the stoichiometric TiCr 1.2 Mn 0.2 Fe 0.6 alloy, the titanium super-stoichiometric Ti 1+ x Cr 1.2 Mn 0.2 Fe 0.6 ( x  = 0.02, 0.05, 0.1) alloys have larger hydrogen storage capacities and lower hydrogen desorption plateau pressures. Among the studied alloys, Ti 1.02 Cr 1.2 Mn 0.2 Fe 0.6 has the best overall properties for hybrid hydrogen storage application, its hydrogen desorption plateau pressure at 318 K is 37.69 MPa, its hydrogen storage capacity is 1.61 wt.% and its dissociation enthalpy (Δ H d ) is 16.67 kJ/mol H 2 .