Highly Processable Covalent Organic Framework Gel Electrolyte Enabled by Side‐Chain Engineering for Lithium‐Ion Batteries

Abstract

Although covalent organic frameworks (COFs) with agraphene-like structure present unique chemical and physical properties,t hey are essentially insoluble and infusible crystalline powders with poor processability,h indering their further practical applications.H ow to improve the processability of COF materials is am ajor challenge in this field. In this contribution, we proposed ag eneral side-chain engineering strategy to construct ag el-state COF with high processability. This method takes advantages of large and soft branched alkyl side chains as internal plasticizers to achieve the gelation of the COF.W es ystematically studied the influence of the length of the side chain on the COF gel formation. Benefitting from their machinability and flexibility,this novel COF gel can be easily processed into gel-type electrolytes with specific shape and thickness,w hich were further applied to assemble lithium-ion batteries that exhibited high cycling stability.

Tailoring the interaction of covalent organic framework with the polyether matrix toward high‐performance solid‐state lithium metal batteries

“…Various strategies have been raised to promote the performance of PEO‐based solid‐state electrolytes, such as inorganic fillers, 33,36,37 additives, 24,38 and porous frameworks 39 . As an upcoming crystalline material, covalent organic frameworks (COFs) permit the atomically precise integration of organic units into an extended structure with periodic skeletons and ordered nanopores, 40–43 and have been deemed as a promising modifiable platform to facilitate the fast ion transport in solid‐state electrolytes 44–47 …”

“…39 As an upcoming crystalline material, covalent organic frameworks (COFs) permit the atomically precise integration of organic units into an extended structure with periodic skeletons and ordered nanopores, [40][41][42][43] and have been deemed as a promising modifiable platform to facilitate the fast ion transport in solid-state electrolytes. [44][45][46][47] Herein, vinyl-functionalized covalent organic frameworks (V-COFs) are rationally designed and grafted with ether-based electrolytes via the direct in situ polymerization affording solid-state electrolytes, which are denoted as poly(ethylene glycol) dimethacrylate/V-COFs (PDM/V-COFs). The prepared V-COF can not only reduce the crystallinity and decrease the glass transition temperature but also improve the mechanical strength of the polyether matrix.…”

Covalent Organic Framework-Derived Quasi-Solid Electrolyte for Low-Temperature Lithium-Ion Battery

“…Recently, specific groups or chemical bonds were chosen and introduced into COF structures. For instance, poly­(ethylene oxide) (PEO) chains were incorporated into the inner space of two-dimensional (2D) COFs via a postsynthetic modification strategy to facilitate fast Li + transport . Besides, a series of ICOFs were designed as solid Li-ion electrolytes, and ionic conductivity is improved by electron-withdrawing substituents weakening ion-pair interactions .…”

Molecular identification and quantification of defect sites in metal-organic frameworks with NMR probe molecules

“…In addition, our method provides a reliable way to quantify the density of defect sites, which comes together with the molecular details of local pore environments. The comprehensive solid-state NMR strategy can be of great value for a better understanding of MOF structures and for guiding the design of MOFs with desired catalytic or adsorption properties.Metal-organic frameworks (MOFs) are an emerging class of porous materials that have enormous potentials in gas separation 1-4 , catalysis 5-10 , drug delivery [11][12][13][14][15] , and energy storage [16][17][18][19] . Typically, MOFs are viewed as crystalline lattices with accessible regular-shaped pores.…”

“…Metal-organic frameworks (MOFs) are an emerging class of porous materials that have enormous potentials in gas separation 1-4 , catalysis 5-10 , drug delivery [11][12][13][14][15] , and energy storage [16][17][18][19] . Typically, MOFs are viewed as crystalline lattices with accessible regular-shaped pores.…”