In order to optimize the microstructure and high temperature electrochemical performances of low-cost AB(5)-type Ml(NiMnAl)(4.2)Co0.3Fe0.5 hydrogen storage electrode alloys, four different preparation methods including normal solidification (NS), normal solidification and 900 degrees C heat treatment (NS + HT), rapid solidification (RS), rapid solidification and 900 degrees C heat treatment (RS + HT) were adopted in this work. All alloys exhibit CaCu5 type hexagonal structure and there is a small amount of A(2)B(7) phase in NS + HT and RS + HT alloys. It is found the using of HT process can decrease the hydrogen equilibrium plateau pressure, the plateau slope and hysteresis at 40, 60 and 80 degrees C. The NS + HT and RS + HT alloys also possess better activation, high rate discharge performance, larger discharge capacity, but poor cycling performance due to the existence of A(2)B(7) phase which can accelerate dissolution of Ni, Mn and Fe elements in KOH alkaline electrolyte. The RS process can make alloy exhibit the best cycling performance especially at 60 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.