Conductivity recovery by redox cycling of yttrium doped barium zirconate proton conductors and exsolution of Ni-based sintering additives
authors Nasani, N; Pukazhselvan, D; Kovalevsky, AV; Shaula, AL; Fagg, DP
nationality International
journal JOURNAL OF POWER SOURCES
author keywords Yttrium doped barium zirconate; Nickel; Sintering additive; Protonic ceramic fuel cells; Electrolyte
keywords OXIDE FUEL-CELLS; CHEMICAL-STABILITY; ELECTRICAL-PROPERTIES; TRANSPORT-PROPERTIES; ELECTROLYTE; FABRICATION; BAZR0.8Y0.2O3-DELTA; SOLUBILITY; PEROVSKITE; CERAMICS
abstract Owing to their high stability and good bulk proton conductivity yttrium doped barium zirconate-based materials are considered as potential electrolytes for protonic ceramic fuel cell applications. Nonetheless, their refractory nature leads to problematic densification that can necessitate the addition of sintering additives. While these additives assist processing, undesirable, strong, negative impacts on proton conductivity have been regularly reported. The current work assesses the potential sintering additives NiO, BaNiOx and BaY2NiO5 and their influence on subsequent electrochemical properties of BaZ-r(0.85)Y(0.15)O(3-delta). All sintering additives allow dense electrolyte materials (>95%) to be formed at temperatures below 1450 degrees C, with enhanced grain growth; with the largest grain growth being offered by the BaNiOx additive. Degradation in overall electrical performances is shown to be bulk related, corresponding to large reductions in bulk conductivity up to two orders of magnitude, whilst grain boundary conductivities are less affected. Most importantly, the current article demonstrates that these high depletions in bulk proton conductivity can be effectively inverted by redox cycling in relatively mild conditions (750 degrees C, cycling from N-2 to H-2 and back to N-2), opening the way to improve processing of these materials whilst maintaining high levels of proton conductivity. (C) 2016 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0378-7753
isbn 1873-2755
year published 2017
volume 339
beginning page 93
ending page 102
digital object identifier (doi) 10.1016/j.jpowsour.2016.11.036
web of science category Chemistry, Physical; Electrochemistry; Energy & Fuels; Materials Science, Multidisciplinary
subject category Chemistry; Electrochemistry; Energy & Fuels; Materials Science
unique article identifier WOS:000390516000012
  ciceco authors
  impact metrics
times cited (wos core): 0
journal impact factor (jcr 2016): 6.395
5 year journal impact factor (jcr 2016): 6.117
category normalized journal impact factor percentile (jcr 2016): 90.189
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