Controllable Fe ion-anchored graphene heterostructures for robust and highly thermal conductive cellulose nanofiber composites

Bo Shan,Yuzhu Xiong

doi:10.1007/s10570-021-04202-0

Abstract

Developing the polymer-based thermal interface materials (TIMs) is one of the most promising approaches to address heat accumulation along with the functionalization, integration, and miniaturization of modern electronics, while it is still a great challenge to balance the thermal conductivity and mechanical properties. In this article, Fe ion-anchored graphene (FeG) is successfully fabricated by a facile in situ Fe reduction of graphene oxide (GO) approach, and then cellulose nanofibers (CNFs)/FeG composites are prepared by vacuum-assisted filtration. FeG exhibits excellent dispersion and exfoliation in CNFs/FeG composites, due to the strong interfacial interaction between CNFs and FeG, such as hydrogen bonds and “Fe–O” complex binding. Thus, CNFs/FeG composite has the largely improved thermal conductivity up to 30.2 W/mK at FeG content of 50 wt%, which is substantially increased by 1160% in comparison with that of pure CNFs. In addition, the mechanical performances of CNFs/FeG-50 are unexpectedly simultaneously enhanced to 244 MPa for tensile strength, 4.10% for elongation at break, and 9.5 GPa for Young’s modulus, outperforming pure CNFs with increase of 137%, 33%, and 121%, respectively. This study provides a significant strategy for the design and construction of high thermal conductivity and high-performance polymeric TIMs in flexible and portable electronics.Graphic Abstract

Highlights

Heat accumulation causes serious efficiency and safety issues in rapidly growing fields, such as aerospace, 5G communication, electric vehicles, and sophisticated equipment manufacturing (Song et al 2018; Ren et al 2020; Chen et al 2017)
With the further increasing Fe ion-anchored graphene (FeG) content to 50 wt%, the thermal conductivity is sharply enhanced to 30.2 W/mK, showing the enhancement of 1160% in comparison with that of pure cellulose nanofiber (CNF), due to the complete thermal conductive paths built by the connection of FeG sheets
The Raman and FTIR spectra clearly reveal that FeG is effectively reduced, and Fe ions are tightly anchored on FeG sheets via strong “functional groups and the strong “Metal–Oxygen” (Fe-O)” complex bonds

Summary

Introduction

Heat accumulation causes serious efficiency and safety issues in rapidly growing fields, such as aerospace, 5G communication, electric vehicles, and sophisticated equipment manufacturing (Song et al 2018; Ren et al 2020; Chen et al 2017). To realize the high-thermal conductivity (K > 10 W/mK) for composite materials, the design of 3D interconnection thermal conduction paths is regarded as the key factors, which is in favor of optimum utilization of finite filler. A superb thermally conducting filler, has been attracting the great interest of many researchers, due to its excellent thermal conductivity (5300 W/mK), high specific surface area and high aspect ratio (Song et al 2018; Balandin et al 2008; Duan et al 2020). Wu et al revealed a significant synergistic effect between the aligned graphene nanosheets (GNs) and 3D interconnected graphene foam (GF), which plays a key role in the formation of thermal percolation networks, leading to the thermal conductivity of 11.16 W/mK at 10.27 vol% (Wu et al 2019)

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