Redox of Dual-Radical Intermediates in a Methylene-Linked Covalent Triazine Framework for High-Performance Lithium-Ion Batteries
journal contributionposted on 2020-12-18, 18:08 authored by Zhiqiang Wang, Shuai Gu, Lujie Cao, Long Kong, Zhenyu Wang, Ning Qin, Muqing Li, Wen Luo, Jingjing Chen, Sisi Wu, Guiyu Liu, Huimin Yuan, Yunfei Bai, Kaili Zhang, Zhouguang Lu
Covalent triazine frameworks (CTFs) are promising electrodes for rechargeable batteries due to their adjustable structures, rich redox sites, and tunable porosity. However, the CTFs usually exhibit inferior electrochemical stability because of the inactivation of the unstable radical intermediates. Here, a methylene-linked CTF has been synthesized and evaluated as a cathode for rechargeable lithium-ion batteries. Electron paramagnetic resonance (EPR) and in situ Raman characterizations demonstrated that the redox activity and reversibility of α-C and triazine radical intermediates are essentially important for the charging/discharging process, which have been efficiently stabilized by the synergetic π conjugation and hindrance effect caused by the adjacent rigid triazine rings and benzene rings in the unique CTF-p framework. Additionally, the methylene groups provided extra redox-active sites. As a result, high capacity and cycling stability were achieved. This work inspires the rational modulation of the radical intermediates to enhance the electrochemical performance of organic electrode materials for the next-generation energy storage devices.
hindrance effectEPRredox-active sitesCTF-p frameworkredox siteselectrochemical stabilitybenzene ringsredox activityRaman characterizationsmethylene-linked CTFDual-Radical Intermediatescycling stabilityα- Ctriazine ringsnext-generation energy storage devicesmethylene groupselectrode materialsintermediateMethylene-Linked Covalent Triazine ...electrochemical performancetunable porosityHigh-Performance Lithium-Ion Batter...lithium-ion batteriessynergetic π conjugation