Effect of AB5 alloy on electrochemical properties of Mm0.80Mg0.20Ni2.56Co0.50Mn0.14Al0.12 hydrogen storage alloy

The La–Mg–Ni based composites Mm0.80 Mg0.20Ni2.56Co0.50Mn0.14Al0.12– x wt.% AB5 (x = 0, 10, 20, 30) alloys were successfully synthesized by ball milling method. The structure and electrochemical characteristics of composites have been investigated systematically. The XRD spectroscopy shows that all these composites are mainly composed of La2Ni7 phase and LaNi5 phase. The electrochemical studies suggest that the maximum discharge capacity (Cmax) of alloy electrodes decreases slightly from 361.8 mAh/g (x = 0) to 337.9 mAh/g (x = 10), 353.9 mAh/g (x = 20) and 352.8 mAh/g (x = 30), while the cycle durability of the composite electrodes is significantly improved. Moreover, the electrochemical kinetic measurements indicate that the x = 20 composite alloy electrode presents the best overall electrochemical properties.

Graphical AbstractThe Mm0.80Mg0.20Ni2.56Co0.50Mn0.14Al0.12–x wt.% AB5 (x = 0, 10, 20, 30) composite alloys were successfully synthesized by ball milling method. The electrochemical investigations reveal that the maximum discharge capacity of alloy electrodes slightly decreases, however, the cyclic capacity retention rate increases after formation composites. The results of the electrochemical kinetic measurements indicate that the x = 20 composite alloy electrode presents the best overall kinetic properties.Figure optionsDownload as PowerPoint slideHighlights
► The AB3–x wt.%AB5 (x = 0, 10, 20, 30) composites were synthesized by ball milling.
► XRD shows that composites are mainly composed of La2Ni7 phase and LaNi5 phase.
► The cycle durability of the composite electrodes is improved.
► The x = 20 composite alloy electrode presents the best overall properties.