Thermoelectric composites of tungsten disulfide and multiwalled carbon nanotubes

Daewoo Suh, Dongmok Lee, Chanyoung Kang, In-Jin Shon, Woochul Kim and Seunghyun Baik
Sungkyunkwan University, KR

Keywords: Thermoelectric, Carbon nanotubes, Tungsten disulfide

Summary:

Thermoelectric materials have received considerable attention as a renewable energy source directly converting thermal energy into electricity. However, materials with high thermoelectric performance typically contain potentially toxic and rare elements. Therefore, environmentally-benign thermoelectric materials need to be developed. Tungsten disulfide (WS2) is a potential candidate due to the high Seebeck coefficient and relatively low thermal conductivity [1]. However, it has a very low electrical conductivity. Here we introduced multiwalled carbon nanotubes (MWNTs) in a WS2 matrix by powder metallurgy to increase electrical conductivity [1]. The insertion of nanotubes with high aspect ratios (less than 1 wt%) significantly increased electrical conductivity (by 12272%) at 300 K with a moderate decrease in Seebeck coefficient by 22% [1]. The thermal conductivity was reduced by 43% by phonon scattering at the interfaces. This resulted in an increase in thermoelectric figure of merit (0.0063) at 300 K by 13100%. The thermoelectric figure of merit also increased with increasing temperature [1]. [1] J. Mater. Chem., 22, 21376 (2012). Authors are from Sungkyunkwan(D.S., D.L., S.B.), Yonsei(C.Kang, W.Kim) and Chonbuk National (I.S.) Universities.