Enhanced electrochemical performance of solution impregnated La_(0.8)Sr_(0.2)Co_(0.8)Ni_(0.2)O_(3-δ) cathode for intermediate temperature solid oxide fuel cells

摘要

Solution impregnated La_(0.8)Sr_(0.2)Co_(0.8)Ni_(0.2)O_3+Gd-doped CeO_2 (LSCN + GDC) cathodes for intermediate temperature solid oxide fuel cells (IT-SOFC) are prepared and their electrochemical properties are evaluated and compared with the conventional LSCN cathodes. The results indicate that the cathode performance can be enhanced by the presence of the nanosized microstructure produced with the solution impregnation method. It is determined that the amount of LSCN loading in the LSCN + GDC composite cathode needs to be higher than 35 wt% in order to achieve a performance superior to that of the conventional LSCN cathode. The optimum amount of LSCN loading is in the range of 45-55 wt% with an activation energy near 1.32 eV for oxygen reduction. At temperatures between 600 and 750 C, the polarization resistance of the 55 wt% LSCN loaded LSCN + GDC cathode is in the range of 1.07 and 0.08 Q cm2, which is only about one half of that for the conventional cathode.