Designing one-step co-assembled Pr1.95Ce0.05CuO4-Ce0.8Pr0.2O1.9 composite cathode with extraordinary oxygen reduction activity for solid oxide fuel cells

Abstract

There remains a major challenge to develop highly active oxygen electrode for solid oxide fuel cells (SOFCs). Herein, we report a one-step co-assembly route for preparing Pr1.95Ce0.05CuO4-Ce0.8Pr0.2O1.9 (PCC-CPO) composite cathode for SOFCs, with a focus on its phase structure, oxygen desorption behavior, electrochemical performance, and oxygen reduction reaction (ORR) process. The PCC-CPO catalyst demonstrates satisfactory ORR activity, as evidenced by a low polarization resistance of 0.04 Ω cm2 at 700 °C. The high peak power density (1.04 W cm−2) is achieved in a single cell with the PCC-CPO cathode. Furthermore, the oxygen reaction kinetic was probed by electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis. The oxygen adsorption-dissociation process is determined to be the rate-limiting step at the electrode interface. This work highlights an effective strategy for rationally designing composite cathode with superior ORR activity and exceptional stability.