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Title: Modeling of the oxygen reduction reaction for dense LSM thin films

In this study, the oxygen reduction reaction mechanism is investigated using numerical methods on a dense thin (La 1-xSr x) yMnO 3±δ film deposited on a YSZ substrate. This 1-D continuum model consists of defect chemistry and elementary oxygen reduction reaction steps coupled via reaction rates. The defect chemistry model contains eight species including cation vacancies on the A- and B-sites. The oxygen vacancy is calculated by solving species transportation equations in multiphysics simulations. Due to the simple geometry of a dense thin film, the oxygen reduction reaction was reduced to three elementary steps: surface adsorption and dissociation, incorporation on the surface, and charge transfer across the LSM/YSZ interface. The numerical simulations allow for calculation of the temperature- and oxygen partial pressure-dependent properties of LSM. The parameters of the model are calibrated with experimental impedance data for various oxygen partial pressures at different temperatures. The results indicate that surface adsorption and dissociation is the rate-determining step in the ORR of LSM thin films. With the fine-tuned parameters, further quantitative analysis is performed. The activation energy of the oxygen exchange reaction and the dependence of oxygen non-stoichiometry on oxygen partial pressure are also calculated and verified using the literature results.
Authors:
ORCiD logo [1] ;  [1] ;  [2] ;  [1] ; ORCiD logo [3] ;  [4] ;  [2] ;  [1]
  1. National Energy Technology Laboratory (NETL) Morgantown, WV (United States)
  2. National Energy Technology Laboratory (NETL) Morgantown, WV (United States); AECOM, Morgantown, WV (United States)
  3. National Energy Technology Laboratory (NETL) Morgantown, WV (United States); West Virginia Univ., Morgantown, WV (United States). C. Eugene Bennett Dept. of Chemistry
  4. National Energy Technology Laboratory (NETL) Morgantown, WV (United States); West Virginia Univ., Morgantown, WV (United States). Dept. of Mechanical and Aerospace Engineering
Publication Date:
Report Number(s):
NETL-PUB-21103
Journal ID: ISSN 1463-9076; PPCPFQ
Type:
Accepted Manuscript
Journal Name:
Physical Chemistry Chemical Physics. PCCP (Print)
Additional Journal Information:
Journal Name: Physical Chemistry Chemical Physics. PCCP (Print); Journal Volume: 19; Journal Issue: 45; Journal ID: ISSN 1463-9076
Publisher:
Royal Society of Chemistry
Research Org:
National Energy Technology Laboratory (NETL) Morgantown, WV (United States); Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Thin Film; Oxygen Reduction Reaction; Multiphysics Simulation; Electrochemical Impedance Analysis
OSTI Identifier:
1440410