Effect of commercial AB5 alloy addition on the electrochemical properties of Ml-Mg-Ni-based hydrogen storage alloys

A commercial AB5 hydrogen storage alloy was used as an additive to improve the electrochemical properties of Ml-Mg-Ni-based hydrogen storage alloys. The effect of AB5 alloy addition on the phase structure, charge/discharge characteristics, and electrochemical kinetics of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 alloy was investigated. The maximum discharge capacity of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 + 4 wt.% AB5 electrode reaches 406 mAh/g. The anodic polarization, cyclic voltammetry, and potential step discharge experiments show that the electrochemical kinetics of the electrode with additives was promoted, with the LaNi5 phase of AB5 alloy acting as electro-catalytic sites in the electrode alloy. The high-rate dischargeability of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 + 4 wt.% AB5 alloy electrode at 1100 mA/g reaches 60.9%, which is 9.4% higher than that of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 alloy electrode. The cycling stability of the electrode with 4 wt.% AB5 alloy has also been improved.