Electrochemical performance of Pr 0.7Sr 0.3Co 0.9Cu 0.1O 3− δ–Ce 0.8Sm 0.2O 1.9 composite cathodes in intermediate-temperature solid oxide fuel cells

Abstract

The electrochemical performance of Pr 0.7Sr 0.3Co 0.9Cu 0.1O 3− δ – xCe 0.8Sm 0.2O 1.9 (PSCC– xSDC, x = 0–40 wt%) composite cathodes has been investigated for their potential utilization in intermediate-temperature solid oxide fuel cells (SOFCs). The results showed that the addition of SDC to PSCC improved remarkably the electrochemical performance of a PSCC cathode, and that a PSCC–35SDC cathode exhibited the best electrochemical performance in the PSCC– xSDC system. When SDC was used as the electrolyte, the interfacial resistance was smallest for 35 wt% SDC, where the value was 0.137 Ω cm 2 at 700 °C and 0.062 Ω cm 2 at 750 °C, much lower than the corresponding interfacial resistance for pure PSCC. At 700 °C, the cathodic overpotential of the PSCC–35SDC cathode in the SDC electrolyte was 70 mV at a current density of 0.5 A cm −2. This is a factor of two lower than that for a pure PSCC cathode (152 mV at 700 °C) under the same current conditions. The maximum power density of a single-cell using PSCC–35SDC as the cathode was 388 and 615 mW cm −2 at 650 and 700 °C, respectively.