Radical Covalent Organic Frameworks: A General Strategy to Immobilize Open‐Accessible Polyradicals for High‐Performance Capacitive Energy Storage

Abstract

Ordered π-columns and open nanochannels found in covalent organic frameworks (COFs) could render them able to store electric energy. However, the synthetic difficulty in achieving redox-active skeletons has thus far restricted their potential for energy storage. A general strategy is presented for converting a conventional COF into an outstanding platform for energy storage through post-synthetic functionalization with organic radicals. The radical frameworks with openly accessible polyradicals immobilized on the pore walls undergo rapid and reversible redox reactions, leading to capacitive energy storage with high capacitance, high-rate kinetics, and robust cycle stability. The results suggest that channel-wall functional engineering with redox-active species will be a facile and versatile strategy to explore COFs for energy storage.

Opportunities of Covalent Organic Frameworks for Advanced Applications

“…[99] To investigate the effect of the density of the free radical species on the energy storage, a three component strategy was employed. [99] To investigate the effect of the density of the free radical species on the energy storage, a three component strategy was employed.…”

Precision Construction of 2D Heteropore Covalent Organic Frameworks by a Multiple‐Linking‐Site Strategy

“…Over the past decades porouso rganic polymers (POPs) have been growing into an exciting field of materialss cienceb ecause of their versatile applicationsi ng as storage and separation, [1][2][3][4][5][6] catalysis, [7][8][9][10] sensors, [11][12][13] energys torage, [14][15][16] and optoelectronics. [17][18][19] The most importantf eature of POPsi st heir porosity, on the basis of whichavariety of applicationsc an be developed.…”

Covalent Organic Frameworks: Chemical Approaches to Designer Structures and Built‐In Functions

“…Organic radicals are interesting species because their unpaired electrons endow the material with redox activity. By incorporating organic radicals into the pore walls, the originally redox‐inactive COFs can be transformed into redox‐active frameworks that enable pseudocapacitive energy storage . Engineering of the pore surface enables the integration of the stable organic radical TEMPO into the pore walls to form [TEMPO] 100 % ‐NiP‐COF (Figure h).…”