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In this study, nanometer WO3 powder was uniformly dispersed into the Cu2SnSe3 powder by ball milling process, and the WO3/Cu2SnSe3 thermoelectric composite was prepared by spark plasma sintering (SPS). The results showed that the nano-WO3 particles were mainly distributed in the grain boundary of Cu2SnSe3 matrix, and the grain growth of Cu2SnSe3 was inhibited. The addition of nano-WO3 could enhance the electrical conductivity of Cu2SnSe3, and while the Seebeck coefficient increased slightly for the 0.4% WO3/Cu2SnSe3 composite. The thermal conductivity was not decreased until the content of WO3 exceeded 1.6%. The highest thermoelectric figure of merit ZT of 0.177 was achieved at 700 K for 0.4% WO3/Cu2SnSe3 composite. The enhancement of ZT value of WO3/Cu2SnSe3 thermoelectric material was mainly attributed to the improvement of the electrical properties.

Addition of nanoparticles into bulk materials is an efficient way to enhance the performance of thermoelectric materials. The nanoZnO particles were introduced into the Cu2SnSe3 matrix by ball milling method, and the ZnO/Cu2SnSe3 composites were fabricated by spark plasma sintering (SPS) technology. The phase constitution and microstructure were characterized by XRD, FESEM. The effects of nanoZnO particles on the electrical and thermal transport were investigated and discussed. The diffraction spectra of all composites samples well corresponded to that of the matrix diffraction plane. The nanoZnO agglomerated into irregular clusters with the size lager than 200nm and distributed on the grain boundary or the surface of Cu2SnSe3 grain, which significantly reduce the lattice thermal conductivity by scattering middle-long wavelength phonons. The optimal ZT value was obtained from the composite sample of 2.4 vol. % ZnO, which is 1.3 times as large as that of the Cu2SnSe3 matrix.