Numerical analysis of current efficiency distributions in a protonic ceramic fuel cell using Nernst-Planck-Poisson model

Abstract Protonic ceramic fuel cells (PCFCs) operating at intermediate temperatures (400 °C~600 °C) are expected to demonstrate a high performance due to proton ( OH O · ) conductivity. However, the current efficiencies of PCFCs are bound to decrease due to electron holes ( h · ) conductivity through the electrolyte and are strongly dependent on influence parameters such as electrolyte thickness and operating temperatures of PCFCs. Consequently, the relationship between current efficiencies and the above-mentioned parameters has been quantitatively evaluated, with the aim of enhancing the former. The defect conductivities in the PCFC have been simulated using two-dimensional Nernst-Planck-Poisson (NPP) system with different operating temperatures and electrolyte thicknesses. Subsequently, the current efficiency distributions are revealed. The influence of the operating temperature on the current efficiency distributions is also clarified. The results further indicated that optimized membrane thickness should be carefully selected according to power density and power efficiency.