Microstructural and electrochemical characterisation of degradation in nickel impregnated scandia-stabilised zirconia electrode during isothermal annealing

Title: Microstructural and electrochemical characterisation of degradation in nickel impregnated scandia-stabilised zirconia electrode during isothermal annealing
Author(s): Chen, J
Ruiz-Trejo, E
Atkinson, A
Brandon, NP
Item Type: Conference Paper
Abstract: © The Electrochemical Society. In this study, we examine the degradation of nickel impregnated scandia-stabilised zirconia (ScSZ) electrode in wet hydrogen at a working temperature of SOFCs. Continuous van der Pauw measurement was carried out when the electrode was aged at 650oC in an atmosphere with 5 vol% hydrogen and 95 vol% nitrogen. A fall in sheet conductivity was found in the electrode during ageing within 1000 min. Electrochemical impedance spectra were collected at a constant time intervals during isothermal annealing at 650oC, 800oC and 950oC for the impregnated electrode, at open circuit. Three resistance contributions were decoupled by equivalent circuit fitting, i.e. the ohmic resistance, the anodic reaction resistance, and the gas diffusion resistance. Secondary electron images of electrodes before and after ageing showed an increase in nickel particle size and a decrease in the number of particles, providing microstructural evidence of coarsening. Nickel coarsening was identified as the main mechanism of degradation for the electrode in wet hydrogen.
Publication Date: 30-May-2017
URI: http://hdl.handle.net/10044/1/54956
DOI: https://dx.doi.org/10.1149/07801.1125ecst
ISBN: 9781607685395
ISSN: 1938-5862
Start Page: 1125
End Page: 1137
Journal / Book Title: ECS Transactions
Volume: 78
Issue: 1
Copyright Statement: © 2017 ECS - The Electrochemical Society
Sponsor/Funder: Engineering & Physical Science Research Council (EPSRC)
Funder's Grant Number: EP/M014045/1
Publication Status: Published
Appears in Collections:Faculty of Engineering
Materials
Earth Science and Engineering



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