A Highly Conductive COF@CNT Electrocatalyst Boosting Polysulfide Conversion for Li-S Chemistry

The catalysis of covalent organic frameworks (COFs) in Li-S chemistry is largely blocked by a weak chemical interaction and low conductivity. Herein, a new kind of diketopyrrolopyrrole (DPP)-based COF is in situ fabricated onto the carbon nanotube (CNT) surface (denoted as COF@CNT) to uncover the electrocatalysis behavior by its strong chemical interaction and highly conductive property. We declare that the electrocatalytic activity of DPP-COF can be maximized by introducing an appropriate content of CNT (66 wt %); the analyses including density functional theory calculations, X-ray photoelectron spectroscopy, Fourier transform infrared, and Raman show that the DPP moiety can mediate the conversion of polysulfides contributed by a CO/C-O bonding conversion. Hence, the modified battery shows a 0.042% decay rate over 1000 cycles and achieves a desirable capacity of 8.7 mAh cm-2 with 10 mg cm-2 sulfur loading and lean electrolyte (E/S = 5). This work will inspire the rational design of COF@support hybrids for various electrocatalysis applications.