Development of (La, Sr)MnO3-based cathodes for intermediate temperature solid oxide fuel cells

Conventional (La, Sr)MnO3 (LSM) electrodes modified by ion impregnation methods showed promising potential as cathodes for intermediate temperature solid oxide fuel cells. After impregnation of ionic conducting- type Gd0.2Ce0.8(NO3)(x) nitrite salt solution into the LSM structure, electrochemical activity of LSM electrodes for the O-2 reduction reaction was substantially enhanced. At 700degreesC, the electrode polarization resistance of impregnated LSM electrodes decreased to 0.72 Omega cm(2) as compared to 26.4 Omega cm(2) for pure LSM electrodes, a reduction in electrode polarization resistance by 36 times. The polarization losses were also reduced substantially. At 300 mA cm(-2) and 700degreesC, overpotential for the O-2 reduction was reduced from 0.79 V on pure LSM to 0.19 V on impregnated LSM electrodes, a reduction in overpotential by four times. Ion-impregnated LSM electrodes showed better performance than those of LSM/Y2O3-ZrO2 and LSM/(Gd,Ce)O-2 composite electrodes as reported in the literature. (C) 2003 The Electrochemical Society.