Bismuth oxide based composite cathode for the intermediate temperature barrier layer free solid oxide fuel cell

The high cost and low reliability caused by the high operation temperature hinder the further commercialization of the solid oxide fuel cell (SOFC) at this stage. Thus, lowering the operation temperature and simplifying the structure of the SOFC are both considered to be effective solutions to solve the current issues. Here, the design, fabrication and actual effect of the La0·8Sr0·2MnO3-(Bi0·75Y0.25)0.93Ce0·07O1.5±δ (LSM-BYC) cathode and La0·8Sr0·2MnO3@(Bi0·75Y0.25)0.93Ce0·07O1.5±δ (LSM@BYC) cathode used for the intermediate temperature barrier layer free SOFC are reported. The results showed that tight interfaces between the abovementioned two composite cathodes and the Y0·16Zr0·84O2-δ (YSZ) electrolyte can be formed by sintering at 800 °C. The higher oxygen ion conductivity and oxygen reaction activity of the LSM-BYC cathode and the LSM@BYC cathode, and much simplified structure of the barrier layer free SOFC all contributed to lowering the ohmic resistance and the polarization resistance, making barrier layer free SOFCs used LSM-BYC cathode and LSM@BYC cathode showed better electrochemical performances at intermediate operation temperature 650 °C from low oxygen partial pressure atmosphere to pure oxygen atmosphere, particularly the latter. What is more, the intermediate temperature barrier layer free SOFC used the LSM-BYC cathode showed better operation stability without obvious activation and degradation during the constant electric current generation over one hundred hours. But the deterioration of the interface between the LSM@BYC cathode and the YSZ electrolyte during the operation was likely to cause the sharp decrease of the electrochemical performance, the solutions of which still need further exploration.