Publications
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Wen, Yabing; Rosnes, Andreas; Jiang, Bo; Prytz, Øystein; Norby, Truls & Haugsrud, Reidar
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(2025).
Nickel-Induced Lattice Defects Limit Proton Uptake in Barium Zirconate Electrolytes.
Journal of the American Chemical Society.
ISSN 0002-7863.
148.
doi:
10.1021/jacs.5c13935.
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Nickel provides essential catalytic properties for hydrogen electrodes in proton-conducting ceramic electrochemical cells. However, Ni diminishes the hydration capability and proton conductivity when incorporated into electrolyte materials including BaZr0.8Yb0.2O3−δ studied here. Through semiquantitative atomic-resolution scanning transmission electron microscopy, density functional theory simulations, X-ray total scattering, and absorption spectroscopy, we reveal that Ni forms point defect clusters with the Yb acceptors wherein oxygen vacancies are trapped and resist hydration. The resulting effective acceptor concentration is described by point defect reactions in quantitative agreement with thermogravimetric measurements of hydration for samples substituted with 2–5 mol % Ni by BaNiO2 addition. Moreover, excess B-site cations due to NiO addition induce the formation of antiphase boundaries (APBs) that are enriched in Yb and thereby deplete the bulk of acceptors, further suppressing hydration. The adverse effects of Ni are thereby resolved into two novel mechanisms, opening new avenues in point defect engineering for high-performance electrolytes.
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Norby, Truls & Wen, Yabing
(2026).
Space Charge Layer Impedance of the Solid-Solid Electrode-Electrolyte Interface.
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Wen, Yabing
(2026).
Hydration, proton transport, and effects of defect interactions in acceptor-substituted BaZrO3.
Universitetet i Oslo.
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Proton-conducting ceramic materials are essential for clean energy devices, including fuel cells and electrolyzers. Acceptor-doped BaZrO₃ is a benchmarked electrolyte material in this field due to its chemical stability and appreciable proton conductivity at intermediate temperatures (300–700 °C). However, most prior studies oversimplified its internal structural defects and assumed ideal material behaviour. The work addresses fundamental questions regarding hydration thermodynamics, proton transport kinetics, and defect interactions—both in bulk (including singly and doubly doped systems) and at interfaces (metal/electrolyte). Compared to many studies that treat these materials within an ideal defect-chemical framework, this work explicitly confronts non-idealities in hydration equilibrium and proton transport behavior and challenges previous data interpretation.
The core objectives are: (i) to determine the true thermodynamics of hydration, including non-ideal behaviour; (ii) to re-evaluate proton diffusivity and the long-held “proton trapping/de-trapping” model; (iii) to clarify the role of Ni as both a sintering aid and a defect modifier; (iv) to characterise space charge layers at Ag/BZY interfaces.
The research is therefore highly relevant to the broader field of ceramic proton conductors and provides reliable fundamental insights for designing improved proton-conducting materials.
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Published
Dec. 21, 2021 4:15 PM
- Last modified
Dec. 21, 2021 4:15 PM