Optimization of solid-state polyaniline/graphene supercapacitor using low-volatility dispersant for higher energy efficiency

Supercapacitor has emerged as one of the important energy storage devices for rapid charging and discharging applications. This research carried out comprehensive studies encompassing the synthesis of conducting polymer, material dispersion, fabrication, and evaluation of supercapacitor performance for different nanomaterial compositions of nanomaterials. Polyaniline was synthesized through the chemical polymerization method, while ethanol was used as a dispersion medium due to its low volatility and adequate colloidal stability. The results of the analysis showed that the protonation of polyaniline through protonic acid doping enhanced the conductivity from 41 to 502 mS/mu m. Electrochemical studies were conducted using a two-electrode system with electrochemical impedance spectrometry and cyclic voltammetry analysis. Doped polyaniline showed significant Faradaic reaction by observing polarization semicircle formation in electrochemical impedance spectrometry and the existence of a redox peak in cyclic voltammetry. The processing of electrochemical impedance spectrometry depicted a distinct difference in specific capacitance held by doped and undoped polyaniline with the values of 163.33 and 15.7 F/g, respectively. Therefore, doped polyaniline was selected to form a composite with graphene at different compositions for subsequent evaluation. Pristine polyaniline and pristine graphene recorded the specific capacitances of 23.5 F/g and 164 F/g, respectively. A nanocomposite supercapacitor with an optimum composition of 60% doped polyaniline and 40% graphene showed high specific capacitance (184.5 F/g), energy density (6.5 W/kg), and power density (671.6 Wh/kg). The specific capacitance of the nanocomposite supercapacitor demonstrated 685.1% and 12.5% better performance than supercapacitors made from pristine graphene and pristine polyaniline, respectively. [GRAPHICS] .