Liu Rongzheng, Zhao Jian, Yang Xu, Liu Malin, Chang Jiaxing, Shao Youlin, Liu Bing
Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China.
Nanomaterials (Basel). 2021 Dec 31;12(1):150. doi: 10.3390/nano12010150.
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 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.
具有新型纳米结构的三维（3D）石墨烯展现出许多优异性能，在能量存储和转换应用方面颇具前景。在此，我们提出了一种基于流化床化学气相沉积（FB-CVD）工艺的新策略，用于制备具有各种纳米结构的3D石墨烯网络（3DGNs）。利用FB-CVD系统的优势制备了特殊设计的SiC-C@石墨烯核壳纳米颗粒，去除SiC核后得到了具有分级纳米结构的3DGNs。3DGNs作为锂硫电池的电极表现良好。C-S阴极在0.1 - 2.0 C的电流密度下具有良好的倍率性能，在0.2 C的电流密度下实现了790 mAhg阴极的初始放电容量。锂硫电池表现出高达94%的稳定库仑效率以及优异的循环性能，在1.0 C的电流密度下，最初280个循环的超低循环衰减率为0.075%。电化学性能的改善归因于连接性石墨烯网络提高了导电性以及特殊的外层石墨烯层减弱了穿梭效应。通过连续的FB-CVD工艺实现了产品的大规模生产，这为3D石墨烯材料的大规模应用开辟了新的前景。
