A solid oxide fuel cell based on a proton-conducting electrolyte (SOFC-H+) is an attractive fuel cell technology because of its high theoretical efficiency. This study deals with the performance analysis of a planar SOFC-H+ using a detailed electrochemical model, which takes into account all cell voltage losses. i.e.. ohmic, activation, and concentration losses. The Fick's Model was used to explain gas diffusion in porous electrodes. The reliability of the developed SOFC-H+ model was verified by comparison with experimental data reported in the literature. The effects of cell design (e.g., the use of anode, cathode, and electrolyte supports), geometry (e.g., thickness of cell components), and operating parameters (e.g., temperature, pressure, and gas composition) on the electrical characteristics of SOFC-H+ were examined. The results indicate that an anode-supported SOFC-H+ shows the best performance under the operating temperature of 1073 K and pressure of 1 atm. Ohmic loss is the major voltage loss in an anode-supported SOFC-H+ due to the relatively low proton conductivity of the electrolyte. Furthermore, the performance of a SOFC-H+ can be improved by decreasing the thickness of electrolyte and cathode, and the content of water in the oxidant, as well as by increasing the operating temperature and pressure. (C) 2010 Elsevier By. All rights reserved.