摘要 : Oxygen reduction and proton conduction originated from hydration are two key steps in the cathode process of protonic ceramic fuel cells. In this work, Pr_6O_(11) is impregnated into a cobalt-free BaCe_(0.2)Fe_(0.8)O_(3-δ) cathode... 展开 Oxygen reduction and proton conduction originated from hydration are two key steps in the cathode process of protonic ceramic fuel cells. In this work, Pr_6O_(11) is impregnated into a cobalt-free BaCe_(0.2)Fe_(0.8)O_(3-δ) cathode, resulting in an improved activity of lattice oxygen and a moderate enhancement of the electrical conductivity, both of which are beneficial for charge transfer, the rate-determining step of oxygen reduction process at the cathode. The polarization resistance of bare BaCe_(0.2)Fe_(0.8)O_(3-δ) cathode for oxygen reduction is 0.115 Ω cm~2 at 700 ℃, which is reduced significantly to 0.039 Ω cm~2 with the addition of 30 wt% Pr_6O_(11). Besides, the hydration ability of the cathode is also improved with Pr_6O_(11), and thus the combination of proton and oxygen is facilitated. A single cell with 30 wt% Pr_6O_(11)-70 wt°/o BaCe_(0.2)Fe_(0.8)O_(3-δ) composite cathode exhibits the highest maximum power density of 1406 mW cm~(-2) at 700 ℃. The composite cathode also shows a good stability. 收起