To improve the electrochemical performance of the MgNi-based alloys, different amounts of iron boride powder prepared by chemical reduction method were introduced by mechanical alloying. The results of powder X-ray diffraction showed these composites had amorphous structures. Cyclic charge-discharge tests showed the cycle stability of the MgNi alloy was improved by FeB. After 50 charge-discharge cycles, the discharge capacity of the MgNi-FeB composite was 60.99% higher than that of pure MgNi alloy. From the 1st cycle to 5th cycle, the discharge capacity faded rapidly; however, from the 6th to 100th cycle the discharge capacity was much more stable. The discharge capacity of cycle 100 remained 190.7 mA h g(-1), which was 93.53% of the 6th cycle. The corrosion resistance of the MgNi alloy in alkaline solution was also increased by FeB, which was confirmed by the results of electrochemical impedance spectroscopy and Tafel polarization tests. (c) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.