High-Performanced Cathode with a Two-Layered R-P Structure for Intermediate Temperature Solid Oxide Fuel Cells

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Author(s)

  • Daoming Huan
  • Zhiquan Wang
  • Ranran Peng
  • Changrong Xia
  • Yalin Lu

Detail(s)

Original languageEnglish
Pages (from-to)4592-4599
Journal / PublicationACS Applied Materials and Interfaces
Volume8
Issue number7
Publication statusPublished - 24 Feb 2016
Externally publishedYes

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 O2- 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. © 2016 American Chemical Society.

Research Area(s)

  • cathode, density functional theory, Ruddlesden-Popper oxide, solid oxide fuel cells, surface exchange coefficient

Bibliographic Note

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