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Title: LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles

Authors:
; ; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE. Assistant Secretary for Fossil Energy. AssistantSecretary for Clean Coal, National Energy TechnologyLaboatory
OSTI Identifier:
889630
Report Number(s):
LBNL-59893
R&D Project: 500601; BnR: AA2530000
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of the Electrochemical Society; Journal Volume: 153; Journal Issue: 6; Related Information: Journal Publication Date: 04/19/2006
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Lu, Chun, Sholklapper, Tal Z., Jacobson, Craig P., Visco, StevenJ., and DeJonghe, Lutgard C.. LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles. United States: N. p., 2006. Web. doi:10.1149/1.2192733.
Lu, Chun, Sholklapper, Tal Z., Jacobson, Craig P., Visco, StevenJ., & DeJonghe, Lutgard C.. LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles. United States. doi:10.1149/1.2192733.
Lu, Chun, Sholklapper, Tal Z., Jacobson, Craig P., Visco, StevenJ., and DeJonghe, Lutgard C.. Tue . "LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles". United States. doi:10.1149/1.2192733. https://www.osti.gov/servlets/purl/889630.
@article{osti_889630,
title = {LSM-YSZ Cathodes with Reaction-Infiltrated Nanoparticles},
author = {Lu, Chun and Sholklapper, Tal Z. and Jacobson, Craig P. and Visco, StevenJ. and DeJonghe, Lutgard C.},
abstractNote = {},
doi = {10.1149/1.2192733},
journal = {Journal of the Electrochemical Society},
number = 6,
volume = 153,
place = {United States},
year = {Tue Jan 31 00:00:00 EST 2006},
month = {Tue Jan 31 00:00:00 EST 2006}
}
  • To improve the LSM-YSZ cathode performance of intermediate temperature solid oxide fuel cells (SOFCs), Sm0.6Sr0.4CoO3-sigma (SSC) perovskite nanoparticles are incorporated into the cathodes by a reaction-infiltration process. The SSC particles are {approx}20 to 80nm in diameter, and intimately adhere to the pore walls of the preformed LSM-YSZ cathodes. The SSC particles dramatically enhance single-cell performance with a 97 percent H2+3 percent H2O fuel, between 600 C and 800 C. Consideration of a simplified TPB (triple phase boundary) reaction geometry indicates that the enhancement may be attributed to the high electrocatalytic activity of SSC for electrochemical reduction of oxygen in amore » region that can be located a small distance away from the strict triple phase boundaries. The implication of this work for developing high-performance electrodes is also discussed.« less
  • No abstract prepared.
  • Porous composites of Sr-doped LaFeO 3 (LSF) and yttria-stabilized zirconia (YSZ) were investigated as conductive scaffolds for infiltrated SOFC cathodes with the goal of producing scaffolds for which only a few perovskite infiltration steps are required to achieve sufficient conductivity. While no new phases form when LSF-YSZ composites are calcined to 1623 K, shifts in the lattice parameters indicate Zr can enter the perovskite phase. Measurements on dense, LSF-YSZ composites show that the level of Zr doping depends on the Sr:La ratio. Because conductivity of undoped LSF increases with Sr content while both the ionic and electronic conductivities of Zr-dopedmore » LSF decrease with the level of Zr in the perovskite phase, there is an optimum initial Sr content corresponding to La 0.9Sr 0.1FeO 3 (LSF91). Although scaffolds made with 100% LSF had a higher conductivity than scaffolds made with 50:50 LSF-YSZ mixtures, the 50:50 mixture provides the optimal interfacial structure with the electrolyte and sufficient conductivity, providing the best cathode performance upon infiltration of La 0.6Sr 0.4Co 0.2Fe 0.8O 3 (LSCF).« less
  • The interaction between nanoparticles of strontium-doped lanthanum manganite (LSM) and single crystal yttria-stabilized zirconia (YSZ) was investigated using atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM)/energy-dispersive x-ray spectroscopy (EDX). Nanoparticles of LSM were deposited directly onto single crystal YSZ substrates (100) using an ultrasonic spray nozzle. As samples were annealed from 850 C to 1250 C, nanoparticles gradually decreased in height and eventually disappeared completely. Subsequent reduction in H{sub 2}/H{sub 2}O at 700 C resulted in the reappearance of nanoparticles. Studies were carried out on identical regions of the sample allowing the same nanoparticles tomore » be characterized at different temperatures. Morphological changes indicate the formation of a thin layer of LSM, and XPS results support the observation by indicating an increase in signal from the La and Sr and a decrease in signal from the Y and Zr with increasing temperature. SEM/EDX was used to verify that the nanoparticles in the reduced sample contained La. The changes in the LSM/YSZ morphology may be important in explaining the non-stationary behavior observed in operating fuel cells. The thin layer of LSM initially results in poor cathode performance; reducing conditions then lead to film disruptions, indicating nano/microporosity, that increase oxygen ion diffusion and performance.« less
  • Boron oxide is a key component to tailor the softening temperature and viscosity of the sealing glass for solid oxide fuel cells. The primary concern regarding the use of boron containing sealing glasses is the volatility of boron species, which possibly results in cathode degradation. In this paper, we report the role of volatile boron species on the electrochemical performance of LSM/YSZ and LSCF cathodes at various SOFC operation temperatures. The transport rate of boron, ~ 3.24×10-12 g/cm2•sec was measured at 750°C with air saturated with 2.8% moisture. A reduction in power density was observed in cells with LSM/YSZ cathodesmore » after introduction of the boron source to the cathode air stream. Partial recovery of the power density was observed after the boron source was removed. Results from post-test secondary ion mass spectroscopy (SIMS) analysis the partial recovery in power density correlated with partil removal of the deposited boron by the clean air stream. The presence of boron was also observed in LSCF cathodes by SIMS analysis, however the effect of boron on the electrochemical performance of LSCF cathode was negligible. Coverage of triple phase boundaries in LSM/YSZ was postulated as the cause for the observed reduction in electrochemical performance.« less