Recent advances in the utilization of covalent organic frameworks (COFs) as electrode materials for supercapacitors

Abstract

This review summarizes the recent advances in the electrode application of covalent organic frameworks (COFs) for supercapacitors, including the design strategies from the molecular scale to morphology control level and their device performance.

A Macromolecule Cathode for High-Performance Li-Ion and Na-Ion Batteries

“…9−13 Theoretically, organic solids as both crystalline and amorphous states are mainly formed by combinations of individual organic molecules attracted by van der Waals interaction forces. 14 So, organic electrodes have enough space to reserve large-radius metal ions, such as Na + ions (1.02 vs 0.76 Å for Li + ). 15,16 Specifically, the HOMO (highest occupied molecular orbital) level or the LUMO (lowest unoccupied molecular orbital) level of the organic molecule can store electrons, and the redox-active functional groups (such as C�O, C�N) can (de)intercalate metal ions reversibly.…”

“…Over the past decade, organic electrodes could be a selection for the next-generation materials since their composition elements are low-cost, resource-rich, and environmentally friendly. − Moreover, compared with inorganic electrodes, the cumulative research achievements have revealed that organic electrodes exhibit distinct electron and metal-ion storage mechanisms in rechargeable batteries. − Theoretically, organic solids as both crystalline and amorphous states are mainly formed by combinations of individual organic molecules attracted by van der Waals interaction forces . So, organic electrodes have enough space to reserve large-radius metal ions, such as Na + ions (1.02 vs 0.76 Å for Li + ). , Specifically, the HOMO (highest occupied molecular orbital) level or the LUMO (lowest unoccupied molecular orbital) level of the organic molecule can store electrons, and the redox-active functional groups (such as CO, CN) can (de)­intercalate metal ions reversibly. − Therefore, these important principles give rise to the organic electrodes’ “single-molecule-energy-storage” ability, indicating that a single organic electrode can have similar abilities for storing distinct metal ions, such as Li + ion and Na + ion.…”

Effect of interlayer slipping on the geometric, thermal and adsorption properties of 2D covalent organic frameworks: a comprehensive review based on computational modelling studies

“…2,3 Given their structural arrangements, porosity and nature, COFs exhibit great potential in numerous applications including catalysis, optoelectrical-conductivity, proton conduction, batteries, gas adsorption/storage/separation, drug/enzyme uptake, environmental remediation, and sensors. 4–21 Besides these applications, various COFs are also responsive towards external stimuli 22 such as light, 23,24 pH 25,26 and solvent. 11,27 Although such COFs are rarely known, they are essential because this property imparts new functions and applications, e.g.…”

Linkage‐Mediated Electronic Structure Modulation in Multicomponent Covalent Organic Frameworks for Dramatically Promoted Photocatalytic Hydrogen Evolution

“…Covalent organic frameworks (COFs), a class of crystalline porous materials made of periodically linked organic units via covalent bonds, have attracted considerable attention for applications in various fields owing to their long-range order, permanent porosity, tunable structures, and customizable functionality. [1][2][3][4][5][6][7][8][9][10][11][12] Especially, the π-conjugation structure both in plane and between stacked layers along with adjustable control over the compositions, endows two-dimensional (2D) COFs with unique optoelectronic properties, making them promising in photocatalysis. [13][14][15] Since the first report on a hydrazonelinked COF used for photocatalytic hydrogen evolution reduction (HER) by Lotsch and co-workers in 2014, [16] COF-based photocatalysis for HER has made impressive progress.…”