Porous Dithiine-Linked Covalent Organic Framework as a Dynamic Platform for Covalent Polysulfide Anchoring in Lithium–Sulfur Battery Cathodes

• DOI: 10.1021/jacs.2c02346
• Publication Date: 2022-05-11T12:43:33Z
• Authors: Sattwick Haldar; Mingchao Wang; Preeti Bhauriyal; Arpan Hazra; Arafat H. Khan; Volodymyr Bon; Mark A. Isaacs; Ankita De; Leonid Shupletsov; Tom Boenke; Julia Grothe; Thomas Heine; Eike Brunner; Xinliang Feng; Renhao Dong; Andreas Schneemann; Stefan Kaskel
• Keywords: Polysulfide; Moiety; Covalent organic framework; Dynamic Covalent Chemistry

Dithiine linkage formation via a dynamic and self-correcting nucleophilic aromatic substitution reaction enables the de novo synthesis of porous thianthrene-based two-dimensional covalent organic framework (COF). For first time, this organo-sulfur moiety is integrated as structural building block into crystalline layered COF. The structure new material deviates from typical planar interlayer π-stacking COF to form undulated layers caused by bending along C-S-C bridge, without loss aromaticity crystallinity overall structure. Comprehensive experimental theoretical investigations model compound, featuring thianthrene moiety, suggest partial delocalization sulfur lone pair electrons over backbone decreasing band gap promoting redox activity. Postsynthetic sulfurization allows for direct attachment polysulfides carbon afford molecular-designed cathode lithium-sulfur (Li-S) batteries with minimized polysulfide shuttle. fabricated coin cell delivers nearly 77% initial capacity even after 500 charge-discharge cycles at mA/g current density. This novel in chemistry an ideal motif designing materials studying advanced electrode Li-S on molecular level.