Tuning hydrogen storage thermodynamic properties of ZrFe_2 by partial substitution with rare earth element Y

摘要

ZrFe2 delivers the advantages of high hydrogen storage capacity and easy activation, but its de-/hydriding pressure is too high for practical application. In this work, we alloyed ZrFe2 with Y to obtain a single C15 Laves phase structure by the proper annealing process. The microstructure and hydrogen storage properties of Zr1-xYxFe2 (x 1/4 0.1-0.4) compounds were investigated. The results show that the cell volume increases and the dissociation pressure decreases with increasing Y content for the Zr-Y-Fe-H system. The Y alloying is beneficial for increasing hydrogen storage capacity despite the worsening plateau slope and hysteresis. The Zr0.6Y0.4Fe2 exhibits the highest hydrogen absorption capacity of 1.77 wt%, while the Zr0.8Y0.2Fe2 shows a dehydriding enthalpy of 25.06 kJ/mol H2 and dehydriding entropy of 116.53 J/mol.K H2, corresponding to the dissociation pressure of 59 atm at 298 K that is suitable for high-pressure hydrogen storage applications. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.