Effect of B₂O₃-Bi₂O₃-PbO frit on the performance of LaBaCo₂O_5+δ cathode for intermediate-temperature solid oxide fuel cells

The effects of B₂O₃-Bi₂O₃-PbO (BBP) frit on the electrochemical performance, electrical conductivity, and thermal expansion of LaBaCo₂O_5+δ (LBCO) cathode were investigated. BBP frit was found to be effective in lowering the sintering temperature of LBCO cathode by about 200 °C and in improving its electrochemical performance within the intermediate-temperature range of 600-800 °C. LBCO with 5 wt.% BBP frit cathode based on Sm_0.2Ce _0.8O_1.9 electrolyte showed the best electrochemical performance, i.e., the lowest area-specific resistance (ASR) and cathodic overpotential. The ASR values were about 64.1%, 66.1%, and 74.5% lower than those of LBCO at 700, 750, and 800 °C, respectively. The cathodic overpotential decreased from 51.0 mV for LBCO to 8.2 mV at a current density of 0.2 A cm^-2 at 700 °C. The electrical conductivity of LBCO with 5 wt.% BBP frit was about 320-330 S cm^-1 at 600-800 °C in air.