STRATEGIES TO IMPROVE THE RELIABILITY OF ANODE-SUPPORTED SOLID OXIDE FUEL CELLS WITH RESPECT TO ANODE REOXIDATION

Solid oxide fuel cells (SOFCs) are highly efficient devices for converting the chemical energy of a fuel into electrical energy featuring high fuel flexibility. Forschungszentrum Julich has been developing the concept of a planar cell design based on a nickel/yttria-stabilized zirconia anode substrate for approximately twenty years. This development work covers the full spectrum ranging from fundamental research in materials science, processing and engineering issues, such as cell and stack design and construction aiming at stationary and mobile applications, up to cell and stack testing and system modeling. The main focus at present is the improvement of long-term stability and reliability for cells and stacks. This contribution will present the concept developed in Julich and the challenges and strategies involved in achieving better reliability here especially by the example of the problem of nickel reoxidation in the anode. Operating conditions causing nickel reoxidation may result in irreversible microstructural changes and macroscopic expansion of the anode, potentially leading to catastrophic cell failure.