Rationally Designed Carbon Fiber@NiCo₂O₄@Polypyrrole Core–Shell Nanowire Array for High-Performance Supercapacitor Electrodes

Abstract

The composite supercapacitor electrodes were rationally fabricated by facile electrochemical deposition of polypyrrole (PPy) on NiCo 2 O 4 nanowire arrays which were grown radially on carbon fiber (CF). When used as electrodes in supercapacitors, the composite nanostructures demonstrated prominent electrochemical performances with a high areal capacitance (1.44[Formula: see text]F/cm 2 at a current density of 2[Formula: see text]mA/cm 2 ), a good rate capability (80.5% when the current density increases from 2[Formula: see text]mA/cm 2 to 20[Formula: see text]mA/cm 2 ), and a good cycling ability (85% of the initial specific capacitance remained after 5000 cycles at a high current density of 10[Formula: see text]mA/cm 2 ). The excellent electrochemical performance of NiCo 2 O 4 @PPy nanostructures can be mainly ascribed to the good electrical conductivity of PPy, the enhanced adherent force between electrode materials and CF to hold the electrode fragments together by means of NiCo 2 O 4 nanowires, the short ion diffusion pathway in ordered porous NiCo 2 O 4 nanowires and the three-dimensional nanostructures.