3D Graphene Fibers Grown by Thermal Chemical Vapor Deposition

Abstract

3D assembly of graphene sheets (GSs) is important for preserving the merits of the single-atomic-layered structure. Simultaneously, vertical growth of GSs has long been a challenge for thermal chemical vapor deposition (CVD). Here, vertical growth of the GSs is achieved in a thermal CVD reactor and a novel 3D graphene structure, 3D graphene fibers (3DGFs), is developed. The 3DGFs are prepared by carbonizing electrospun polyacrylonitrile fibers in NH and subsequently in situ growing the radially oriented GSs using thermal CVD. The GSs on the 3DGFs are densely arranged and interconnected with the edges fully exposed on the surface, resulting in high performances in multiple aspects such as electrical conductivity (3.4 × 10 -1.2 × 10 S m ), electromagnetic shielding (60 932 dB cm g ), and superhydrophobicity and superoleophilicity, which are far superior to the existing 3D graphene materials. With the extraordinary properties along with the easy scalability of the simple thermal CVD, the novel 3DGFs are highly promising for many applications such as high-strength and conducting composites, flexible conductors, electromagnetic shielding, energy storage, catalysis, and separation and purification. Furthermore, this strategy can be widely used to grow the vertical GSs on many other substrates by thermal CVD.

3D Laser Scribed Graphene Derived from Carbon Nanospheres: An Ultrahigh‐Power Electrode for Supercapacitors

“…[35] The presence of the 2D peak is evidence for the formation of stacked layers of graphene. [36] With increasing laser power from 3.0% to 5.5%, I D /I G ratio decreases first and reaches a minimum of 0.398 at the laser power of 4.5% ( Figure 1C). When laser power increases from 5.0% to 5.5%, the I D /I G ratio increases, which suggests that at these high powers, the CNS-LSG is destroyed by laser.…”

“…The Raman spectra show three main peaks: G peak around 1580 cm −1 which is commonly assigned to graphitic carbon, D peak around 1350 cm −1 which results from lattice defects and 2D peak an overtone generally present at 2700 cm −1 . The presence of the 2D peak is evidence for the formation of stacked layers of graphene . With increasing laser power from 3.0% to 5.5%, I D / I G ratio decreases first and reaches a minimum of 0.398 at the laser power of 4.5% (Figure C).…”

Graphene‐Based Fibers: Recent Advances in Preparation and Application

“…h) SEM image of the resulting 3D graphene fibers. g,h) Reproduced with permission . Copyright 2018, Wiley‐VCH.…”

“…Flexible SCs based on the nonwoven fabric of improved GBFs exhibited a high areal capacitance of 1060 mF cm −2 and the capacitance could be further enhanced to 7398 mF cm −2 by overlaying serval layers of these fabrics. Alternatively, a 3D GBF assembly was obtained by vertically growing graphene nanosheet on carbon nanofibers via CVD (Figure g,h) and it featured high electrical conductivity (3.4 × 10 4 to 1.2 × 10 5 S m −1 ), rich nanosized pores and lightweight. These features ensure the 3D GBF assembly with an ultrahigh specific shielding effectiveness (SSE/ t ) of 60 932 dB cm 2 g −1 .…”

“…c,d) Morphologies of the GBF synthesized by CVD methods. c,d) Adapted with permission . Copyright 2018, Wiley‐VCH.…”