Accelerating effect of polarization on electrode/electrolyte interface generation and electrocatalytic performance of Er0.4Bi1.6O3 decorated Sm0.95CoO3-δ cathodes

Abstract

Bi2O3-based composite cathodes of solid oxide fuel cells are generally sintered at a low temperature of 750–800 °C, but the detailed information regarding the generation of electrode/electrolyte interface and its effect on the polarization performance are scarcely known. Here we assemble nanostructured 10–40 wt% Er0.4Bi1.6O3 decorated Sm0.95CoO3-δ (ESB-SmC) composite cathodes on 8 mol% yttria-stabilized zirconia electrolyte without sintering at high temperatures and the best performance is obtained on 20 wt% ESB decorated SmC, achieving a peak power density of 1.66 W cm−2 at 750 °C. We adopt a stepwise annealing approach under open circuit and polarization conditions, so as to in situ evaluate the extent of electrode/electrolyte interface generation. The results show that under open circuit conditions, the electrode/electrolyte interface of 20 wt% ESB decorated SmC electrode can be generated by annealing at 750 °C and higher, but the polarization remarkably accelerates the interface generation at lower temperatures of 600–700 °C. The present study provides new insights into the electrode/electrolyte interface generation and polarization performance of bismuth oxide based composite cathodes under the operating conditions of solid oxide fuel cells.