Synthesis, characterization and evaluation of cation-ordered LnBaCo2O5+δ as materials of oxygen permeation membranes and cathodes of SOFCs

Zhang, Kun and Ge, Lei and Ran, Ran and Shao, Zongping and Liu, Shaomin (2008) Synthesis, characterization and evaluation of cation-ordered LnBaCo2O5+δ as materials of oxygen permeation membranes and cathodes of SOFCs. Acta Materialia, 56 (17). pp. 4876-4889. ISSN 1359-6454

Abstract

LnBaCo2O5+δ (Ln = La, Pr, Nd, Sm, Gd, and Y) was synthesized via an EDTA-citrate complexing process. The particular Ln3+ dopant had a significant effect on the oxide's phase structure/stability, oxygen content, electrical conductivity, oxygen permeability, and cathode performance. Stable, cation-ordered oxides with layered lattice structures were obtained with medium-sized Ln3+ ions over a wide range of oxygen partial pressures, a property essential for applications as oxygen separation membranes and solid oxide fuel cell (SOFC) cathodes. PrBaCo2O5+δ demonstrated the highest oxygen flux (∼5.09 × 10-7 mol cm-2 s-1 at 900 °C), but this value was still significantly lower than that of Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite (∼3.1 × 10-6 mol cm-2 s-1 at 900 °C). The observed difference was attributed to the much longer diffusion distance through a polycrystalline membrane with a layered lattice structure than through cubic perovskite because bulk diffusion was the rate-limiting step of permeation. An area-specific resistance of ∼0.213 Ω cm2 was achieved at 600 °C with a PrBaCo2O5+δ cathode, suggesting that the layer-structured oxides were promising alternatives to ceramic membranes for SOFC cathodes.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 07 Aug 2019 03:57
Last Modified: 09 Aug 2019 04:54
Uncontrolled Keywords: LnBa2Co2O5+d, mixed conductor, cation-ordered, SOFC, ceramic membrane
Fields of Research : 03 Chemical Sciences > 0302 Inorganic Chemistry > 030206 Solid State Chemistry
09 Engineering > 0904 Chemical Engineering > 090404 Membrane and Separation Technologies
Socio-Economic Objective: B Economic Development > 86 Manufacturing > 8606 Industrial Chemicals and Related Products > 860601 Industrial Gases
Identification Number or DOI: 10.1016/j.actamat.2008.06.004
URI: http://eprints.usq.edu.au/id/eprint/36465

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