A performance study of AB5 hydrogen storage alloys with Co being replaced by Be-Cu

Detailed investigations using XRD, EDS and SEM reveal that upon increasing the content of Be-Cu, the phase structure of the alloy La0.6Ce0.2Pr0.05Nd0.15 Ni3.55Co0.75-xMn0.4Al0.3 (Cu0.06Be0.04)(x) (x = 0, 0.15, 0.30, 0.45, 0.60, 0.75) varies and the content of LaNi5 phase increases with the cell volume increasing from 89.43 angstrom(3) (x = 0) to 89.72 angstrom(3) (x = 0.45). In doing so, the maximum capacity increases from 308.3 mA h g(-1) (x = 0) to 321.9 mA h g(-1) (x = 0.45), and then decreases to 313.7 mA h g(-1) (x = 0.75). The capacity decay rate after 100 cycles (D-100) decreases from 1.29 mA h g(-1)cycle(-1) (x = 0) to 1.06 mA h g(-1)cycle(-1) (x = 0.45), and then increases to 1.27 mA h g(-1)cycle(-1) (x = 0.75). High-rate capacities of all alloys were improved as a result of increasing the Be-Cu content. The electrochemical kinetics of the sample alloys have also been investigated using electrochemical impedance spectroscopy (EIS). The results indicate that the kinetic performances of hydrogen storage alloys significantly improve as Co was replaced by Be-Cu. In summary, the overall performance of the new alloys significantly improved, especially at x = 0.45. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.