Cyclic stability test of AB2 type (Ti, Zr)(Ni, Mn, V, Fe)2.18 for stationary hydrogen storage in water contaminated hydrogen

• Ti0.24Zr0.76Ni1.2Mn0.64V0.14Fe0.18 and the sample with 1%La addition were examined.
• Using hydrogen including 40 ppm water, absorption/desorption was carried out 30 times.
• The addition of La improved cyclic stability against the water contamination.

Totalized Hydrogen Energy Utilization System (THEUS), which consists of fuel cells, water electrolyzers, hydrogen storage and their auxiliary components, is proposed for the stationary application. In the previous researches, mischmetal-based MmNi5 compound was used for the stationary hydrogen storage in THEUS. However, the cost of mischmetal is so expensive that can be an obstacle to the practical use of THEUS. In addition, since THEUS utilizes hydrogen produced by water electrolysis, it is necessary to confirm the influence of the water contamination on the metal hydride reactivity. The samples were Ti0.24Zr0.76Ni1.2Mn0.64V0.14Fe0.18 (Sample A) and the sample with 1 at.%-La addition (Sample B). Using hydrogen including 40 ppm-water, hydrogen absorption and desorption was carried out 30 times. The degradation of hydrogen storage capacity was observed for Sample A while not observed for La-added Sample B. The results revealed that the addition of La improved cyclic stability against the water contamination.