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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]

Supercapacitors with outstanding power density, excellent cycle stability, extremely fast rate performance and environmental friendliness have been widely studied. The performance of supercapacitors is highly dependent on the electrode materials. In this study, Ni-Co-S system was selected and composited as electrode material. Firstly, the NiCo2O4 electrode was prepared by hydrothermal method, and it was then transformed into NiCo2S4 electrode by ion exchanging method. Then, with chemical bath deposition (CBD) method, the NiCo2S4 @ NiCo2O4 composite electrode with 3D network structure was obtained. Further electrochemical studies (CV/Charge-Discharge curves) and SEM images confirm the better specific capacitance and cycle stability of NiCo2S4 @ NiCo2O4 composite electrode than that of the single component NiCo2O4 electrode, showing great application prospect. [ABSTRACT FROM AUTHOR]