The AB(5) alloy and Co powders have been mixed at various weight ratios to form AB(5)-Co composite electrodes. The discharge properties such as discharge capacity, discharge plateau, and cycling stability are investigated by charge and discharge testing using Arbin battery testing equipment. Synergistic effects in the composite electrodes contribute to significant improvements of the discharge behavior. For instance, the composite AB(5)-25%Co electrode shows a high discharge capacity of 395.1 mAh/g, which is significantly higher than that of ABs or Co electrode, and good cycling stability. The discharge process is also characterized by electrochemical impedance spectroscopy. Moreover, the electrochemical discharge mechanism is discussed. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.