Low-temperature co-sintering for fabrication of zirconia/ceria bi-layer electrolyte via tape casting using a Fe2O3 sintering aid

A.S Mehranjani,D.J Cumming,D.C Sinclair,R.H Rothman

doi:10.1016/j.jeurceramsoc.2017.05.018

A.S Mehranjani, D.J Cumming + Show 2 more

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https://doi.org/10.1016/j.jeurceramsoc.2017.05.018

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Abstract

Abstracts Bilayer electrolytes have potential in solid oxide cells to improve ionic conduction whilst blocking electronic conduction. GDC/YSZ bilayer electrolyte processing has proven problematic due to thermochemical instability at high sintering temperatures. We first match the shrinkage profile of the two bulk materials using a Fe 2 O 3 sintering additive. Additions of 5 mol% of Fe 2 O 3 in the GDC layer and 2 mol% of Fe 2 O 3 in the YSZ layer prevents delamination during co-sintering. The addition of Fe 2 O 3 promotes densification, enabling achievement of a dense bilayer at a reduced sintering temperature of 1300 °C; ∼150 °C below conventional sintering temperatures. Elemental analysis showed the compositional distribution curves across the bilayer interface to be asymmetric when Fe 2 O 3 is employed. The Fe 2 O 3 increases the total conductivity of the bilayer electrolyte by an order of magnitude; this is explained by the effect of Fe 2 O 3 on reducing the resistive solid solution interlayer at YSZ/GDC interface from ∼15 to ∼5 μm.

Highlights

Solid oxide electrolysis cells (SOECs) are important electrochemical devices that can be used for energy storage by converting electrical into chemical energy [1,2]
The results presented here demonstrate that the fabrication of bilayer electrolyte supports for planar Solid Oxide Cells (SOC)’s with a YSZ blocking layer is possible by tape casting and co-sintering
Bilayer 8YSZ/GDC10 electrolytes have been successfully fabricated by tape casting and reduced-temperature co-sintering at 1300 ◦C

Summary

Introduction

Solid oxide electrolysis cells (SOECs) are important electrochemical devices that can be used for energy storage by converting electrical into chemical energy [1,2]. Research on SOECs has focused largely on water reduction for hydrogen production and significant development has been achieved in recent years [3,4]. Co-electrolysis with a Fischer-Tropsch (F-T) process could convert/store wind or nuclear electrical energy into synthetic fuel by utilising CO2 as a feedstock. High performance Solid Oxide Cells (SOC) typically consist of a fuel electrode support with a thin yttria-stabilised zirconia (8YSZ) electrolyte used to minimise the ohmic electrolyte contribution. If sufficient ionic conductivity can be achieved, electrolyte supported cells are an interesting configuration to be further investigated due to ease of manufacturing

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