Modeling And Analysis On The Anode Electrolyte Interface In Solid Oxide Fuel Cell

Solid oxide fuel cell(SOFC) has been regarded as a promising candidate for power generation in the future due to its distinguished attributes like high efficiency, strong fuel flexibility and environmentally friendly feature. At present it is confronted with a couple of drawbacks like short lifetime and high cost that hinder its more widely application. Therefore researchers have been attempting to enhance its performance and competitiveness from all aspects in all kinds of ways. The present thesis is dedicated to the establishment of a numerical model on planar SOFC and will further try to improve its performance from the aspect of its anode-electrolyte interface optimization.The tool used in the modeling is finite element software COMSOL. In the thesis, numerical models focused on the the anode-electrolyte-cathode repeated assembly of SOFC were successfully built, one with thick electrolyte layer while the other one with thin electrolyte layer. They are a bit different in equations, while both of them take charge transport, gas transport and electrochemical reaction in cells into account.The first model focuses on cells with 5 different anode/electrolyte geometric interfaces and is aimed to find the cell with the best electrochemical performance. Results reveal that the cell with deep ellipse interface obtains the highest current density under different voltages. Further optimization on this geometry demonstrates denser and deeper architecture leads to better performance, roughly 32% of current density improvement can be observed compared to flat interface cell at 0.7 V operating voltage. The other model focuses on investigating the influences that rectangular anode/electrolyte interface will have on single cell performance in anode-supported SOFC, the distributions of gas species, electric and ionic potential and activation overpotential in the cell are obtained through simulation. It is found that the rectangular interface cell with 100 ?m thickness gap apparently is superior to flat interface cell, its maximum power density improvement can reach as much as 48%. Besides, specific analysis are conducted on the cause of its performance improvement, factors that influence the improvement are suggested. Besides, a comparison between simulation result and experimental data confirmed its reliability.The thesis put forward the concept of interface enlargement factor in solid oxide fuel cells and confirmed its positive correlation with SOFC electrochemical performance. It can provide good direction to the research of electrode/electrolyte optimization for better SOFC performance.