Hydrogenation properties of amorphous 2Mg+Fe/x wt% Ni materials prepared by mechanical alloying (x=0, 100, 200)

Mechanical alloying (MA) process was used to synthesize amorphous 2Mg + Fe/x wt% Ni hydrogen storage materials. The structure, thermodynamic and electrochemical properties of these materials has been examined. The nickel addition is advantageous for the formation of Mg-Fe amorphous structures and for the improvement of the electrochemical properties of the studied alloys. With the increasing of nickel content. at first cycle, the discharge capacity of the 2Mg-Fe alloys increases first and then decreases reaching a maximum of 155 mAh g(-1) at x = 100. For all 2Mg + Fe studied materials, MA with nickel effectively reduced the degradation rate of the studied electrodes. This result indicates that the nickel content does help to inhibit the corrosion of the alloy electrode in the KOH solution. On the other hand, the concentration of hydrogen in produced amorphous 2Mg + Fe/x wt% Ni alloys strongly decreases with increasing nickel contents. The hydrogen content at 300 degrees C in these materials was 3.25, 1.55 and 0.35 wt% for x = 0, 100 and 200, respectively. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.