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Composite oxide ionic conductors consisting of Zr0.85Y0.15O1.925 (YSZ) and La9.33Si6O26 (LSO) have been synthesized by a modified coprecipitation method. X-ray diffraction, electron microscope, and complex impedance were adopted to investigate the phase component, microstructures, and conductivities, respectively. The results show that the average grain sizes of the composite powders and as-sintered pellets are less than 20 nm and 200 nm, respectively. The conductivity of the composite materials composed of 94 wt% YSZ and 6 wt% LSO is 0.215 S/cm at 700 ℃. The conductivity of the composite is three times higher than that of the polycrystalline YSZ and has two orders in magnitude higher than that of the polycrystalline LSO at 700 ℃. By analyzing the impedance spectra and modulus spectra, the grain-boundary effect on the conductivity improvement is investigated and the conductive mechanisms of the composite materials are discussed.


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Synthesis and characterization of Zr0.85Y0.15O1.925-La9.33Si6O26 composite electrolyte for application in SOFCs

Show Author's information Chaofeng LIUaHong ZHANGaJunxiao XIAaZhicheng LIa,b,*( )
School of Materials Science and Engineering, Central South University, Changsha 410083, China
State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China

Abstract

Composite oxide ionic conductors consisting of Zr0.85Y0.15O1.925 (YSZ) and La9.33Si6O26 (LSO) have been synthesized by a modified coprecipitation method. X-ray diffraction, electron microscope, and complex impedance were adopted to investigate the phase component, microstructures, and conductivities, respectively. The results show that the average grain sizes of the composite powders and as-sintered pellets are less than 20 nm and 200 nm, respectively. The conductivity of the composite materials composed of 94 wt% YSZ and 6 wt% LSO is 0.215 S/cm at 700 ℃. The conductivity of the composite is three times higher than that of the polycrystalline YSZ and has two orders in magnitude higher than that of the polycrystalline LSO at 700 ℃. By analyzing the impedance spectra and modulus spectra, the grain-boundary effect on the conductivity improvement is investigated and the conductive mechanisms of the composite materials are discussed.

Keywords:

Zr0.85Y0.15O1.925, La9.33Si6O26, composite materials, coprecipitation synthesis, oxygen ionic conductivity
Received: 16 November 2012 Revised: 09 December 2012 Accepted: 11 December 2012 Published: 09 January 2013 Issue date: December 2012
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Publication history

Received: 16 November 2012
Revised: 09 December 2012
Accepted: 11 December 2012
Published: 09 January 2013
Issue date: December 2012

Copyright

© The author(s) 2012

Acknowledgements

The authors acknowledge the support of the National Nature Science Foundation of China (Nos. 50872155 and 51172287). Much thanks to Dr. Haitao ZHOU for his useful information about this work. The first author also acknowledges the close discussion with Mr. Kaiming ZHANG and Mr. Hui YU.

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