The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys
AbstractEffects of substitutions of rare earth (RE) elements (Y, La, Ce, and Nd) to the Zr-based AB2 multi-phase metal hydride (MH) alloys on the structure, gaseous phase hydrogen storage (H-storage), and electrochemical properties were studied and compared. Solubilities of the RE atoms in the main Laves phases (C14 and C15) are very low, and therefore the main contributions of the RE additives are through the formation of the RENi phase and change in TiNi phase abundance. Both the RENi and TiNi phases are found to facilitate the bulk diffusion of hydrogen but impede the surface reaction. The former is very effective in improving the activation behaviors. −40 °C performances of the Ce-doped alloys are slightly better than the Nd-doped alloys but not as good as those of the La-doped alloys, which gained the improvement through a different mechanism. While the improvement in ultra-low-temperature performance of the Ce-containing alloys can be associated with a larger amount of metallic Ni-clusters embedded in the surface oxide, the improvement in the La-containing alloys originates from the clean alloy/oxide interface as shown in an earlier transmission electron microscopy study. Overall, the substitution of 1 at% Ce to partially replace Zr gives the best electrochemical performances (capacity, rate, and activation) and is recommended for all the AB2 MH alloys for electrochemical applications. View Full-Text
Share & Cite This Article
Young, K.-H.; Ouchi, T.; Nei, J.; Moghe, D. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys. Batteries 2016, 2, 25.
Young K-H, Ouchi T, Nei J, Moghe D. The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys. Batteries. 2016; 2(3):25.Chicago/Turabian Style
Young, Kwo-Hsiung; Ouchi, Taihei; Nei, Jean; Moghe, Dhanashree. 2016. "The Importance of Rare-Earth Additions in Zr-Based AB2 Metal Hydride Alloys." Batteries 2, no. 3: 25.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.