Hydrogen absorption alloys for Nickel-Hydrogen rechargeable batteries

Abstract

PCT characterristics and the electrode performance on laves phase Zr-Mn alloy were studied. The effects of substitution of Zr by Ti and of Mn by Ni were investigated. The influence of the compositional deviation from the stoichiometry were also studied. The electrode test was performed in the electrolyte flood open type cell. The Zr1-yTiyNixMn1. 8-x V0. 2 alloy showed its maximum capacity of 390 mAh/g when x=1.2 and y=0.2. This is due to the improvement of the homogeneity and activity of alloys. The high rate capacity increase with the decrease of B/A ratio. The probable reason is that the mechanical strength of the alloy decreases as B/A ratio decreases. Thus the specific surface area increases more rapidly by the self-break-down of the alloy powder during charge/discharge cycles. For B site rich alloys, the metallographical homogeneity are improved while hydrogen equilibrium pressure increases.