Affiliation:
1. Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education) College of Physics Jilin University Changchun 130012 China
2. Department of Mechanical and Mechatronics Engineering Waterloo Institute for Nanotechnology University of Waterloo Waterloo ON N2L 3G1 Canada
3. School of Materials Science and Engineering Changchun University of Science and Technology Changchun 130022 China
Abstract
AbstractIron‐based perovskite air electrodes for protonic ceramic cells (PCCs) offer broad application prospects owing to their reasonable thermomechanical compatibility and steam tolerance. However, their insufficient electrocatalytic activity has considerably limited further development. Herein, oxygen‐vacancy‐rich BaFe0.6Ce0.2Sc0.2O3−δ (BFCS) perovskite is rationally designed by a facile Sc‐substitution strategy for BaFe0.6Ce0.4O3‐δ (BFC) as efficient and stable air electrode for PCCs. The BFCS electrode with an optimized Fe 3d‐eg orbital occupancy and more oxygen vacancies exhibits a polarization resistance of ≈ 0.175 Ω cm2 at 600 °C, ≈ 1/3 of the BFC electrode (≈0.64 Ω cm2). Simultaneously, BFCS shows favorable proton uptake with a low proton defect formation enthalpy (− 81 kJ mol−1). By combining soft X‐ray absorption spectroscopy and electrical conductivity relaxation studies, it is revealed that the enhancement of Fe4+–O2− interactions in BFCS promotes the activation and mobility of lattice oxygen, triggering the activity of BFCS in both oxygen reduction and evolution reactions (ORR/OER). The single cell achieves encouraging output performance in both fuel cell (1.55 W cm−2) and electrolysis cell (−2.96 A cm−2 at 1.3 V) modes at 700 °C. These results highlight the importance of activating lattice oxygen in air electrodes of PCCs.
Funder
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities