Composition design of (LaCeCa)1(NiMnAl)5 alloys by uniform design method and their hydrogen storage performance

Abstract

Rare-earth-based AB5-type alloys are strong candidates for use in solid state hydrogen storage applications; however, their capacity needs to be improved. To efficiently optimize the hydrogen storage performance of AB5-type alloys, the effects of the substitution of Ce and Ca for La (A side) and Mn and Al for Ni (B side) on the structural properties and hydrogenation/dehydrogenation performance of the (LaCeCa)1(NiMnAl)5 alloy series were studied systematically using the uniform design method. X-ray diffraction analysis and scanning electron microscopy showed that all the designed alloys consisted of a single uniform LaNi5 phase. The atomic radii and contents of the constituent elements had a determining effect on the cell volume and properties of the alloys. The maximum hydrogen storage capacity of the (LaCeCa)1(NiMnAl)5 alloy series is approximately 1.7 wt%, which is much higher than the theoretical hydrogen storage capacity of LaNi5 (1.39 wt%).