Comprehensive models for evaluating electrolyte hole conductivity and its impacts on the protonic ceramic fuel cell

Abstract Solid oxide fuel cell with proton-conducting electrolyte is a clean and efficient device for electricity generation. This kind of electrolyte exhibits both protonic and hole conductivities at intermediate temperature. The former one is necessary, while the latter one would cause leakage current and loss of output voltage. The electrolyte hole conductivity is a major concern due to its remarkable impact on the cell capacity. Hereby, a practical model is proposed to evaluate the effective hole conductivity of the working cell. Compared with previous models, conductivity distribution in the electrolyte is fully considered, which makes this model more applicable to a variety of working conditions. Furthermore, by accounting for leakage current, conductivity distribution within the electrolyte as well as involved polarizations, a comprehensive model for predicting cell output is developed. In the aspect of experiment, cell samples with different electrolyte thicknesses are fabricated, and are served as illustrative cases to examine our model. The calculated output voltages accord with our experiments. Meanwhile, impacts of operating conditions on both electrolyte conductivities and electric energy utility are quantified by our model. Our model is helpful to the cell designer when predicting cell capacity and its proper working conditions.