Covalent organic frameworks (COFs) with periodic channels and tunable chemical structures have been widely considered as promising electrode materials in rechargeable batteries. However, the design and construction of high-performance COFs-based electrodes still face some challenges in the introduction of multiple efficient redox centers as well as the reduction of dead mass. To address these issues, a unique COF containing double active centers (C═N and N═N) is developed as an anode in rechargeable lithium-ion batteries (LIBs). The as-prepared COF displays excellent electrochemical performance due to its remarkable structural stability and the existence of many active groups. Meanwhile, its electrochemical performance is significantly better than that of the small molecule compound or the linear polymer with the same construction units. Even at a high current density of 5 A/g, the LIBs with COF electrodes remain at a high discharge capacity of 227 mAh/g after 2000 cycles. Moreover, the distinction in electrochemical performances of these three materials is further revealed by calculation. This study illustrates the importance of molecular structure design for improving the performance of organic electrodes.

The large π-conjugated system and dense active sites in tribenzoquinoxaline-5,10-dione (3BQ) enable it to deliver excellent lithium storage performance.

Organic cathode materials have potential applications in rechargeable batteries due to their several advantages such as high specific capacity, flexible designability, plentiful raw materials, environmental friendliness, and renewability. However, their high solubility in organic electrolytes strongly impedes the further research progress. Thus, it is highly desirable to develop some new strategies to address this issue. Herein, we report one method to address this dissolution issue by increasing molecular weight without reducing theoretical capacity, where a novel Calix[8]quinone (C8Q) with 8 p-benzoquinone units connected by methylene groups was designed and prepared in a good yield (total: 23%). C8Q exhibits higher cycle stability (268 mAh g À1 ) in lithium-ion batteries (LIBs) compared to the same series of substances Calix[4]quinone (C4Q, 30 mAh g À1 ) and Calix[6]quinone (C6Q, 207 mAh g À1 ) after 100 cycles at 0.2 C. Moreover, C8Q shows better electrochemical performance in 4.2 M LiTFSI-AN highly-concentrated electrolyte with special aggregate structure configured with high-dissociation salt LiTFSI and low-viscosity solvent acetonitrile (AN), namely, C8Q possesses high capacity (340 mAh g À1 after 100 cycles at 0.2 C), superior rate ability (440 mAh g À1 at 0.1 C and 167 mAh g À1 at 5 C), and ultra-long cycle life (220 mAh g À1 after 1000 cycles at 0.5 C). This work could provide a promising strategy to address the dissolution issue of organic electrode materials in organic electrolyte.

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The commercialization of sodium ion batteries (SIBs) accelerated the research and development of electrode materials. Organic electrodes have less restriction on the battery system and have received more attention. However,...

Against the background of great attention on linear polymers and covalent organic frameworks, some small-molecule organic compounds have shown great potential as cathodes for sodium-ion batteries due to their high...

As promising electrode materials, porous organic polymers (POPs) have been extensively investigated for rechargeable lithium-ion batteries (LIBs) owing to their significant surface area, tunable redox nature, open channels, and π-conjugated system. Herein, a nitrogen-rich two-dimensional triazine-containing microporous polymer (ACT) is designed and developed as an electrode material of a half-cell for rechargeable lithium-ion storage. The specialized porous and conjugated structure improves the effectiveness of electron transformation and physicochemical stability. Since it has a higher molecular weight, it performs well over exceptionally long cycling performance. According to the results, ACT-based LIBs display stable rate performance and may deliver a specific capacity of 247 mAh g–1 after more than 4000 cycles at 5 A g–1. Additionally, extensive experimental investigation and calculations are used to examine the lithium-ion diffusion mechanism of double active sites in the ACT. This work offers a possible strategy to design excellent organic materials of electrochemical performance for next-generation high-performance LIBs.