Self-Assembly Construction of Carbon Nanotube Network-Threaded Tetrathiafulvalene-Bridging Covalent Organic Framework Composite Anodes for High-Performance Hybrid Lithium-Ion Capacitors

Hybrid lithium-ion capacitors (HLICs), a special class of electrochemical energy storage devices composed of battery-type anodes and capacitor-type cathodes, have the potential to bridge the gap between high-energy-density batteries and high-power-density capacitors. Nevertheless, the key challenge for developing high-performance HLICs is the imbalances of the electrochemical kinetics and lifespans between the battery-type anodes and capacitor-type cathodes. Herein, the self-assembly preparation of the 3D-crosslinked carbon nanotube (CNT) network-threaded tetrathiafulvalene-bridging covalent organic framework (TITCOF) composite via in situ growth of the 2D-stacked TTF-COF capping layer alongside the outer walls of 3D-interlaced CNTs is reported. Originated for the electron-donating and redox-switchable TTF units, the TTF-COF component has abundant active sites and high charge conductivity for reversible Li+ storage. Moreover, due to the 3D-assembled architecture, the TTF-COF/CNT composite possesses abundant open nanochannels for ion transfer and 3D-interconnected conductive CNT network for electron transfer. When used in HLICs, the TITCOF/CNT composite anodes exhibit ultrahigh specific capacity (609 mAh g at 100 mA g(-1)) and outstanding power density (12 000 W kg at 4000 mA g(-1)). Herein, the design of advanced COF composite materials with high activity, porosity, and conductivity can be a promising route for boosting the overall performances of high-power-type energy storage devices.

Automated summary

This study reports the self-assembly preparation of a 3D-crosslinked carbon nanotube network-threaded tetrathiafulvalene-bridging covalent organic framework composite, which serves as the anode for hybrid lithium-ion capacitors. This composite exhibits high specific capacity and outstanding power density, showing promise for enhancing the performance of high-power energy storage devices.