Thermoelectric Properties of Sb2Te3-Based Nanocomposites with Graphite

Antimony-telluride-based nanocomposite samples containing different weight fractions of graphite (Sb 2 Te 3 + x % graphite, where x = 0.0, 0.5, 1.0, and 2.5%) are synthesized and studied. The samples are produced by a solid-state reaction with the use of a ball mill. X-ray diffraction measurements show that the Sb 2 Te 3 phase is present in the nanocomposites. All of the diffraction peaks are identified as corresponding to the rhombohedral structure of symmetry . No additional peaks related to graphite are observed because of its low content. Moreover, the X-ray data show the insolubility of graphite in Sb 2 Te 3 : the peaks related to Sb 2 Te 3 remain unchanged upon the addition of graphite. The thermal conductivity, thermoelectric power, and resistivity of the samples are studied in the temperature range 80 K ≤ T ≤ 320 K. The thermal conductivity k of the nanocomposite decreases several times compared to the thermal conductivity of single-crystal Sb 2 Te 3 and reaches k ≈ 0.95 W m –1 K –1 at x = 0.5%. The parameter k unsteadily depends on the content of graphite. The thermoelectric power of the nanocomposites with graphite at x = 1.0% is higher compared to that of nanostructured Sb 2 Te 3 .