A high-performance, cobalt-free cathode for intermediate-temperature solid oxide fuel cells with excellent CO2 tolerance

• Published in: Journal of power sources Vol. 319; pp. 178 - 184
• Main Authors: Bu, Yun-fei, Zhong, Qin, Chen, Dong-Chang, Chen, Yu, Lai, Samson Yuxiu, Wei, Tao, Sun, Hai-bin, Ding, Dong, Liu, Meilin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2016
• Subjects: Cathode; Co-free; CO2-Stability; Perovskite; Solid oxide fuel cell; Co-free; CO2-Stability; Perovskite; Cathode; Solid oxide fuel cell
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2016.04.064

Compared with some cobalt-rich cathodes which have been proven to yield high performance in SOFCs, interest in cobalt-free cathodes has increased due to their reduced thermal expansion coefficients (TECs), high structural stability, and CO2 tolerance. In this report, a new robust Co-free complex perovskite oxide PrLa0.4Ba0.6Fe0.8Zn0.2O5+δ (PLBFZ) has been synthesized and evaluated. The TEC is 14.4 × 10−6 K−1. With the introduction of Sm0.2Ce0.8O2 (SDC), the composite cathode PLBFZ-SDC with a mass ratio of 7:3 (PLBFZ-SDC 73) exhibited the best electrocatalytic activity for oxygen reduction under OCV conditions, with polarization values of 0.044, 0.079, 0.124, 0.251, 0.572, and 1.297 Ω cm−2 at 800, 750, 700, 650, 600, and 550 °C, respectively. The power densities of the cell were 1309, 1079, 788 and 586 mW cm−2 at 750, 700, 650, and 600 °C, respectively. Moreover, it appears to have good stability in air containing 1% CO2 (volume ratio) for 150 h based on Raman and polarization resistance (Rp) analysis. These results suggest that PLBFZ and its SDC composite are promising cathodes for IT-SOFCs. •PLBFZ–SDC was evaluated as a cathode for IT-SOFC firstly.•Thermal expansion coefficients of PLBFZ are lower than cobalt-containing cathodes.•The PLBFZ appears a certain ability of CO2 tolerance.•The ORR and cell performance were improved by the doping Pr into the A site of LBFZ.