A number of design changes for improving the alkali metal thermo-electric converter (AMTEC) cell performance are investigated. In this study, both the material used in AMTEC cell and the dimensions of the cell are changed at the same time. Two different hot side temperatures, T-hot = 1173 K and T-hot = 1023 K, are tested. The condenser temperature, T-cond, is kept at 623 K. Results show that the maximum cell conversion efficiency and the maximum electrical power output take place for different cases. Comparing the PX-SA in operation at T-hot = 1173 K with the one proposed here, the maximum electrical power output and the maximum cell conversion efficiency increased by 43 and 44%, respectively. The corresponding values for Thor = 1023 K are 46 and 48%. (C) 2001 Elsevier Science B.V. All rights reserved.