3D resistor-network modeling of infiltrated SOFC electrodes

For first time a 3D simulation for infiltrated electrodes taking into account the charge transfer resistance (CT) for computing the admittance is developed. By employing a three-dimensional voxelised resistor network, we study the electrode resistance as a function of electrode microstructure and material conductivities. The simulated electrodes consist of pores, metal and ion conductor material and were generated from a random sphere insertion model which emulates the experimental procedure of the infiltration process. To both evaluate and validate the proposed model, a comparison with numerical models and experimental results from the literature is used. More accurate results closely related to those observed experimentally and the use of the main characteristics of the infiltrated electrodes as input parameters are benefits of 3D modeling. The results show that the model for the admittance and TPBL curves have the same behavior as a function of the amount of infiltrated material. This similarity is fulfilled when the diffusion of gas in the pores of the electrode is not the limiting process for the calculation of the admittance, and when the percolation of the ionic and electronic conducting phases are considered in the calculation for TPBL.