Wet spun cellulose nanocrystal/MXene hybrid fiber regulated by bridging effect for high electrochemical performance supercapacitor

Cellulose nanocrystals (CNC) possess a large aspect ratio, high crystallinity, good mechanical performance, and environmental friendliness. It can be used as a frame and spacer of two-dimensional conductive materials, which reduces the stacking effect and is conducive to enhancing the mechanical and electrochemical properties of two-dimensional materials. In this study, CNC-regulated MXene fibers with high electrical conductivity (344.67 S cm⁻¹) were prepared by wet spinning. There is a strong bridging effect between CNC molecules rich in -OH and MXene molecules. This makes them have good compatibility and is good to the preparation of uniform dispersion solution. The prepared hybrid fibers exhibit superior electrochemical performance. In three-electrode system, the volumetric capacitance of the hybrid fibers reaches up to 885.6 F cm⁻³ (0.38 A cm⁻³). The energy density of symmetric supercapacitors assembled from CNC/MXene hybrid fibers is 11.30 mWh cm⁻³, and the power density is 11.40 mW cm⁻³. Furthermore, after 9000 charge-discharge cycles, the capacitance maintains 93% of its initial capacity, demonstrating outstanding cycle stability. It is believed that this study can provide a simple and effective method for the preparation of portable and wearable energy storage devices.