Microfluidic‐Assembled Covalent Organic Frameworks@Ti3C2Tx MXene Vertical Fibers for High‐Performance Electrochemical Supercapacitors

• Published in: Advanced materials (Weinheim) 2023-11, Vol.35 (46), p.n/a
• Main Authors: Zhu, Xiaolin, Zhang, Yang, Man, Zengming, Lu, Wangyang, Chen, Wei, Xu, Jianhong, Bao, Ningzhong, Chen, Wenxing, Wu, Guan
• Format: Article
• Language: English
• Subjects: Accessibility; Capacitance; Charge density; Density distribution; Electrochemical analysis; Electrodes; Electrons; Energy storage; Fibers; hierarchical fibers; Materials science; microfluidic fabrication; Microfluidics; MXenes; porous channels; Supercapacitors; Tubes; vertical channels; wearable applications
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202307186

The delicate design of innovative and sophisticated fibers with vertical porous skeleton and eminent electrochemical activity to generate directional ionic pathways and good faradic charge accessibility is pivotal but challenging for realizing high‐performance fiber‐shaped supercapacitors (FSCs). Here, hierarchically ordered hybrid fiber combined vertical‐aligned and conductive Ti3C2Tx MXene (VA‐Ti3C2Tx) with interstratified electroactive covalent organic frameworks LZU1 (COF‐LZU1) by one‐step microfluidic synthesis is developed. Due to the incorporation of vertical channels, abundant redox active sites and large accessible surface area throughout the electrode, the VA‐Ti3C2Tx@COF‐LZU1 fibers express exceptional gravimetric capacitance of 787 F g−1 in a three‐electrode system. Additionally, the solid‐state asymmetric FSCs deliver a prominent energy density of 27 Wh kg−1, capacitance of 398 F g−1 and cycling life of 20 000 cycles. The key to high energy storage ability originates from the decreased ions adsorption energy and ameliorative charge density distribution in vertically aligned and active hybrid fiber, accelerating ions transportation/accommodation and interfacial electrons transfer. Benefiting from excellent electrochemical performance, the FSCs offer sufficient energy supply to power watches, flags, and digital display tubes as well as be integrated with sensors to detect pulse signals, which opens a promising route for architecting advanced fiber toward the carbon neutrality market beyond energy‐storage technology. A high‐performance electrochemical supercapacitor based on vertically structured covalent organic frameworks@Ti3C2Tx MXene fiber is developed via one‐step microfluidic synthesis. Due to vertical ion transport channels, sufficient ion‐accessible area, decreased ion adsorption energy, excellent pseudocapacitive activity, and strong interfacial electron migration, the supercapacitors exhibit large capacitance, high energy density, excellent cycling stability, and wearable applications.