Covalent–Organic Frameworks: Advanced Organic Electrode Materials for Rechargeable Batteries

Abstract

energy-storage systems with high specific energy, long lifespan, and excellent safety. [5][6][7] Among them, the rechargeable secondary batteries have been demonstrated as the most promising candidate for electricity storage and utilization. [8][9][10][11] As one of the most popular batteries, lithium-ion batteries (LIBs) have found immense success in consumer electronics and electric vehicles, and are under the consideration for energy-storage power stations. [12][13][14] However, the commercial LIBs based on transition metal-based inorganic compounds have encountered a bottleneck. [15][16][17] The charge storage of inorganic electrode materials is governed by the oxidation-state variation of transition metal centers and achieved a charge balance with the insertion of counterions. [18] Restricted by crystal lattice and structure stability, the size and valence of counterions are required to match the crystal structures, which severely limit further improvement of energy density. [19][20][21] Clearly, these factors intrinsically weaken the versatility of inorganic materials. For instance, the similar electrode materials, which are successful in LIBs, are not suitable for other alkali ions batteries. [22][23][24] Additionally, from the viewpoint of economical and renewable factors of mineral resources, the existing LIBs based on transition metals (e.g., cobalt, nickel, and manganese) are difficult to meet the requirement of large-scale energy storage. [25] Nowadays, various demands have been raised up for the state-ofthe-art batteries, not only in the enhancement of cycle life, fast charging, and safety, but also in the focus of cost, lightweight, pollution-free, and environmental benign. [26,27] Under this background, researchers gradually shift their studies on novel batteries system and electrode materials. [28][29][30][31] Among them, explorations on the possibility of using organic compounds as potential alternatives of current inorganic electrode materials have never been stopped. [32,33,66] Organics have been demonstrated as promising electrode candidates due to their variety, sustainability, relatively low cost, and environmental friendliness. [34][35][36] The structural diversity implies that the richness of organic materials will provide abundant options and room in this field. The molecule engineering means that the electrochemical properties of organic electrodes can be rationally tuned with different functional groups, which exhibits a good designability of organic materials. These important features allow various designable synthetic routes and convenient functionalization. Although organic electrode materials are endowed with many advantages, their development and Covalent-organic frameworks (COFs), featuring structural diversity, framework tunability and functional versatility, have emerged as promising organic electrode materials for rechargeable batteries and garnered tremendous attention in recent years. The adjustable pore configuration, coupled with the functionalization of frameworks through ...

Electrochemical Study of Poly(2,6‐Anthraquinonyl Sulfide) as Cathode for Alkali‐Metal‐Ion Batteries

“…[1][2][3][4] Organic electrode materials possess unique advantages not only in sustainability and degradability, but also in low carbon footprint and are eco-friendly as well as low cost because many organic electrode materials could be extracted from nature and biomass. [5][6][7][8] Besides, the theoretical capacity of organic electrode materials can be controlled and designed through molecular structure engineering. [9][10][11] Therefore, organic materials as electrodes applied for metal-ion batteries have fascinated researchers gradually in recent years.…”

Asymmetric Supercapacitors Based on Hierarchically Nanoporous Carbon and ZnCo2O4 From a Single Biometallic Metal-Organic Frameworks (Zn/Co-MOF)

“…The two primary energy storage devices, batteries and supercapacitors (SCs), have their own pros and cons. Batteries deliver high energy density and efficiency but relatively low power density determined by their energy storage mechanisms (Zhou et al, 2016 ; Chen et al, 2017 ; Wang et al, 2017 ; Sun et al, 2020 ). Meanwhile, SCs exhibit high power density and a long cycle life with low energy density (Shaibani et al, 2017 ; Cai et al, 2018 ; Shao et al, 2018 ; Yi et al, 2020 ).…”

Towards the room-temperature synthesis of covalent organic frameworks: a mini-review

“…Unlike the boronate ester and boroxine-linked COFs, most nitrogen-based COFs, including imine, azine, hydrazone, squaraine, phenazine, imide, and triazine-linked COFs, exhibit remarkable hydrolytic stability. Compared with other nitrogen-based linkages, such as imine, azine, and hydrazine linkages, CS-COF and CTFs exhibit exceptional chemical stability owing to the formation of ring-fused phenazine and triazine units, respectively [41][42][43][44][45].…”