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Hydrogen has a strong potential for use as an alternative fuel provided that it can be stored in a safe and efficient way. One possibility is to store it as a solid hydride using suitable metals or alloys. Metal hydrides have been widely studied as storage materials but most alloys are unable to fulfil the requirements of a competitive hydrogen storage unit that can be exploited in practical applications. Recently in work by Sahlberg et al. was studied absorption capacity of hydrogen in the TiVZrNbHf BCC high-entropy alloy. They report the alloy absorbs and stores extremely large amounts of hydrogen approaching hydrogen to metal ratio H/M to 2.5. This enormous stored capacity was attributed to internal lattice stresses, promoting hydrogen to occupy both tetrahedral and also octahedral interstitial positions. Such a full occupation is unique and has never been observed in transition metal hydrides before. In this article, we prepared similar TiVZrNbX alloys (X = Cr, Ni, Fe, Ag and Ta) and examined their ability to store hydrogen (in our case deuterium). The effect of lattice strains, promoting transport and storage of hydrogen (deuterium) was examined. Our comparison provides evidence that solid solutions do not have the highest storage capacity, but rather alloys composed of intermetallic compounds.
Keywords: Hydrogen storage, metalhydride, high-entropy alloy, absorbtion capacity, X-ray diffraction© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.