Polyindole Embedded Nickel/Zinc Oxide Nanocomposites for High-Performance Energy Storage Applications

Abstract

Conducting polymers integrated with metal oxides create opportunities for hybrid capacitive electrodes. In this work, we report a one-pot oxidative polymerization for the synthesis of integrated conductive polyindole/nickel oxide (PIn/NiO), polyindole/zinc oxide (PIn/ZnO), and polyindole/nickel oxide/zinc oxide (PNZ). The polymers were analyzed thoroughly for their composition and physical as well as chemical properties by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–Vis), and thermogravimetric analysis (TGA). The PIn and its composites were processed into electrodes, and their use in symmetrical supercapacitors in two- and three-electrode setups was evaluated by cyclic voltammetry (CV), galvanostatic discharge (GCD), and electrochemical impedance spectroscopy (EIS). The best electrochemical charge storage capability was found for the ternary PNZ composite. The high performance directly correlates with its uniformly shaped nanofibrous structure and high crystallinity. For instance, the symmetrical supercapacitor fabricated with PNZ hybrid electrodes shows a high specific capacitance of 310.9 F g−1 at 0.5 A g−1 with an energy density of 42.1 Wh kg−1, a power density of 13.2 kW kg−1, and a good cycling stability of 78.5% after 5000 cycles. This report presents new electrode materials for advanced supercapacitor technology based on these results.

The Fabrication of Amine‐Incorporated Zinc Complex/Carbon Dot Composite Electrodes Using Gamma Irradiation for High‐Performance Supercapacitors

“…The elemental distribution of the CDs‐4EDA‐2Zn composite was also uniform, as determined from the SEM‐EDS mapping shown in Figure 1c‐h, indicating the uniform amine incorporation of zinc complex/carbon dots composite. The uniform distribution of zinc‐based compounds has been observed in various composites [50–51] …”

“…The uniform distribution of zinc-based compounds has been observed in various composites. [50][51] . This indicates the good compatibility between zinc compounds and carbon-based materials.…”

“…It is also worth pointing out that our supercapacitor based on CD-4EDA-2Zn gave excellent performance when compared to those in several previous studies based on zinc-based/carbon-based composites. Various composites based on zinc compounds, especially ZnO, and carbon-based materials, such as graphene, [57][58] graphene oxide (GO), [59] reduced graphene oxide (rGO), [60] carbon aerogel, [50] polypyrrole (PPy), [59] polyindole, [51] activated carbon, [61] porous carbon, [62] graphene quantum dots (GQDs), [63] and carbon nanotubes, [64] have been reported (Table 1). The specific capacitance of our fabricated supercapacitor is comparable to those previously mentioned.…”

Hydrotrope-assisted interconnected mesoporous polyindole-decorated carbon nanotubes: synthesis, characterisation, and fabrication of asymmetric supercapacitor

“…[1][2][3][4] Several techniques involving the simplest one-pot routes, such as chemical oxidation, 2 emulsions, 5 interfacial, electrochemical oxidation, 6 and electrospinning, 7 and even the complex routes involving templating DNA 7 have been reported. Furthermore, their ability to interact physicochemically ex situ and even better with in situ 8 polymerisations with inorganic materials have led PIN to be considered a promising electrode material with several applications, such as for water treatment, 7,9 electrochemical charge storage devices (ESD), such as supercapacitors, 10 corrosion protection, 11 sensors, and light-emitting diodes (LED). 1 Among these, owing to the better electrochemical response, a greater focus has been on using ESD in supercapacitors.…”

“…1 Among these, owing to the better electrochemical response, a greater focus has been on using ESD in supercapacitors. 10,12,13 Supercapacitors are ESD that primarily store and release energy via a redox action between two electrostatically charged layers in the presence of an electrolyte, which are divided using an insulating separator. 14 The redox action is an effect of moving ions between the electrolyte and electrode material at the interface.…”