Electrochemical properties of nanocrystalline (Zr,La)(V,Ni) 2.25 alloy

Abstract

Nanocrystalline Zr 0.975La 0.025V 0.56Ni 1.69 material was prepared by mechanical alloying (MA) and subsequent annealing. XRD analysis showed that, after 35 h milling, the alloy had decomposed into an amorphous phase. Following the annealing in high purity argon at 1070 K for 0.5 h, XRD confirmed the formation of the C15-type structure. This alloy was used as the negative electrode for a Ni–MH x battery. The electrochemical results showed very little difference between the nanocrystalline and polycrystalline powders, as compared with the substantial difference between these powders and the amorphous powder. In the annealed nanocrystalline Zr 0.975La 0.025V 0.56Ni 1.69 powders, discharge capacities of up to 135 mA h g −1 (at 160 mA g −1 discharge current) were measured. The MA process has recently emerged as a novel technique for producing nanostructured alloy powders with interesting electrochemical properties.