The effects of the substitution of Ti and La for Zr in ZrMn0.7V0.2Co0.1Ni1.2 hydrogen storage alloys on the phase structure and electrochemical properties

In this paper, phase structure and electrochemical properties of the overstoichiometric hydrogen storage electrode alloys Zr1-xTix (Mn0.7V0.2Co0.1Ni1.2) have been investigated. The results showed that when the Ti content increased, the content of the C15 Laves phase decreased while that of the C14 Laves phase increased. At same time, the high Ti content inhibited the appearance of secondary phase Zr7M10 in the alloys. When x=0. 2, the storage hydrogen electrode alloy Zr0.8Ti0.2 (Mn0.7V0.2Co0.1Ni1.2) possessed the maximum discharge capacity 354mAh/g, and preserved 91% of total capacity at current 300mA/g. Due to a few La additation, the alloy Zr0.75Ti0.2La0.05Mn0.7V0.2Co0.1Ni1.2 reached the maximum capacity 372mAh/g after 4 cycles, compared to 14 cycles for the alloy without La, and preserved 93% of the maximum capacity after 30 cycles.