Sugar-Derived Carbon-Based Fiber with Core-Sheath Structure for Fiber-Shaped Supercapacitors with High Strength and Superior Capacitive Performance

Fiber-shaped supercapacitors are pivotal for wearable device advancement, yet they struggle to achieve both high strength and energy density, hindering their daily practicality in wearable electronic devices. In this study, a sugar-derived carbon-based fiber with a core-sheath structure is designed to enhance the overall performance of fiber supercapacitors. The porous multi-walled carbon nanotubes (MWCNTs) sheath is bonded by sugar-derived carbon （SDC）, which effectively prevents aggregation between the MWCNTs, providing a large adsorption surface for the fiber, consequently yielding excellent electrochemical performance, with a specific capacity of 236.7 F cm⁻³. The sugar-derived core fibers function as the current collector for the fiber electrode, contributing significantly to the mechanical properties (213 MPa). The assembled fiber-shaped supercapacitors demonstrate outstanding energy density (5.67 mWh cm⁻³ at power density of 45 mW cm⁻³) and flexibility, which can provide stable energy for various electronic devices and has great potential for application in wearable devices.