Comparison of Hydrogen-Storage Properties of Mg-14Ni-3Fe_2O_3-3Ti and Mg-14Ni-2Fe_2O_3-2Ti-2Fe

摘要

Magnesium with oxides or transition elements prepared by mechanical grinding under H_2 (reactive mechanical grinding) showed relatively high hydriding and dehydriding rates when the content of additives was about 20 wt%. Ni, Fe2_O_3, and Fe were chosen as the oxides or transition elements to be added. Ti was also selected since it was considered to increase the hydriding and dehydriding rates by forming Ti hydride. Samples Mg-14Ni-3Fe_2O_3-3Ti (Sample A) and Mg-14Ni-2Fe_2O_3-2Ti-2Fe (Sample B) were prepared by reactive mechanical grinding, and their hydrogen storage properties were compared. The activated Sample A had a little smaller hydriding rate than the activated Sample B, but a higher dehydriding rate than the activated Sample B. Sample A exhibits quite a larger dehydriding rate and quantity of hydrogen desorbed for 60 min than any other Mg-xNi-yFe_2O_3-zM (M=transition metals) samples. An addition of a relatively larger amount of Ti is considered to lead to quite a high hydriding rate and a high dehydriding rate of Sample A.