Materials for Energy Conversion
Materials for energy conversion are a growing research area of the Department of Functional Materials.
In addition to the synthesis of various materials (e.g., metal oxides, polymers), the characterization of thermoelectric properties is in the scope of our work. Research topics deal with the defect chemical investigations of the applied materials and on materials properties. Concepts for the realization of thermoelectric generators for waste heat recuperation with high energy efficiency adjusted to the ambient conditions (exhaust gas temperatures, exhaust gas mass flow, etc.) are as important as modeling and simulation of the overall system and belong therefore to our field of research.
The emphasis is on materials synthesis and on processing of the synthesized powders to compact devices or films using a thick-film technology or aerosol deposition (room temperature impact consolidation).
An extensive characterization of the material properties is carried out in synthetic gas mixtures having different electrical measurement methods. Besides the study of the electrical conductivity (four-wire resistance measurement and impedance spectroscopy), the determination of the Seebeck coefficient is an important criterion. For this purpose, a special test setup available. The properties can be determined from room temperature up to 1000 °C under varying gas compositions.
The broad spectrum characterization opens the possibility to analyze and describe the materials by defect chemical methods.
The following methods are available for our research activities as pointed out above:
- Materials synthesis (powder synthesis via mixed oxide route and wet chemical precipitation)
- Materials characterization: scanning electron microscope (SEM) with elemental analysis (EDX) and variable pressure (ESEM)
- Production of compacts (uniaxial and isostatic pressing, density determination using a helium pycnometer)
- Film technology (screen printing technology and aerosol deposition, room temperature impact consolidation)
- Characterization of thermoelectric properties: measuring setup to determine both the Seebeck coefficient (thermopower) and the conductivity as a function of temperature and gas composition
Prof. Dr.-Ing. Ralf Moos, Phone: +49 (0)921 55 7400, Ralf.Moos@uni-bayreuth.de