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

Covalent Organic Framework/Aluminum Oxide Composite Nanosheets as a Separator for High-Performance Lithium–Sulfur Batteries

“…In this work, we designed and synthesized a multifunctional barrier coating as a separator in Li–S batteries (Scheme ), which was prepared through in situ growth of a sulfonic acid-functionalized covalent organic framework (SO 3 –COF) on an aluminum oxide substrate, generating a composite material named as Al 2 O 3 -G-COF SO 3 . Compared with conventional separators, the Al 2 O 3 -G-COF SO 3 composite has several significant advantages: (1) the ordered open channels of COFs provide express routes for the rapid transportation of Li + , significantly reducing the energy barrier of ion diffusion; (2) the existence of sulfonic acid groups in the composite with its skeleton structure being ion-selective, which can effectively suppress the shuttle effect caused by polysulfide migration, promote the migration of Li + , and enhance the efficiency of Li–S batteries; − (3) the addition of alumina greatly improves the wettability of the separator to the electrolytes, which increases the Li + mobility and effectively enhances the chemisorption of polysulfides; − and (4) COFs are made up of lightweight elements such as C, H, N, O, B, and so on, which are favorable for improving the total energy density of batteries . We anticipate that the application of this composite separator in Li–S batteries should significantly enhance battery performance and extend the battery cycle life, thereby providing new strategies for designing the next generation of Li–S batteries.…”

“…The permanent porosity of COFs can confine polysulfides physically in the cathode region and facilitate the conduction of lithium ions, while the abundant heteroatoms in building blocks and linkages can interact with sulfur species through sulfiphilic, lithiophilic, and electrostatic interactions, thereby resulting in a high sulfur utilization efficiency and cycling stability. Recently, there have been several examples demonstrating the preponderance of COFs as separators for enhancing the electrochemical performance of Li–S batteries. − For example, Cao et al developed a 2D lithiated COF nanosheet (Li-CON) layer, which has ordered lithiated sites in the intrinsic nanopores of Li-CON . These lithiated sites can greatly facilitate the transport of lithium ions, owing to the low diffusion barrier.…”

Combination of covalent organic frameworks (COFs) and polyoxometalates (POMs): the preparation strategy and potential application of COF–POM hybrids

“…[11][12][13] As reported, COFs possess a wide range of potential applications, including gas storage and separation, 14,15 catalysis, 16,17 sensing, 18,19 advanced electronics, 20,21 and drug delivery. 22,23 They are also extremely lightweight and have a high surface area, making them attractive for use in energy storage systems such as batteries 24,25 and supercapacitors. 26,27 In recent studies, scientists have thoroughly investigated the topological semimetal and higher-order topological insulator properties of COFs through quantum chemical calculations, which are important for a deeper understanding of COFs and for the design and development of their properties.…”