One-Step Braiding of Flexible Coaxial Asymmetric Fibrous Supercapacitors

ABSTRACT: Fibrous energy storage devices, especially coaxial fibrous supercapacitors (FSCs), have extensive promising applications in new-generation wearable electronics. Nevertheless, few studies have been conducted concerning simultaneously achieving a high electrochemical performance, mechanical robustness, and convenient and efficient fabrication of coaxial FSCs. Here, a coaxial asymmetric FSC (CAFSC) prepared by a one-step braiding method is reported. Our high-speed braiding machine simultaneously combines and braids pre-prepared anodes, separator yarns, and cathodes of the CAFSC at high production rates. The CAFSC realizes a high energy density of 17.25???46.33 ??W h cm???2 at a power density of 1.75???9.66 mW cm???2 while maintaining outstanding mechanical properties (90.1% capacitance retention after 1500 bending cycles and ability to lift a weight of 200 g) and a long cycling life (91.6% capacitance retention after 10,000 cycles), outperforming most of the reported FSCs. The flexible watchband weaved with two serially connected CAFSCs can power a commercial digital watch. This work presents a universal strategy to prepare high-performance CAFSCs for next-generation wearable electronics.

Automated summary

The study introduces a coaxial asymmetric FSC (CAFSC) prepared by a one-step braiding method, which shows excellent performance in terms of electrochemistry, mechanical stability, and efficient fabrication. The CAFSC achieves high energy density, outstanding mechanical properties, and long cycling life, outperforming most reported FSCs, demonstrating great potential for future wearable electronics applications.