Improvement in Hydriding and Dehydriding Features of Mg-TaF5-VCl3 Alloy by Adding Ni and x wt% MgH2 (x=1, 5, and 10) Together with TaF5 and VCl3

In our previous work, TaF5 and VCl3 were added to Mg, leading to the preparation of samples with good hydriding and dehydriding properties. In this work, Ni was added together with TaF5 and VCl3 to increase the reaction rates with hydrogen and the hydrogen-storage capacity of Mg. The addition of Ni together with TaF5 and VCl3 improved the hydriding and dehydriding properties of the TaF5 and VCl3-added Mg. MgH2 was also added with Ni, TaF5, and VCl3 and Mg-x wt% MgH2-1.25 wt% Ni-1.25 wt% TaF5-1.25 wt% VCl3 (x = 0, 1, 5, and 10) were prepared by reactive mechanical milling. The addition of MgH2 decreased the particle size, lowered the temperature at which hydrogen begins to release rapidly, and increased the hydriding and dehydriding rates for the first 5 min. Adding 1 and 5 wt% MgH2 increased the quantity of hydrogen absorbed for 60 min, H-a (60 min), and the quantity of hydrogen released for 60 min, H-d (60 min). The addition of MgH2 improved the hydriding-dehydriding cycling performance. Among the samples, the sample with x = 5 had the highest hydriding and dehydriding rates for the first 5 min and the best cycling performance, with an effective hydrogen-storage capacity of 6.65 wt%.

Automated summary

In this study, Ni was added to Mg along with TaF5 and VCl3 to enhance the reaction rates with hydrogen and the hydrogen-storage capacity. The addition of MgH2 further improved the hydriding and dehydriding properties by reducing particle size, lowering the release temperature of hydrogen, and increasing rates of hydrogen absorption and desorption. Among the samples, the one with x = 5 showed the best cycling performance and the highest hydrogen-storage capacity.