ICT2014 Abstracts

Thermoelectric nanocomposites are of great interest because that many interfaces are introduced to reduce the lattice thermal conductivity, thus the thermoelectric performance can be improved. In some nanocomposites, the lattice thermal conductivity is approaching its minimum value, therefore to further reduce the lattice thermal conductivity is difficult and researchers are trying to enhance the power factor. Here we propose a new effect that utilizes phase inequality in the nanocomposite to enhance the power factor. By numerical simulation based on the combination of Onsager equations and Boltzmann transport equations, we show that the power factor can be 2~3 times larger than that of each phase in a 2-phase nanocomposite, when the thermal conductivity and electrical conductivity of one phase are much lower than those of the other, and the Seebeck coefficient of one phase is much greater than the other. Moreover, we found that when a 0-3 composite is formed, it is better to fill a high thermal conductivity ‘0 dimensional’ phase to enhance the power factor, and the volume ratio of the ‘0 dimensional’ phase should be greater than 50%. Our results will aid the design of high performance thermoelectric nanocomposites