Study On Combined Modification Of Oxygen Electrode For Reversible Solid Oxide Fuel Cell-electrolysis Cell

A solid oxide fuel cell (SOFC) is an electrochemical setup to convert chemical energy offuels into electric energy. A solid oxide electrolysis cell (SOEC) was reversibly operated as toSOFCs. H2/CO can be generated from H2O/CO2via an SOEC. A reversible cell integrated SOFCwith SOEC. In this study, LSM, LSCF and SSC oxygen electrodes are prepared for reversibleSOFCs. Electrochemical performance and stability of the oxygen electrodes for cells wereinvestigated, and degradation mechanism was demonstrated.LSM and LSCF electrodes prepared by screen printing were used for reversible SOFCs.After long-term steam electrolysis operation, SOEC deteriorated. Microstructure of post-test cellswas studied that delamination of LSM from YSZ and GDC from YSZ caused the deterioration.Furthermore, LSM-infiltrated YSZ oxygen electrode was prepared for reversible SOFC, so as toimprove the electrochemical performance and operational stability of the cell.Nano-sized LSM-YSZ, LSCF-YSZ, and SSC-YSZ oxygen electrodes were prepared for reversibleSOFCs by an infiltration process, with improved electrode performance and electro-catalyticactivity. Cell degradation in electrolysis mode is attributed to agglomeration of nano-particles,which has been observed during post-test SEM analysis. Agglomeration of infiltrated LSCFparticles is possibly responsible for the performance degradation of the cell. Rversible cells withSSC-YSZ oxygen electrodes degraded due to delamination of SSC-YSZ oxygen electrod fromYSZ electrolyte and coarsening of Ni particles. H2O/CO2co-electrolysis was investigated onLSCF-infiltrated YSZ oxygen electrode.In conclusion, this dissertation has established a solid foundation for development ofhigh-activity and high-stability oxygen electrodes.