Experimental Analysis of the Effect of Cathodic CO2 Supply to Industrial Solid Oxide Fuel Cells

In the SOS-CO2 cycle, a newly developed hybrid cycle for blue power production, the SOFC cathode is supplied with a CO2-rich oxidizing stream, while the anode is fed with a reformate mixture. The performance and the durability of 25 cm2 Ni-YSZ anode-supported SOFCs are experimentally evaluated under the SOS-CO2 cycle conditions for 150 h. By testing symmetric cells with LSCF-GDC and LSC-GDC electrodes, the effects of the CO2-rich atmosphere on the cathodic material are also investigated. The results show that the loss of performance caused by the cathodic supply of CO2 is stable in time, but also reversible when switching back to air. The cathodic supply of CO2 causes both an increase of the polarization resistance and of the ohmic resistance, suggesting a reduction of electronic conductivity compatible with formation of carbonates on the perovskite surface.