Hybrid\nComposite Ni(OH)₂@NiCo₂O₄ Grown on\nCarbon Fiber Paper for High-Performance Supercapacitors

Abstract

We\nhave successfully fabricated and tested the electrochemical performance\nof supercapacitor electrodes consisting of Ni­(OH)₂ nanosheets\ncoated on NiCo₂O₄ nanosheets grown on carbon\nfiber paper (CFP) current collectors. When the NiCo₂O₄ nanosheets are replaced by Co₃O₄ nanosheets,\nhowever, the energy and power density as well as the rate capability\nof the electrodes are significantly reduced, most likely due to the\nlower conductivity of Co₃O₄ than that of NiCo₂O_4. The 3D hybrid composite Ni­(OH)₂/NiCo₂O₄/CFP electrodes demonstrate a high areal capacitance\nof 5.2 F/cm² at a cycling current density of 2 mA/cm², with a capacitance retention of 79% as the cycling current\ndensity was increased from 2 to 50 mA/cm². The remarkable\nperformance of these hybrid composite electrodes implies that supercapacitors\nbased on them have potential for many practical applications.