AbstractsEngineering

The work presented within this thesis focuses on the synthesis, characterisation and processing of novel materials for use within solid oxide fuel cells. A range of perovskite materials, previously shown to have potential for solid oxide fuel cell applications, were selected for further studies. These included LaMnO\(_3\), SrFeO\(_{3-δ}\) and Sr\(_{0.8}\)Ti\(_{0.6}\)Nb\(_{0.4}\)O\(_{3-δ}\). These materials were doped with various dopants, including cations such as V\(^{5+}\) and Ti\(^{4+}\) and also SiO\(_4\)\(^{4-}\) oxyanions. Once doped, the materials were analysed by X-ray powder diffraction and underwent testing to ascertain their suitability for use as solid oxide fuel cell electrodes. This included identifying structural stability in anode conditions alongside thermal expansion studies. Overall, improvements over undoped samples were noted, especially for Sr\(_{0.8}\)Ti\(_{0.6}\)Nb\(_{0.4}\)O\(_{3-δ}\) samples doped with V\(^{5+}\) and SrFeO\(_{3-δ}\) samples doped with SiO\(_4\)\(^{4-}\), although LaMnO\(_3\) doped with Ti\(^{4+}\) proved less successful. Production methods for the formation of microtubular solid oxide fuel cells were also investigated. Powder processing for paste formation was examined, for subsequent use in extrusion. The extrusion process was also investigated, alongside debinding and sintering studies. The development of a reliable and repeatable process for cell production proved difficult, especially on a smaller scale necessary to facilitate the testing of novel materials.