Effect of double substitution on hydrogen absorption-desorption properties of Ti2CrV alloy

• Published in: International journal of hydrogen energy 2024-05, Vol.68, p.1048-1056
• Main Authors: Ruz, Priyanka, Kumar, Asheesh, Wajhal, Sourabh, Banerjee, Seemita, Jain, Dheeraj, Krishna, P.S.R., Sudarsan, V.
• Format: Article
• Language: English
• Subjects: Cyclic stability; Double substitution; Hydrogen absorption-desorption; Neutron diffraction; X-ray diffraction
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.04.185

Doubly substituted Ti2CrV alloy with composition Ti1.5Sc0.3CrVNi0.2 was prepared by arc melting method followed by annealing. The annealed alloy exists in body centred cubic (BCC) structure and shows fast kinetics for hydrogen absorption and desorption at room temperature. BCC phase of the alloy undergoes phase transformation to face centred cubic (FCC) hydride phase with H atoms occupying tetrahedral sites in the lattice, reaching an overall H/M ratio >2.2 (storage capacity ∼ 4 wt%). Storage capacity decreases by 40% in the 2nd cycle and then stabilizes at a value of ∼2.5 wt% for the subsequent 10 cycles. A drastic reduction in hydride desorption temperature upon double substitution (Sc and Ni substitution in Ti2CrV alloy) has been confirmed by DSC studies. Furthermore, the change in isotope effect in doubly substituted Ti2CrV alloy is discussed in light of thermal stabilities of the hydrides and deuterides. [Display omitted] •Ti2CrV alloy doubly substituted by Sc and Ni has been prepared via arc melting method.•The hydrogen uptake of Ti1.5Sc0.3CrVNi0.2 alloy is > 2.2H/M at room temperature.•Neutron diffraction studies confirmed occupancy of H atoms in tetrahedral sites.•Synergistic effect of Sc and Ni double substitution causes remarkable decrease in desorption temperature of Ti2CrV alloy.•Isotope effects in Ti2CrV–H2/D2 and Ti1.5Sc0.3CrVNi0.2-H2/D2 systems have been studied.