Asymmetric supercapacitor based on flexible TiC/CNF felt supported interwoven nickel-cobalt binary hydroxide nanosheets

Abstract

Nanostructured nickel-cobalt binary hydroxide (NiCoBH) is widely investigated as supercapacitor electrode material. However, the aggregation and poor electrical conductivity of NiCoBH limit its practical application as a supercapacitor. In this work, a flexible free-standing hierarchical porous composite composed of NiCoBH nanosheets and titanium carbide-carbon nanofiber (NiCoBH@TiC/CNF) is fabricated through electrospinning and microwave assisted method. The as-prepared composites exhibit desirable electrochemical performances, including high specific capacitance, cycling stability, and rate capability. In particular, the NiCoBH41@TiC/CNF composite electrode exhibits a maximum specific capacitance of 2224 F g−1 at the current density of 0.5 A g−1 and excellent cyclic stability of 91% capacity retention after 3000 cycles at 5.0 A g−1. To expand its practical application, an asymmetric supercapacitor (ASC) is fabricated using the NiCoBH41@TiC/CNF composite as the positive electrode and active carbon as the negative electrode. The ASC exhibits a prominent energy density of 55.93 Wh kg−1 and a high power density of 18,300 W kg−1 at 5.0 A g−1. The superior electrochemical property is attributed to the uniform dispersion of NiCoBH nanosheets on the TiC/CNF felt matrix. The TiC/CNF felt with uniformed TiC nanoparticles makes the fiber surface more suitable for growing NiCoBH nanosheets and simultaneously enhances the conductivity of electrode.