Abstract
Reduced graphene oxide (rGO) aerogels with a three-dimensional (3D) interconnected network provides continuous heat transport paths in multi-directions. However, the high porosity of rGO aerogels commonly leads to very low thermal conductivity (TC), and defects and grain boundaries of rGO sheets result in a high extent of phonon scattering, which is far from satisfying the requirement of thermal interface materials (TIMs). Here, a compressible graphitized-rGO/polyimide (g-rGO/PI) aerogel was prepared by the ice-template method and “molecular welding” strategy. The regular cellular structure and closely packed cell walls bring the g-rGO/PI aerogel high compressibility, which made the aerogel can maintain the continuous thermal transport paths well even in highly compacted status. The rGO sheets in the cell wall surface are welded up by g-PI during imidization and graphitization treatment, providing efficient channels for phonon transportation in the 3D network. The g-rGO/PI aerogel in a compressive strain of 95% has a high TC in the plane of 172.5 W m−1k−1 and a high TC through the plane of 58.1 W m−1k−1, which is superior to other carbon-based TIMs previously reported.
Highlights
With the rapid development of portable devices and high-power electronics, severe heat dissipation issues greatly threaten the reliability and performance of the high-tech devices [1,2,3]
Horizontal graphene papers are commonly used as the heat spreading components due to their high in-plane thermal conductivity (TC) values (1100–3200 W m−1K−1 [7,8,9,10,11])
The excellent thermal transport performances only along a one-dimensional direction are attributed to the van der Waals forces between graphene layers hindering the transport of phonons leading to thermal resistance [20]
Summary
With the rapid development of portable devices and high-power electronics, severe heat dissipation issues greatly threaten the reliability and performance of the high-tech devices [1,2,3]. The excellent thermal transport performances only along a one-dimensional direction are attributed to the van der Waals forces between graphene layers hindering the transport of phonons leading to thermal resistance [20] These graphene-based TIMs reported in previous literatures [7,8,9,10,11,12,13,14,15,16,17,18] are far from satisfying the requirement in advanced TIMs for portable devices and high-power electronics. PI transforms into the graphitic structure and integrates with rGO sheets, providing a channel for phonon transmission and leading an enhancement of thermal transport performances
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