Hybrid porous Ni(OH)2-MnO2 nanosheets/plasma-grafted MWCNTs for boosted supercapacitor performance |
| |
Authors: | Ai-Wen Chai Cheng-Chien Wang Chuh-Yung Chen |
| |
Affiliation: | 1. Department of Chemical Engineering, National Cheng Kung University, 1, University Road, 70101 Tainan City, Taiwan;2. Department of Chemical and Materials Engineering, Southern Taiwan University of Science and Technology, 1, Nan-Tai Street, Yungkang District, Tainan City, 71005 Taiwan |
| |
Abstract: | The utilization of nickel hydroxide and manganese dioxide solely as high-performance supercapacitive materials is hindered by their low capacitance retention and electrical conductivity. As Ni(OH)2 and MnO2 give a synergistic effect, porous Ni(OH)2-MnO2 nanosheets with a thickness of 9 nm are successfully grown on carbon fiber (CF) via a single-step hydrothermal co-deposition method. Multi-walled carbon nanotubes (CNT) are grafted with maleic anhydride (MA) through plasma-grafted process, followed by thiol-ene reaction to synthesize CNT-MA−S (CMS) to increase their aqueous dispersion behavior. The electrochemical properties of Ni(OH)2-MnO2 are further enhanced by dip-coating CMS on nanosheets. The composition and morphology of CMS and Ni(OH)2-MnO2 nanosheets are characterized using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), electron spectroscopy for chemical analysis (ESCA), transmission electron microscopy (TEM), thermogravimetric analyses (TGA), nuclear magnetic resonance (NMR), and Raman spectroscopy. The electrochemical characteristics of fabricated electrodes are analyzed using cyclic voltammetry and chronopotentiometry methods. CF−Ni(OH)2-MnO2/CMS electrode is successfully synthesized without using any binder, exhibited ultrahigh specific capacitance (2049 F g−1 at a current density of 1 A g−1), and excellent capacitance retention (>80 %) at 2 A g−1 charge/discharge rate after 5000 cycles. |
| |
Keywords: | binder-free electrode carbon nanotubes plasma-induced grafting supercapacitor |
|
|