Development of Ti1.02Cr2-x-yFexMny (0.6≤x≤0.75, y=0.25, 0.3) alloys for high hydrogen pressure metal hydride system

To save compressor investment and promote operation efficiency of hydrogen refueling station, the hydrogen storage alloys for high-pressure hydrogen metal hydride tank is developed. Ti1.02Cr2-x-yFexMny (0.6 <= x <= 0.75, y=0.25, 0.3) alloys with main structure of C14 type Laves phase and low dehydrogenation enthalpy were prepared by plasma arc melting and heat treatment. Pressure-composition-temperature measurements show that hydrogen desorption plateau pressures increase with Cr substituted by Fe increasing. The maximum and reversible hydrogen storage capacities are more than 1.85 and 1.65 wt% at 201 K respectively. The hydrogen desorption plateau slopes are all less than 0.5. The symmetry weakening of 2a sites may deteriorate the plateau slop characteristic. Ti1.02Cr0.95Fe0.75Mn0.3 and Ti1.02Cr1.0Fe0.75Mn0.25 alloys are suitable for high pressure hybrid tank which can supply the effective hydrogen (more than 70 MPa) about 40.0, 44.2, 46.9 kg/m(3) with 45, 70, 90 MPa compressor, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.