Interface Effects on the Ionic Conductivity of Doped Ceria-Yttria-Stabilized Zirconia Heterostructures

Daniele Pergolesi; Elisa Gilardi; Emiliana Fabbri; Vladimir Roddatis; George F Harrington; Thomas Lippert; John A Kilner; Enrico Traversa

doi:10.1021/acsami.8b01903

Interface Effects on the Ionic Conductivity of Doped Ceria-Yttria-Stabilized Zirconia Heterostructures

ACS Appl Mater Interfaces. 2018 Apr 25;10(16):14160-14169. doi: 10.1021/acsami.8b01903. Epub 2018 Apr 16.

Authors

Daniele Pergolesi¹, Elisa Gilardi¹, Emiliana Fabbri¹, Vladimir Roddatis², George F Harrington^{3

4

5}, Thomas Lippert^{1

6

7}, John A Kilner^{3

7}, Enrico Traversa^{8

9}

Affiliations

¹ Paul Scherrer Institut , 5232 Villigen-PSI , Switzerland.
² Institute of Materials Physics , University of Göttingen , 37077 Göttingen , Germany.
³ Department of Materials , Imperial College London , London SW7 2BP , United Kingdom.
⁴ Next-Generation Fuel Cell Research Centre , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan.
⁵ Department of Materials Science and Engineering , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States.
⁶ Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry , ETH Zürich , Vladimir-Prelog-Weg 1-5/10 , 8093 Zürich , Switzerland.
⁷ International Institute for Carbon Neutral Energy Research (WPI-I2CNER) , Kyushu University , 744 Motooka , Nishi-ku, Fukuoka 819-0395 , Japan.
⁸ School of Materials and Energy , University of Electronic Science and Technology of China , 2006 Xiyuan Road , Chengdu 611731 , Sichuan People's Republic of China.
⁹ NAST Center & Department of Chemical Science and Technology , University of Rome Tor Vergata , 00133 Rome , Italy.

PMID: 29617562
DOI: 10.1021/acsami.8b01903

Abstract

Multilayered heterostructures of Ce_0.85Sm_0.15O_2-δ and Y_0.16Zr_0.92O_2-δ of a high crystallographic quality were fabricated on (001)-oriented MgO single crystal substrates. Keeping the total thickness of the heterostructures constant, the number of ceria-zirconia bilayers was increased while reducing the thickness of each layer. At each interface Ce was found primarily in the reduced, 3+ oxidation state in a layer extending about 2 nm from the interface. Concurrently, the conductivity decreased as the thickness of the layers was reduced, suggesting a progressive confinement of the charge transport along the YSZ layers. The comparative analysis of the in-plane electrical characterization suggests that the contribution to the total electrical conductivity of these interfacial regions is negligible. For the smallest layer thickness of 2 nm the doped ceria layers are electrically insulating and the ionic transport only occurs through the zirconia layers. This is explained in terms of a reduced mobility of the oxygen vacancies in the highly reduced ceria.

Keywords: ceria; fuel cells; heterostructures; interfaces; thin films; zirconia.