Cathode Micromodel of Solid Oxide Fuel Cell

A comprehensive micromodel considering all forms of polarization in the cathode of the solid oxide fuel cell was developed which governs the complex interdependency among the transport phenomena, electrochemical processes (charge-transfer and surface diffusion), and the microstructure of the electrode and their combined effect on the cathode overpotential under different operating conditions. To make the model more generalized, we consider possible oxygen reduction mechanisms, reactions at the cathode/electrolyte interface, grain interior and grain boundary effects on the total resistance, both ordinary diffusion and Knudsen diffusion, active three-phase boundary length as a function of ionic/electronic particle size ratio and volume fraction, the exchange current density as a function of gases concentration, etc. Incorporated with reliable experimental data, the model can be used as a tool to design a high performance cathodes. © 2003 The Electrochemical Society. All rights reserved.