Fiber supercapacitors with high energy density based on braiding structure.

Coaxial structure fiber supercapacitor has received extensive attention due to its good integrity and excellent electrochemical performance. However, the complicated preparation process, precise technical requirements and low yield restricted its development. A coaxial structure fiber supercapacitor with an operating voltage of 1.6 V was prepared by braiding a core yarn of AC@CNT (AC is activated carbon and CNT is carbon nanotubes) negtive electrode and a braided yarn of NiCo₂S₄@CNT positive electrode. This braiding strategy is simple and efficient, and the fabricated fiber supercapacitor has a high energy density (energy density of 35.1 mW·h/cm³ at power density of 233.2 mW/cm³) and outstanding flexibility (no obvious change after bending 1 000 cycles in cyclic voltammetry curve). The braided fiber supercapacitors show excellent integrability. The output voltage of 2-unit tandem fiber supercapacitors reaches 3.2 V, which can light up the "DHU 70" pattern composed of 65 LEDs. This work provides a new strategy for the preparation of coaxial structure fiber supercapacitors. [ABSTRACT FROM AUTHOR]