Processing and Characterisation of Tubular Solid Oxide Fuel Cell (SOFC) Cathodes using a Novel Manufacturing Technique

This thesis investigates a novel method for manufacturing a tubular solid oxide fuel cell cathode. The work involved depositing a lanthanum nickel ferrite / lanthanum strontium manganite cathode onto an yttria stabilized zirconia electrolyte using an electroless co-deposition technique. The lanthanum nickel ferrite is a promising cathode material but suffers from degradation at the high temperatures encountered during the sintering process which is required during conventional cathode processing. The novel technique employed in this work does not involve these high temperatures so the investigation was focused on whether co-deposition could be employed to use the lanthanum nickel ferrite (LNF). The experimental work involved co-deposition of conventional cathode materials – lanthanum strontium manganite and yttria stabilized zirconia onto both planar and tubular sections of alumina substrates, under the environment of both acid and alkaline baths. This was followed by repeating the procedure using lanthanum nickel ferrite onto tubular and planar yttria stabilized zirconia substrates. The performance of these co-deposited cathodes was characterized using optical and scanning electron microscopy, energy dispersive X-ray analysis and electrochemical analysis. These were planar fuel cells so as to allow basic testing of the cells. The work thus demonstrated that electroless co-deposition of tubular cathodes incorporating LNF was successful – both via SEM / EDX characterisation and basic electrical testing. Factors which affected the coating deposition and performance were also investigated and a comprehensive overview of the development of solid oxide fuel cells is also detailed.