In order to make thermoelectric generation system practicable, high-performance thermoelectric material should be developed. At present, in all of the middle- temperature thermoelectric materials, PbTe is used the most widely but it has a severe pollution to environment. And its thermoelectric performance figure (ZTmax=0.9) is still very low. Therefore it is necessary to develop new type high-performance and environment friendly middle-temperature thermoelectric materials. As a type of potential...