Role of Electrolyte Concentration Enduring the Supercapacitor Performance of Tin Oxide-Graphene Nanoplatelets-Polyaniline Nanocomposite

The enhancement of energy storage performance in flexible electrochemical supercapacitors depends on the strategic design of advanced electrode materials. Transition metal oxides (TMOs) are attracting increasing research interest, specifically as innovative electrode materials designed for energy storage systems. The limited electrical conductivity and lack of ion transport of the tin oxide (SnO₂) matrix restrict its applications. Polyaniline (PANI) and graphene nanoplatelets (GNPs) were incorporated to improve the mechanical robustness and the charge storage capacity of the (SnO₂)-based composites. In contrast to earlier research, where the performance of SnO₂-based electrodes is generally assessed at one concentration of the electrolyte, the article conducts a systematic study of the performance of the material in terms of electrolyte molarity in a SnO_2-GNPs-PANI ternary nanocomposite. These findings prove the alliance between the electrolyte concentration and ternary electrode design in enhancing ion mobility, kinetics of charge-transfers, and pseudocapacitive contribution as KOH molarity increases. Structural and morphological features of the synthesized materials were examined using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The electrochemical properties were evaluated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) tests, and electrochemical impedance spectroscopy (EIS). When it is combined with GNP, the specific capacitance of the SnO₂ electrode increases from 473 to 702 F/g; additionally, incorporating PANI matrices yield in a ternary SnO₂-GNPs-PANI nanocomposite, with the specific capacitance rising up to 1244 F/g at a current density of 1.3 A/g in 1 M KOH. Furthermore, electrochemical analysis was performed to investigate the impact of electrolyte concentration on the SnO₂-GNP-PANI nanocomposite in 1, 3, and 6 M KOH solutions. The ternary nanocomposite shows improved performance, reaching specific capacitances of 1244, 1338, and 1586 F/g, respectively. An asymmetrically-configured supercapacitor system employing SnO₂-GNPs-PANI as the positive electrode, while activated carbon (AC) as the negative electrode. These findings confirm the significant influence of both electrode composition and electrolyte molarity on optimizing supercapacitor performance, laying the groundwork for highly efficient energy storage devices.