The performances of La1−xCexNi5 (0 ≤ x ≤ 1) hydrogen storage alloys studied by powder microelectrode

The structure and electrochemical properties of AB5-type hydrogen storage alloys La1−xCexNi5 (0 ≤ x ≤ 1) were studied systematically by XRD method and powder microelectrode technique (PME). The structure analysis results indicated that all the alloys have typical CaCu5 single-phase structure. As x value increased, the cell parameter a and the cell volume decreased but cell parameter c increased slightly. PME study results showed that, the element substitution of Ce for La in LaNi5 can enlarge the activation cycles number, but at higher Ce content, the activation cycles number was almost not affected by the Ce content. As the Ce content in the La1−xCexNi5 alloy increased, the discharge potential of alloys shifted towards negative direction, the activity of electron transfer reaction of hydrogen oxidation on the alloy surface increased, the maximum current output ability of the alloy and the hydrogen diffusion coefficient in the bulk of alloy were improved, and the capacity decay rate was reduced significantly.