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Titolo:
LA2ZR2O7 FORMATION AND OXYGEN REDUCTION KINETICS OF THE LA0.85SR0.15MNYO3, O-2(G)VERTICAL-BAR-YSZ SYSTEM
Autore:
MITTERDORFER A; GAUCKLER LJ;
Indirizzi:
ETH ZURICH,DEPT MAT,CHAIR NONMETALL MAT,SWISS FED INST TECHNOL CH-8092 ZURICH SWITZERLAND ETH ZURICH,DEPT MAT,CHAIR NONMETALL MAT,SWISS FED INST TECHNOL CH-8092 ZURICH SWITZERLAND
Titolo Testata:
Solid state ionics
fascicolo: 3-4, volume: 111, anno: 1998,
pagine: 185 - 218
SICI:
0167-2738(1998)111:3-4<185:LFAORK>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
YTTRIA-STABILIZED ZIRCONIA; OXIDE FUEL-CELLS; SR-DOPED LAMNO3; IMPEDANCE SPECTROSCOPY; PLATINUM-ELECTRODES; AIR ELECTRODE; AC-IMPEDANCE; POLARIZATION PHENOMENA; THERMODYNAMIC ANALYSIS; Y2O3-STABILIZED ZRO2;
Keywords:
LANTHANUM ZIRCONATE (LA2ZR2O7); LANTHANUM STRONTIUM MANGANITE (LSM); OXYGEN REDUCTION; ELECTROCHEMICAL KINETICS; ELECTROCHEMICAL IMPEDANCE; SOLID OXIDE FUEL CELL (SOFC);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
75
Recensione:
Indirizzi per estratti:
Citazione:
A. Mitterdorfer e L.J. Gauckler, "LA2ZR2O7 FORMATION AND OXYGEN REDUCTION KINETICS OF THE LA0.85SR0.15MNYO3, O-2(G)VERTICAL-BAR-YSZ SYSTEM", Solid state ionics, 111(3-4), 1998, pp. 185-218

Abstract

Nucleation and growth of lanthanum zirconate (LZO) between (001) single crystals of 9.5 mol% Y2O3-stabilized ZrO2 (YSZ) and porous La0.85Sr0.15MnyO3=delta (y = 0.95... .10) perovskites were investigated. The perovskites were screen-printed on the solid electrolyte and sintered in air at 1373 K for short periods. High resolution transmission electron microscopy, electrochemical impedance spectroscopy, and atomic force microscopy were employed for interface characterization. The manganese concentration in the perovskite affects the onset of nucleation andthe growth rate of lanthanum zirconate. Excess lanthanum oxide withinthe perovskite reacts immediately with YSZ to form dense LZO layers. Layer growth kinetics is controlled by bulk diffusion of cations. Stoichiometric perovskite leads to the reductive formation of cubic LZO islands at the cathode/electrolyte interface after a few minutes of sintering, The A-site deficient perovskite is characterized by the reductive dissolution of Mn into YSZ in the early sintering stage and by a pronounced surface diffusion of cations. After the critical Mn concentration in the perovskite is reached, reductive nucleation of LZO originates. Island growth is controlled by surface diffusion of cations and the supply of lanthanum. The electrochemical properties of the cathode/YSZ interfaces are strongly influenced by the formation of LZO at the triple phase boundary. Charge transfer, dissociation of adsorbed molecular oxygen ions, and surface diffusion of atomic oxygen are discriminated from electrochemical impedance data. (C) 1998 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/09/20 alle ore 10:37:39