Abstract:AB₅ hydrogen storage alloys La_0.54Ce_0.28Pr_0.18Ni_4−xCo_0.6Mn_0.35Al_x (x=0.1, 0.2, 0.3) were prepared by arc melting method under an Ar atmosphere. The results show that the contents of Ni and Al have obvious influences on the microstructure and electrochemical properties of the alloys. Both the lattice parameters and the cell volumes decrease with decreasing x value. Moreover, the discharge capacity at different temperatures, the high rate discharge property, and the cycling life of the alloy electrode are also in close relationship with the x value. When x value increases from 0.1 to 0.3, the discharge capacities with a discharge current density of 60 mA/g slightly decreases at 25 ℃, but evidently deteriorates at −40 ℃, the high-rate property gravely decreases, and the cycle life of the alloy electrode is improved in some extent. Therefore, it is meaningful to control Al content for the AB₅ hydrogen storage alloys used in Ni/MH batteries.

Key words: Ni/MH batteries; AB₅ hydrogen storage alloy; electrochemical properties