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Title: In-Operando Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability

Abstract

Through this project we developed a new in-operando 18O-isotope exchange technique, and determined the oxygen reduction reaction (ORR) kinetics and mechanisms in various solid oxide fuel cell (SOFC) cathodes under real operating conditions of applied voltage. We were able to measure and determine oxygen surface exchange coefficients of labeled oxygen with La 0.8Sr 0.2MnO 3 (LSM), La 0.6Sr 0.4Co 0.2Fe 0.8O 3 (LSCF) and other cathode material samples with varying compositions. We related the cell polarization conditions to the surface exchange process and surface exchange coefficient, and suggested a model to describe this relation. Our findings imply that LSCF keeps its higher exchange rate performance over LSM under real operating conditions. Changing the A-site cation ratio in LSM can enhance its performance, especially under cathodic polarizations larger than -400mV. Cathode powder composites of LSM and LSCF with YSZ and GDC show lower exchange coefficient values under applied polarization compared to the single constituent powder samples, probably due to limited contact between the powder particles. Using our model and basic electrochemical properties of the cathode materials we are able to successfully predict the exchange kinetic properties of SOFC cathode material under real operating conditions of applied voltage / current from surfacemore » exchange coefficients obtained in the absence of an applied bias.« less

Authors:
 [1]
  1. Univ. of Maryland, College Park, MD (United States)
Publication Date:
Research Org.:
Univ. of Maryland, College Park, MD (United States)
Sponsoring Org.:
USDOE Office of Fossil Energy (FE), Clean Coal and Carbon (FE-20)
OSTI Identifier:
1432203
Report Number(s):
DOE-UMD-FE0026190
DOE Contract Number:  
FE0026190
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; cathode; SOFC; operando

Citation Formats

Wachsman, Eric D. In-Operando Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability. United States: N. p., 2018. Web. doi:10.2172/1432203.
Wachsman, Eric D. In-Operando Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability. United States. doi:10.2172/1432203.
Wachsman, Eric D. Fri . "In-Operando Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability". United States. doi:10.2172/1432203. https://www.osti.gov/servlets/purl/1432203.
@article{osti_1432203,
title = {In-Operando Evaluation of Solid Oxide Fuel Cell (SOFC) Cathodes for Enhanced Oxygen Reduction Reaction (ORR) Activity and Durability},
author = {Wachsman, Eric D.},
abstractNote = {Through this project we developed a new in-operando 18O-isotope exchange technique, and determined the oxygen reduction reaction (ORR) kinetics and mechanisms in various solid oxide fuel cell (SOFC) cathodes under real operating conditions of applied voltage. We were able to measure and determine oxygen surface exchange coefficients of labeled oxygen with La0.8Sr0.2MnO3 (LSM), La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) and other cathode material samples with varying compositions. We related the cell polarization conditions to the surface exchange process and surface exchange coefficient, and suggested a model to describe this relation. Our findings imply that LSCF keeps its higher exchange rate performance over LSM under real operating conditions. Changing the A-site cation ratio in LSM can enhance its performance, especially under cathodic polarizations larger than -400mV. Cathode powder composites of LSM and LSCF with YSZ and GDC show lower exchange coefficient values under applied polarization compared to the single constituent powder samples, probably due to limited contact between the powder particles. Using our model and basic electrochemical properties of the cathode materials we are able to successfully predict the exchange kinetic properties of SOFC cathode material under real operating conditions of applied voltage / current from surface exchange coefficients obtained in the absence of an applied bias.},
doi = {10.2172/1432203},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {3}
}