Investigation of Fe-substituted in BaZr0.8Y0.2O3-delta proton conducting oxides as cathode materials for protonic ceramics fuel cells

摘要

Cathode materials containing proton conductivity for protonic ceramics fuel cells (PCFCs) can increase the three phase boundary length of the air/cathode/electrolyte, and thus increase the reaction rate of proton with oxygen-species to form water in cathode side. In this work, a serious of Fe-substituted in BaZr0.8Y0.2O3-delta proton conducting oxides, abbreviated as BaZr(0.8-x)FexY(0.2)O(3-delta) (BZFY-2, BZFY-4, BZFY-6, BZFY-8), were synthesized and investigated as cathode materials for PCFCs, considering the phase structure, mean valence state and electrochemical performance. Accordingly, anode supported button cells using BaZr0.8-xFexY0.2O3-delta as cathodes are fabricated, and then performed from 700 to 550 degrees C. The cell performance with BZFY-6 presents optimal electrochemical performance with different Fe doping amount, and the peak power density of 322.23 mW cm(-2) and the corresponding polarization resistance of 0.28 Omega cm(2) are observed at 700 degrees C. Moreover, the corresponding electrode polarization processes are further studied by the distribution function of relaxation time (DRT) analysis, and three peaks of P1, P2 and P3 in DRT curves correspond the proton bulk diffusion, electrochemical reaction processes, and adsorption as well as diffusion process of oxygen, respectively. Preliminary results demonstrate that BZFY-6 can be a competitive promising for PCFCs. (C) 2019 Elsevier B.V. All rights reserved.