Abstract:The non-stoichiometric high rate discharge hydrogen storage alloys series MlNi_3.85Co_0.45Mn_0.4Al_0.3X_0.1(Ml represents the lanthanum-rich mischmetal, and X=Mg,Si,Sn) were prepared. The XRD and EDS results show that the high catalysis active miscellaneous La₂Ni₇phase forms except for main phase LaNi₅ in the alloy body. The high rate discharge performance of hydrogen storage alloys electrode was improved because of the formation of La₂Ni₇ phase. The discharge capacities at 0.2C, 1C and 5C discharge rate reach 320mAh·g^-1, 300mAh·g^-1and 260mAh·g^-1respectively when X is (Mg+Si). At the same scanning rate of circular volt—ampere testing, the surface anode oxidation peak current and peak area of the alloy containing (Mg+Si) electrode are far more larger than that of the high cobalt alloy MlNi_3.55Co_0.75Mn_0.4Al_0.3(AB₅). Furthermore, the cobalt content of the hydrogen storage alloy containing (Mg+Si) decreases by 40% and the high rate discharge performance improves obviously compare to high cobalt AB₅ alloys, it is promising that the hydrogen storage alloy containing (Mg+Si) becomes to an ideal dynamic battery cathode material.

Key words:   low cobalt; high rate discharge; hydrogen storage alloys； (Mg+Si)； preparation