Stability of Ni-YSZ Anode for SOFCs in Methane Fuel: The Effects of Infiltrating La0.8Sr0.2FeO3-δ and Gd-Doped CeO2 Materials

Improving carbon deposition resistance of Ni/YSZ anode in hydrocarbon fuels is crucial for the stability operation of solid oxide fuel calls (SOFCs). In this work, La0.8Sr0.2FeO3-delta (LSF) and Gd-doped CeO2 (GDC) are infiltrated into Ni-YSZ anodes for carbon deposition resistance, while LSF is infiltrated into YSZ cathode backbone for oxygen reduction reaction. The structure design allowed simultaneously fabrication of cathode and anode catalyst, greatly simplifying the preparation process. The distribution of relaxation times (DRT) method is applied to isolate the contributions of electrode polarization processes and illuminate the role of infiltrated LSF and GDC. It is found that LSF nano particles layer reduces the electrocatalysis of Ni, which increases the resistance associating to mass transfer process in H-2 or CH4 conversion. As compared with LSF, GDC can improves the electrochemical performance of cell, due to its high ionic conductivity, extending the three phase boundary and facilitating the charge transfer process. For the stability test in wet CH4, cells with LSF and GDC modified anode show excellent carbon deposition resistance, where no significant performance degradation is occurred in more than 100 h operation at 0.25 A.cm(-2) and 750 degrees C. This is ascribed to the LSF and GDC inhibiting carbon deposition process. (C) 2018 The Electrochemical Society.