A Nitrogen‐Rich 2D sp²‐Carbon‐Linked Conjugated Polymer Framework as a High‐Performance Cathode for Lithium‐Ion Batteries

Abstract

A two‐dimensional (2D) sp2‐carbon‐linked conjugated polymer framework (2D CCP‐HATN) has a nitrogen‐doped skeleton, a periodical dual‐pore structure and high chemical stability. The polymer backbone consists of hexaazatrinaphthalene (HATN) and cyanovinylene units linked entirely by carbon–carbon double bonds. Profiting from the shape‐persistent framework of 2D CCP‐HATN integrated with the electrochemical redox‐active HATN and the robust sp2 carbon‐carbon linkage, 2D CCP‐HATN hybridized with carbon nanotubes shows a high capacity of 116 mA h g−1, with high utilization of its redox‐active sites and superb cycling stability (91 % after 1000 cycles) and rate capability (82 %, 1.0 A g−1 vs. 0.1 A g−1) as an organic cathode material for lithium‐ion batteries.

2D Poly(arylene vinylene) Covalent Organic Frameworks via Aldol Condensation of Trimethyltriazine

“…[10] While promising optoelectronic properties have been reported in some of these, [11] the highly polarized C-N links might limit the charge carrier delocalization (which marginalizes semiconducting applications of 1D conjugated polyazomethines). [13] These materials are 2D analogues of poly-(phenylene cyanovinylene)s CN-PPV [14] that have been used as semiconducting polymers in organic light emitting diodes [15] although not as commonly as the parent, noncyanated PPVs. Very recently,s everal groups have reported cyanovinylene linked COFs prepared by Knoevenagel condensation of multidentate benzylcyanides (acting as CÀHa cids) with dialdehydes.…”

“…[12] New efficient methods for preparing C À Clinked 2D polymers are thus highly desirable. [2b] Recognizing the remarkable advantages of these first sp 2 -carbon linked COFs, [13] we also point out some limitations such as out-of-plane distortions caused by steric clash of the CN group with the adjacent aromatic rings and increased reactivity of the polarized cyanovinylene groups (hydrolysis,M ichael addition, intramolecular cyclization by electrophilic attack of CN on the aromatic rings [14] ). [13] These materials are 2D analogues of poly-(phenylene cyanovinylene)s CN-PPV [14] that have been used as semiconducting polymers in organic light emitting diodes [15] although not as commonly as the parent, noncyanated PPVs.…”

Designed Synthesis of a 2D Porphyrin‐Based sp2Carbon‐Conjugated Covalent Organic Framework for Heterogeneous Photocatalysis

“…[9][10][11][12][13][14] Thanks to the effort of many groups,s everal types of COFs with stable linkages,s uch as amide, [9,10] azine, [11] thiazole, [12] and heteroaromatic dioxin, [13] have been reported. [9][10][11][12][13][14] Thanks to the effort of many groups,s everal types of COFs with stable linkages,s uch as amide, [9,10] azine, [11] thiazole, [12] and heteroaromatic dioxin, [13] have been reported.…”

“…[14] Fore xample,J iang et al reported that a2Dpyrene-based sp 2 c-COF shows interesting magnetic properties [14d] and can be stable upon exposure to air for over one year. [14] This could be explained by the low reversibility of the formation of C = Cbonds and the synthesis of sp 2 carbon-linked COFs has been proven to be ab ig challenge. [14b] However,a lthough these sp 2 carbonlinked COFs can be very stable,only very few examples have been reported until now.…”

“…[14c] Very recently,F eng et al demonstrated that 2D CCP-HATN can serve as an organic cathode material for lithium-ion batteries with superb cycling stability (91 % after 1000 cycles). [14,15] Theu tilization of 2D COFs as heterogeneous photocatalysts has attracted al ot of attention recently,m ainly due to their intrinsic properties such as extended p-conjugated networks and aligned pore channels. [14] This could be explained by the low reversibility of the formation of C = Cbonds and the synthesis of sp 2 carbon-linked COFs has been proven to be ab ig challenge.…”