Engineering and Optimisation of Materials and Components for Metal-Supported Solid Oxide Fuel Cells
Solid Oxide Fuel Cells present tremendous prospects for the future of clean energy. However, the use of expensive materials, alongside the complexity and the high cost of production, have posed major challenges on the uptake and commercialisation of this technology. In addition, the high energy losses within the available systems are responsible for the underwhelming power efficiencies. This work aims to address these issues through a comprehensive approach that is comprised of three experimental themes. The first set of experiments covers the fabrication of metal-supported disc-shaped cells, with the use of inexpensive stainless steel and Ni-Fe (nickel-iron) alloys as substrate materials. Active layers, in the form of functional coatings, were deposited via a scalable and low-waste technique called Direct Ceramic Ink-Jet Printing. This method repeatedly produced coatings with 10-20 μm thicknesses, which permits the utilisation of lower cell operating temperatures. A complete functioning prototype cell, with a Ni-Fe support, was prepared using optimised parameters and was subjected to the current-voltage measurements in 4% H2. The second part of the work investigates the catalytic properties of the Ni-Fe thin films made via pulsed laser deposition. Two electrolyte-supported half cells were fabricated under optimised conditions and characterised using electrochemical impedance spectroscopy, showcasing results without the concentration polarisation losses. In the form of 170 nm metallic films, Ni-Fe anodes had shown a capacity to oxidise fuel, offering extensive opportunities for portable applications. The final section looks at the use of ink-jet printing infiltration for the purpose of reducing activation polarisation losses, whereby the formation of nanostructures on top of the existing electrode scaffolds proliferates the triple phase boundary and enhances electrochemical performances. The infiltrated symmetric cells had all shown improved results in comparison with the reference samples, in some cases displaying a 19 times reduction in anode resistance.
Materials Science, Fuel Cells, Solid Oxide Fuel Cells, Nanotechnology, Electrochemistry
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