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

Pengfei Liu; Xiaofeng Li; Peng Min; Xiyuan Chang; Chao Shu; Yun Ding; Zhong-Zhen Yu

doi:10.1007/s40820-020-00548-5

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

Nanomicro Lett. 2020 Nov 11;13(1):22. doi: 10.1007/s40820-020-00548-5.

Authors

Pengfei Liu^{1

2}, Xiaofeng Li³, Peng Min¹, Xiyuan Chang², Chao Shu¹, Yun Ding¹, Zhong-Zhen Yu^{4

5}

Affiliations

¹ Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
² State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China.
³ Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China. xfli@mail.buct.edu.cn.
⁴ State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China. yuzz@mail.buct.edu.cn.
⁵ Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, People's Republic of China. yuzz@mail.buct.edu.cn.

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. formula image

Electronic supplementary material: The online version of this article (10.1007/s40820-020-00548-5) contains supplementary material, which is available to authorized users.

Keywords: Anisotropic aerogels; Epoxy composites; Fracture toughness; Graphene; Thermal conductivity.