In-situ investigation of quantitative contributions of the anode, cathode, and electrolyte to the cell performance in anode-supported planar SOFCs

A novel method that embeds Pt voltage probes into the triple-phase boundary (TPB) is developed. Moreover, the quantitative contributions of the anode, the cathode, and the electrolyte to cell performance are investigated in situ for anode-supported planar solid oxide fuel cells (SOFCs). The voltage and maximum output power density (MOPD) measured by the probes, which are placed on both sides of the electrolyte, account for 97.3% and 94.4%, respectively, of those of the cell during the instantaneous current-voltage testing. When the stack is discharged at 0.32 A cm^-2 for 200 h, the voltage drops of the anode, the cathode, and the electrolyte account for 76.9%, 15.4%, and 7.7%, respectively, of the total voltage drop of the unit cell. The ohmic resistance of the unit cell primarily depends on the resistance that results from the TPB. The variation in cell resistance is mainly attributed to the increase in anode polarization resistance caused by Ni particle agglomeration. However, cell voltage is more sensitive to the TPB ohmic resistance, which may be the primary factor for SOFC degradation.