Reversible Hydrogenation Of Ab2-Type Zr?Mg?Ni?V Based Hydrogen Storage Alloys

The development of hydrogen energy is hindered by the lack of high-efficiency hydrogen storage materials. To explore new high-capacity hydrogen storage alloys, reversible hydrogen storage in AB2-type alloy is realized by using A or B-side elemental substitution. The substitution of small atomic-radius element Zr and Mg on A-side of YNi2 and partial substitution of large atomic-radius element V on B-side of YNi2 alloy was investigated in this study. The obtained ZrMgNi4, ZrMgNi3V, and ZrMgNi2V2 alloys remained single Laves phase structure at asannealed, hydrogenated and dehydrogenated states, indicating that the hydrogen-induced amorphization and disproportionation was eliminated. From ZrMgNi4 to ZrMgNi2V2 with the increase of the degree of vanadium substitution, the reversible hydrogen storage capacity increased from 0.6 wt% (0.35H/M) to 1.8 wt% (1.0H/M), meanwhile the lattice stability gradually increased. The ZrMgNi2V2 alloy could absorb 1.8 wt% hydrogen in about 2 h at 300 K under 4 MPa H2 pressure and reversibly desorb the absorbed hydrogen in approximately 30 min at 473 K without complicated activation process. The prominent properties of ZrMgNi2V2 elucidate its high potential for hydrogen storage application.