A robust conductive covalent organic framework for ultra-stable potassium storage

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 11; no. 45; pp. 24661 - 24666
• Main Authors: Li, Yu-Yang, Xiao, Ji-Miao, Xie, Mo, Wu, Lei-Feng, Chen, Yan-Fei, Yuan, Shuai, Bin, De-Shan, Zuo, Jing-lin
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.11.2023
• Subjects: Anodes; Charge transfer; Conductivity; Electrode materials; Ion storage; Nonaqueous electrolytes; Robustness
• DOI: 10.1039/d3ta05959f
• ISSN: 2050-7488

Redox-active covalent organic frameworks (COFs) have garnered significant attention in the field of K-ion batteries (KIBs), but their applications are mainly hampered by their low electronic conductivity and insufficient cyclability owing to the large size of K-ions. Herein, we report a Ni-bis(dithiolene) and tetrathiafulvalene-based COF (Ni-TTF) with promising electronic conductivity and exceptional stability for high-performance KIB anodes. The redox-active units of Ni-bis(dithiolene) and tetrathiafulvalene (TTF) provide accessible sites for K-ion storage. The one-dimensional tunnel structure and good conductivity of Ni-TTF enabled fast charge (K + /e − ) transfer. The reticular network structure maintained its stability in organic electrolyte and ensured a resilient electrode to sustain repeated K-ion intercalation/deintercalation. As a result, Ni-TTF delivered a high reversible capacity of 223 mA h g −1 over more than 800 cycles at a current density of 1C (0.3 A g −1 ). Moreover, Ni-TTF achieved ultrastable cyclability, without discernible capacity fading after 2500 cycles at 2C, ranking it among the best organic anode materials for KIBs. This contribution opened a new avenue in the design of robust COFs with promising redox activity and improved conductivity for ultrastable K-ion storage. A conductive and redox-active COF (Ni-TTF) have been synthesized and applied as an promising anode for KIBs, exhibiting remarkable stability with no capacity loss after 2500 cycles at 2C, making it one of the best organic anode materials for KIBs.