Proton Conductivity of Ni, Y Co-Doped BaZrO&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt;

Hiroya Morishita,Yumiko Ikebe,Eriko Ban

doi:10.4236/msce.2018.66002

Abstract

Dense sintered bodies of proton conducting BaZrO3 (BZ) and Y-doped BaZrO3 (BZ-Y) were obtained at 1600℃ for a short sintering time of 5 hours, by the addition of NiO as a sintering promotion agent. The relative density and grain growth of samples, Ni-doped BaZrO3 (BZ-N) and Ni, Y co-doped BaZrO3 (BZ-NY), were increased with increasing Ni addition. The sinterability of BZ-NY was greatly improved just to add only 0.6 mol% Ni and the relative density of this sample was more than 98%, in contrast to that of 60% at most for BZ-Y without Ni addition. Electrical conductivity of BZ-NY added Ni 1.0 mol%, BaZr0.91Ni0.01Y0.08O3-α, was more than 10-3 S.cm-2 at 900℃ in a wet 1% hydrogen atmosphere, which value was 10 times higher than that of BZ-Y. In addition, the kind of electrical conduction carrier and an ionic transport number were also examined by employing various concentration cells. It was found that the proton conduction was dominant for both BZ-N and BZ-NY samples, although BZ-NY showed scarcely oxygenion conduction approximately 10% in a high temperature range higher than 800℃. From these results, as mall amount of Ni addition found to be effective for improvement of both the sinterability and the electrical conductivity.

Highlights

The electrochemical device employing proton conducting perovskite-type oxide has a great potential for practical applications, such as a large scale fuel cell and hydrogen sensor etc. [1]
The relative density of BZ-NY doped with Ni higher than a molar ratio of 0.006 remarkably improves, contrast to that of BZ-NY without Ni is 60% at most
The relative density and grain growth of BZ-N and BZ-NY samples were increased with increasing Ni doping

Summary

Introduction

The electrochemical device employing proton conducting perovskite-type oxide has a great potential for practical applications, such as a large scale fuel cell and hydrogen sensor etc. [1]. The BZ doped with additive is very difficult to sinter, that is, high temperature more than 1700 ̊C is necessary to obtain a high-density sample. BZ sample without sintering additives shows low conductivity for grain-boundary resistivity even though a long time heat treatment at high temperature was carried out [1] [5] [6] [7]. In other word, it is connected for elucidation of the influence of interfacial reaction between the electrolyte and the electrode, diffusion of Ni and the coefficient of thermal expansion. It is very important for the fundamental research and application to understand the roll of Ni additive mechanism

Methods

Results

Conclusion