Hydrogen storage properties of new A3B2-type TiZrNbCrFe high-entropy alloy

• Published in: International journal of hydrogen energy 2021-07, Vol.46 (46), p.23757-23766
• Main Authors: Floriano, Ricardo, Zepon, Guilherme, Edalati, Kaveh, Fontana, Gabriel L.B.G., Mohammadi, Abbas, Ma, Zhongliang, Li, Hai-Wen, Contieri, Rodrigo J.
• Format: Article
• Language: English
• Subjects: C14 laves phase; CALPHAD (Calculation of phase diagrams); High-entropy alloys (HEAs); Hydrogen storage; Metal hydrides
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.04.181

Crystal structure and hydrogen storage properties of a novel equiatomic TiZrNbCrFe high-entropy alloy (HEA) were studied. The selected alloy, which had a A3B2-type configuration (A: elements forming hydride, B: elements with low chemical affinity with hydrogen) was designed to produce a hydride with a hydrogen-to-metal atomic ratio (H/M) higher than those for the AB2- and AB-type alloys. The phase stability of alloy was investigated through thermodynamic calculations by the CALPHAD method. The alloy after arc melting showed the dominant presence of a solid solution C14 Laves phase (98.4%) with a minor proportion of a disordered BCC phase (1.6%). Hydrogen storage properties investigated at different temperatures revealed that the alloy was able to reversibly absorb and fully desorb 1.9 wt% of hydrogen at 473 K. During the hydrogenation, the initial C14 and BCC crystal structures were fully converted into the C14 and FCC hydrides, respectively. The H/M value was 1.32 which is higher than the value of 1 reported for the AB2- and AB-type HEAs. The present results show that good hydrogen storage capacity and reversibility at moderate temperatures can be attained in HEAs with new configurations such as A3B2/A3B2H7. [Display omitted] •Novel TiZrNbCrFe a A3B2-type alloy was designed for hydrogen storage.•TiZrNbCrFe alloy showed a dominant presence of C14 Laves and minor BCC phases.•TiZrNbCrFe alloy reversibly absorb and fully desorb 1.9 wt% (H/M = 1.32) of hydrogen at 473 K.•After hydrogenation, the C14 and BCC phases were fully converted into the C14 and FCC hydrides.