A novel processing method of Sr_0.7Y_0.3CoO _2.65-δ cathode for intermediate temperature solid oxide fuel cells

The oxygen-deficient perovskite Sr_0.7Y_0.3CoO _2.65-δ (SYCO) is recently investigated as cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). However, the conventional preparation methods are both energy and time consuming, which greatly hinders the commercialization of this material. In the present study, the calcination and cathode-electrolyte sintering processes are systematically investigated as a function of calcination temperature and time; and a novel cathode processing method has been established. SYCO powder calcined at 900 C for 8 h with impurities due to incomplete phase formation, rather than the phase pure product, has been chosen for pristine cathode fabrication. The purity of this cathode can be further improved during the quick cathode-Gd _0.2Ce_0.8O_1.9 (GDC) electrolyte sintering step. The XRD results confirm that the formation of undesirable secondary phase has been successfully avoided by adopting relatively low sintering temperature and short sintering time. SEM images demonstrate that the as-prepared electrode possesses good adherence between cathode and electrolyte. The polarization resistance of the cathode prepared in this method reaches 0.28 Ω cm ² at 700 C, significantly smaller than that of the cathode prepared by using phase pure product as the initial cathode material. This novel preparation route provides a new method of developing electrodes with high electrochemical performance for SOFCs.