Comparison of Different Perovskite Cathodes in Solid Oxide Fuel Cells

This study compares the electrochemical performance of three perovskite cathode materials, La0.6Sr0.4Co0.2Fe0.8O3 (LSCF), Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCF), and Sm0.5Sr0.5Co0.2Fe0.8O3 (SSCF), at different operating temperatures, in order to provide optimal operating condition and performance for different solid oxide fuel cells. Among these three cathodes, BSCF has the highest power density of 39 mW cm(-2) at 600 degrees C, 88 mW cm(-2) at 650 degrees C, and 168 mW cm(-2) at 700 degrees C; LSCF has the highest power density of 263 mW cm(-2) at 750 degrees C and 456 mW cm(-2) at 800 degrees C. The cathode overpotentials have the same trend as the power densities. Activation energies for the total cathode area specific resistance (ASR) are calculated to be 0.44 eV, 0.38 eV, and 0.52 eV for the LSCF, BSCF, and SSCF cathodes, respectively. Stability testing of 100 h shows that the open circuit voltages of the LSCF and BSCF cathodes drop 16.1% and 22.9% at 800 degrees C, respectively, as well as 15.3% and 11.3% at 600 degrees C, respectively, indicating that the LSCF cathode is more stable at 800 degrees C while the BSCF cathode is more stable at 600 degrees C. This work should provide important guidance for the solid oxide fuel cell designs and properties.