Characterization of the conductivity distribution and leakage current in proton-conducting ceramic electrolyte through modeling and sensitivity analysis

Abstract

For ceramic proton-conducting fuel cell, electrolyte hole conductivity and leakage current are critical issues. In this paper, simulation is performed to deal with their influences on the cell. Impacts of electrolyte conductivity distribution and leakage current are incorporated in the simulation. In addition, button cells with BaCe0.6Zr0.3Y0.1O3-δ electrolyte are prepared to verify this simulation. The model-predicted cell performance matches the experiment. Based on the model, effective hole conductivities of the electrolyte under diverse working conditions are simulated, and conductivity distribution profiles across the electrolyte are figured out. Then, based on the simulation, the influence of the water content of the fuel on the cell is discussed in detail, and optimal water content is given. Finally, sensitivity analysis is performed to quantify the influence degrees of experimental settings on the electrolyte leakage current and the cell output voltage. It turns out that temperature has the most significant impact, while the influence degrees of electrolyte thickness and water content in the fuel are less than that of the temperature; and cell performance is not sensitive to the water content in the air on the cathode side in the studied cases.