Study on the phase structure and electrochemical properties of RE0.93Mg0.07Ni2.96Co0.60Mn0.37Al0.17 hydrogen storage alloy

In our endeavor to improve overall properties of the La–Mg–Ni–Co type alloys, RE0.93Mg0.07Ni2.96Co0.60Mn0.37Al0.17 hydrogen storage electrode alloy with low magnesium content was obtained by inductive melting. The phase structure and electrochemical characteristics of the alloy were investigated by XRD and electrochemical measurement. The results indicate that RE0.93Mg0.07Ni2.96Co0.60 Mn0.37Al0.17 alloy has multi-phase microstructure containing the CaCu5 structure of LaNi5 phase as matrix phase and a little of LaNi3 phase as the secondary phase. The maximum discharge capacity of RE0.93Mg0.07Ni2.96Co0.60Mn0.37Al0.17 alloy reaches 359 mAh/g, which is 7.2% higher than that of commercial AB5 alloy electrode. The discharge capacity of RE0.93Mg0.07Ni2.96Co0.60Mn0.37Al0.17 alloy electrode at 233 K is up to 147 mAh/g, which is 308.3% higher than that of commercial AB5 alloy electrode. Meanwhile, the discharge capacity of RE0.93Mg0.07Ni2.96Co0.60Mn0.37Al0.17 alloy can reach 92.7% of commercial AB5 alloy after 100 charge/discharge cycles.