Pore-size dominated electrochemical properties of covalent triazine frameworks as anode materials for K-ion batteries

• Published in: Chemical science (Cambridge) Vol. 1; no. 33; pp. 7695 - 771
• Main Authors: Li, Shu-Ying, Li, Wen-Hao, Wu, Xing-Long, Tian, Yuyang, Yue, Jieyu, Zhu, Guangshan
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 07-09-2019
• Subjects: Anodes; Batteries; Electrochemical analysis; Electrode materials; Homology; Interlayers; Ion storage; Pore size; Porosity; Size effects; Storage capacity
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c9sc02340b

Two homologous covalent triazine frameworks (CTFs) have been developed for the first time as anode materials for high performance K-ion batteries (KIBs). The two-dimensional sheet-like structure as well as the regular channels in CTFs enable the process of intercalation/deintercalation of K-ions into/from the CTF interlayers reversibly. Particularly, a size effect of the porous structure is found to dominate the K-ion storage behavior. CTF-0 with a smaller pore size displays a higher K-ion storage capacity than CTF-1. Molecular simulations reveal the operation mechanism, showing that the depotassiation process in CTF-0 is exothermic while the depotassiation in CTF-1 is endothermic, which makes the deintercalation of K-ions from CTF-0 more feasible than from CTF-1 and contributes to the higher reversible capacity of CTF-0. This work provides a promising strategy for rational design of high-performance organic anode materials by structural modulation at the molecular scale.
Pore-size dominated K-ion storage behaviour in covalent triazine frameworks.