Enhancing thermal transport efficiency in carbon composites using nanospacers

Abstract

Improved thermal transport efficiency of carbon-based composites has been achieved by inserting metallic spacers within the temperature range of 50-150 C. Al 2 O 3 , Ni, and SnO nano-particles are used as nanospacers in the graphite-like thin films, forming well-developed carbon framework. The composites show 42.5-57.7% increase in thermal conductivity (k), as compared with the pristine carbon. Among all the samples Al-inserted carbon composites exhibited the highest k value of 1128 W m À1 K À1 at 50 C.The metallic nanopowders serve not only as filler but also as connective points for creating additional path for the heat conduction, leading to highly-efficient thermal diffusion. The apparent k value is found to be an increasing function of electrical conductivity, revealing that the conduction of free electrons is analogous to the thermal transport. The present work provided useful information concerning the thermal conduction and heat dissipation efficiencies of carbon-based composites, benefiting the design of thermal devices, e.g., heat sink and heat exchanger.

Thermal Transport on Graphene-Based Thin Films Prepared by Chemical Exfoliations from Carbon Nanotubes and Graphite Powders

“…This finding reveals that the efficiency of thermal transport of heat sinks depends not only on the intrinsic thermal properties (e.g., intrinsic k value), but also on the physical and mechanical preparation method (e.g., compressive treatment). Using the same test platform, the GN-G2 sample was found to possess higher k value than the other designs of heat sinks such as CNT/GN hybrid (1991 W/m K at 323 K) [2] and Al 2 O 3 -coated graphite (1128 W/m K at 323 K) [3]. It can be concluded that the selection of carbon materials is the major contributor to the thermal conduction.…”

“…Both CNTs and GNs have been demonstrated to display high theoretical thermal conductivities (k), thus heralding beneficial applications in heat exchangers and thermal management systems. It is generally recognized that low-temperature operation and efficient heat dissipation are key factors in determining the lifetime and the speed in current electronic and photonic devices [1,3]. Industrially, the most commonly-used materials for heat sinks are still Al and Cu, which possess lower k values and higher true densities, as compared to carbonaceous materials.…”