An improved electrochemical model is developed to study the ammonia fed solid oxide fuel cell based on proton conducting electrolyte (SOFC-H). Including the chemical reaction kinetics of NH3 catalytic thermal decomposition, the present model can be used to predict the performance of the NH3 fed SOFC-H at an intermediate temperature (i.e. 773 K). Comparison between the simulation results using the present model and experimental data from literature validates the accuracy of this model. Parametrical analyses reveal that at a high operating temperature (i.e. 1073 K), the NH3 fuel is completely decomposed to H-2 and N-2 within a very thin layer (30 mu m) near the anode surface of an SOFC-H. It is also found that operating the NH3 fed SOFC-H at an intermediate temperature of 773 K is feasible due to sufficiently high rate of NH3 decomposition. However, further decreasing the temperature to 673 K is not recommended as less than 10% NH3 fuel can be decomposed to H-2 and N-2 in the SOFC-H. The effects of current density and electrode microstructure on the performance of the NH3 fed SOFC-H are also studied. It is found that increasing electrode porosity and pore size is beneficial to increase the partial pressure of H-2 at the anode-electrolyte interface. The model developed in this paper can be extended to 2D or 3D models to study practical tubular or planar SOFCs. (c) 2008 Elsevier B.V. All rights reserved.