Tuning Hydrogen Storage Properties in La_1−xY_xNi_4.5Cu_0.5 (x = 0.1; 0.2; 0.3; 0.4, 0.5) Alloys

Abstract

Metal hydrides of AB5 compositions have been investigated over the years as they offer extraordinary volumetric hydrogen densities with high cycling stability and purity of released hydrogen. Moreover, by doping with different elements, the sorption properties of alloys can be significantly changed according to their foreseen applications. In this contribution, we report the synthesis routes and hydrogenation characteristics of La1−xYxNi4.5Cu0.5. The synthesized alloys exhibit excellent structural purity with all reflections indexed by the hexagonal P6/mmm structure. It was found that the Y content can easily tune (raise) the equilibrium pressures of the pressure–composition isotherms, while overall gravimetric density remains at a level exceeding 1.5 wt.% up to x = 0.3 then strongly decreases. The pressure range for desorption can be tuned from 1.5 to 5 bars at room temperature. Some alloys (x = 0; 0.2) exhibit very good stability during 1000 cycles of hydrogen loading and unloading. Furthermore, activation of the alloys is prompt, making them good candidates for stationary hydrogen storage, non-mechanical hydrogen compressors, or soft actuators.

Keywords

• hydrogen storage
• AB5 alloys
• metal hydrides