Cathode/Electrolyte Interactions and Their Expected Impact On SOFC Performance

This is the authors' abstract. We don't add key points for this paper.

The cathode characteristics and cathode/electrolyte interactions were studied. Both dense and porous cathode films have been deposited on ZrO 2 and CeO 2 -based electrolyte substrates by using a novel spin coating technique. La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 (LSCF) and La 0.8 Sr 0.2 MnO 3 (LSM) were found compatible with (CeO 2 ) 0.8 (SmO 1.5 ) 0.2 (CSO) substrates at temperatures up to 1200°C. However, LSCF and LSM reacted with (ZrO 2 ) 0.84 (YO 1.5 ) 0.16 (YSZ), forming La 2 Zr 2 O 7 and SrZrO 3 . The impact of interfacial reactions on cell performance was studied by AC impedance spectroscopy. The LSCF/CSO system showed the lowest electrode resistance and overpotential. Interactions were observed between LSCF (or LSM) and YSZ in the 1000°C to 1200°C range, which resulted in high interfacial resistance. If indeed YSZ is the electrolyte of choice, both operating and processing temperatures must be maintained below 800°C. The introduction of CSO buffer layer between LSCF (or LSM) and YSZ alleviates this limitation. Our results show that this layer impedes interfacial reactions which, in term, affect cell performance.