Effect of the addition mechanism of ZnO sintering aid on densification, microstructure and electrical properties of Ba(Zr,Y)O3-delta proton-conducting perovskite
authors Soares, HS; Antunes, I; Loureiro, FJA; Perez-Coll, D; Willinger, MG; Brandao, AD; Mather, GC; Fagg, DP
nationality International
journal INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
author keywords Yttrium-doped barium zirconate (BZY); ZnO sintering Additive; Solid-state electrochemistry; Space-charge analysis
keywords DOPED BARIUM ZIRCONATE; TEMPERATURE; ELECTROLYTE; BAZRO3; BAZR0.9Y0.1O3-DELTA; FABRICATION; BEHAVIOR; CERATE; CELLS
abstract We explore three different potential mechanisms to introduce 4 mol% ZnO sintering additive to the promising yttrium-doped barium zirconate (Ba(Zr,Y)O3-delta, BZY) proton conductor. The mechanisms involve Zn substitution for Y, Zr, or B-site cation excess. The addition of ZnO promotes high densification levels (up to 98% of the theoretical value) at 1300 degrees C, irrespective of the mechanism. However, scanning electron microscopy shows that the B-site cation excess mechanism leads to an impaired grain growth compared to the other mechanisms. Rietveld refinement of the lattice-parameters and scanning transmission electron microscopy-energy dispersive X-ray spectroscopy indicates that Zn resides in both grains and grain boundaries in all cases. Determination of partial conductivities demonstrates that the Zr substitution mechanism provides slightly higher values of bulk protonic conductivity, as well as a higher hydration enthalpy. In contrast, the B-site excess mechanism provides the highest specific grain-boundary conductivity, as a result of greater Zn segregation to the grain boundary. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn 0360-3199
isbn 1879-3487
year published 2021
volume 46
issue 52
beginning page 26466
ending page 26477
digital object identifier (doi) 10.1016/j.ijhydene.2021.05.109
web of science category 12
subject category Chemistry, Physical; Electrochemistry; Energy & Fuels
unique article identifier WOS:000674605600001
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