High performance proton-conducting solid oxide fuel cells with a stable Sm0.5Sr0.5Co3−δ–Ce0.8Sm0.2O2−δ composite cathode

A Sm0.5Sr0.5CoO3−δ–Ce0.8Sm0.2O2−δ (SSC–SDC) composite is employed as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs). BaZr0.1Ce0.7Y0.2O3−δ (BZCY) is used as the electrolyte, and the system exhibits a relatively high performance. An extremely low electrode polarization resistance of 0.066 Ω cm2 is achieved at 700 °C. The maximum power densities are: 665, 504, 344, 214, and 118 mW cm−2 at 700, 650, 600, 550, and 500 °C, respectively. Moreover, the SSC–SDC cathode shows an essentially stable performance for 25 h at 600 °C with a constant output voltage of 0.5 V. This excellent performance implies that SSC–SDC, which is a typical cathode material for SOFCs based on oxide ionic conductor, is also a promising alternative cathode for H-SOFCs.