Improvement of electrochemical performance by fluorinated multiwall carbon nanotubes interlayer in lithium–sulfur battery

In this paper, the effects of ordinary multiwalled carbon nanotubes (MWCNTs) interlayer and novel fluorinated carbon nanotube (F-MWCNTs) interlayer on the electrochemical performance of lithium–sulfur (Li–S) batteries were investigated. After fluorination of graphitized MWCNTs, F-WMCNTs with a core–shell structure (fluorocarbon atomic ratio C/F = 1:1) can be obtained. The surface of F-WMCNTs was fluorinated to form a fluorinated carbon structure, while the internal structure of the original MWCNTs remains. F-MWCNTs/MWCNTs and cellulose fibers form a 3D crosslinked network structure, which effectively captures polysulfides. This layer was confirmed by scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). The F-MWCNTs interlayer Li–S battery maintained specific capacities of 1026 mAh/g, 938 mAh/g, and 764 mAh/g at 1C, 2C, and 3C, respectively, showing excellent rate performance.