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Title: Kinetics of oxidation of fuel cell cathode materials lanthanum strontium manganates (III)(IV) at actual working conditions: In situ powder diffraction studies

Abstract

Strontium substituted lanthanum manganates(III)(IV), La{sub 1{minus}x}Sr{sub x}MnO{sub 3+{delta}} (LSM) are cathode materials for high temperature solid oxide fuel cells/SOFC. Time resolved synchrotron X-ray powder diffraction methods have been used to study the kinetics of oxidation of lanthanum strontium manganates(III, IV) in a flow of oxygen. The process studied is La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00} + {delta}/2O{sub 2}{leftrightarrow}La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00+{delta}} (for x = 0.00, 0.10, 0.15). A contraction of the unit cell is observed on oxidation of the materials. The unit cell volume changes linearly with the mean oxidation state of the manganese. Rate constants for the process can consequently be determined from time resolved X-ray diffractograms. The reactions follow first-order kinetics. Arrhenius plots based on rate constants determined at 4 temperatures in the range 700--900 C are linear as an indication that only one rate determining step is involved. The activation energy for oxidation is 136 kJmol{sup {minus}1} for LaMnO{sub 3.00}, 179 kJmol{sup {minus}1} for La{sub 0.90}Sr{sub 0.10}Mn{sub 1.01}O{sub 3.01}, and 160 kJmol{sup {minus}1} for La{sub 0.84}Sr{sub 0.15}Mn{sub 1.01}O{sub 3.00}.

Authors:
;  [1]; ;  [2]
  1. Odense Univ. (Denmark). Dept. of Chemistry
  2. Brookhaven National Lab., Upton, NY (United States). Chemistry Dept.
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY
Sponsoring Org.:
Statens Naturvidenskabelige Forskningsraad, Copenhagen (Denmark); USDOE, Washington, DC (United States)
OSTI Identifier:
329121
DOE Contract Number:  
AC02-76CH00016
Resource Type:
Journal Article
Journal Name:
Journal of Solid State Chemistry
Additional Journal Information:
Journal Volume: 141; Journal Issue: 1; Other Information: PBD: 15 Nov 1998
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 30 DIRECT ENERGY CONVERSION; OXIDATION; LANTHANUM OXIDES; STRONTIUM OXIDES; MANGANESE OXIDES; SOLID ELECTROLYTE FUEL CELLS; X-RAY DIFFRACTION; KINETICS; ACTIVATION ENERGY; STOICHIOMETRY; EXPERIMENTAL DATA

Citation Formats

Andersen, E K, Andersen, I G.K., Norby, P, and Hanson, J C. Kinetics of oxidation of fuel cell cathode materials lanthanum strontium manganates (III)(IV) at actual working conditions: In situ powder diffraction studies. United States: N. p., 1998. Web. doi:10.1006/jssc.1998.7964.
Andersen, E K, Andersen, I G.K., Norby, P, & Hanson, J C. Kinetics of oxidation of fuel cell cathode materials lanthanum strontium manganates (III)(IV) at actual working conditions: In situ powder diffraction studies. United States. https://doi.org/10.1006/jssc.1998.7964
Andersen, E K, Andersen, I G.K., Norby, P, and Hanson, J C. Sun . "Kinetics of oxidation of fuel cell cathode materials lanthanum strontium manganates (III)(IV) at actual working conditions: In situ powder diffraction studies". United States. https://doi.org/10.1006/jssc.1998.7964.
@article{osti_329121,
title = {Kinetics of oxidation of fuel cell cathode materials lanthanum strontium manganates (III)(IV) at actual working conditions: In situ powder diffraction studies},
author = {Andersen, E K and Andersen, I G.K. and Norby, P and Hanson, J C},
abstractNote = {Strontium substituted lanthanum manganates(III)(IV), La{sub 1{minus}x}Sr{sub x}MnO{sub 3+{delta}} (LSM) are cathode materials for high temperature solid oxide fuel cells/SOFC. Time resolved synchrotron X-ray powder diffraction methods have been used to study the kinetics of oxidation of lanthanum strontium manganates(III, IV) in a flow of oxygen. The process studied is La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00} + {delta}/2O{sub 2}{leftrightarrow}La{sub 1{minus}x}Sr{sub x}MnO{sub 3.00+{delta}} (for x = 0.00, 0.10, 0.15). A contraction of the unit cell is observed on oxidation of the materials. The unit cell volume changes linearly with the mean oxidation state of the manganese. Rate constants for the process can consequently be determined from time resolved X-ray diffractograms. The reactions follow first-order kinetics. Arrhenius plots based on rate constants determined at 4 temperatures in the range 700--900 C are linear as an indication that only one rate determining step is involved. The activation energy for oxidation is 136 kJmol{sup {minus}1} for LaMnO{sub 3.00}, 179 kJmol{sup {minus}1} for La{sub 0.90}Sr{sub 0.10}Mn{sub 1.01}O{sub 3.01}, and 160 kJmol{sup {minus}1} for La{sub 0.84}Sr{sub 0.15}Mn{sub 1.01}O{sub 3.00}.},
doi = {10.1006/jssc.1998.7964},
url = {https://www.osti.gov/biblio/329121}, journal = {Journal of Solid State Chemistry},
number = 1,
volume = 141,
place = {United States},
year = {1998},
month = {11}
}