Effects of Preparation Methods on the Thermoelectric Performance of SWCNT/Bi₂Te₃ Bulk Composites

Single-walled carbon nanotube (SWCNT)/Bi₂Te₃ composite powders were fabricated via a one-step in situ reductive method, and their corresponding bulk composites were prepared by a cold-pressing combing pressureless sintering process or a hot-pressing process. The influences of the preparation methods on the thermoelectric properties of the SWCNT/Bi₂Te₃ bulk composites were investigated. All the bulk composites showed negative Seebeck coefficients, indicating n-type conduction. A maximum power factor of 891.6 μWm^-1K^-2 at 340 K was achieved for the SWCNT/Bi₂Te₃ bulk composites with 0.5 wt % SWCNTs prepared by a hot-pressing process, which was ~5 times higher than that of the bulk composites (167.7 μWm^-1K^-2 at 300 K) prepared by a cold-pressing combing pressureless sintering process, and ~23 times higher than that of the bulk composites (38.6 μWm^-1K^-2 at 300 K) prepared by a cold-pressing process, mainly due to the enhanced density of the hot-pressed bulk composites.