Mechanochemical strategy assisted morphology recombination of COFs for promoted kinetics and LiPS transformation in Li–S batteries

Abstract

A covalent organic frameworks (COFs) material with regular pores and stable structure can be used as the host of lithium-sulfur batteries to improve battery kinetics and polysulfides conversion. Herein, we designed and synthesized two kinds of rod-liked bulk COFs by adjusting different pore sizes (COF-BTD and COF-TFB), unfortunately, the active sites masking and sluggish kinetics have not met our expectations. Generally, the available layered COFs prepared from mechanochemical can expose abundant active sites and favorable kinetics than bulk COFs. Thus, simple mechanical ball milling is applied to activate the above COFs (M-COFs group). It is worth noting that layered R–COF–BTD is directly synthesized from rod-liked precursors by simple morphological reconstruction. A series of characterization methods are used to systematically explore the advantages of the group of M-COFs@S electrodes in the cycling process, including the effects of specific morphology on the kinetics and transformation of polysulfides. Our research provides a feasible plan for the development and selection of the host material of lithium-sulfur batteries.