Zirconium-Modified Medium-Entropy Alloy [sub.85]Cr[sub.15] for Hydrogen Storage

• Published in: Materials 2024-04, Vol.17 (8)
• Main Authors: Saksl, Karel, Matvija, Miloš, Fujda, Ma, Ballóková, Beáta, Varcholová, Dagmara, Kubaško, Jakub, Möllmer, Jens, Lange, Marcus, Podobová, Mária
• Format: Article
• Language: English
• Subjects: Alloys; Fuel cell industry; Hydrogen as fuel; International economic relations; Zirconium; Zirconium alloys
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17081732

In this study, we investigate the effect of small amounts of zirconium alloying the medium-entropy alloy (TiVNb)[sub.85]Cr[sub.15], a promising material for hydrogen storage. Alloys with 1, 4, and 7 at.% of Zr were prepared by arc melting and found to be multiphase, comprising at least three phases, indicating that Zr addition does not stabilize a single-phase solid solution. The dominant BCC phase (HEA1) is the primary hydrogen absorber, while the minor phases HEA2 and HEA3 play a crucial role in hydrogen absorption/desorption. Among the studied alloys, Zr4 (TiVNb)[sub.81]Cr[sub.15]Zr[sub.4] shows the highest hydrogen storage capacity, ease of activation, and reversibly retrievable hydrogen. This alloy can absorb hydrogen at room temperature without additional processing, with a reversible capacity of up to 0.74 wt.%, corresponding to hydrogen-to-metal ratio H/M = 0.46. The study emphasizes the significant role of minor elemental additions in alloy properties, stressing the importance of tailored compositions for hydrogen storage applications. It suggests a direction for further research in metal hydride alloys for effective and safe hydrogen storage.