Effect of polypyrrole on the capacitance enhancement of the spherical ZnS-ZnO/G-C3N4 nanocomposite for supercapacitor applications

Abstract ZnS-ZnO/graphitic carbon nitride (G-C3N4) nanocomposite has been synthesized using the hydrothermal method, in which 0.05 g G-C3N4 is added through the composite formation. Moreover, brain-like shape polypyrrole is prepared using the oxidation polymerization method. The XRD confirms the crystalline nature of these materials, and the SEM and TEM analyses confirm the morphological properties of these materials, in which 2D G-C3N4 nanosheets are formed. 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 specific capacitance (CS) 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− 1, respectively. Also, the capacitance retention values are 88.6 and 90.2% without/with polypyrrole addition till 500 cycles. These values confirm the behavior of the polypyrrole material in the enhancement of the supercapacitor efficiency, storage capacity, and stability.