Probing the reaction pathway in (La_(0.8)Sr_(0.2))_(0.95)MnO_(3+δ) using libraries of thin film microelectrodes
Abstract
Libraries of (La_(0.8)Sr_(0.2))_(0.95)MnO_(3+δ) (LSM) thin film microelectrodes with systematically varied thickness or growth temperature were prepared by pulsed laser deposition, and a novel robotic instrument was used to characterize these libraries in automated fashion by impedance spectroscopy. The measured impedance spectra are found to be described well by an electrochemical model based on a generalized transmission model for a mixed conducting oxide, and all trends are consistent with a reaction pathway involving oxygen reduction over the LSM surface followed by diffusion through the film and into the electrolyte substrate. The surface activity is found to be correlated with the number of exposed grain boundary sites, which decreases with either increasing film thickness (at constant growth temperature) or increasing film growth temperature (at constant thickness). These findings suggest that exposed grain boundaries in LSM films are more active than exposed grains towards the rate-limiting surface process, and that oxygen ion diffusion through polycrystalline LSM films is faster than many prior studies have concluded.
Additional Information
© Royal Society of Chemistry 2015. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Received 03 Apr 2015, Accepted 02 Aug 2015, First published online 27 Aug 2015. The authors would like to thank McAllister Technical Services for their help in designing and assembling the automated impedance microprobe, and Ben Meyers and Xinqi Chen at University for their assistance in performing the FIB-SEM and SIMS characterization, respectively. This work was funded by the National Science Foundation via awards DMR-0520565 and EFRI-1038307, the Resnick Sustainability Institute at the California Institute of Technology, the National Central University of Taiwan, and the W. M. Keck Foundation. Selected facilities used were supported by the National Science Foundation via Northwestern University's MRSEC, DMR-1121262.Attached Files
Published - c5ta02428e.pdf
Supplemental Material - c5ta02428e1.pdf
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Additional details
- Alternative title
- Probing the Reaction Pathway in (La0.8Sr0.2)0.95MnO3+δ Using Libraries of Thin Film
- Eprint ID
- 59958
- Resolver ID
- CaltechAUTHORS:20150828-120355577
- NSF
- DMR-0520565
- NSF
- EFRI-1038307
- Resnick Sustainability Institute
- National Central University, Taiwan
- W. M. Keck Foundation
- NSF
- DMR-1121262
- Created
-
2015-08-28Created from EPrint's datestamp field
- Updated
-
2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute