Issue 16, 2023

Tuning proton kinetics in BaCo0.4Fe0.4Zr0.2–XYXO3–δ triple ionic-electronic conductors via aliovalent substitution

Abstract

The BaCo0.4Fe0.4Zr0.1Y0.1O3−δ (BCFZY0.1) triple ionic-electronic conductor (TIEC) has received thorough investigation as a potential cathode in protonic ceramic fuel cells (PCFCs) due to its excellent oxygen reduction reaction and concurrent conduction of electrons, oxygen ions, and protons. Proton conductivity and surface reactivity are paramount in PCFC cathodes to improve the active reaction area. However, few instances of direct proton kinetic measurements have been reported. In this work, a suite of BaCo0.4Fe0.4Zr0.2−XYXO3−δ (X = 0, 0.1, 0.2) materials is synthesized and evaluated through hydrogen permeation and electrical conductivity relaxation measurements to investigate the effect of aliovalent substitution of Y3+ for Zr4+ on bulk proton conductivity and surface kinetics. The permeation results suggest that aliovalent substitution significantly improves the proton conductivity upon a 10% B-site doping of Y, while further incorporation of Y slightly decreases conductivity from the 10% optimum. Through three separate conductivity relaxation measurements, oxidation, hydration, and isotopic switching, an improvement in the proton kinetics with Y-doping is observed in humidified oxidizing conditions, emulating conditions in intermediate-temperature electrochemical devices. These observations suggest that aliovalient doping plays an important role in the incorporation and mobility of protons in TIEC materials.

Graphical abstract: Tuning proton kinetics in BaCo0.4Fe0.4Zr0.2–XYXO3–δ triple ionic-electronic conductors via aliovalent substitution

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Supplementary files

Article information

Article type
Paper
Submitted
05 Feb 2023
Accepted
27 Mar 2023
First published
03 Apr 2023
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2023,11, 8929-8938

Tuning proton kinetics in BaCo0.4Fe0.4Zr0.2–XYXO3–δ triple ionic-electronic conductors via aliovalent substitution

J. H. Duffy, H. W. Abernathy and K. S. Brinkman, J. Mater. Chem. A, 2023, 11, 8929 DOI: 10.1039/D3TA00654A

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