A Pyrene-4,5,9,10-Tetraone-Based Covalent Organic Framework Delivers High Specific Capacity as a Li-Ion Positive Electrode

• Published in: Journal of the American Chemical Society Vol. 144; no. 21; pp. 9434 - 9442
• Main Authors: 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.
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.06.2022; Amer Chemical Soc
• Subjects: carbon nanotubes; cathodes; Chemistry; Chemistry, Multidisciplinary; electrochemistry; lithium batteries; microscopy; Physical Sciences; Science & Technology
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.2c02196

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 X = 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–1 as normalized to the active COF material at a current density of 200 mA g–1, 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–1 at 5000 mA g–1 (18.5C). Using operando 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.