3D Lamellar-Structured Graphene Aerogels for Thermal Interface Composites with High Through-Plane Thermal Conductivity and Fracture Toughness

Abstract

Highlights Lamellar-structured graphene aerogels with vertically aligned and closely stacked high-quality graphene lamellae are fabricated. The superior thermally conductive capacity of the aerogel endows epoxy with a high through-plane thermal conductivity of 20.0 W m −1 K −1 at 2.30 vol% of graphene content. The nacre-like structure endows the epoxy composite with enhanced fracture toughness. Abstract Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers, the resulting nanocomposites usually exhibit low through-plane thermal conductivities, limiting their application as thermal interface materials. Herein, lamellar-structured polyamic acid salt/graphene oxide (PAAS/GO) hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by lyophilization. Subsequently, PAAS monomers are polymerized to polyimide (PI), while GO is converted to thermally reduced graphene oxide (RGO) during thermal annealing at 300 °C. Final graphitization at 2800 °C converts PI to graphitized carbon with the inductive effect of RGO, and simultaneously, RGO is thermally reduced and healed to high-quality graphene. Consequently, lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time, and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene lamellae. After vacuum-assisted impregnation with epoxy, the resultant epoxy composite with 2.30 vol% of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m −1 K −1 , 100 times of that of epoxy, with a record-high specific thermal conductivity enhancement of 4310%. Furthermore, the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness, ~ 1.71 times of that of epoxy. Electronic supplementary material The online version of this article (10.1007/s40820-020-00548-5) contains supplementary material, which is available to authorized users.

Lightweight, Flexible Cellulose-Derived Carbon Aerogel@Reduced Graphene Oxide/PDMS Composites with Outstanding EMI Shielding Performances and Excellent Thermal Conductivities

“…However, as the amount of CCA@rGO increases further, the internal rGO of CCA@rGO tends to agglomerate, which reduces the density of the thermal conductivity network inside the CCA@rGO/PDMS electromagnetic shielding composites [ 56 , 57 ]. However, with the further increase in the loading of CCA@rGO, the rGO inside CCA@rGO tends to agglomerate, which decreases the density of the thermal conductivity network inside the CCA@rGO/PDMS EMI shielding composites, thus adversely affecting the λ and α of the CCA/PDMS EMI shielding composites [ 58 ].

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Dimensionality, Function and Performance of Carbon Materials in Energy Storage Devices

“…To increase the thermal conductivity of the macroscale assembled carbons, Xin et al [ 107 ] fabricated a densely stacked porous graphene film with use of a mechanical compression method, showing an excellent thermal conductivity over 1400 W m −1 K −1 due to the substantially reduced contact thermal resistance. Furthermore, Liu et al [ 108 ] fabricated a lamellar structured 3D graphene aerogels which composed of vertically aligned and densely stacked graphene nanosheets and demonstrated an excellent out‐of‐plane thermal conductivity. When compositing with polyamic acid salt followed by a bidirectional freeze‐drying method, a superior out‐of‐plane thermal conductivity was afforded with a very high value over 20 W m −1 K −1 .…”

Development of high thermally conductive and electrically insulated epoxy nanocomposites with high mechanical performance

“…Recent developments in electronic technology have enabled the integration and miniaturization of microelectronic devices, allowing more transistors to be integrated into a single chip for better performance. [1][2][3][4][5] The increase of miniaturization, high-degree integration, and multifunctionalities of those modern devices release more heat, which will greatly affect their performance and reliability, and bring huge challenges to the development of microelectronics. [6][7][8][9] Polymer-based nanocomposites with enhanced thermal conductivity have been demonstrated as effective thermal management materials to solve those overheating issue.…”

“…In consequence, the development of polymer nanocomposites with desired mechanical performance, high thermal conductivity, and electrical insulation has attracted much attention. [4,[10][11][12][13][14][15][16][17][18] The traditional thermally conductive polymer-based nanocomposites are produced by simply adding a kind of inorganic filler, leading to poor thermal conductivity, high cost, and reduced mechanical properties, thus greatly hindering its practical application in industry. [19] Recent studies revealed that the effective method to meet this challenge of improving the thermal conductivity of polymer-based composites is to establish a three-dimensional (3D) interconnection thermal network in the polymer matrix.…”