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Title: Novel fabrication routes to nickel-based cermet electrodes for solid oxide cells
Author: Lomberg, Ma'ayan Marina
ISNI:       0000 0004 5349 6281
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2015
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Solid oxide cells (SOCs) are promising energy conversion devices in which the chemical energy of fuels is converted into electrical energy in an efficient manner. It is generally accepted that electrode microstructure plays an important role in determining the performance and durability of SOCs. The electrode is required to contain large amount of active reaction sites, termed triple phase boundaries (TPBs), to promote the electrochemical reaction. At the same time, effective transport pathways need to be established to and from each TPB. Therefore, the microstructure-performance relationships need to be understood in order to develop highly efficient electrodes. In this study a novel electrode, prepared by infiltration of nickel nano-particles into Gadolinium doped Ceria porous scaffold, is proposed. The research aims to understand the fundamental phenomena underpinning SOC operation for steam electrolysis/H2 oxidation in these electrodes and to establish the relationship between the microstructure of the infiltrated electrode and electrode performance. The electronic conductivity of infiltrated electrodes was tested by the van der Pauw method over the temperature range 20-700 °C. Electrochemical behaviour was assessed for fuel cell and electrolysis modes using three electrode AC and DC measurements. The microstructure was studied by SEM and FIB techniques, including 3-D imaging and quantification. Ultimately, this is to allow electrodes to be designed with desired characteristics. In addition, a novel approach for electrode preparation by Selective Laser Sintering (SLS) was evaluated by conducting a proof of concept study. This fabrication technique enables the porosity and pattern of the electrode to be controlled by regulating the parameters of the laser (laser power and laser speed). The feasibility of using this novel technique for solid oxide cells was demonstrated. A method for the fabrication of high performance 'electrodes by design' through the combination of the two techniques in which the scaffold preparation by SLS is followed by infiltration is in prospect.
Supervisor: Brandon, Nigel; Offer, Gregory Sponsor: Energy Futures Group
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral