The performance of Solid Oxide Fuel Cells (SOFCs) degrades due to various reactions. Lack of a general model based on these reactions that predicts SOFCs long-time performance with few assumptions, limits commercialization of SOFCs. In this work, a detailed mathematical model is constructed to evaluate SOFCs long-term performance with regard to operating conditions. Most of the reactions that greatly deteriorates SOFCs components; such as Ni coarsening and oxidation, anode pore diameter changes, deterioration of anode conductivity and electrolyte conductivity, and sulfur poisoning are considered in this model to ensure that it yields reliable and precise results. A broad literature survey indicated that previously developed models only account for a part of these reactions and hence they do not provide accurate results. Rest of the models, on the other hand, are regression models that have been fitted to experimental data and thus are valid in a limited range of operating parameters.
According to the sensitivity analysis, current has a substantial impact on SOFCs performance. While, temperature and H2 partial pressure influence SOFCs performance less. Drawing larger current from SOFCs and running them at higher temperature and lower H2 pressure degrade cells faster.
Our findings illustrated that performance of SOFCs drops markedly in the early hours of operation, but degradation rate declines significantly after almost 1500 hours.
The sulfur poisoning model developed in the present work, exhibits impacts of current and H2S concentration on SOFCs fed with hydrocarbon-based fuels, unlike previously models that focused on H2-supplied SOFCs.