Enhanced mechanical stability of Ni-YSZ scaffold demonstrated by nanoindentation and electrochemical impedance spectroscopy

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Title: Enhanced mechanical stability of Ni-YSZ scaffold demonstrated by nanoindentation and electrochemical impedance spectroscopy
Authors: Song, B
Ruiz-Trejo, E
Brandon, N
Item Type: Journal Article
Abstract: The electrochemical performance of Ni-YSZ SOFC anodes can quickly degrade during redox cycling. Mechanical damage at interfaces significantly decreases the number of active triple phase boundaries. This study firstly focuses on the sintering temperature impact on YSZ scaffold mechanical properties. The YSZ scaffold sintered at 1200 °C exhibited 56% porosity, 28.3 GPa elastic modulus and 0.97 GPa hardness and was selected for further redox cycling study. The Ni infiltrated YSZ scaffold operated at 550 °C had an initial stabilized polarisation resistance equal to 0.62 Ω cm2 and only degraded to 2.85 Ω cm2 after 15 redox cycles. The active triple phase boundary density was evaluated by FIB-SEM tomography, and degraded from 28.54 μm−2 to 19.36 μm−2. The YSZ scaffold structure was robust after 15 redox cycles, as there was no observation of the framework fracturing in both SEM and FIB-SEM images, which indicated that the mechanical stability of YSZ scaffold improves the anode stability during redox cycling. Nonetheless, Ni agglomeration could not be prevented within Ni-YSZ scaffolds and this needs further consideration.
Issue Date: 15-Aug-2018
Date of Acceptance: 23-May-2018
URI: http://hdl.handle.net/10044/1/60309
DOI: https://dx.doi.org/10.1016/j.jpowsour.2018.05.075
ISSN: 0378-7753
Publisher: Elsevier
Start Page: 205
End Page: 211
Journal / Book Title: Journal of Power Sources
Volume: 395
Copyright Statement: © 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/BY/4.0/).
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/M014045/1
Keywords: 09 Engineering
03 Chemical Sciences
Publication Status: Published
Online Publication Date: 2018-06-15
Appears in Collections:Faculty of Engineering
Earth Science and Engineering

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