A Truxenone‐based Covalent Organic Framework as an All‐Solid‐State Lithium‐Ion Battery Cathode with High Capacity

Abstract

All-solid-state lithium ion batteries (LIBs) are ideal for energy storage given their safety and long-term stability. However, there is a limited availability of viable electrode active materials. Herein, we report a truxenone-based covalent organic framework (COF-TRO) as cathode materials for allsolid-state LIBs. The high-density carbonyl groups combined with the ordered crystalline COF structure greatly facilitate lithium ion storage via reversible redox reactions. As a result, a high specific capacity of 268 mAh g À1 , almost 97.5 % of the calculated theoretical capacity was achieved. To the best of our knowledge, this is the highest capacity among all COF-based cathode materials for all-solid-state LIBs reported so far. Moreover, the excellent cycling stability (99.9 % capacity retention after 100 cycles at 0.1 C rate) shown by COF-TRO suggests such truxenone-based COFs have great potential in energy storage applications.

Supramolecular Self‐Assembled Multi‐Electron‐Acceptor Organic Molecule as High‐Performance Cathode Material for Li‐Ion Batteries

“…Potentially, a single HATAQ molecule is capable of accepting up to 12 Li-ions and 12 electrons, which makes it, to the best of our knowledge, one of the only few examples of small-molecule organic cathode materials capable of accepting more than 10 electrons. [55,56] The global minimum structures of HATAQ-nLi (n = 1, 2, 3,4,5,6,7,8,9,10,11,12) are shown in Figure S28, Supporting Information. According to our results in Figure 5a, electrochemical reduction of HATAQ with Li can be formally divided into two distinct processes: a formal reduction of quinone moieties is taking place upon reduction with up to 6 Li (n = 1-6); and further reduction of hexaazatriphenylene core with Li (n = 7-12).…”

“…So far, a number of diverse structural motifs have been investigated as organic cathode materials in rechargeable LIBs, namely, conjugated polycarbonyl compounds, [7][8][9][10][11] conducting polymers, [12] persistent radical derivatives, [13][14][15] organosulfur derivatives, [16][17][18][19] and redox-active heterocycles, [20][21][22] which have particularly shown great promise. However, in most organic electrodes, issues associated with low electronic conductivity and material dissolution in typical organic solvents, used in electrolytes alongside lithium salt, generally result in poor cycling performance, rapid capacity fading as well as low Coulombic efficiency.…”

Controllable Synthesis and Performance Modulation of 2D Covalent–Organic Frameworks

“…In 2020, a high-density carbonyl framework, COF-TRO, was synthesized and designed to be a cathode in Li-ion battery by Zhang and co-workers (Figure 14b). [237] The redox-active truxenones (TRO) on skeleton underwent reversible 6 Li + lithiation/delithiation processes (Figure 14c). This redox process was able to drastically promote Li + storage ability and delivered a high capacity of 268 mAh g -1 (at 0.1 C) to COF-TRO-based sandwich structure battery.…”

Recent advances of covalent organic frameworks in lithium ion batteries

“…Aromatic carbonyl derivates in group 2 directly connect carbonyl groups to the aromatic core, and negative charge is dispersed by delocalization. 23 Group 3 consists of compounds that are quinone substructures, and their stability depends on the formation of additional aromatic systems. Group 3 has a high carbonyl utilization.…”