High cross‐plane thermoelectric performance of carbon nanotube sponge films

Abstract

In this study, carbon nanotubes (CNTs) are packed to prepare CNT films with chemical-vapor-deposition method and vacuum filtration, then the films are piled up to make anisotropic three-dimensional CNT sponges (CNS). This sponge is demonstrated to be a promising thermoelectric material. Its cross-plane figure of merit (ZT⊥) is much larger than that along the in-plane direction (ZT∥), and the maximum ZT⊥ is about 2.99 × 10−3 at 290 K. This high ZT⊥ is attributed to small thermal conductivity of CNS in ⊥ direction, because of small size of pores in CNS and the low k of CNTs along the radial direction.