Lightweight Cellulose Nanofibril/Reduced Graphene Oxide Aerogels with Unidirectional Pores for Efficient Electromagnetic Interference Shielding

Abstract

Lightweight and compressible aerogels have been widely considered as promising materials for electromagnetic interference (EMI) shielding. Herein, a lightweight cellulose nanofibril/reduced graphene oxide carbon aerogel fabricated by unidirectional freeze‐drying and pyrolysis processes is reported. The results show that the aerogels with unidirectionally aligned pores possess better compression resilience and EMI shielding performance in the radial direction. The unidirectional aerogel with low density (≈0.0058 g cm−3) exhibits a high EMI shielding effectiveness (SE) of ≈33 dB at 8.2–12.4 GHz and a specific EMI SE of 5759 dB cm3 g−1. Therefore, the fabricated aerogel demonstrates a promising potential in the field of next‐generation EMI shielding materials.

Facile preparation of large-scale expanded graphite/polydimethylsiloxane composites for highly-efficient electromagnetic interference shielding

“…The remarkable electrical conductivity and highly anisotropic spatial structure are critical factors affecting the electromagnetic shielding effectiveness of a material. 30,32 The EMI shielding capabilities of HOGF/PDMS composites were characterized in a frequency range of 8.2 to 12.4 GHz, which is frequently adopted in the elds of military and communication. The EMI shielding efficiency can be dened as the logarithmic ratio of incoming power to transmitted power and expressed in dB.…”

“…31 In addition, the oriented structure is benecial for the formation of conducting paths, which will lead to an improvement in electrical conductivity and EMI shielding efficiency. 32 Various strategies including unidirectional/bidirectional freeze casting, 33,34 self-assembly, 35 3D printing, 35,36 electrical/ magnetic eld assistance, 33,37 and chemical vapor deposition methods 38 have been employed to construct oriented conducting networks. Unfortunately, these fabrication approaches usually involve complex preparation processes, special production equipment and large energy consumption, which are the challenges faced by manufacturing industries.…”

“…31 In addition, the oriented structure is beneficial for the formation of conducting paths, which will lead to an improvement in electrical conductivity and EMI shielding efficiency. 32…”

Structured Ultra‐Flyweight Aerogels by Interfacial Complexation: Self‐Assembly Enabling Multiscale Designs

“…In fact, it is well known that rGO aerogels lack any mechanical properties and are fragile as a direct consequence of the weak interfaces formed by nanosheets, even at high concentrations. [58] This limits practical applications of traditional rGO aerogels. Figure S15 (Supporting Information) confirms that the traditional rGO aerogels, derived from freeze-drying of W-GO 1.0 vol% suspension, do not recover their shape after compression.…”

Hydrogel-based composites beyond the porous architectures for electromagnetic interference shielding

“…Multiple reflections of the incident EMWs to the channel walls will be enhanced if the EMWs propagate perpendicular to the aligned pore channels [25,88]. Meanwhile, the anisotropic pore structures afford [89][90][91] stronger compressive properties in the specific direction [92][93][94][95].…”