Ultralow thermal conductivity in tetrahydrofuran clathrate hydrate

The detailed knowledge of the low thermal conductivity of host-guest compounds is essential to improve our fundamental understanding of heat conduction in complex solids and develop high-performance thermoelectric materials. In this Letter, the intrinsic ultralow thermal conductivity (0.44 & PLUSMN; 0.06 W m(-1) K-1 in 140-190 K) of the tetrahydrofuran (THF) clathrate hydrate is characterized by the time-domain thermoreflectance technique. The underlying heat conduction mechanism is further investigated by non-equilibrium molecular dynamics simulations. We find that trapped THF molecules do harmonic motions and behave as parts of a crystalline structure, thus playing negligible roles in thermal conductivity reduction. The large unit cell and complex cage-like host structure dominate the low thermal conductivity of the THF hydrate.

Automated summary

The tetrahydrofuran (THF) clathrate hydrate exhibits an ultra-low thermal conductivity, with the trapped THF molecules playing a negligible role in reducing thermal conductivity, which is mainly dominated by the large unit cell and complex cage-like host structure.