Development of Ti-Zr-Mn-Cr-V based alloys for high-density hydrogen storage

Two series of Ti1-xZrxMn1.1Cr0.7V0.2 (x = 0.05, 0.06, 0.07, 0.1) and Ti0.95Zr0.05Mn1.8-yCryV0.2 (y = 0.5, 0.7, 0.9) alloys were developed for high-density hydrogen storage units. The effect of partial substitution of Zr for Ti and Cr for Mn on microstructures as well as hydrogen storage performances was systematically investigated. All prepared alloys are determined as a single phase of C14-type Laves structure and uniform element distribution. As Ti is increasingly substituted with Zr in the Ti1-xZrxMn1.1Cr0.7V0.2 (x = 0.05-0.1) alloys, the hydrogen storage capacity increases gradually, while the plateau pressures decrease drastically. For Ti0.95Zr0.05Mn1.8-yCryV0.2 (y = 0.5-0.9) alloys, with the increase substitution of Cr for Mn, equilibrium pressure hysteresis of de-hydrogenation improves significantly, while the plateau pressures and the hydrogen storage capacity decrease slightly. Among the studied alloys, Ti0.95Zr0.05Mn0.9Cr0.9V0.2 is the most suitable for high-density hydrogen storage units with excellent cycling performances. The hydrogen storage capacity is 1.78 wt% in gravimetry and 118.33 kg/m(3) in volumetry. The desorption plateau pressure at 90 degrees c is 9.37 MPa with extremely low hysteresis, and dissociation enthalpy is - 21.64 kJ mol(-1). This work provides a guideline for the alloy composition design of Ti-based alloys. (C) 2021 Elsevier B.V. All rights reserved.