High-performance La–Mg–Ni-based alloys prepared with low cost raw materials.

La–Mg–Ni-based hydrogen storage alloys showed good application prospects owing to their high hydrogen storage capacity. However, the poor cycling stability was a key problem. In order to improve the cycling stability, low cost YFe 0.85 master alloy was used as raw material to prepare La–Mg–Ni-based La 0.8- x Y x Mg 0.2 Ni 3-0.85 x Fe 0.85 x (x = 0.50, 0.55, 0.60) hydrogen storage alloys by powder sintering method. The alloys were mainly composed of PuNi 3 phase and MgCu 4 Sn phase. With the increase of Y and Fe, the cell parameters of PuNi 3 phase decreased. Lower mismatch coefficient promoted the cycling stability. As the case of x = 0.60, the capacity retention rate rose up to 95.45%. Aside from the cycling stability, appropriate substitution content contributed to higher capacity and satisfactory kinetics. As the case of x = 0.55, the hydrogen storage capacity reached 1.529 wt%, and hydriding time for the x = 0.60 alloy shrank to 76.7% of that for alloys without Y and Fe at 303 K. [Display omitted] • Y and Fe co-doping transfers LaNi 5 phase into PuNi 3 and MgCu 4 Sn phases. • Y and Fe co-doping increases the hydrogen storage capacity. • Y and Fe co-doping into La–Mg–Ni-based alloy promotes the cycling stability. [ABSTRACT FROM AUTHOR]