Reduced ionic conductivity in biaxially compressed ceria

Weida Shen,Jun Jiang,Joshua L Hertz

doi:10.1039/c4ra00820k

Abstract

Thin film multilayers composed of Y2O3-doped CeO2(YDC) with CeO2, with Ce0.70Zr0.30O2(CZO30), or with Ce0.55Zr0.45O2(CZO45) were fabricated to systematically quantify the effect of biaxial compressive strain on oxygen ion conductivity in YDC.

Highlights

Decreasing the operating temperature of solid oxide fuel cells (SOFCs) to below z600 C is crucial to wider commercialization of this power technology in both stationary and portable power applications.[1,2,3] For this to happen, the low temperature oxygen ion conductivity of electrolyte materials, such as yttria-stabilized zirconia (YSZ), must be increased
Three different types of multilayers composed of Ce0.90Y0.10O2Àd (YDC) with CeO2, with Ce0.70Zr0.30O2 (CZO30), or with Ce0.55Zr0.45O2 (CZO45), were prepared
By Vegard's law, the lattice parameters of CZO45 and CZO30 solid solutions can be estimated as 5.29 Aand 5.33 A, respectively

Summary

Introduction

Decreasing the operating temperature of solid oxide fuel cells (SOFCs) to below z600 C is crucial to wider commercialization of this power technology in both stationary and portable power applications.[1,2,3] For this to happen, the low temperature oxygen ion conductivity of electrolyte materials, such as yttria-stabilized zirconia (YSZ), must be increased. A unique fabrication method that allows creation of thin lms with composition controlled at the single nanometer level within wide solid solution compositional spaces was used This technique enables continuously variable compressive strains to be induced in the YDC layers by controlling the Ce/Zr atomic ratio— and thereby the lattice parameter—in the CZO layers. Another key bene t of using CZO instead of rare earth or other oxides is that both component lms in the multilayer are cubic uorite structure, increasing the likelihood of obtaining coherent interfaces. CZO has a cubic structure at low Zr concentrations of x < 0.5, but can be tetragonal or monoclinic at higher concentrations.[22,23] Only cubic CZO is employed in this work

Experimental

Results and discussion

Conclusions