Improved hydrogen storage kinetics of nanocrystalline and amorphous Ce–Mg–Ni-based CeMg12-type alloys synthesized by mechanical milling

In this paper, ball milling was used to prepare CeMg₁₁Ni + x wt% Ni (x = 100, 200) alloys having nanocrystalline and amorphous structures. The structures of the alloys and their electrochemical and gaseous kinetic performances were systematically investigated. It was shown that the increase in Ni content was beneficial to the formation of nanocrystalline and amorphous structures, and it significantly enhanced the electrochemical and gaseous hydrogen storage performances of as-milled alloys. In addition, the hydrogen storage capacities of the alloys fluctuated greatly with variation in milling duration. The maximum values of hydrogen capacity detected by varying the milling durations were 5.949 wt% and 6.157 wt% for x = 100 and 200 alloys, respectively. Similar results were observed for the hydriding rates and high-rate discharge abilities (HRD) of the as-milled alloys. The dehydriding rate increased with the increase in milling duration. The reduction in hydrogen desorption activation was the reason for enhanced gaseous hydrogen storage kinetics.

Addition of Ni and milling are beneficial for forming nanocrystalline and amorphous structures, thus enhancing the hydrogen storage kinetics of CeMg₁₂-type alloys.