Electrochemical characterization of LaBaCuCoO5+δ–Sm0.2Ce0.8O1.9 composite cathode for intermediate-temperature solid oxide fuel cells

In order to improve the electrochemical performance of the LaBaCuCoO5+δ (LBCC) electrode, LaBaCuCoO5+δ–Ce0.8Sm0.2O1.9 (LBCC–SDC) are prepared and characterized for potential application as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on an SDC electrolyte. Electrical conductivity, thermal expansion and electrochemical properties are investigated by four probing DC technique, dilatometry, AC impedance and polarization techniques, respectively. It is found that the thermal expansion coefficient (TEC) and electrical conductivity decrease with the increase of SDC content in LBCC–SDC composites. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures show that the addition of SDC to LBCC improves the electrochemical performance of a LBCC cathode, and that a LBCC–SDC20 cathode exhibits superior electrochemical performance in the LBCC–SDCx composite cathodes. Moreover, even when the content of SDC is up to 40 wt%, the area specific resistance of the LBCC–SDC40 composite cathode on SDC electrolyte is lower than the corresponding interfacial resistance for pure LBCC at 650–800 °C. The power density of the Ni–SDC/SDC/LBCC–SDC20 cell is 615 mW cm−2 at 800 °C. These results indicate that LBCC–SDCx is a potential cathode material for application in IT-SOFCs.

Graphical abstract. In order to improve the electrochemical performance of the LaBaCuCoO5+δ (LBCC) electrode, LaBaCuCoO5+δ–Ce0.8Sm0.2O1.9 (LBCC–SDC) are prepared and characterized for potential application as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on an SDC electrolyte.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The introduction of SDC into LaBaCuCoO5+δ reduced the thermal expansion coefficient of cathode. ► The ASR of LBCC–SDC20 cathode on SDC electrolyte was as low as 0.051 Ω cm2 at 700 °C. ► LaBaCuCoO5+δ–Ce0.8Sm0.2O1.9 (LBCC–SDC) cathode is a good candidate for operation at or below 700 °C.