Materials and concepts for solid oxide fuel cells (SOFCs) in stationary and mobile applications

Solid oxide fuel cells (SOFCs) are a forward-looking technology for highly efficient, environmentally–friendly power generation. The electrochemically active single cell is a multilayer structure consisting of ceramic and metallic materials with different electrical transport properties. Materials for electrodes should exhibit electronic and ionic conductivity in combination with porosity and catalytic activity, whereas the electrolyte has to be a purely ionically conducting and gas-tight membrane. All components have to show well-adjusted thermal expansion behavior, chemical compatibility of material interfaces and chemical stability in the prevailing temperature and gas atmosphere. The performance and long-term stability of the single cell is significantly increased by the use of suitable materials, a proper design of the cell and an optimized microstructure at the electrode/electrolyte interfaces. The application of appropriate technologies for the production of single cells with optimized microstructure becomes even more important for highly efficient SOFCs operating in the medium and low temperature range.