Hydrogen Sorption in Ti0.9Zr0.1Fe0.9Ni0.1 Alloy

TiFe-based alloys are promising materials for hydrogen storage due to their low cost and relatively high hydrogen storage capacity. However, their practical application is limited by demanding activation conditions, typically requiring temperatures above 400°C and high hydrogen pressures. In this work, the Ti0.9Zr0.1Fe0.9Ni0.1 hydride was investigated by means of X-ray diffraction, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, and Mössbauer spectroscopy. Hydrogen sorption measurements showed that the activation temperature was reduced to 220°C without compromising the hydrogen storage capacity of 1.62 wt%. Rietveld refinement confirmed the TiFe-type cubic structure as well as secondary Fe-containing phases present in both the parent alloy and its hydride. Mössbauer spectra revealed two spectral components associated with the TiFe-based matrix and secondary phases, respectively. The observed changes in the hyperfine parameters after hydrogenation indicate modifications of the local electronic environment of Fe atoms induced by hydrogen incorporation into the crystal structure.