Theoretical studies on the electrochemical and mechanical properties and microstructure optimization of micro-tubular solid oxide fuel cells

A comprehensive thermal fluid electrochemistry model for the analysis of the electrochemical performance and a thermal mechanical model for the analysis of the mechanical behavior of micro-tubular solid oxide fuel cell (mtSOFC) are presented. Material properties for the models are determined by the available theory and experiment and linked to the compositions and microstructures of the materials. Good agreement between the theoretical and experimental I-V relations is obtained. The mode is used to examine the effects of various parameters on the electrochemical and mechanical performance of mtSOFC. Collecting current from both sides of the anode is found to significantly increase the cell output. Increasing the Ni content or reducing the Ni particle size is generally helpful for improving the electrochemical performance, but the increased Ni content reduces the mechanical stability. The suitable Ni content is thus obtained. The LSM content is inconsequential to the mechanical stability and should be determined by achieving high electrochemical performance. Properly designed mtSOFCs are shown to provide high current outputs. Therefore, mtSOFC is a promising technology with both the benefits of planar SOFC for high current density and tubular SOFC for thermal cycling endurance. (C) 2013 Elsevier B.V. All rights reserved.