Improved thermoelectric properties of multi-walled carbon nanotubes/Ag2Se via controlling the composite ratio

The developments of high-efficiency thermoelectric materials are extremely exigent for energy harvesting. In this study, a novel MWCNTs/Ag2Se (MCAS) composite was successfully fabricated by a typical one-pot hydrothermal method and its thermoelectric properties were discussed in the temperature range of 300-420 K. The SEM patterns revealed that the microparticle diameter of Ag2Se for MCAS was about 10 times smaller than that of pure Ag2Se, which contributed to the intimate contact and mutual effect at the MCAS interfaces. The thermoelectric measurements indicated that 1%MCAS obtained the optimal thermoelectric figure of merit (ZT) value, ascribed to the outstanding electrical conductivity of the MWCNTs and the declining thermal conductivity of the 1%MCAS. The electrical conductivity of 1%MCAS was 3.0 times higher than that of Ag2Se, and the lattice thermal conductivity was decreased by 55.3% at 300 K. This study provides a new strategy for designing Ag2Se-based thermoelectric materials and promoting thermoelectric performance.