Analytical, 1-Dimensional Impedance Model of a Composite Solid Oxide Fuel Cell Cathode

作者：Mortensen J E^*; Sogaard M; Jacobsen T

来源：Journal of the Electrochemical Society, 2014, 161(3): F161-F175.

DOI：10.1149/2.077401jes

An analytical, 1-dimensional impedance model for a composite solid oxide fuel cell cathode is derived. It includes geometrical parameters of the cathode, e.g., the internal surface area and the electrode thickness, and also material parameters, e.g., the surface reaction rate and the vacancy diffusion coefficient. The model is successfully applied to a total of 42 impedance spectra, obtained in the temperature range 555 degrees C-852 degrees C and in the oxygen partial pressure range 0.028 atm-1.00 atm for a cathode consisting of a 50/50 wt% mixture of (La0.6Sr0.4)(0.99)CoO3-delta and Ce0.9Gd0 1O1.95-delta. The surface exchange coefficient in oxygen for T = 802 degrees C and po(2) = 1.00 atm is found to be k(EX) = 1.42 x 10(-4) m s(-1) and with an activation energy of E-a = 107 kJ mol(-1), in fair agreement with literature. A parameter variation and a steady state analysis is performed, verifying the soundness of the model and providing both qualitative and quantitative information on the evolution of the impedance spectra of cathodes with changing parameters.

• 出版日期2014