Hydrotropically Engineered Polyindole-Encapsulated Flower Shape Nanostructured MoS₂ Conductive Framework for Asymmetric Supercapacitors

Abstract

Hydrotropes are compounds that improve organic− inorganic incompatibility in aqueous solutions. Although organic solvents have been used for a long time in different polymerization techniques (such as chemical oxidation, electrospinning, emulsion, and interfacial techniques), they are costly and environmentally unsustainable. As a result, aqueous polymerization has been favored through surfactants in order to improve organic interaction within. However, mixed morphology, low yield, poor electrochemical performance, and increased processing costs have been one of the major challenges that come with the use of water. Hence, for the first time, we report hydrotropically engineered facile polymerization of indole templated over MoS 2 nanoflowers (MF) in water. Morphological analysis through field emission scanning electron microscopy (FESEM) revealed uniformly decorated polyindole (PIN) over petals of MF with no agglomeration and was further corroborated with Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The charge storage and transfer were also investigated using the UV−vis spectroscopy technique. In addition to this, electrochemical studies were performed through cyclic voltammetry, galvanic charging discharging, and impedance analysis. The studies revealed that the enhanced specific capacitance of the PIN-decorated MF nanocomposite (PM) was found to be 240 F/g at 0.5 A/g. Furthermore, the cyclic stability studies revealed an impressive 89.3% specific capacitance retention at 0.5 A/g after 3000 cycles. Finally, to supplement the synthesized PM in real time applications, the material was used in the fabrication of an asymmetric supercapacitor device and was connected in series with a light emitting diode (LED) to augment the conductive nature of the material. Furthermore, the device was also used to power a digital stopwatch with a timer function for at least 15 min, suggesting the charge storage ability of the device. Decisively, this work highlights the facile technique to synthesize PM using a hydrotrope, tetra n-octyl ammonium bromide (TOAB), and can be a potential candidate as an electrode material for a range of charge storage applications.