Gao Hui, Neale Alex R, Zhu Qiang, Bahri Mounib, Wang Xue, Yang Haofan, Xu Yongjie, Clowes Rob, Browning Nigel D, Little Marc A, Hardwick Laurence J, Cooper Andrew I
Materials Innovation Factory and Department of Chemistry, University of Liverpool, 51 Oxford Street, Liverpool L7 3NY, U.K.
Stephenson Institute for Renewable Energy, Department of Chemistry, University of Liverpool, Peach Street, Liverpool L69 7ZF, U.K.
J Am Chem Soc. 2022 Jun 1;144(21):9434-9442. doi: 10.1021/jacs.2c02196. Epub 2022 May 19.
Electrochemically active covalent organic frameworks (COFs) are promising electrode materials for Li-ion batteries. However, improving the specific capacities of COF-based electrodes requires materials with increased conductivity and a higher concentration of redox-active groups. Here, we designed a series of pyrene-4,5,9,10-tetraone COF (PT-COF) and carbon nanotube (CNT) composites (denoted as PT-COFX, where = 10, 30, and 50 wt % of CNT) to address these challenges. Among the composites, PT-COF50 achieved a capacity of up to 280 mAh g as normalized to the active COF material at a current density of 200 mA g, which is the highest capacity reported for a COF-based composite cathode electrode to date. Furthermore, PT-COF50 exhibited excellent rate performance, delivering a capacity of 229 mAh g at 5000 mA g (18.5C). Using Raman microscopy the reversible transformation of the redox-active carbonyl groups of PT-COF was determined, which rationalizes an overall 4 e/4 Li redox process per pyrene-4,5,9,10-tetraone unit, accounting for its superior performance as a Li-ion battery electrode.
具有电化学活性的共价有机框架材料（COFs）是很有前景的锂离子电池电极材料。然而，提高基于COF的电极的比容量需要具有更高电导率和更高浓度氧化还原活性基团的材料。在此，我们设计了一系列芘-4,5,9,10-四酮COF（PT-COF）与碳纳米管（CNT）的复合材料（表示为PT-COFX，其中X = 10、30和50 wt%的CNT）来应对这些挑战。在这些复合材料中，PT-COF50在200 mA g的电流密度下，以活性COF材料归一化后的容量高达280 mAh g，这是迄今为止基于COF的复合阴极电极所报道的最高容量。此外，PT-COF50表现出优异的倍率性能，在5000 mA g（18.5C）时容量为229 mAh g。通过拉曼显微镜确定了PT-COF中氧化还原活性羰基的可逆转变，这解释了每个芘-4,5,9,10-四酮单元总体上4 e/4 Li的氧化还原过程，说明了其作为锂离子电池电极的优异性能。
