Conference article

Investigation of Electrical; Structural and Thermal Stability Properties of Cubic (Bi<sub>2</sub>O<sub>3</sub>)<sub>1-x-y</sub>(Dy<sub>2</sub>O<sub>3</sub>)<sub>x</sub>(Ho<sub>2</sub>O<sub>3</sub>)<sub>y</sub> Ternary System

Refik Kayali
Department of Physics, Science-Literature Faculty, Nigde University, Nigde, Turkey

Murivet Kasikci
Department of Physics, Science-Literature Faculty, Nigde University, Nigde, Turkey

Semra Durmus
Department of Physics, Science-Literature Faculty, Erciyes University, Kayseri, Turkey

Mehmet Ari
Department of Physics, Science-Literature Faculty, Erciyes University, Kayseri, Turkey

Download articlehttp://dx.doi.org/10.3384/ecp110571219

Published in: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden

Linköping Electronic Conference Proceedings 57:12, p. 1219-1226

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Published: 2011-11-03

ISBN: 978-91-7393-070-3

ISSN: 1650-3686 (print), 1650-3740 (online)

Abstract

In the scope of this work; (Bi2O3)1-x-y(Dy2O3)x(Ho2O3)y ternary system (x=1;3;5;7;9;11 mol % and y=11;9;7;5;3;1 mol %; dopant concentrations) sample materials were developed using solid state reaction method sintering each of them at 650; 700; 750; 800 °C for 48 hours. Structural; electrical and thermal properties of these samples which are candidate of electrolyte for solid oxide fuel cells (SOFCs) have been evaluated by means of XRD; four-probe method; and TGA / DTA. XRD measurements showed that except the samples annealed at 650 oC; all the other samples have stabilized d- Bi2O3 phase. It was seen that duration of sintering time and temperature was rather effective on the formation of the stabilized sample materials and their other properties; such as electrical and structural properties. It was seen that the electrical conductivities of all the examples developed sintering at 700; 750 and 800 °C for 48 hours increases with the increasing temperature having numerical values varying in the range of 7;65x10-2 O.cm-1 - 6;11x10-1 O.cm-1. Activation energy of the sample A6 was calculated and it was found 0.97 eV. On the other hand; the main purpose of this study is to find an electrolyte which does not have any degradation in its properties with time; this maybe caused either interaction between the different electrochemical cell materials or by instability of the ionic conductor under operation conditions. During the heating/cooling process; the four-point probe conductivity measurements have been performed. The hysteresis curve was obtained for this sample due to time interval difference of heating/cooling processes. It was observed that there is no gradation in the structure of the sample.

Keywords

Electrolyte; Solid state reaction; Fuel cell; Electrical conductivity; XRD; Four- probe point method

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