Technology offer: High-efficient thermoelectric materials
Certain materials are known to generate an electric potential when exposed to a temperature gradient (Seebeck effect) and a temperature difference when a voltage is applied (Peltier effect).
A lot of sources of waste heat are suitable for generating electrical power using such thermoelectric materials. On the other hand, there is a need to provide electrically operated cooling devices without moving parts. Therefore, there is great interest in devising thermoelectric materials with significantly higher efficiency than is currently available.
Scientists at the Max Planck Institute for Solid State Research have developed a new type of thermoelectric materials having a substantially improved Seebeck coefficient. The technology exploits the considerable effect of grain boundaries on the electrical conductivity as well as the Seebeck coefficient.
As basic material oxides and complex oxides of certain metals can be chosen (for example SrTiO3 or CeO2). A nanocrystalline powder of this material with grain sizes less than 100 nm is pressed into a compact (Fig. 1). This results in a significantly higher Seebeck coefficient in comparison to a single crystal. It could be shown that this is a direct result of the grain boundaries in the pressed body of nanocrystalline grains. This discloses new opportunities to enhance the figure of merit of thermoelectric oxides.
- High efficiency
- Low cost
- Easy to manufacture
- Applicable under both oxidizing (e.g. air) and reducing (e.g. gas exhaust) conditions
- Nontoxic and environmental friendly
- Method applicable to wide range of metal oxides
More information: www.max-planck-innovation.de/en/industry/technology_offers