Effect of LaH3-TiH2 composite additive on the hydrogen storage properties of Mg2Ni alloys

A novel LaH3-TiH2 composite additive was prepared by ball milling LaH3 and TiH2 at a 1:1 weight ratio. Kinetic measurements on the hydrogenation reaction indicated that the LaH3-TiH2 composite additive could significantly improve the hydrogen absorption properties of Mg2Ni. In comparison with that of a pure Mg2Ni alloy and a composite material combining Mg2Ni + 10 wt.% LaH3, the hydrogen storage capacity of the Mg2Ni + 10 wt.% (LaH3-TiH2) composite was 0.251 wt.% and 0.559 wt.% higher at 423 K within 100 s, respectively. Moreover, the composite additive revealed an excellent effect on ameliorating the thermodynamic properties of the Mg2Ni hydride. The decomposition onset temperature of the Mg2Ni + 10 wt.% (LaH3-TiH2) composite hydride was 17 and 13 K lower than that of the pure Mg2NiH4 and Mg2Ni + 10 wt.% TiH2 composite, respectively. X-ray diffraction (XRD) results indicated that the LaH3 in the LaH3-TiH2 composite additive were converted to LaH2 by the catalytic effect of TiH2 during the hydrogenation cycles and that the process enhanced the kinetic properties of hydrogen storage for Mg2Ni alloy.