Stoichiometry and annealing condition on hydrogen capacity of TiCr2-x AB2 alloys

McGrath, Alexander J.; Wadge, Matthew D.; Adams, Marcus; Manickam, Kandavel; Ling, Sanliang; Walker, Gavin S.; Grant, David M.

Abstract

This study presents the effect of stoichiometry and annealing condition on Ti–Cr AB2-type hydrogen storage alloys. Prior to annealing the majority phase of the as-cast alloys was the C14 Laves phase, with separate Ti and Cr phases. Annealing treatment (1273 K/14 d) led to a transition from C14 to C15 Laves phase structure. Both C14 (as-cast) and C15 (annealed) cell size increased with Ti content, up to a ratio (Cr/Ti) of 1.6, due to B-site Ti substitution in the lattice up to a limit. Pressure composition isotherm (PCI) measurements demonstrated alloys containing a greater Ti content had a better maximum hydrogen storage capacity (1.5 vs. 1.03 wt%) and lower plateau pressure (9.4 vs. 15.8 bar) at 253 K. Annealing resulted in a lower storage capacity (1.05 vs. 1.49 wt%), greater plateau pressure (ca. 30 bar) and flatter plateau slope (25 % reduction in plateau slope). Reduction in hydrogen storage capacity of annealed alloys could be due to diffusion of residual Cr in the alloy into the C15 Laves phase during the annealing process, thereby changing the local composition as confirmed through X-ray diffraction (XRD).

Citation

McGrath, A. J., Wadge, M. D., Adams, M., Manickam, K., Ling, S., Walker, G. S., & Grant, D. M. (2024). Stoichiometry and annealing condition on hydrogen capacity of TiCr2-x AB2 alloys. International Journal of Hydrogen Energy, 53, 582-591. https://doi.org/10.1016/j.ijhydene.2023.12.062

• Journal Article Type: Article
• Acceptance Date: Dec 7, 2023
• Online Publication Date: Dec 18, 2023
• Publication Date: Jan 31, 2024
• Deposit Date: Dec 21, 2023
• Publicly Available Date: Dec 21, 2023
• Journal: International Journal of Hydrogen Energy
• Print ISSN: 0360-3199
• Electronic ISSN: 1879-3487
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 53
• Pages: 582-591
• DOI: https://doi.org/10.1016/j.ijhydene.2023.12.062
• Keywords: Hydrogen storage; Metal hydrides; AB2 alloys; TiCr
• Public URL: https://nottingham-repository.worktribe.com/output/28714136
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0360319923063620