Effect of Polypyrrole on the Capacitance Enhancement of the Spherical ZnS–ZnO/g-C3N4 Nanocomposite for Supercapacitor Applications

The ZnS–ZnO/graphitic carbon nitride (g-C3N4) nanocomposite was synthesized using the hydrothermal method, incorporating 0.05 g of g-C3N4 during the composite formation. The crystalline nature of the materials was confirmed through X-ray diffraction analysis. Scanning electron microscope and transmission electron microscope analyses revealed the morphological properties of the materials. The nanocomposite exhibited 2D g-C3N4 nanosheets with a thickness of 7.8 nm. Additionally, the nanocomposite consisted of spherical particles with an average particle size of 15 nm, which were distributed over the 2D g-C3N4 sheets. ZnS–ZnO/g-C3N4 nanocomposite consists of spherical particles with an average particle size of 15 nm that covers the 2D g-C3N4 sheets. ZnS–ZnO/g-C3N4 nanocomposites without/with polypyrrole are used as a paste for the two-symmetric electrodes hybrid supercapacitor. The charge (0.5 to 1.3 A/g), cyclic voltammetry (0.0 to 1.0 potential window), impedance, and stability for the prepared supercapacitor are studied using electrochemical measurements. ZnS–ZnO/g-C3N4 supercapacitors have a specific capacitance of 15.1 and 152.2 F/g without/with the physical addition of polypyrrole, respectively. Also, they have energy density values of 1.17 and 11.87 W h/kg, respectively. Through the Randles cell, The Rs in the supercapacitor without/with polypyrrole are 6.9 and 6.65 Ω, respectively. While the values of the semicircle diameter (Rct) are 0.37 and 0.25 Ω, respectively. Also, the capacitance retention values are 88.6 and 90.2% without/with polypyrrole addition until 500 runs of charge/discharge. These values confirm the behavior of the polypyrrole material in the enhancement of the supercapacitor efficiency, storage capacity, and stability.