Electrode materials for AMTEC play a significant role in its power output and efficiency. TiN, RhW and Rh2W alloys have been studied to determine the best performing material over a wide range of temperature similar to1000-2000 K. The power output is related to the grain growth of the electrode material. By simulation and analysis this study examines power degradation of AMTEC due to the grain size and leads to the performance of RhW material as best among them. (C) 2004 Published by Elsevier B.V.