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

摘要

Nanostructured nickel-cobalt binary hydroxide (NiCo-BH) is widely investigated as supercapacitor electrode material. However, the aggregation and poor electrical conductivity of NiCo-BH limit its practical application as a supercapacitor. In this work, a flexible free-standing hierarchical porous composite composed of NiCo-BH nanosheets and titanium carbide-carbon nanofiber (NiCo-BH@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 NiCo-BH41@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 NiCo-BH41@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 NiCo-BH nanosheets on the TiC/CNF felt matrix. The TiC/CNF felt with uniformed TiC nanoparticles makes the fiber surface more suitable for growing NiCo-BH nanosheets and simultaneously enhances the conductivity of electrode. (C) 2016 Elsevier B.V. All rights reserved.