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Spatial Effects between Two 3D Self‐Supported Carbon‐Nanotube‐Based Skeleton as Binder‐Free Cathodes for Lithium‐Sulfur Batteries
Author(s) -
Guo Lianzhen,
Li Xinyan,
Xu Zhuijun,
Zhou Shenglin,
Zhang Xiaohua,
Ni Jiangfeng,
Cheng Yajun,
Yang Zhaohui
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202002090
Subject(s) - materials science , carbon nanotube , sulfur , cathode , nanotube , faraday efficiency , composite material , lithium–sulfur battery , electrochemistry , coating , chemical engineering , nanotechnology , electrode , chemistry , engineering , metallurgy
In this manuscript a deep comparison of the spatial effect is conducted between vertically‐aligned carbon nanotube array (CNTA) and 3D inter‐connected carbon nanotube sponge (CNTS) based self‐supported and adhesive free cathode material for lithium‐sulfur battery. Melt impregnation (M–CNTA/S and M‐CNTS/S) and solution penetration (S‐CNTA/S and S‐CNTS/S) methods are separately carried out to introduce sulfur into two carbon nanotube‐based matrix. Besides, random distributed carbon nanotube powders (RCNT)‐based cathode made through a slurry coating process is also prepared for comparison. As a result, the aligned CNTA skeleton has the most efficient transfer paths and regular nanometer‐sized gaps, which greatly benefit the directional transmission of electrons, better rate performance, smaller cell resistance and long cyclic stability. Especially, the cell made by M‐CNTA/S delivers an outstanding high‐rate performance of 3 C −859.3 mAh g −1 , 5 C −833.1 mAh g −1 and 10 C −702.8 mAh g −1 , with a capacity retention of 77 % and coulombic eciency (∼100 %) after 200 cycles at a rate of 3 C. Meanwhile, the interconnected CNTS has a larger pore diameter and 3D conductive network, which benefits higher sulfur loading and electrochemical activity of sulfur. In particular, the M‐CNTS/S with a sulfur content up to 60 wt %, achieves an impressive multiplier performance of 0.5 C 1285 mAh g −1 , 1 C 1030 mAh g −1 and 3 C 900 mAh g −1 . The retention of the capacity reaches around 88 % after 100 charge‐discharge cycles at 3 C. The current observation reveals the crucial effects from the spatial structure and sulfur impregnation method on the performance of carbon nanotube/sulfur (C/S)‐based cathodes for lithium‐sulfur batteries, which serves as important guidance for the development of high‐performance cathode materials.