High-performance PrBaCo2O5+δ–Ce0.8Sm0.2O1.9 composite cathodes for intermediate temperature solid oxide fuel cell

PrBaCo2O5+δ–Ce0.8Sm0.2O1.9 (PBCO–SDC) composite material are prepared and characterized as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction result proves that there are no obvious reaction between the PBCO and SDC after calcination at 1100 °C for 3 h. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures shows that the addition of SDC to PBCO improved remarkably the electrochemical performance of a PBCO cathode, and that a PBCO–30SDC cathode exhibits the best electrochemical performance in the PBCO–xSDC system. The total interfacial resistances Rp is the smallest when the content of SDC is 30 wt%, where the value is 0.035 Ω cm2 at 750 °C, 0.072 Ω cm2 at 700 °C, and 0.148 Ω cm2 at 650 °C, much lower than the corresponding interfacial resistance for pure PBCO. The maximum power density of an anode-supported single cell with PBCO–30SDC cathode, Ni–SDC anode, and dense thin SDC/LSGM (La0.9Sr0.1Ga0.8Mg0.2O3−δ)/SDC tri-layer electrolyte are 364, 521 and 741 mW cm−2 at 700, 750 and 800 °C, respectively.