Mass Production of 3D Connective Graphene Networks by Fluidized Bed Chemical Vapor Deposition and Its Application in High Performance Lithium-Sulfur Battery

Rongzheng Liu,Jiaxing Chang,Xu Yang,Youlin Shao,Jian Zhao,Bing Liu,Malin Liu

doi:10.3390/nano12010150

Abstract

Three−dimensional (3D) graphene with novel nano−architectures exhibits many excellent properties and is promising for energy storage and conversion applications. Herein, a new strategy based on the fluidized bed chemical vapor deposition (FB−CVD) process was proposed to prepare 3D graphene networks (3DGNs) with various nano−architectures. Specially designed SiC−C@graphene core/shell nanoparticles were prepared taking the advantages of the FB−CVD system, and 3DGNs with hierarchical nanostructures were obtained after removing the SiC core. The 3DGNs performed well as electrodes of lithium–sulfur batteries. The C–S cathode showed good rate performance at the current density of 0.1–2.0 C, and an initial discharge capacity of 790 mAhg−1 cathode was achieved at a current density of 0.2 C. The Li−S batteries showed stabilized coulombic efficiency as high as 94% and excellent cyclic performance with an ultra low cyclic fading rate of 0.075% for the initial 280 cycles at a current density of 1.0 C. The improved electrochemical performance was ascribed to the enhanced conductivity by the connective graphene networks and the weakened shuttle effect by the special outer graphene layers. Mass production of the products was realized by the continuous FB−CVD process, which opens up new perspectives for large scale application of 3D graphene materials.

Highlights

Since its discovery in 2004, graphene has drawn increasing attention and has been intensively investigated due to its unique and excellent properties, such as huge specific surface area, high electrical conductivity and electron mobility, robust mechanical performance, good flexibility, high thermal conductivity, and efficient light absorption [1,2,3].Over the past decades, graphene has been widely explored for applications in batteries, electrochemical capacitors, catalysis, hydrogen storage, environmental remediation and sensors [4,5,6,7]
To combine the construction of 3D graphene networks (3DGNs) with hierarchical nanostructures in scientific perspective and the mass production in engineering perspective, we proposed a novel strategy by fluidized bed chemical vapor deposition (FB−CVD)
Preparation of the 3DGNs: The SiC−C@graphene nanoparticles were prepared by a fluidized bed chemical vapor deposition (FB−CVD) method

Summary

Introduction

Graphene has been widely explored for applications in batteries, electrochemical capacitors, catalysis, hydrogen storage, environmental remediation and sensors [4,5,6,7]. Due to the strong van der Waals interactions and high inter−sheet junction contact resistance, isolated graphene sheets usually undergo irreversible agglomeration. To avoid the restacking of graphene sheets, the two−dimensional (2D) graphene is generally assembled into three−dimensional (3D) architectures with ordered structures. Three−dimensional (3D) graphene enormously maintains properties of 2D graphene in bulk and enhances graphene utilization for practical applications. Studies on graphene have shown explosive growth, especially 3D graphene in the field of electrochemical energy storage [8,9,10]

Methods

Results

Conclusion