Title: Multifactor theoretical study on ionic transport numbers of mixed oxygen ionic-electronic conducting oxides determined by the electromotive force method
Abstract: The electromotive force (EMF) method is widely applied to measure the ionic transport numbers ( t i ) of mixed oxygen-ionic and electronic conducting oxides. However, the results determined by the EMF method are the average/apparent t i ( t i a p p ), subjected to a given gradient of oxygen partial pressure ( P O 2 ), rather than t i at a specific P O 2 , making it challenging to reveal the accurate properties of materials. In this study, to clarify the impact of this issue, a precise defect distribution model of Gd doped CeO 2 (GDC), considering defect equilibrium and local charge neutrality, is built. A multifactor theoretical analysis is conducted to compare t i a p p and t i of the membrane at different sides. The modeling results reveal that a thick membrane is recommended for avoiding the influence of membrane thickness on t i a p p . When there is a large difference of P O 2 between two sides of the GDC membrane ( P O 2 h i g h P O 2 P O 2 l o w P O 2 > 10 25 ), t i a p p is inclined to t i at the side of high P O 2 . Only when both sides of the GDC membrane are reducing atmosphere, t i a p p of the modified EMF method is approximately the average of t i at both sides. The findings of this study are instructive for the rational application of EMF methods. • The impact of apparent ionic transport numbers of the EMF method is clarified. • A precise model of defect distribution in GDC membrane is built. • A multifactor theoretical analysis is conducted to compare ionic transport numbers.
Publication Year: 2023
Publication Date: 2023-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 6
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