High temperature thermoelectric materials

Preparation of high temperature p-type Oxide-based thermoelectric
Prof. Yuanhua Lin, State Key Laboratory of New Ceramics and Fine Processing, Dept.
of Materials Science & Engineering, Tsinghua University, Beijing 100084, China.
Email: [email protected]
Thermoelectric materials can directly convert heat into electric energy and vice
versa through the thermoelectric phenomena in solids, which hold great promise for
clean energy generation by transforming the heat into electricity due to the Seebeck
effect. As for the TE materials, a large thermoelectric power S, large electrical
conductivity σ, and low thermal conductivity κ are highly desired for the development
of a practical thermoelectric materials. Many efforts have been devoted in these recent
years to improving TE properties to misfit-layered oxides materials. It is generally
believed that texturation with high grain orientation in polycrystalline oxides ceramics
can be used to improve the electrical, mechanical and optical properties. Some
previous experimental results revealed that highly preferred orientation could be
effective in reducing the resistivity due to the shorter carrier path and the reduction in
the scattering of the carriers at the grain boundaries or defects.
Based on the previous research results, in this research project, we will consider
the high-temperature oxide TE materials. Misfit-layered cobaltites, such as NaCo2O4,
Ca3Co4O9, Ca2Co2O5, Bi2Sr2Co2Ox, have attracted much attention due to their
promising TE properties and high decomposition temperatures, especially
Ca-Co-O-based compounds.One way is to improve the electric conductivity, and
another way is to reduce the thermal conductivity. Therefore, we will choose some
special processing technology to make the oxide ceramics high dense and high
orientation to improve its electric conductivity. Additionally, we will control the grain
size by the processing technology to control the thermal conductivity properties. It
will be helpful to improve the thermoelectric properties.