Taming Polysulfides in an Li-S Battery With Low-Temperature One-step Chemical Synthesis of Titanium Carbide Nanoparticles From Waste PTFE.

Suyao Liu,Guang Hu,Jinlong Jiang,Jun Luo,Yuting Xiong,Zhe Chen,Guofeng Rui,Tao Mei,Liangbiao Wang,Kailong Zhang

doi:10.3389/fchem.2021.638557

Abstract

In this work, titanium carbide (TiC) nanoparticles have been successfully synthesized at much lower temperatures of 500°C using cheaper starting materials, such as waste polytetrafluoroethylene (PTFE) (carbon source) and titanium and metallic sodium, than the traditional carbothermal reduction of TiO2 at 1,800°C. An XRD pattern proved the formation of face-centered cubic TiC, and TEM images showed the obtained TiC nanoparticles with an average size of approximately 50 nm. In addition, the separator coated with TiC nanoparticles as an active material of interlayer effectively mitigates the shuttling problem by taming the polysulfides in Li–S batteries compared with a traditional celgard separator. The assembled cell realizes good cycling stability with 501 mAh g−1 and a low capacity fading of 0.1% per cycle after 300 cycles at 1 C due to high utilization of the sulfur-based active species.

Highlights

Transition metal carbides have recently received much attention for their important applications in the mechanical and aerospace industries (Das et al, 2002; Rasaki et al, 2018)
We have developed a new method to synthesize titanium carbide (TiC) nanoparticles by using waste PTFE as a carbon source at a low temperature of 500°C
The refined lattice parameter a 4.3253 Å is extracted from the XRD pattern, which is close to the literature value of a 4.3270 Å (JCPDS card No 65-0242)

Summary

INTRODUCTION

Transition metal carbides have recently received much attention for their important applications in the mechanical and aerospace industries (Das et al, 2002; Rasaki et al, 2018). In an Li–S battery, the synthesized TiC can be used to enhance the cycling performance through the strong polar binding interactions with sulfur species and can better suppress the diffusion of lithium polysulfides (LiPS) compared with other materials (Zhang et al, 2016; Cui et al, 2018; Zhang et al, 2018; Zhang et al, 2019). The strong chemical sorption and high electrical conductivity make it an ideal sulfur host for Li–S batteries. In the TiC–TiO2/S composite, TiC can chemically bond with polysulfides and improve the electrical conductivity of the assembled cells (Cui et al, 2019; Geng et al, 2021). The cycling performance and rate performance were based on the galvanostatic test (1 C 1,675 mA g−1)

RESULTS AND DISCUSSION

CONCLUSION

DATA AVAILABILITY STATEMENT