Fabrication of a Covalent Triazine Framework Functional Interlayer for High-Performance Lithium-Sulfur Batteries.

Ben Hu,Xiaogang Zhang,Chong Xu,Peng Li,Hui Dou,Derong Luo,Zengjie Fan,Bing Ding

doi:10.3390/nano12020255

Ben Hu, Xiaogang Zhang + Show 6 more

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https://doi.org/10.3390/nano12020255

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Abstract

The shuttling effect of polysulfides is one of the major problems of lithium–sulfur (Li–S) batteries, which causes rapid capacity fading during cycling. Modification of the commercial separator with a functional interlayer is an effective strategy to address this issue. Herein, we modified the commercial Celgard separator of Li–S batteries with one-dimensional (1D) covalent triazine framework (CTF) and a carbon nanotube (CNT) composite as a functional interlayer. The intertwined CTF/CNT can provide a fast lithium ionic/electronic transport pathway and strong adsorption capability towards polysulfides. The Li–S batteries with the CTF/CNT/Celgard separator delivered a high initial capacity of 1314 mAh g−1 at 0.1 C and remained at 684 mAh g−1 after 400 cycles−1 at 1 C. Theoretical calculation and static-adsorption experiments indicated that the triazine ring in the CTF skeleton possessed strong adsorption capability towards polysulfides. The work described here demonstrates the potential for CTF-based permselective membranes as separators in Li–S batteries.

Highlights

covalent triazine framework (CTF)/carbon nanotube (CNT) can provide a fast lithium ionic/electronic transport pathway and strong adsorption capability towards polysulfides
A CTF/CNT/Celgard separator was prepared by vacuum filtering the mixed dispersion of CTF, CNT, and polyvinylidene difluoride (PVDF) on the commercial Celgard separator, which was used for assembling the Li–S batteries (Figure 1b)
CNT, the CTF powders dropped off the separators

Summary

Introduction

CTF/CNT can provide a fast lithium ionic/electronic transport pathway and strong adsorption capability towards polysulfides. To reduce the shuttling effect of polysulfides, tremendous efforts have been devoted to developing nanostructured sulfur hosts, such as carbon-based materials, conductive polymers, transition metal oxides, and their composites [7,8,9,10,11,12,13]. These sulfur–host materials can enhance the polysulfide retention by physically confining the polysulfide intermediates in the pores. Nanomaterials 2022, 12, 255 designing light-weight interlayers with strong capture ability towards polysulfides is highly desired for achieving high-performance Li–S batteries

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