Abstract
An electrochemical deposition technique was used to fabricate polypyrrole (Ppy)/NiO nanocomposite electrodes for supercapacitors. The nanocomposite electrodes were characterized and investigated by Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS). The performance of supercapacitor electrodes of Ppy/NiO nanocomposite was enhanced compared with pristine Ppy electrode. It was found that the Ppy/NiO electrode electrodeposited at 4 A/cm−2 demonstrated the highest specific capacitance of 679 Fg−1 at 1 Ag−1 with an energy density of 94.4 Wh kg−1 and power density of 500.74 W kg−1. Capacitance retention of 83.9% of its initial capacitance after 1000 cycles at 1 Ag−1 was obtained. The high electrochemical performance of Ppy/NiO was due to the synergistic effect of NiO and Ppy, where a rich pores network-like structure made the electrolyte ions more easily accessible for Faradic reactions. This work provided a simple approach for preparing organic–inorganic composite materials as high-performance electrode materials for electrochemical supercapacitors.
Highlights
Supercapacitors, as storage devices, play a main role in bridging the gap between conventional capacitors and batteries[1]
For 2 and 4 mA cm−2 the voltage increases to the supersaturation region with time due to the increases in the number of charge carriers and the critical grain size or the formation of oligomers of the Ppy1%-DBSA2%/NiO97%graphite sheet (GS) deposited on the GS electrode
The temporary decays appear as a small valley in the voltage curves at 6, 8, and 10 mA cm−2, which correspond to the diffusion limitation of the oxidation process on the Py monomer, and small peaks appear after the valley is revealed to the nucleation end growth of the P py[21,22]
Summary
Supercapacitors, as storage devices, play a main role in bridging the gap between conventional capacitors and batteries[1]. Conducting polymers can be used as electrodes to compensate for the low energy density of carbon structures because of their highly reversible oxidation–reduction, pseudocapacitance and high electrical conductivity[2,3]. The fabrication of Ppy electrodes by electropolymerization of pyrrole is an interesting technique that allows pyrrole and certain dopants to be oxidized at the electrode surface by applying an anodic potential or a current or potentiodynamic window (cyclic voltammetry) to form a polymer film[7]. High electrical conductivity and thermal stability of Ppy films were obtained using aromatic anionic dopants. Compared with the electrode materials based on carbon derivatives or conducting polymers, Research and Technological Applications (SRTA-City), P.O. Box 21934, New Borg El‐Arab City, Alexandria, Egypt. A new nanocomposite of Ppy/NiO electrodes were fabricated via one–step facile electrochemical deposition method at different currents onto the surface of graphite sheet. The electrochemical behavior of the as-prepared electrodes was investigated by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS)
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