Improving the stability of La0.6Sr0.4Co0.2Fe0.8O3-δ electrode for solid oxide fuel cells by introducing sintering inhibitors

Abstract

In this study, nano-sized Al2O3 and Gd0.1Ce0.9O1.95 (GDC) particles are added to La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode material as sintering inhibitors for solid oxide fuel cells (SOFC) to improve the stability of the cell performance. Studies reveal that as the amount of the inhibitors increases, the sintering activation energy of the composite LSCF sample increases, resulting in retarded sintering kinetics indicated by the suppressed grain size of the sintered composite LSCF cathode. Long-term durability tests show that due to the enhanced stability of the microstructure of the composite LSCF cathode, the composite cathode exhibits improved performance stability. Furthermore, both the Al2O3 and GDC additions can improve the hardness and elastic modulus of the cathode, while the electrical conductivity of both cathodes exceed 100 S/cm and can still meet the requirements for the SOFC in the operation temperature range of 600–800 °C. In light of the boosted electrochemical durability of the Al2O3-added LSCF cathode and much lower cost of Al2O3 compared to the rare-earth element based GDC materials, LSCF cathode with a proper amount of the nano-sized Al2O3 inhibitors is a good solution to enhance the mechanical property, electrochemical durability of LSCF cathode for the SOFCs at low cost.