title: High-Performanced Cathode with a Two-Layered R-P Structure for Intermediate Temperature Solid Oxide Fuel Cells.
abstract: Driven by the mounting concerns on global warming and energy crisis, intermediate temperature solid-oxide fuel cells (IT-SOFCs) have attracted special attention for their high fuel efficiency, low toxic gas emission, and great fuel flexibility. A key obstacle to the practical operation of IT-SOFCs is their sluggish oxygen reduction reaction (ORR) kinetics. In this work, we applied a new two-layered Ruddlesden-Popper (R-P) oxide, Sr3Fe2O7-δ (SFO), as the material for oxygen ion conducting IT-SOFCs. Density functional theory calculation suggested that SFO has extremely low oxygen ion formation energy and considerable energy barrier for O(2-) diffusion. Unfortunately, the stable SrO surface of SFO was demonstrated to be inert to O2 adsorption and dissociation reaction, and thus restricts its catalytic activity toward ORR. Based on this observation, Co partially substituted SFO (SFCO) was then synthesized and applied to improve its surface vacancy concentration to accelerate the oxygen adsorptive reduction reaction rate. Electrochemical performance results suggested that the cell using the SFCO single phase cathode has a peak power density of 685 mW cm(-2) at 650 °C, about 15% higher than those when using LSCF cathode. Operating at 200 mA cm(-2), the new cell using SFCO is quite stable within the 100-h' test.
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.
authors: Daoming
authors: D
authors: Huan
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.
authors: Zhiquan
authors: Z
authors: Wang
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.
authors: Zhenbin
authors: Z
authors: Wang
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China.|Hefei National Laboratory of Physical Science at the Microscale, University of Science and Technology of China , Hefei, 230026 Anhui China.
authors: Ranran
authors: R
authors: Peng
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.
authors: Changrong
authors: C
authors: Xia
authors: CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China , Hefei, 230026 Anhui China.|Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China.|Hefei National Laboratory of Physical Science at the Microscale, University of Science and Technology of China , Hefei, 230026 Anhui China.|National Synchrotron Radiation Laboratory, University of Science and Technology of China , Hefei 230026, P. R. China.
authors: Yalin
authors: Y
authors: Lu
keywords: Ruddlesden−Popper oxide; cathode; density functional theory; solid oxide fuel cells; surface exchange coefficient