La–Ni Based Alloy Modification by Ce and Fe for the Next Hydrogen Storage in Low-Temperature Metal Hydrides

Abstract

La–Ni based alloys have been established as suitable materials for reversible hydrogen storage. Low-temperature metal hydrides (LT MH) facilitate hydrogen storage at ambient temperatures and pressure of 1–1.5 MPa. Nevertheless, further research and modifications of these alloys are needed. In this paper, the parent LaNi₅ alloy was modified by partially replacing La with Ce and Ni with Fe. The alloys were prepared in two different ways: conventional melting of pure powder metals, and thermochemical reaction using corresponding metal chlorides. Steps were taken to optimize the time-temperature parameters of alloy synthesis. A comparative analysis of the obtained alloy samples followed. Hydrogen sorption isotherms were obtained for the unmodified LaNi₅ and modified (La_0.5Ce_0.5)Ni₅ samples made from pure powder metals. Due to strong oxidation of the alloys prepared from metal chlorides, sorption isotherms for these alloys were not obtained.