Materials for solid oxide fuel cells and batteries
In the energy mix of the future, highly efficient, decentralized energy converters such as fuel cells and storage systems for electrical energy play a key role.
Solid oxide fuel cell
IEK-1's research activities in the area of solid oxide fuel cells are integrated in Forschungszentrum Jülich's overall SOFC research and address the synthesis, preparation, and processing of materials into functional structures, layers, and components.
For this work, IEK-1 has a wide range of different technologies at its disposal, starting with the production of coatings no more than a nanometre thick all the way to voluminous components with dimensions in the range of tens of centimetres.
Materials research begins with the synthesis of new, alternative materials, or materials whose chemical composition has been varied. Such materials are used for anodes, cathodes, electrolytes, contact, insulation, and protective layers. Other activities concern the modification of commercial materials, processing of materials via transport agents into pastes, slips, suspensions, as well as transportable or compressible powders, up to and including the fabrication of cells on a manufacturing scale.
In addition to the optimal functional properties of each material (physical, electrochemical, mechanical), the priorities of research and development always also include processability of the materials into components with manufacturing processes appropriate for industrial applications.
A wide variety of ceramic technology techniques are available for this purpose, such as tape casting, screen printing, slip casting, pressing (including isostatic pressing, hot isostatic pressing (HIP), and cold isostatic pressing (CIP)), centrifugal and dip coating, as well as roll coating.
The plant engineering is supplemented on the one hand by thin-film techniques such as sputtering, electron-beam evaporation and deposition from the chemical gas phase, and on the other hand, by thermal spraying, such as atmospheric, low-pressure, thin-film-low-pressure and suspension-plasma spraying, as well as high-speed flame spraying.
In addition to the powder-synthesis and processing facilities, special characterization methods, such as particle-size, pore and surface analysis, viscosimetry, light, confocal, and scanning electron microscopy, laser topography, and facilities for measuring gas tightness (air, helium), are available. Mechanical characterization of the samples is conducted in IEK-2, while electrochemical characterization of the individual cells is performed in IEK-3.
The images show the fracture surface of a typical anode-supported IEK-1 SOFC with its diverse functional layers and specially adapted microstructures, diverse manufacturable cell geometries and coating of the metallic interconnects with protective or contact layers, which is also performed in IEK-1.
Solid state batteries
In the past years, work has begun on lithium batteries. The activities concerning this type of battery draw directly on our 20-year expertise acquired through solid-oxide fuel cell research. The goal of the development is new, improved types of batteries for stationary and mobile applications with robust long-term stability during stochastic charging and discharging processes.