Incorporating Conducting Polypyrrole into a Polyimide COF for Carbon‐Free Ultra‐High Energy Supercapacitor

Abstract

Redox‐active covalent organic frameworks (COFs) store charges but possess inadequate electronic conductivity. Their capacitive action works by storing H+ ions in an acidic electrolyte and is typically confined to a small voltage window (0–1 V). Increasing this window means higher energy and power density, but this risks COF stability. Advantageously, COF's large pores allow the storage of polarizable bulky ions under a wider voltage thus reaching higher energy density. Here, a COF–electrode–electrolyte system operating at a high voltage regime without any conducting carbon or redox active oxides is presented. Conducting polypyrrole (Ppy) chains are synthesized within a polyimide COF to gain electronic conductivity (≈10 000‐fold). A carbon‐free quasi‐solid‐state capacitor assembled using this composite showcases high pseudo‐capacitance (358 mF cm−2@1 mA cm−2) in an aqueous gel electrolyte. The synergy among the redox‐active polyimide COF, polypyrrole and organic electrolytes allows a wide‐voltage window (0–2.5 V) leading to high energy (145 μWh cm−2) and power densities (4509 μW cm−2). Amalgamating the polyimide‐COF and the polypyrrole as one material minimizes the charge and mass transport resistances. Computation and experiments reveal that even a partial translation of the modules/monomers intrinsic electronics to the COF imparts excellent electrochemical activity. The findings unveil COF‐confined polymers as carbon‐free energy storage materials.

Hydroxide ion-conducting viologen–bakelite organic frameworks for flexible solid-state zinc–air battery applications

“…1a). [39][40][41] It was followed by the other characteristic peaks from aromatic groups like triazine around 172 ppm (i) and aromatic peak around 151 ppm (h). The aliphatic peaks for the building blocks around 65 ppm (b) were intact.…”

Effective Iodine Adsorption by Nitrogen-Rich Nanoporous Covalent Organic Frameworks

“…Recently, a class of organic polymeric porous materials with crystalline and periodic structures, that is, covalent organic frameworks (COFs), − have shown highly promising potential in the applications of heterogeneous catalysis, − chemical sensing, bio-imaging, , and photodynamic therapy, − proton conduction, and energy storage, − as well as adsorption and separation to kinds of ions and molecules, − including iodine. − Due to their inherent porosity and strong covalent bonding of the organic components with light elements such as C, H, O, and N, COF materials not only show low density and relatively high stability but also display chemical tenability. − For instance, functional organic moieties with photoresponsive activity, proton-transport properties, and even chiral centers have been introduced into the COFs during the syntheses of precursors or post-modification of the constructed frameworks for photocatalysis, − proton conduction, ,− and asymmetric catalysis, − respectively. Previous works on iodine adsorption revealed that by decorating the framework with nitrogen-rich groups, the adsorption capacity of iodine can be significantly improved. − Thus, introducing nitrogen-rich groups into the COFs should be a feasible way for the fabrication of effective iodine adsorbents.…”

Covalent Organic Frameworks for Capacitive Energy Storage: Recent Progress and Technological Challenges

“…In another study, Vaidhyanathan and co‐workers further loaded redox‐active and conductive polypyrrole into COFs nanochannels and constructed a Ppy@COF hybrid, which exhibited a nearly 10 000‐fold increased electrical conductivity. [ 71 ] The synergies between polypyrrole and redox‐active imide linking bonds in the COF provided a high areal specific capacitance of 358 mF cm − 2 at 1 mA cm − 2 in a carbon‐free quasi‐solid‐state capacitor.…”