Enhancement of thermoelectric figure of merit in binary-phased La(0.3)Ce(0.37)Fe(3)CoSi(2)-PbTe materials

To enhance the Seebeck coefficient and reduce the thermal conductivity while maintaining a satisfied electrical conductivity, a disordered structure was introduced into the La(0.3)Ce(0.37)Fe(3)CoSi(2) crystalline by adding a low-melting-point lead telluride (PbTe). The results suggest that the disordered structure created by the melted PbTe at 870 K can be partly preserved into the La(0.3)Ce(0.37)Fe(3)CoSb(12) materials at room temperature. With the existence of the disordered structure the Seebeck coefficient at 773 K is increased from 143 mu VK(-1) to 265 mu VK(-1) while the thermal conductivity is reduced from 2.12 Wm(-1) K(-1) to 1.60Wm(-1)K(-1), nevertheless the electrical conductivity is dropped from 78,000 Phi (-1)m(-1)' to 23,500 Phi (-1)m(-1). A figure of merit of 0.95 at 773 K is observed for the material containing 40% PbTe.