On the Thermodynamic Stability and the Kinetic Activity of SOFC Materials

Abstract

Materials research in solid oxide fuel cells has been driven by the recognition of developing novel constituents which enable faster kinetics and greater power, in order to reduce the cost of SOFC systems (e.g. $/kW). When an SOFC is operating with very high current density, the physical properties of its constituents may not be the same as these at the conditions of low current density or open circuit voltage. This is particularly true for the SOFC cathode, the reduction electrode which dissociates oxygen molecules to oxygen ions, because the cathode is generally considered to be the cell component that limits the electrochemical performance of anode-supported planar SOFCs. The aimed of this paper is to address a fundamental question: how do fast kinetics and high current in an operating SOFC affect the thermodynamic states of its material constituents.