Electrochemical characteristics of the Mg1-xLaxNi (x=0, 0.05, 0.10) alloy synthesized by mechanical alloying

The amorphous Mg1-xLaxNi (x = 0, 0.05, 0.10) alloys (a-Mg1-xLaxNi) were prepared by mechanical alloying (MA). Electrochemical properties of the alloy electrodes were characterized, the results showed that the specimens had large electrochemical discharge capacities at room temperature. The X-ray diffraction (XRD) results showed that the amorphous Mg1-xLaxNi alloys decomposed into the crystalline Mg2NiH4 and Ni phases as the increase in electrochemical cycle number of the samples, which was the main reason for the discharge capacity losses of the electrodes. The cyclic life and differential thermal analysis (DTA) results showed that partially replacing Mg by appropriate amounts of La leads to an improvement of cyclic stability due to an increase of the thermal stability. In addition, the SEM analysis results showed that the replacement of Mg by La could prevent the MgNi alloy from a decrease in particle size. Over all, the amorphous Mg0.95La0.05Ni alloy showed the best electrochemical properties. (C) 2003 Elsevier B.V. All rights reserved.