Affiliation:
1. Center for Micro Nano Systems School of Information Science and Technology (SIST) Fudan University 200433 Shanghai P. R. China
2. SPECIFIC‐IKC Department of Materials Science and Engineering Faculty of Science and Engineering Swansea University SA1 8EN Swansea UK
3. College of Engineering Swansea University SA1 8EN Swansea UK
4. MACH 1 Faculty of Science and Engineering Swansea University SA1 8EN Bay Campus Swansea UK
5. C6 Tech Unit 3 Oxwich Court SA6 8RA Valley way, Enterprise Park Swansea UK
Abstract
AbstractCarbon‐based materials are becoming a promising candidate for thermoelectricity. Among them, graphene shows limited scope due to its ultra‐high thermal conductivity (κ). To develop graphene‐based thermoelectric devices, reduction of κ is highly desired while maintaining reasonably high electrical conductivity (σ). Herein, multiwalled carbon nanotubes (MWCNTs) and carbon black (CB) fillers are added into few layered graphene (FLG) to produce all‐carbon composites yielding ultra‐low thermal conductivity (κ) desired for thermoelectric applications. The novel preparation method of pristine FLG realizes very low κ of 6.90 W m−1 K−1 at 1248 K, which further reduces to 0.57, 0.81, and 0.69 W m−1 K−1 at the same temperature for FLG + MWCNTs, FLG + CB, and FLG + MWCNTs + CB, respectively. As‐prepared FLG composites also maintain reasonably high σ, whilst the Seebeck coefficient shows over a factor of five improvement after the inclusion of carbon‐based fillers. Consequently, the power factor (PF) is significantly improved. The ultralow κ is attributed to the increased thermal boundary resistance among graphene sheet boundaries. The realization of ultralow κ with simultaneous improvement in Seebeck coefficients and relatively small drops in σ with a facile and unique synthesis technique, highlight the potential of these composites.
Funder
National Natural Science Foundation of China
Engineering and Physical Sciences Research Council
European Regional Development Fund
Subject
Electronic, Optical and Magnetic Materials