Pr0.7Ba0.3Co0.8-xFe0.2NixO3−δ perovskite: High activity and durable cathode for intermediate-to-low-temperature proton-conducting solid oxide fuel cells

The development of triple-conductivity (H+/O2−/e−) durable cathode with effective oxygen reduction reaction (ORR) activity is significant to boost the application of proton-conducting solid oxide fuel cell (H–SOFC) at intermediate-to-low-temperature. Herein, we developed the Pr0.7Ba0.3Co0.8-xFe0.2NixO3−δ (x = 0, 0.1, 0.2, 0.3) cathode material with triple-conductivity. Based on the distribution of relaxation time results, it is found that nickel doping enhanced the surface exchange kinetics and boosted bulk charge transfer. As a result, Pr0.7Ba0.3Co0.6Fe0.2Ni0.2O3−δ (PBCFN2) shows better ORR activity with lower polarization resistance (0.043 Ω cm2) and higher power output (1.61 W cm−2) for H–SOFC at 700 °C. Meanwhile, PBCFN2 also shows suitable durability at 600 °C (0.919 A cm−2 for ∼105 h). In general, this research may provide a beneficial instruction for further research and optimization for triple-conducting cathodes in intermediate-to-low-temperature H–SOFC.